fix wrong id in scrollbar

idk if this is a compiler error but leaving the ascii pre-caching in results
in the pointer to the font structure to be corrupted before font.get_glyph()

.gitignore

@@ -2,3 +2,7 @@
 *.a
 build/*
 **/.ccls-cache
+perf.data*
+*.rdc
+test_renderer
+resources/shaders/compiled/**

.gitmodules

@@ -1,3 +0,0 @@
-[submodule "lib/raylib.c3l"]
-	path = lib/raylib.c3l
-	url = https://github.com/NexushasTaken/raylib.c3l

ARCHITECTURE.md

@@ -1,184 +0,0 @@
-## High level overview
-
-Under the hood every element has an id, this id allows the library to store state
-between frames.
-Elements are also cached such that when the ui tree is rebuilt at the beginning of
-every frame the element data structure doesn't have to be rebuilt.
-
-Elements are arranged in a tree, nodes are container elements that can contain other
-elements, leafs are elements that cannot contain other elements.
-
-Every element has a size and a position, containers also have to keep track of their
-layout information and some other state.
-
-Elements can push commands into the draw stack, which is a structure that contains
-all the draw commands that the user application has to perform do display the ui
-correctly, such commands include drawing lines, rectangles, sprites, text, etc.
-
-
-```text
-            +-----------+
-            | ug_init() |
-            +-----+-----+
-                  |
-                  |
-                  |
-        +---------v----------+
-        |ug_input_keyboard() |
-        |ug_input_mouse()    <----+
-        |ug_input_clipboard()|    |
-        |        ...         |    |
-        +---------+----------+    |
-                  |               |
-                  |               |
-          +-------v--------+      |
-          |ug_frame_begin()|      |
-          +-------+--------+      |
-                  |               |
-                  |               |
-        +---------v----------+    |
-        |ug_window_start()   |    |
-   +---->ug_container_start()|    |
-   |    |ug_div_start()      |    |
-   |    |        ...         |    |
-   |    +---------+----------+    |
-   |              |               |
-   |              |               |
-multiple +--------v---------+     |
- times   |ug_layout_row()   |     |
-   |     |ug_layout_column()|     |
-   |     |ug_layout_float() |     |
-   |     |       ...        |     |
-   |     +--------+---------+     |
-   |              |               |
-   |              |               |
-   |       +------v------+        |
-   |       |ug_button()  |        |
-   |       |ug_text_box()|        |
-   |       |ug_slider()  |        |
-   |       |     ...     |        |
-   |       +------+------+        |
-   |              |               |
-   +--------------+               |
-                  |               |
-         +--------v---------+     |
-         |ug_window_end()   |     |
-         |ug_container_end()|     |
-         |ug_div_end()      |     |
-         |       ...        |     |
-         +--------+---------+     |
-                  |               |
-                  |               |
-                  |               |
-           +------v-------+       |
-           |ug_frame_end()|       |
-           +------+-------+       |
-                  |               |
-                  |               |
-                  |               |
-           +------v-------+       |
-           |user draws the|       |
-           |      ui      +-------+
-           +------+-------+
-                  |
-                  |quit
-                  |
-           +------v-------+
-           | ug_destroy() |
-           +--------------+
-```
-
-### Layouting
-
-Layouting happens in a dynamic grid, when a new element is inserted in a non-floating
-manner it reserves a space in the grid, new elements are placed following this grid.
-
-Every div has two points of origin, one for the row layout and one for the column
-layout, named origin_r and origin_c respectively
-
-origin_r is used when the row layout is used and it is used to position the child
-elements one next to the other, as such it always points to the top-right edge
-of the last row element
-
-```text
-Layout: row
-#: lost space
-              Parent div
-x---------------------------------+
-|[origin_c]                       |
-|[origin_r]                       |
-|                                 |
-|                                 |
-|                                 |
-|                                 |
-|                                 |
-|                                 |
-|                                 |
-+---------------------------------+
-
-              Parent div
-+-----x---------------------------+
-|     |[origin_r]                 |
-| E1  |                           |
-|     |                           |
-x-----+---------------------------+
-|[origin_c]                       |
-|     |                           |
-|     |                           |
-|     |                           |
-|     |                           |
-|     |                           |
-+-----+---------------------------+
-
-              Parent div
-+-----+----------+-----x----------+
-|     |    E2    |     |[origin_r]|
-|  E1 +----------+     |          |
-|     |##########| E3  |          |
-+-----+##########|     |          |
-|################|     |          |
-+----------------x-----+----------+
-|                [origin_c]       |
-|                |                |
-|                |                |
-|                |                |
-+----------------+----------------+
-```
-
-TODO: handle when the content overflows the div
-- Use a different concept, like a view or relative space, for example the child
-div could have position `[0,0]` but in reality it is relative to the origin of the
-parent div
-- each div could have a view and a total area of the content, when drawing everything
-is clipped to the view and scrollbars are shown
-- individual elements accept dimensions and the x/y coordinates could be interpreted
-as offset if the layout is row/column or absolute coordinates if the leayout is floating
-
-A div can be marked resizeable or fixed, and static or dynamic. The difference being
-that resizeable adds a resize handle to the div and dynamic lets the content overflow
-causing scrollbars to be drawn
-
-### Notes
-
-How elements determine if they have focus or not
-
-```C
-// in begin_{container} code
-calculate focus
-set has_focus property
-
-
-
-// in the element code
-if(PARENT_HAS_FOCUS()) {
-	update stuff
-} else {
-	fast path to return
-}
-```
-
-How to get ids:
-	1. use a name for each element
-	2. supply an id for each element
-	3. use a macro and the line position as id and then hash it
-	4. use a macro, get the code line and hash it

LAYOUT

@@ -0,0 +1,243 @@
+               Div Children Alignment             
++------------------------------------------------+
+|TOP-LEFT              TOP              TOP-RIGHT|
+|                                                |
+|                                                |
+|                                                |
+|                                                |
+|                                                |
+|                                                |
+|LEFT                 CENTER                RIGHT|
+|                                                |
+|                                                |
+|                                                |
+|                                                |
+|                                                |
+|                                                |
+|BOTTOM-LEFT          BOTTOM         BOTTOM-RIGHT|
++------------------------------------------------+
+
+ALIGNMENT CHART:
++------------------------------+----------------------+------------------------------+-----------------------+------------------------------+----------------------+
+|       TOP-LEFT,  ROW:        |  TOP-LEFT, COLUMN:   |          BOTTOM, ROW:        |     BOTTOM, COLUMN:   |       TOP-RIGHT,  ROW:       |  TOP-RIGHT, COLUMN:  |
+|                              |                      |                              |                       |                              |                      |
+| +------------------------- - |    +----------- -    |                              |        +----+         |                              |  - -----------+      |
+| |+-------++-----++-----+     |    |+-------+        |                              |        | E1 |         |                              |      +-------+|      |
+| ||  E1   || E2  ||     |     |    ||  E1   |        |                              |        |    |         |  - -----------------------+  |      |  E1   ||      |
+| ||       |+-----+|  E3 |     |    ||       |        |                              |        +----+         |    +-------++-----++-----+|  |      |       ||      |
+| |+-------+       |     |     |    |+-------+        |    +-------+        +---+    |       +------+        |    |  E1   || E2  ||     ||  |      +-------+|      |
+| |                +-----+     |    |+----+           |    |  E1   |+------+|E3 |    |       |  E2  |        |    |       |+-----+|  E3 ||  |         +----+|      |
+| '                            |    || E2 |           |    |       ||  E2  ||   |    |       |      |        |    +-------+       |     ||  |         | E2 ||      |
+| '                            |    |+----+           |    +-------++------++---+    |       +------+        |                    +-----+|  |         +----+|      |
+|                              |    |+---------+      | - ------------------------ - |         +--+          |                           '  |    +---------+|      |
+|                              |    ||   E3    |      |                              |         |E3|          |                           '  |    |   E3    ||      |
+|                              |    |+---------+      |                              |         +--+          |                              |    +---------+|      |
+|                              |    '                 |                              |   - ----------- -     |                              |               '      |
+|                              |    '                 |                              |                       |                              |               '      |
+|                              |                      |                              |                       |                              |                      |
++------------------------------+----------------------+------------------------------+-----------------------+------------------------------+----------------------+
+|         LEFT, ROW:           |     LEFT, COLUMN:    |     BOTTOM-RIGHT, ROW:       | BOTTOM-RIGHT, COLUMN: |          TOP, ROW:           |     TOP, COLUMN:     |
+|                              |                      |                              |                       |                              |                      |
+|                              |    '                 |                              |                 '     |                              |  - -------------- -  |
+|    '                         |    |+-------+        |                              |        +-------+|     |                              |     +----------+     |
+|    |               +----+    |    ||  E1   |        |                           '  |        |  E1   ||     |  - ----------------------- - |     |    E1    |     |
+|    |+------+       |    |    |    ||       |        |                    +-----+|  |        |       ||     |     +------++----++-----+    |     |          |     |
+|    ||      |+-----+|    |    |    |+-------+        |    +-------+       |     ||  |        +-------+|     |     |  E1  || E2 || E3  |    |     +----------+     |
+|    ||  E1  || E2  || E3 |    |    |+----+           |    |  E1   |+-----+|  E3 ||  |           +----+|     |     |      |+----+|     |    |      +--------+      |
+|    ||      |+-----+|    |    |    || E2 |           |    |       || E2  ||     ||  |           | E2 ||     |     +------+      |     |    |      |   E2   |      |
+|    |+------+       |    |    |    |+----+           |    +-------++-----++-----+|  |           +----+|     |                   +-----+    |      +--------+      |
+|    |               +----+    |    |+---------+      |  - -----------------------+  |      +---------+|     |                              |       +------+       |
+|    '                         |    ||   E3    |      |                              |      |   E3    ||     |                              |       |  E3  |       |
+|    '                         |    |+---------+      |                              |      +---------+|     |                              |       |      |       |
+|                              |    '                 |                              |    - -----------+     |                              |       +------+       |
+|                              |    '                 |                              |                       |                              |                      |
++------------------------------+----------------------+------------------------------+-----------------------+------------------------------+----------------------+
+|      BOTTOM-LEFT,  ROW:      | BOTTOM-LEFT, COLUMN: |        RIGHT, ROW:           |     RIGHT, COLUMN:    |        CENTER, ROW:          |    CENTER, COLUMN:   |
+|                              |                      |                              |                       |                              |                      |
+|                              |    '                 |                              |                 '     |                              |           |          |
+|                              |    |+-------+        |                              |        +-------+|     |              |               |     +-----------+    |
+|                              |    ||  E1   |        |                          '   |        |  E1   ||     |              |               |     |    E1     |    |
+| '                            |    ||       |        |                    +----+|   |        |       ||     |              |   +----+      |     |     |     |    |
+| |                +-----+     |    |+-------+        |     +------+       |    ||   |        +-------+|     |    +------+  |   |    |      |     +-----------+    |
+| |+-------+       |     |     |    |+----+           |     |      |+-----+|    ||   |           +----+|     |    |      |+----+|    |      |      +---------+     |
+| ||  E1   |+-----+|  E3 |     |    || E2 |           |     |  E1  || E2  || E3 ||   |           | E2 ||     | ---|--E1--||-E2-||-E3-|---   |  ----|---E2----|---- |
+| ||       || E2  ||     |     |    |+----+           |     |      |+-----+|    ||   |           +----+|     |    |      |+----+|    |      |      +---------+     |
+| |+-------++-----++-----+     |    |+---------+      |     +------+       |    ||   |      +---------+|     |    +------+  |   |    |      |       +-------+      |
+| +------------------------- - |    ||   E3    |      |                    +----+|   |      |   E3    ||     |              |   +----+      |       |  E3   |      |
+|                              |    |+---------+      |                          '   |      +---------+|     |              |               |       |   |   |      |
+|                              |    +----------- -    |                          '   |                 '     |              |               |       +-------+      |
+|                              |                      |                              |                 '     |                              |           |          |
+|                              |                      |                              |                       |                              |                      |
++------------------------------+----------------------+------------------------------+-----------------------+------------------------------+----------------------+
+
+div (
+	align: TOP-LEFT | LEFT | BOTTOM-LEFT | BOTTOM | BOTTOM-RIGHT | RIGHT | TOP-RIGHT | RIGHT | CENTER
+	size_x/y: EXACT(x) | GROW() | FIT(min, max)
+	scroll_x/y: true | false
+	resize_x/y: true | false
+	layout: ROW | COLUMN
+)
+
+align: alignment of the children elements
+size: how the div should be sized
+scroll: enables scrollbars
+layout: the layout direction of the children
+
+         COLUMN                                    ROW
+ +--------------------+   +----------------------------------------------------+
+ | +----------------+ |   |+----------------+                                  |
+ | |                | |   ||                |+------------+                    |
+ | |                | |   ||                ||            |+------------------+|
+ | |       E1       | |   ||       E1       ||     E2     ||        E3        ||
+ | |                | |   ||                ||            |+------------------+|
+ | |                | |   ||                |+------------+                    |
+ | +----------------+ |   |+----------------+                                  |
+ |   +------------+   |   +----------------------------------------------------+
+ |   |            |   |
+ |   |     E2     |   |
+ |   |            |   |               (both have center alignment)
+ |   +------------+   |
+ |+------------------+|
+ ||                  ||
+ ||        E3        ||
+ ||                  ||
+ ||                  ||
+ |+------------------+|
+ +--------------------+
+ 
+Element {
+	id: uint
+	sizing: { min_w, min_h max_w, max_h }
+	bounds: { x, y, w, h }
+}
+
+id: unique identifier of the element
+sizing: the size that the element wants
+bounds: the absoulte bounds that the element got assigned
+
+Rendering
+=========
+
+Rendering happens when the element is called (immediately for leaf widgets like buttons and at the end
+for root widgets like divs). The drawing is done on the bounds assigned to the widget, these bounds
+have a one-frame delay on the current layout.
+
+The layout is calculated by each div at the end of their block and at frame end all the sizes and positions 
+are assigned at frame end by iterating the element tree.
+
+ElemDiv {
+	align: TOP-LEFT | LEFT | BOTTOM-LEFT | BOTTOM | BOTTOM-RIGHT | RIGHT | TOP-RIGHT | RIGHT | CENTER
+	size_x/y: { min, max }
+	scroll_x/y: true | false
+	layout: ROW | COLUMN
+	children_size_x/y: { min, max }
+}
+
+size:
+	- min != max      -> FIT sizing, fit to the content but respect the min and max size
+	- min == max == 0 -> GROW sizing, grow to the max amount of space possible
+	- min == max != 0 -> EXACT sizing
+children_size: the size of the combined children sizes
+
+
+
+root(size_x: screen width, size_y: screen height, layout: ROW) {
+
+	div1(layout: COLUMN, size_x: FIT, size_y GROW, resize_x: true) {
+		E1()
+		E2()
+		E3()
+		E4()
+	} <-(end div 1)
+
+	div2(size_x: GROW, size_y: GROW) {
+		...
+	} <-(end div 2)
+
+	div3(layout: COLUMN, size_x: FIT, size_y: GROW) {
+		E5()
+		E6()
+		E7()
+	} <-(end div 3)
+
+} <-(end root)
+(frame end)
+
+
++-Root-Div------------------------------------------------+
+|+-Div-1----------++-Div-2--------------------++-Div-3---+|
+||+--------------+||                          ||+-------+||
+|||     E1       |||                          |||  E5   |||
+|||              |||                          |||       |||
+||+--------------+||                          ||+-------+||                 [Root Div]
+||+--------------+||                          ||+-------+||                     |
+|||     E2       |||                          |||  E6   |||          +----------+----+-------+
+|||              |||                          |||       |||          v               v       v
+||+--------------+||                          ||+-------+||       [Div 1]         [Div 2] [Div 3]
+||+------+        ||                          ||+-------+||          |                       |
+|||      |        ||                          |||  E7   |||     +----+----+----+             |
+|||  E3  |        ||                          |||       |||     v    v    v    v             |
+|||      |        ||                          ||+-------+||    [E1] [E2] [E3] [E4]      +----+----+
+||+------+        ||                          ||         ||                             v    v    v
+||+------+        ||                          ||         ||                            [E5] [E6] [E7]
+|||      |        ||                          ||         ||
+|||  E4  |        ||                          ||         ||
+|||      |        ||                          ||         ||
+||+------+        ||                          ||         ||
+||                ||                          ||         ||
+|+----------------++--------------------------++---------+|
++---------------------------------------------------------+
+
+the call order is as follows
+
+E1()       -> updates the children size of div1
+E2()       -> " "
+E3()       -> " "
+E4()       -> " "
+end div1() -> updates the children size of root
+end div2() -> updates the children size of root
+E5()       -> updates the children size of div3
+E6()       -> " "
+E7()       -> " "
+end root() -> does nothing
+
+at frame end:
+	* Root: the root has a size constraint of fit so the bounds get assigned the whole window
+	* Div 1: the width has a size of fit, so it gets set to the children bounds, the height is set
+	  to the root height since it has a height of GROW
+		- E1 to E4 get laid out
+	* Div 2: it has a width of GROW which is **along** the layout axis, so it gets added to grow list
+	  the height gets set to the root height
+	* Div 3: the width is FIT, so it gets set to the content width, the height gets se to the root
+	  height.
+		- E5 to E7 get laid out
+	* Div 2: is given a width (if there were other contending grow divs along the layout axis they
+	  would also get sized).
+		- Now that div 2 has a size all it's children can be given a size
+
+Styling
+=======
+
+The element bounds include the whole CSS box model:
+
++---------------------------------------------+
+|                   MARGIN                    |
+|    +-----------------------------------+    |
+|    |xxxxxxxxxxx   BORDER   xxxxxxxxxxxx|    |
+|    |x+-------------------------------+x|    |
+|    |x|            PADDING            |x|    |
+|    |x|   +-----------------------+   |x|    |
+|    |x|   |                       |   |x|    |
+|    |x|   |        CONTENT        |   |x|    |
+|    |x|   |                       |   |x|    |
+|    |x|   +-----------------------+   |x|    |
+|    |x|                               |x|    |
+|    |x+-------------------------------+x|    |
+|    |xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx|    |
+|    +-----------------------------------+    |
+|                                             |
++---------------------------------------------+
+
+Styling happens via a .css file, the sizing strictly refers to the content, so if the the user
+requests an exact size of 100px*100px the content box will have those dimensions, but the element
+bounds will be larger.

LICENSE

@@ -0,0 +1,165 @@
+                   GNU LESSER GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+
+  This version of the GNU Lesser General Public License incorporates
+the terms and conditions of version 3 of the GNU General Public
+License, supplemented by the additional permissions listed below.
+
+  0. Additional Definitions.
+
+  As used herein, "this License" refers to version 3 of the GNU Lesser
+General Public License, and the "GNU GPL" refers to version 3 of the GNU
+General Public License.
+
+  "The Library" refers to a covered work governed by this License,
+other than an Application or a Combined Work as defined below.
+
+  An "Application" is any work that makes use of an interface provided
+by the Library, but which is not otherwise based on the Library.
+Defining a subclass of a class defined by the Library is deemed a mode
+of using an interface provided by the Library.
+
+  A "Combined Work" is a work produced by combining or linking an
+Application with the Library.  The particular version of the Library
+with which the Combined Work was made is also called the "Linked
+Version".
+
+  The "Minimal Corresponding Source" for a Combined Work means the
+Corresponding Source for the Combined Work, excluding any source code
+for portions of the Combined Work that, considered in isolation, are
+based on the Application, and not on the Linked Version.
+
+  The "Corresponding Application Code" for a Combined Work means the
+object code and/or source code for the Application, including any data
+and utility programs needed for reproducing the Combined Work from the
+Application, but excluding the System Libraries of the Combined Work.
+
+  1. Exception to Section 3 of the GNU GPL.
+
+  You may convey a covered work under sections 3 and 4 of this License
+without being bound by section 3 of the GNU GPL.
+
+  2. Conveying Modified Versions.
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+  If you modify a copy of the Library, and, in your modifications, a
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+
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+(ten or fewer lines in length), you do both of the following:
+
+   a) Give prominent notice with each copy of the object code that the
+   Library is used in it and that the Library and its use are
+   covered by this License.
+
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+
+  4. Combined Works.
+
+  You may convey a Combined Work under terms of your choice that,
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+
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+
+   c) For a Combined Work that displays copyright notices during
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+
+   d) Do one of the following:
+
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+
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+
+   e) Provide Installation Information, but only if you would otherwise
+   be required to provide such information under section 6 of the
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+   necessary to install and execute a modified version of the
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+   you use option 4d0, the Installation Information must accompany
+   the Minimal Corresponding Source and Corresponding Application
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+   Information in the manner specified by section 6 of the GNU GPL
+   for conveying Corresponding Source.)
+
+  5. Combined Libraries.
+
+  You may place library facilities that are a work based on the
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+facilities that are not Applications and are not covered by this
+License, and convey such a combined library under terms of your
+choice, if you do both of the following:
+
+   a) Accompany the combined library with a copy of the same work based
+   on the Library, uncombined with any other library facilities,
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+
+   b) Give prominent notice with the combined library that part of it
+   is a work based on the Library, and explaining where to find the
+   accompanying uncombined form of the same work.
+
+  6. Revised Versions of the GNU Lesser General Public License.
+
+  The Free Software Foundation may publish revised and/or new versions
+of the GNU Lesser General Public License from time to time. Such new
+versions will be similar in spirit to the present version, but may
+differ in detail to address new problems or concerns.
+
+  Each version is given a distinguishing version number. If the
+Library as you received it specifies that a certain numbered version
+of the GNU Lesser General Public License "or any later version"
+applies to it, you have the option of following the terms and
+conditions either of that published version or of any later version
+published by the Free Software Foundation. If the Library as you
+received it does not specify a version number of the GNU Lesser
+General Public License, you may choose any version of the GNU Lesser
+General Public License ever published by the Free Software Foundation.
+
+  If the Library as you received it specifies that a proxy can decide
+whether future versions of the GNU Lesser General Public License shall
+apply, that proxy's public statement of acceptance of any version is
+permanent authorization for you to choose that version for the
+Library.

README.md

@@ -0,0 +1 @@
+Welcome to the ugui library.

TODO

@@ -1,32 +1,136 @@
 # TODOs, semi-random sorting
+
 [x] Implement glyph draw command
 [x] Implement div.view and scrollbars
-[ ] Port font system from C to C3 (rewrite1)
+[x] Port font system from C to C3 (rewrite1)
 [ ] Update ARCHITECTURE.md
-[ ] Write a README.md
-[ ] Use an arena allocator for cache
+[x] Write a README.md
+[x] Use an arena allocator for cache
 [ ] Do not redraw if there was no update (no layout and no draw)
-[ ] Better handling of the active and focused widgets, try
-    to maintain focus until mouse release (fix scroll bars)
+[ ] Do command buffer damage tracking based on a context grid (see rxi writeup)
+[x] Better handling of the active and focused widgets, try to maintain focus until mouse release (fix scroll bars)
+[x] Clip element bounds to parent div, specifically text
+[ ] Resizeable divs
+[x] Implement a z index and sort command buffer based on that
+    [ ] Ctx.set_z_index()
+    [x] Sort command buffer on insertion
+[x] Standardize element handling, for example all buttons do almost the same thing, so write a lot 
+    of boiler plate and reuse it
+[x] The id combination in gen_id() uses an intger division, which is costly, use another combination 
+    function that is non-linear and doesn't use division
+[ ] Animations, somehow
+[x] Maybe cache codepoint converted strings
+[x] Fix scroll wheel when div is scrolled
+[ ] Be consistent with the initialization methods some are foo.new() and some are foo.init()
+[ ] Implement image loading (.bmp, .ff, .qoi and .png), in the future even lossy images like .jpg
+    [x] .qoi
+    [ ] .ff
+    [ ] .bmp
+    [ ] .png
+    [ ] .jpg
+[ ] gif support?
+[x] layout_set_max_rows() and layout_set_max_columns()
+[x] Maybe SDF sprites??
+[x] Stylesheets and stylesheet import
+[x] use SDF to draw anti-aliased rounded rectangles https://zed.dev/blog/videogame
+[ ] Subdivide modules into ugui::ug for exported functions and ugui::core for
+    internal use functions (used to create widgets)
+[x] The render loop RAPES the gpu, valve pls fix
+[x] The way the element structures are implemented wastes a lot of memory since
+    each struct Elem, struct Cmd, etc. is as big as the largest element. It would
+    be better to use a different allcation strategy.
+[ ] Add a way to handle time events like double clicks
+[x] Fix how padding is applied in push_rect. In CSS padding is applied between the border and the
+    content, the background color is applied starting from the border. Right now push_rect() offsets
+    the background rect by both border and padding
+[x] Investigate why the debug pointer (cyan rectangle) disappears... 
+
+## Layout
+
+[x] Flexbox
+[x] Center elements to the row/column
+[x] Text wrapping / reflow
+[x] Implement a better and unified way to place a glyph and get the cursor position, maybe with a struct
+[x] Correct whitespace handling in text (\t \r etc)
+[x] Consider a multi-pass recursive approach to layout (like https://github.com/nicbarker/clay)
+    instead of the curren multi-frame approach.
+[x] Implement column/row sizing (min, max)
+[x] Implement a way to size the element as the current row/column size
+    *   +-------------+
+    *   |             |
+    *   +-------------+
+    *   +--+
+    *   |  |
+    *   +--+
+    *   <------------->
+    *     column size
+    See the calculator example for why it is useful
+[ ] Find a way to concile pixel measurements to the mm ones used in css, for example in min/max sizing
+    of elements
+[x] Center elements to div (center children_bounds to the center of the div bounds and shift the origin accordingly)
+[x] Use containing_rect() in position_element() to skip some computing and semplify the function
+[x] Rename position_element() to layout_element()
+[x] Make functions to mark rows/columns as full, to fix the calculator demo
+
+## Input
+
+[x] Keyboard input
+[x] Mouse scroll wheel
+[ ] Touch input
+[x] Do not set input event to true if the movement was zero (like no mouse movement)
+[x] Use input event flags, for example to consume the input event
+[x] Fix bug in text box: when spamming keys you can get multiple characters in the text input field
+    of the context, this causes a bug where only the first char is actually used
 
 ## Commands
-[x] rect commads should have:
-	* border width
-	* border radius
-[x] add a command to update an atlas
 
-## Atlases
+[x] rect commads should have:
+    - border width
+    - border radius
+[x] add a command to update an atlas
+[x] New window command, useful for popups
+[x] Text command returns the text bounds, this way we can avoid the pattern 
+    draw_text(a, pos) -> off = compute_bounds(a) -> draw_text(b, pos+off) -> ...
+[ ] Rounded rectangle with different radius for each corner
+
+## Atlas
+
 [ ] Add an interface to create, destroy, update and get atlases based on their ids
 [ ] Implement multiple font atlases
+[ ] Pixel format conversion
 
 ## Fonts
-[ ] Fix the missing alpha channel
+
+[x] Fix the missing alpha channel
 [x] Fix the alignment
 
-## Raylib
-[ ] Implement type (Rect, Color, Point) conversion functions between rl:: and ugui::
-[x] Implement pixel radius rounding for border radius
-
 ## Widgets
-[ ] Dynamic text box to implement an fps counter
-[ ] Button with label
+
+[x] Dynamic text box to implement an fps counter
+[x] Button with label
+[x] Text Input box
+[ ] Icon Buttons
+[x] Switch
+[x] Checkbox
+[ ] Selectable text box
+
+## API
+
+[ ] Introduce a Layout structure that specifies the positioning of elements inside
+    a Div element. This would allow specifying alignment, maximum and minimum sizing
+    margins between children, etc.
+    This is different from style which is applied per-element.
+[ ] Remove Ids for element that don't need them. Such elements are button, toggles,
+    and all elements which do not have internal data that has to be cached and/or
+    queried by the user for later use. This allows for smaller caches and in general
+    reduces some load, since most of the stuff is recomputed for every frame.
+
+## SDL3 Renderer
+
+[x] smart batching
+[x] maybe use instancing since we are always drawing the same geometry. With instancing every
+    different quad could have its coulour, border and radius with much better performance than
+    issuing a draw call for every quad (and uploading it)
+    https://rastertek.com/dx11win10tut48.html
+    https://www.braynzarsoft.net/viewtutorial/q16390-33-instancing-with-indexed-primitives
+[ ] implement min and max fps

lib/libgrapheme.c3l/Makefile

@@ -1,3 +0,0 @@
-all:
-	make -C thirdparty/libgrapheme
-	cp thirdparty/libgrapheme/libgrapheme.a linux-x64/libgrapheme.a

lib/libgrapheme.c3l/libgrapheme.c3i

@@ -1,46 +0,0 @@
-module grapheme;
-
-const uint GRAPHEME_INVALID_CODEPOINT = 0xFFFD;
-
-enum BidirectionalDirection {
-	GRAPHEME_BIDIRECTIONAL_DIRECTION_NEUTRAL,
-	GRAPHEME_BIDIRECTIONAL_DIRECTION_LTR,
-	GRAPHEME_BIDIRECTIONAL_DIRECTION_RTL,
-}
-
-fn isz bidirectional_get_line_embedding_levels(uint *, isz, ichar *, isz) @extern("grapheme_bidirectional_get_line_embedding_levels");
-
-fn isz bidirectional_preprocess_paragraph(uint *, isz, BidirectionalDirection, uint *, isz, BidirectionalDirection *) @extern("grapheme_bidirectional_preprocess_paragraph");
-
-fn isz bidirectional_reorder_line(uint *, uint *, isz, uint *, isz) @extern("grapheme_bidirectional_reorder_line");
-
-fn isz decode_utf8(char *, isz, uint *) @extern("grapheme_decode_utf8");
-fn isz encode_utf8(uint, char *, isz) @extern("grapheme_encode_utf8");
-
-fn bool is_character_break(uint, uint, ushort *) @extern("grapheme_is_character_break");
-
-fn bool is_lowercase(uint *, isz, isz *) @extern("grapheme_is_lowercase");
-fn bool is_titlecase(uint *, isz, isz *) @extern("grapheme_is_titlecase");
-fn bool is_uppercase(uint *, isz, isz *) @extern("grapheme_is_uppercase");
-
-fn bool is_lowercase_utf8(char *, isz, isz *) @extern("grapheme_is_lowercase_utf8");
-fn bool is_titlecase_utf8(char *, isz, isz *) @extern("grapheme_is_titlecase_utf8");
-fn bool is_uppercase_utf8(char *, isz, isz *) @extern("grapheme_is_uppercase_utf8");
-
-fn isz next_character_break(uint *, isz) @extern("grapheme_next_character_break");
-fn isz next_line_break(uint *, isz) @extern("grapheme_next_line_break");
-fn isz next_sentence_break(uint *, isz) @extern("grapheme_next_sentence_break");
-fn isz next_word_break(uint *, isz) @extern("grapheme_next_word_break");
-
-fn isz next_character_break_utf8(char *, isz) @extern("grapheme_next_character_break_utf8");
-fn isz next_line_break_utf8(char *, isz) @extern("grapheme_next_line_break_utf8");
-fn isz next_sentence_break_utf8(char *, isz) @extern("grapheme_next_sentence_break_utf8");
-fn isz next_word_break_utf8(char *, isz) @extern("grapheme_next_word_break_utf8");
-
-fn isz to_lowercase(uint *, isz, uint *, isz) @extern("grapheme_to_lowercase");
-fn isz to_titlecase(uint *, isz, uint *, isz) @extern("grapheme_to_titlecase");
-fn isz to_uppercase(uint *, isz, uint *, isz) @extern("grapheme_to_uppercase");
-
-fn isz to_lowercase_utf8(char *, isz, char *, isz) @extern("grapheme_to_lowercase_utf8");
-fn isz to_titlecase_utf8(char *, isz, char *, isz) @extern("grapheme_to_titlecase_utf8");
-fn isz to_uppercase_utf8(char *, isz, char *, isz) @extern("grapheme_to_uppercase_utf8");

lib/libgrapheme.c3l/manifest.json

@@ -1,9 +0,0 @@
-{
-  "provides": "grapheme",
-  "targets": {
-    "linux-x64": {
-      "dependencies": [],
-      "linked-libraries": ["grapheme", "c"]
-    }
-  }
-}

lib/libgrapheme.c3l/project.json

@@ -1,44 +0,0 @@
-{
-  // Language version of C3.
-  "langrev": "1",
-  // Warnings used for all targets.
-  "warnings": ["no-unused"],
-  // Directories where C3 library files may be found.
-  "dependency-search-paths": [".."],
-  // Libraries to use for all targets.
-  "dependencies": ["grapheme"],
-  // Authors, optionally with email.
-  "authors": ["Alessandro Mauri <alemauri001@gmail.com"],
-  // Version using semantic versioning.
-  "version": "0.1.0",
-  // Sources compiled for all targets.
-  "sources": [],
-  // C sources if the project also compiles C sources
-  // relative to the project file.
-  // "c-sources": [ "csource/**" ],
-  // Output location, relative to project file.
-  "output": "build",
-  // Architecture and OS target.
-  // You can use 'c3c --list-targets' to list all valid targets.
-  // "target": "windows-x64",
-  "features": [
-    // See rcore.c3
-    //"SUPPORT_INTERNAL_MEMORY_MANAGEMENT",
-    //"SUPPORT_STANDARD_FILEIO",
-    //"SUPPORT_FILE_SYSTEM_FUNCTIONS",
-    //"SUPPORT_DATA_ENCODER",
-    // See text.c3
-    //"SUPPORT_TEXT_CODEPOINTS_MANAGEMENT",
-    //"SUPPORT_TEXT_C_STRING_MANAGEMENT",
-    //"SUPPORT_RANDOM_GENERATION",
-    //"SUPPORT_RAYGUI",
-    //"RAYGUI_NO_ICONS",
-    //"RAYGUI_CUSTOM_ICONS",
-  ],
-  // Global settings.
-  // CPU name, used for optimizations in the LLVM backend.
-  "cpu": "generic",
-  // Optimization: "O0", "O1", "O2", "O3", "O4", "O5", "Os", "Oz".
-  "opt": "O0"
-  // See resources/examples/project_all_settings.json and 'c3c --list-project-properties' to see more properties.
-}

lib/libgrapheme.c3l/thirdparty/libgrapheme

@@ -1 +0,0 @@
-Subproject commit 65b354f0fcb1d925f4340dbb4415ea06e8af2bec

lib/libschrift.c3l/Makefile

@@ -1,3 +0,0 @@
-all:
-	make -C thirdparty/libschrift
-	cp thirdparty/libschrift/libschrift.a linux-x64/libschrift.a

lib/libschrift.c3l/libschrift.c3

@@ -1,58 +0,0 @@
-module schrift;
-
-def SftFont = void*;
-def SftUChar = uint;
-def SftGlyph = uint;
-
-const int SFT_DOWNWARD_Y = 0x01;
-
-struct Sft
-{
-	SftFont   font;
-	double    xScale;
-	double    yScale;
-	double    xOffset;
-	double    yOffset;
-	int       flags;
-}
-
-struct SftLMetrics
-{
-	double ascender;
-	double descender;
-	double lineGap;
-}
-
-struct SftGMetrics
-{
-	double advanceWidth;
-	double leftSideBearing;
-	int    yOffset;
-	int    minWidth;
-	int    minHeight;
-}
-
-struct SftKerning
-{
-	double xShift;
-	double yShift;
-}
-
-struct SftImage
-{
-	void *pixels;
-	int   width;
-	int   height;
-}
-
-extern fn char* sft_version() @extern("sft_version");
-
-extern fn SftFont loadmem(void* mem, usz size) @extern("sft_loadmem");
-extern fn SftFont loadfile(char* filename) @extern("sft_loadfile");
-extern fn void freefont(SftFont font) @extern("sft_freefont");
-
-extern fn int lmetrics(Sft* sft, SftLMetrics* metrics) @extern("sft_lmetrics");
-extern fn int lookup(Sft* sft, SftUChar codepoint, SftGlyph* glyph) @extern("sft_lookup");
-extern fn int gmetrics(Sft* sft, SftGlyph glyph, SftGMetrics* metrics) @extern("sft_gmetrics");
-extern fn int kerning(Sft* sft, SftGlyph leftGlyph, SftGlyph rightGlyph, SftKerning* kerning) @extern("sft_kerning");
-extern fn int render(Sft* sft, SftGlyph glyph, SftImage image) @extern("sft_render");

lib/libschrift.c3l/manifest.json

@@ -1,9 +0,0 @@
-{
-  "provides" : "schrift",
-  "targets" : {
-    "linux-x64" : {
-      "dependencies" : [],
-      "linked-libraries" : ["schrift", "c"]
-    }
-  }
-}

lib/libschrift.c3l/project.json

@@ -1,45 +0,0 @@
-{
-  // Language version of C3.
-  "langrev": "1",
-  // Warnings used for all targets.
-  "warnings": [ "no-unused" ],
-  // Directories where C3 library files may be found.
-  "dependency-search-paths": [ ".." ],
-  // Libraries to use for all targets.
-  "dependencies": [ "schrift" ],
-  // Authors, optionally with email.
-  "authors": [ "Alessandro Mauri <alemauri001@gmail.com" ],
-  // Version using semantic versioning.
-  "version": "0.1.0",
-  // Sources compiled for all targets.
-  "sources": [ ],
-  // C sources if the project also compiles C sources
-  // relative to the project file.
-  // "c-sources": [ "csource/**" ],
-  // Output location, relative to project file.
-  "output": "build",
-  // Architecture and OS target.
-  // You can use 'c3c --list-targets' to list all valid targets.
-  // "target": "windows-x64",
-  "features": [
-    // See rcore.c3
-    //"SUPPORT_INTERNAL_MEMORY_MANAGEMENT",
-    //"SUPPORT_STANDARD_FILEIO",
-    //"SUPPORT_FILE_SYSTEM_FUNCTIONS",
-    //"SUPPORT_DATA_ENCODER",
-    // See text.c3
-    //"SUPPORT_TEXT_CODEPOINTS_MANAGEMENT",
-    //"SUPPORT_TEXT_C_STRING_MANAGEMENT",
-    //"SUPPORT_RANDOM_GENERATION",
-
-    //"SUPPORT_RAYGUI",
-    //"RAYGUI_NO_ICONS",
-    //"RAYGUI_CUSTOM_ICONS",
-  ],
-  // Global settings.
-  // CPU name, used for optimizations in the LLVM backend.
-  "cpu": "generic",
-  // Optimization: "O0", "O1", "O2", "O3", "O4", "O5", "Os", "Oz".
-  "opt": "O0",
-  // See resources/examples/project_all_settings.json and 'c3c --list-project-properties' to see more properties.
-}

lib/libschrift.c3l/thirdparty/libschrift

@@ -1 +0,0 @@
-Subproject commit 24737d2922b23df4a5692014f5ba03da0c296112

lib/raylib.c3l

@@ -1 +0,0 @@
-Subproject commit c7ebe054ce16136c1128fab54fcce4921044293e

manifest.json

@@ -0,0 +1,11 @@
+{
+  "provides" : "ugui",
+  "sources" : [ "src/**" ],
+  "targets" : {
+    "linux-x64" : {
+      "link-args" : [],
+      "dependencies" : ["schrift"],
+      "linked-libraries" : []
+    }
+  }
+}

project.json

@@ -1,55 +0,0 @@
-{
-  // Language version of C3.
-  "langrev": "1",
-  // Warnings used for all targets.
-  "warnings": [ "no-unused" ],
-  // Directories where C3 library files may be found.
-  "dependency-search-paths": [ "lib" ],
-  // Libraries to use for all targets.
-  "dependencies": [ "raylib", "schrift", "grapheme" ],
-  "features": [
-    // See rcore.c3
-    //"SUPPORT_INTERNAL_MEMORY_MANAGEMENT",
-    //"SUPPORT_STANDARD_FILEIO",
-    //"SUPPORT_FILE_SYSTEM_FUNCTIONS",
-    //"SUPPORT_DATA_ENCODER",
-    // See text.c3
-    //"SUPPORT_TEXT_CODEPOINTS_MANAGEMENT",
-    //"SUPPORT_TEXT_C_STRING_MANAGEMENT",
-    //"SUPPORT_RANDOM_GENERATION",
-    //"SUPPORT_RAYGUI",
-    //"RAYGUI_NO_ICONS",
-    //"RAYGUI_CUSTOM_ICONS",
-  ],
-  // Authors, optionally with email.
-  "authors": [ "John Doe <ale@shitposting.expert>" ],
-  // Version using semantic versioning.
-  "version": "0.1.0",
-  // Sources compiled for all targets.
-  "sources": [ "src/**" ],
-  // C sources if the project also compiles C sources
-  // relative to the project file.
-  // "c-sources": [ "csource/**" ],
-  // Include directories for C sources relative to the project file.
-  // "c-include-dirs": [ "csource/include" ],
-  // Output location, relative to project file.
-  "output": "build",
-  // Architecture and OS target.
-  // You can use 'c3c --list-targets' to list all valid targets.
-  // "target": "windows-x64",
-  // Targets.
-  "targets": {
-    "ugui": {
-      // Executable or library.
-      "type": "executable",
-      // Additional libraries, sources
-      // and overrides of global settings here.
-    },
-  },
-  // Global settings.
-  // CPU name, used for optimizations in the LLVM backend.
-  "cpu": "generic",
-  // Optimization: "O0", "O1", "O2", "O3", "O4", "O5", "Os", "Oz".
-  "opt": "O0",
-  // See resources/examples/project_all_settings.json and 'c3c --list-project-properties' to see more properties.
-}

src/atlas.c3

@@ -0,0 +1,131 @@
+module ugui;
+
+import std::io;
+
+faultdef CANNOT_PLACE, INVALID_TYPE;
+
+enum AtlasType {
+	ATLAS_GRAYSCALE,
+	ATLAS_R8G8B8A8,
+}
+
+// black and white atlas
+struct Atlas {
+	AtlasType type;
+	Id id;
+
+	ushort width, height;
+	char[] buffer;
+
+	Point row;
+	ushort row_h;
+}
+
+// bytes per pixel
+macro usz AtlasType.bpp(type)
+{
+	switch (type) {
+	case ATLAS_GRAYSCALE: return 1;
+	case ATLAS_R8G8B8A8: return 4;
+	}
+}
+
+macro typeid AtlasType.underlying(type)
+{
+	switch (type) {
+	case ATLAS_GRAYSCALE: return char;
+	case ATLAS_R8G8B8A8: return uint;
+	}
+}
+
+/*
+// FIXME: in and out types are not always known at compile time
+macro @pixel_convert(p, AtlasType $in, AtlasType $out)
+{
+	$if $in == $out:
+		return p;
+	$else
+		$switch
+		$case $in == ATLAS_R8G8B8A8 && $out == ATLAS_GRAYSCALE:
+			var r = ((p >> 0)  & 0xff);
+			var g = ((p >> 8)  & 0xff);
+			var b = ((p >> 16) & 0xff);
+			var a = ((p >> 24) & 0xff);
+			if (a == 0)	return (char)0;
+			return (ATLAS_GRAYSCALE.underlying())(((float)r+g+b) / 3.0f);
+		$case $in == ATLAS_GRAYSCALE && $out == ATLAS_R8G8B8A8:
+			var x = (char)(p/3.0);
+			return (ATLAS_R8G8B8A8.underlying())(x|(x<<8)|(x<<16)|(255<<24));
+		$default: $error "Unimplemented pixel format conversion";
+		$endswitch
+	$endif
+}
+*/
+
+fn void? Atlas.new(&atlas, Id id, AtlasType type, ushort width, ushort height)
+{
+	atlas.id = id;
+	atlas.type = type;
+	atlas.width = width;
+	atlas.height = height;
+
+	atlas.buffer = mem::new_array(char, (usz)atlas.width*atlas.height*type.bpp());
+}
+
+fn void Atlas.free(&atlas)
+{
+	free(atlas.buffer);
+}
+
+
+/*
+ * pixels -> +--------------+-----+
+ *           |              |     | h
+ *           |              |     | e
+ *           |              |     | i
+ *           |              |     | g
+ *           |              |     | h
+ *           |              |     | t
+ *           +--------------+-----+
+ *           |<--- width -->|
+ *           |<----- stride ----->|
+ * bytes per pixels are inferred and have to be the same
+ * as the atlas type
+ */
+// place a rect inside the atlas
+// uses a row first algorithm
+// TODO: use a skyline algorithm https://jvernay.fr/en/blog/skyline-2d-packer/implementation/
+fn Point? Atlas.place(&atlas, char[] pixels, ushort w, ushort h, ushort stride)
+{
+	Point p;
+
+	if (atlas.row.x + w <= atlas.width && atlas.row.y + h <= atlas.height) {
+		p = atlas.row;
+	} else {
+		atlas.row.x = 0;
+		atlas.row.y = atlas.row.y + atlas.row_h;
+		atlas.row_h = 0;
+		if (atlas.row.x + w <= atlas.width && atlas.row.y + h <= atlas.height) {
+			p = atlas.row;
+		} else {
+			return CANNOT_PLACE?;
+		}
+	}
+
+	usz bpp = atlas.type.bpp();
+	for (usz y = 0; y < h; y++) {
+		for (usz x = 0; x < w; x++) {
+			char[] buf = atlas.buffer[(usz)(p.y+y)*atlas.width*bpp + (p.x+x)*bpp ..];
+			char[] pix = pixels[(usz)y*stride*bpp + x*bpp ..];
+
+			buf[0..bpp-1] = pix[0..bpp-1];
+		}
+	}
+
+	atlas.row.x += w;
+	if (h > atlas.row_h) {
+		atlas.row_h = h;
+	}
+
+	return p;
+}

src/cache.c3

@@ -1,4 +1,4 @@
-module cache(<Key, Value, SIZE>);
+module cache{Key, Value, SIZE};
 
 /* LRU Cache
  * The cache uses a pool (array) to store all the elements, each element has
@@ -9,21 +9,19 @@ module cache(<Key, Value, SIZE>);
  * the elements that were not recently used.
  */
 
-// FIXME: this module should really allocate all resources on an arena or temp
-//        allocator, since all memory allocations are connected and freeing
-//        happens at the same time
-
 import std::core::mem;
+import std::core::mem::allocator;
 import std::collections::bitset;
 import std::collections::map;
 
-def BitArr = bitset::BitSet(<SIZE>) @private;
-def IdTable = map::HashMap(<Key, usz>) @private;
-def IdTableEntry = map::Entry(<Key, usz>) @private;
+alias BitArr = bitset::BitSet{SIZE};
+alias IdTable = map::HashMap{Key, usz};
+alias IdTableEntry = map::Entry{Key, usz};
 
 const usz CACHE_NCYCLES = (usz)(SIZE * 2.0/3.0);
 
 struct Cache {
+	Allocator allocator;
 	BitArr present, used;
 	IdTable table;
 	Value[] pool;
@@ -42,57 +40,75 @@ macro Cache.cycle(&cache) @private {
 	}
 }
 
-fn void! Cache.init(&cache)
+fn void? Cache.init(&cache, Allocator allocator)
 {
-	cache.table.new_init(capacity: SIZE);
+	cache.allocator = allocator;
+	cache.table.init(allocator, capacity: SIZE);
 	// FIXME: this shit is SLOW
 	foreach (idx, bit : cache.used) { cache.used[idx] = false; }
 	foreach (idx, bit : cache.present) { cache.present[idx] = false; }
-	cache.pool = mem::new_array(Value, SIZE);
+	cache.pool = allocator::new_array(allocator, Value, SIZE);
 }
 
 fn void Cache.free(&cache)
 {
 	(void)cache.table.free();
-	(void)mem::free(cache.pool);
+	(void)allocator::free(cache.allocator, cache.pool);
 }
 
-fn Value*! Cache.search(&cache, Key id)
+fn Value*? Cache.search(&cache, Key id)
 {
 	// get_entry() faults on miss
 	IdTableEntry* entry = cache.table.get_entry(id)!;
 
-	/* MISS */
+	/* MISS, wrong key */
 	if (entry.key != id) {
-		return SearchResult.MISSING?;
+		cache.table.remove(id)!;
+		return NOT_FOUND?;
 	}
 
 	/* MISS, the data is not valid (not present) */
 	if (!cache.present[entry.value]) {
 		// if the data is not present but it is still in the table, remove it
 		cache.table.remove(id)!;
-		return SearchResult.MISSING?;
+		return NOT_FOUND?;
 	}
 
 	/* HIT, set as recently used */
+	//io::printfn("HIT: %d [%d]", entry.value, entry.key);
 	cache.used[entry.value] = true;
 	return &(cache.pool[entry.value]);
 }
 
+fn void Cache.remove(&cache, Key id)
+{
+	IdTableEntry*? entry = cache.table.get_entry(id);
+	if (catch entry) {
+		return;
+	}
+
+	// found, remove it
+	cache.present[entry.value] = false;
+	(void)cache.table.remove(id);
+}
+
 /* Look for a free spot in the present bitmap and return its index */
 /* If there is no free space left then just return the first position */
 fn usz Cache.get_free_spot(&cache) @private
 {
+	// TODO: in the upgrade to c3 1.7.5 use @bitsof()
 	const BITS = $typeof(cache.present.data[0]).sizeof*8;
 	foreach (idx, d: cache.present.data) {
-		if (d.clz() != BITS) {
-			return idx*BITS + BITS-d.clz();
+		if (d != $typeof(d).max) {
+			usz spot = idx*BITS + BITS-d.clz();
+			if (cache.used[spot]) unreachable("free spot is not actually free: %d", spot);
+			return spot;
 		}
 	}
 	return 0;
 }
 
-fn Value*! Cache.insert_at(&cache, Value *g, Key id, usz index) @private
+fn Value*? Cache.insert_at(&cache, Value* g, Key id, usz index) @private
 {
 	// TODO: verify index, g and id
 	Value* spot;
@@ -109,17 +125,17 @@ fn Value*! Cache.insert_at(&cache, Value *g, Key id, usz index) @private
 }
 
 // Insert an element in the cache, returns the index
-fn Value*! Cache.insert_new(&cache, Value* g, Key id)
+fn Value*? Cache.insert_new(&cache, Value* g, Key id)
 {
 	usz index = cache.get_free_spot();
 	return cache.insert_at(g, id, index);
 }
 
-fn Value*! Cache.get_or_insert(&cache, Value* g, Key id, bool *is_new = null)
+fn Value*? Cache.get_or_insert(&cache, Value* g, Key id, bool *is_new = null)
 {
-	Value*! c = cache.search(id);
+	Value*? c = cache.search(id);
 	if (catch e = c) {
-		if (e != SearchResult.MISSING) {
+		if (e != NOT_FOUND) {
 			return e?;
 		} else {
 			// if the element is new (inserted) set the is_new flag

src/cmd.c3

@@ -0,0 +1,217 @@
+module ugui;
+
+import std::io;
+import std::collections::list;
+
+// command type
+enum CmdType {
+	CMD_RECT,
+	CMD_UPDATE_ATLAS,
+	CMD_SPRITE,
+	CMD_SCISSOR,
+	CMD_REQ_SKIP_FRAME,
+}
+
+// command to draw a rect
+struct CmdRect {
+	Rect rect;
+	ushort radius;
+	Color color;
+}
+
+struct CmdUpdateAtlas {
+	Id id;
+	char* raw_buffer;
+	short width, height, bpp;
+}
+
+struct CmdSprite {
+	Id texture_id;
+	SpriteType type;
+	Rect rect;
+	Rect texture_rect;
+	Color hue;
+}
+
+// if rect is zero Rect{0} then reset the scissor
+struct CmdScissor {
+	Rect rect;
+}
+
+// command structure
+struct Cmd (Printable) {
+	CmdType type;
+	int z_index; 
+	union {
+		CmdRect rect;
+		CmdUpdateAtlas update_atlas;
+		CmdSprite sprite;
+		CmdScissor scissor;
+	}
+}
+
+// command queue
+alias CmdQueue = list::List{Cmd};
+
+
+fn int Cmd.compare_to(Cmd a, Cmd b)
+{
+	if (a.z_index == b.z_index) return 0;
+	return a.z_index > b.z_index ? 1 : -1;
+}
+
+
+// FIXME: This sorting method does not fully respect layer ordering for popups.
+//        Popups that start on the same layer but are enqueued at different times
+//        may still be rendered on top of each other, even if the first popup
+//        has elements in higher layers than the second. The current approach
+//        does not truly sort by layer; it only moves elements from higher layers
+//        to the end of the queue as they are encountered.
+fn void? CmdQueue.sort(&queue)
+{
+	CmdQueue stack;
+	stack.init(allocator::tmem);
+
+	for (isz i = queue.len()-1; i > 0; i--) {
+		Cmd cur = (*queue)[i];
+		Cmd next = (*queue)[i - 1];
+		// cur < next
+		if (cur.compare_to(next) < 0) {
+			stack.push(next);
+			queue.remove_at(i-1);
+		}
+	}
+
+	usz l = stack.len();
+	for (usz i; i < l; i++) {
+		queue.push(stack.pop())!;
+	}
+
+}
+
+// implement the Printable interface
+fn usz? Cmd.to_format(Cmd* cmd, Formatter *f) @dynamic
+{
+	usz ret;
+	
+	ret += f.printf("Cmd{ type: %s, z_index: %d, ", cmd.type, cmd.z_index)!;
+	switch (cmd.type) {
+	case CMD_RECT:
+		ret += f.print("CmdRect")!;
+		ret += io::struct_to_format(cmd.rect, f, false)!;
+	case CMD_SCISSOR:
+		ret += f.print("CmdScissor")!;
+		ret += io::struct_to_format(cmd.scissor, f, false)!;
+	case CMD_SPRITE:
+		ret += f.print("CmdSprite")!;
+		ret += io::struct_to_format(cmd.sprite, f, false)!;
+	case CMD_UPDATE_ATLAS:
+		ret += f.print("CmdUpdateAtlas")!;
+		ret += io::struct_to_format(cmd.update_atlas, f, false)!;
+	case CMD_REQ_SKIP_FRAME:
+		ret += f.print("Skip Frame Request")!;
+	}
+	
+	ret += f.print("}")!;
+	return ret;
+}
+
+macro bool cull_rect(Rect rect, Rect clip = {0,0,short.max,short.max})
+{
+	bool no_area = rect.w <= 0 || rect.h <= 0;
+	return no_area || !rect.collides(clip);
+}
+
+// FIXME: this whole thing could be done at compile time, maybe
+macro Ctx.push_cmd(&ctx, Cmd cmd, int z_index)
+{
+	cmd.z_index = z_index;
+	Rect rect;
+	switch (cmd.type) {
+	case CMD_RECT: rect = cmd.rect.rect;
+	case CMD_SPRITE: rect = cmd.sprite.rect;
+	default: return ctx.cmd_queue.push(cmd);
+	}
+	if (cull_rect(rect, ctx.div_scissor)) {
+//		println("NOPE: ", cmd.rect.rect, cmd.z_index);
+//		unreachable();
+		return;
+	}
+	return ctx.cmd_queue.push(cmd);
+}
+
+fn void? Ctx.push_scissor(&ctx, Rect rect, int z_index)
+{
+	Cmd sc = {
+		.type = CMD_SCISSOR,
+		.scissor.rect = rect.intersection(ctx.div_scissor),
+	};
+	ctx.push_cmd(sc, z_index);
+}
+
+fn void? Ctx.reset_scissor(&ctx, int z_index) => ctx.push_cmd({.type=CMD_SCISSOR,.scissor.rect=ctx.div_scissor}, z_index);
+
+fn void? Ctx.push_rect(&ctx, Rect rect, int z_index, Style* style)
+{
+	Rect border        = style.border;
+	ushort radius      = style.radius;
+	Color bg           = style.bg;
+	Color border_color = style.secondary;
+
+	// FIXME: this implies that the border has to be uniform
+	if (!border.is_null()) {
+		Cmd cmd = {
+			.type = CMD_RECT,
+			.rect.rect = rect,
+			.rect.color = border_color,
+			.rect.radius = radius + border.x,
+		};
+		ctx.push_cmd(cmd, z_index);
+	}
+
+	Cmd cmd = {
+		.type = CMD_RECT,
+		.rect.rect = {
+			.x = rect.x + border.x,
+			.y = rect.y + border.y,
+			.w = rect.w - (border.x+border.w),
+			.h = rect.h - (border.y+border.h),
+		},
+		.rect.color = bg,
+		.rect.radius = radius,
+	};
+	ctx.push_cmd(cmd, z_index);
+}
+
+// TODO: accept a Sprite* instead of all this shit
+fn void? Ctx.push_sprite(&ctx, Rect bounds, Rect texture, Id texture_id, int z_index, Color hue = 0xffffffffu.to_rgba(), SpriteType type = SPRITE_NORMAL)
+{
+	Cmd cmd = {
+		.type = CMD_SPRITE,
+		.sprite.type = type,
+		.sprite.rect = bounds,
+		.sprite.texture_rect = texture,
+		.sprite.texture_id = texture_id,
+		.sprite.hue = hue,
+	};
+	ctx.push_cmd(cmd, z_index);
+}
+
+fn void? Ctx.push_update_atlas(&ctx, Atlas* atlas)
+{
+	Cmd up = {
+		.type = CMD_UPDATE_ATLAS,
+		.update_atlas = {
+			.id = atlas.id,
+			.raw_buffer = atlas.buffer,
+			.width = atlas.width,
+			.height = atlas.height,
+			.bpp = (ushort)atlas.type.bpp(),
+			},
+		};
+	// update the atlases before everything else
+	ctx.push_cmd(up, -1);
+}
+
+macro Ctx.dbg_rect(&ctx, Rect r, uint c = 0xff000042u) => ctx.push_rect(r, int.max, &&(Style){.bg=c.to_rgba()})!!;
+

src/core.c3

@@ -0,0 +1,396 @@
+module ugui;
+
+import mtree;
+import cache;
+
+
+import std::io;
+import std::core::string;
+import std::core::mem::allocator;
+import std::collections::pair;
+import std::sort;
+
+
+macro println(...)
+{
+	$for var $i = 0; $i < $vacount; $i++:
+		io::print($vaexpr[$i]);
+	$endfor
+	io::printn();
+}
+
+
+// element ids are just long ints
+alias Id = uint;
+
+enum ElemType {
+	ETYPE_NONE,
+	ETYPE_DIV,
+	ETYPE_BUTTON,
+	ETYPE_SLIDER,
+	ETYPE_TEXT,
+	ETYPE_SPRITE,
+}
+
+bitstruct ElemFlags : uint {
+	bool updated : 0;
+	bool is_new  : 1; // element is new in the cache
+	bool shown   : 2; // element has been shown (drawn) this frame
+}
+
+bitstruct ElemEvents : uint {
+	bool key_press     : 0;
+	bool key_release   : 1;
+	bool key_repeat    : 2;
+	bool mouse_hover   : 3;
+	bool mouse_press   : 4;
+	bool mouse_release : 5;
+	bool mouse_hold    : 6;
+	bool update        : 7;
+	bool text_input    : 8;
+	bool has_focus     : 9;
+}
+
+// element structure
+struct Elem {
+	Id id;
+	int tree_idx;
+	ElemFlags flags;
+	ElemEvents events;
+	Rect bounds;
+	Rect children_bounds;
+	ElemType type;
+	Layout layout;
+	int z_index;
+	union {
+		ElemDiv div;
+		ElemButton button;
+		ElemSlider slider;
+		ElemText text;
+		ElemSprite sprite;
+	}
+}
+
+
+const uint MAX_ELEMENTS = 256;
+const uint MAX_COMMANDS = 2048;
+const uint STACK_STEP = 10;
+const uint ROOT_ID    = 1;
+const uint TEXT_MAX   = 64;
+
+
+// Tuple of Element pointers, used when it is useful to get both parent and child
+alias PElemTuple = pair::Pair{Elem*, Elem*};
+
+// relationships between elements are stored in a tree, it stores just the ids
+alias IdTree = mtree::MTree{Id};
+
+// elements themselves are kept in a cache
+alias ElemCache = cache::Cache{Id, Elem, MAX_ELEMENTS};
+
+faultdef INVALID_SIZE, EVENT_UNSUPPORTED, WRONG_ELEMENT_TYPE, WRONG_ID;
+
+struct InputData {
+	InputEvents events;
+	struct mouse {
+		Point pos, delta;
+		// mouse_down:      bitmap of mouse buttons that are held
+		// mouse_updated:   bitmap of mouse buttons that have been updated
+		// mouse_released = mouse_updated & ~mouse_down
+		// mouse_pressed  = mouse_updated & mouse_down
+		MouseButtons down;
+		MouseButtons updated;
+		// scroll wheel
+		Point scroll;
+	}
+	struct keyboard {
+		char[TEXT_MAX] text;
+		usz text_len;
+		ModKeys modkeys;
+	}
+}
+
+struct Ctx {
+	IdTree tree;
+	ElemCache cache;
+	CmdQueue cmd_queue;
+	StyleMap styles;
+	// total size in pixels of the context
+	ushort width, height;
+	Font font;
+	SpriteAtlas sprite_atlas;
+
+	bool skip_frame;
+
+	bool has_focus;
+	InputData input, current_input;
+
+	Id hover_id;
+	Id focus_id;
+
+	Rect div_scissor; // the current div bounds used for scissor test
+	int active_div; // tree node indicating the current active div
+}
+
+// return a pointer to the parent of the current active div
+fn Elem*? Ctx.get_parent(&ctx)
+{
+	Id parent_id = ctx.tree[ctx.active_div]!;
+	Elem* parent = ctx.cache.search(parent_id)!;
+	return parent;
+}
+
+macro @bits(#a) => $typeof(#a).sizeof*8;
+macro Id.rotate_left(id, uint $n) => (id << $n) | (id >> (@bits(id) - $n));
+const uint GOLDEN_RATIO = 0x9E3779B9;
+
+// generate an id combining the hashes of the parent id and the label
+// with the Cantor pairing function
+fn Id? Ctx.gen_id(&ctx, Id id2)
+{
+	// FIXME: this is SHIT
+	Id id1 = ctx.tree.get(ctx.active_div)!;
+	// Mix the two IDs non-linearly
+	Id mixed = id1 ^ id2.rotate_left(13);
+	mixed ^= id1.rotate_left(7);
+	mixed += GOLDEN_RATIO;
+	return mixed;
+}
+
+// compute the id from arguments and the line of the call
+macro Id @compute_id(...)
+{
+	Id id = (Id)$$LINE.hash() ^ (Id)@str_hash($$FILE);
+	$for var $i = 0; $i < $vacount; $i++:
+		id ^= (Id)$vaexpr[$i].hash();
+	$endfor
+	return id;
+}
+
+// get or push an element from the cache, return a pointer to it
+// resets all flags except is_new which is set accordingly
+fn PElemTuple? Ctx.get_elem(&ctx, Id id, ElemType type)
+{
+	bool is_new;
+	Elem* parent;
+	Elem* elem;
+	parent = ctx.get_parent() ?? &&(Elem){};
+
+	elem = ctx.cache.get_or_insert(&&(Elem){}, id, &is_new)!;
+	elem.flags = (ElemFlags)0;
+	elem.flags.is_new = is_new;
+	elem.flags.shown = true;
+	elem.id = id;
+	elem.layout = {};
+	if (is_new == false && elem.type != type) {
+		return WRONG_ELEMENT_TYPE?;
+	} else {
+		elem.type = type;
+	}
+	elem.z_index = parent.z_index;
+	elem.tree_idx = ctx.tree.add(ctx.active_div, id)!;
+	return {elem, parent};
+}
+
+// find an element, does not allocate a new one in cache
+// THIS HAS TO BE A MACRO SINCE IT RETURNS A POINTER TO A TEMPORARY VALUE
+macro Elem* Ctx.find_elem(&ctx, Id id)
+{
+	Elem*? elem;
+	elem = ctx.cache.search(id);
+	if (catch elem) {
+		return &&(Elem){};
+	}
+	return elem;
+}
+
+fn Elem*? Ctx.get_active_div(&ctx)
+{
+	Id id = ctx.tree.get(ctx.active_div)!;
+	return ctx.cache.search(id);
+}
+
+fn void? Ctx.init(&ctx, Allocator allocator)
+{
+	ctx.tree.init(MAX_ELEMENTS, allocator);
+	defer catch { (void)ctx.tree.free(); }
+
+	ctx.cache.init(allocator)!;
+	defer catch { (void)ctx.cache.free(); }
+
+	ctx.cmd_queue.init(allocator::mem, MAX_COMMANDS);
+	defer catch { (void)ctx.cmd_queue.free(); }
+
+	ctx.styles.init(allocator);
+	ctx.styles.register_style(&DEFAULT_STYLE, @str_hash("default"));
+	defer catch { ctx.styles.free(); }
+
+	ctx.active_div = 0;
+}
+
+fn void Ctx.free(&ctx)
+{
+	(void)ctx.tree.free();
+	(void)ctx.cache.free();
+	(void)ctx.cmd_queue.free();
+	(void)ctx.font.free();
+	(void)ctx.sprite_atlas.free();
+	(void)ctx.styles.free();
+}
+
+fn void? Ctx.frame_begin(&ctx)
+{
+	// 1. Reset the active div
+	// 2. Get the root element from the cache and update it
+	ctx.active_div = 0;
+	Elem* elem = ctx.get_elem(ROOT_ID, ETYPE_DIV)!.first;
+	ctx.active_div = elem.tree_idx;
+	// The root should have the updated flag only if the size of the window
+	// was changed between frasmes, this propagates an element size recalculation
+	// down the element tree
+	elem.flags.updated = ctx.input.events.resize;
+	// if the window has focus then the root element also has focus, no other
+	// computation needed, child elements need to check the mouse positon and
+	// other stuff
+	//elem.flags.has_focus = ctx.has_focus;
+
+	elem.bounds = {0, 0, ctx.width, ctx.height};
+	elem.z_index = 0;
+	elem.div.scroll_x.enabled = false;
+	elem.div.scroll_y.enabled = false;
+	elem.layout.dir = ROW;
+	elem.layout.anchor = TOP_LEFT;
+	elem.layout.w = @exact(ctx.width);
+	elem.layout.h = @exact(ctx.height);
+
+	ctx.div_scissor = elem.bounds;
+
+	ctx.skip_frame = false;
+}
+
+fn void? Ctx.frame_end(&ctx)
+{
+	Elem* root = ctx.get_active_div()!;
+	if (root.id != ROOT_ID) {
+		return WRONG_ID?;
+	}
+
+	// 2. clear input fields
+	ctx.input = ctx.current_input;
+	ctx.current_input.events = {};
+	ctx.current_input.mouse.scroll = {};
+	ctx.current_input.mouse.updated = BTN_NONE;
+	ctx.current_input.keyboard.text_len = 0;
+
+	// DO THE LAYOUT
+	ctx.layout_element_tree()!;
+
+	foreach (idx, id : ctx.tree.elem_vec) {
+		if (!ctx.tree.is_used((int)idx)) continue;
+		Elem* c = ctx.find_elem(id);
+		// reset events
+		c.events = {};
+		// reset shown flag
+		// TODO: use shown_last_frame to avoid this loop entirely
+		c.flags.shown = false;
+	}
+
+	// Propagate input events to the right elements
+	ctx.set_elem_events(ctx.hover_id);
+	ctx.set_elem_events(ctx.focus_id);
+
+
+	// 1. clear the tree
+	ctx.tree.nuke();
+
+	// send atlas updates
+	if (ctx.font.should_update) {
+		ctx.push_update_atlas(&ctx.font.atlas)!;
+		ctx.font.should_update = false;
+	}
+	if (ctx.sprite_atlas.should_update) {
+		ctx.push_update_atlas(&ctx.sprite_atlas.atlas)!;
+		ctx.sprite_atlas.should_update = false;
+	}
+
+	// send skip frame request
+	if (ctx.skip_frame) {
+		ctx.cmd_queue.push({.type = CMD_REQ_SKIP_FRAME});
+	}
+
+	// sort the command buffer by the z-index
+	// FIXME: sorting the buffer fucks with scissor commands that have to be kept in place
+	// TODO: instead of sorting at the end perform ordered inserts into the command buffer
+	//sort::countingsort(ctx.cmd_queue, fn uint(Cmd c) => c.z_index+1);
+	ctx.cmd_queue.sort()!;
+
+	// debug
+$if $feature(DEBUG_POINTER):
+	// draw mouse position
+	Cmd cmd = {
+		.type = CMD_RECT,
+		.z_index = int.max-1, // hopefully over everything else
+		.rect.rect = {
+			.x = ctx.input.mouse.pos.x - 2,
+			.y = ctx.input.mouse.pos.y - 2,
+			.w = 4,
+			.h = 4,
+		},
+		.rect.color = 0xff00ffffu.to_rgba()
+	};
+	ctx.cmd_queue.push(cmd);
+$endif
+}
+
+
+macro bool Ctx.is_hovered(&ctx, Elem *elem) => ctx.input.mouse.pos.in_rect(elem.bounds);
+
+// Check if the element is hovered and/or focused, if it is update the context ids.
+// The order in which the elements are passed to this function is not relevant
+fn void Ctx.update_hover_and_focus(&ctx, Elem* elem)
+{
+	bool hover = ctx.is_hovered(elem);
+	bool focus = ctx.focus_id == elem.id || (hover && ctx.is_mouse_pressed(BTN_ANY));
+
+	if (hover) {
+		Elem* prev_hover = ctx.find_elem(ctx.hover_id);
+		bool different = prev_hover.id != elem.id;
+		bool still_hovered = ctx.is_hovered(prev_hover);
+		bool shown = prev_hover.flags.shown;
+		bool above = prev_hover.z_index > elem.z_index;
+
+		hover = !(different && still_hovered && shown && above);
+	}
+
+	if (focus) {
+		Elem* prev_focus = ctx.find_elem(ctx.hover_id);
+		bool different = prev_focus.id != elem.id;
+		bool shown = prev_focus.flags.shown;
+		bool above = prev_focus.z_index > elem.z_index;
+
+		focus = !(different && shown && above);
+	}
+
+	if (hover) ctx.hover_id = elem.id;
+	if (focus) ctx.focus_id = elem.id;
+}
+
+// FIXME: this does not work with touch
+fn void Ctx.set_elem_events(&ctx, Id id)
+{
+	bool hover = id == ctx.hover_id;
+	bool focus = id == ctx.focus_id;
+	Elem* e = ctx.find_elem(id);
+
+	e.events = {
+		.has_focus     = focus,
+		.mouse_hover   = hover,
+		.mouse_press   = hover && focus && ctx.is_mouse_pressed(BTN_ANY),
+		.mouse_release = hover && focus && ctx.is_mouse_released(BTN_ANY),
+		.mouse_hold    = hover && focus && ctx.is_mouse_down(BTN_ANY),
+		.key_press     = focus && ctx.input.events.key_press,
+		.key_release   = focus && ctx.input.events.key_release,
+		.key_repeat    = focus && ctx.input.events.key_repeat,
+		.text_input    = focus && (ctx.input.keyboard.text_len || ctx.input.keyboard.modkeys & KMOD_TXT),
+	};
+}

src/fifo.c3

@@ -1,49 +0,0 @@
-module fifo(<Type>);
-
-import std::core::mem;
-
-fault FifoErr {
-	FULL,
-	EMPTY,
-}
-
-// TODO: specify the allocator
-
-struct Fifo {
-	Type[] arr;
-	usz out;
-	usz count;
-}
-
-fn void! Fifo.init(&fifo, usz size)
-{
-	fifo.arr = mem::new_array(Type, size);
-	fifo.out = 0;
-	fifo.count = 0;
-}
-
-fn void Fifo.free(&fifo)
-{
-	(void)mem::free(fifo.arr);
-}
-
-fn void! Fifo.enqueue(&fifo, Type *elem)
-{
-	if (fifo.count >= fifo.arr.len) {
-		return FifoErr.FULL?;
-	}
-	usz in = (fifo.out + fifo.count) % fifo.arr.len;
-	fifo.arr[in] = *elem;
-	fifo.count++;
-}
-
-fn Type*! Fifo.dequeue(&fifo)
-{
-	if (fifo.count == 0) {
-		return FifoErr.EMPTY?;
-	}
-	Type *ret = &fifo.arr[fifo.out];
-	fifo.count--;
-	fifo.out = (fifo.out + 1) % fifo.arr.len;
-	return ret;
-}

src/font.c3

@@ -0,0 +1,227 @@
+module ugui::font;
+
+import schrift;
+import std::collections::map;
+import std::core::mem;
+import std::core::mem::allocator;
+import std::io;
+import std::ascii;
+
+
+// ---------------------------------------------------------------------------------- //
+//                                CODEPOINT                                           //
+// ---------------------------------------------------------------------------------- //
+
+// unicode code point, different type for a different hash
+alias Codepoint = uint;
+
+//macro uint Codepoint.hash(self) => ((uint)self).hash();
+
+// ---------------------------------------------------------------------------------- //
+//                                FONT ATLAS                                          //
+// ---------------------------------------------------------------------------------- //
+
+/* width and height of a glyph contain the kering advance
+ * (u,v)
+ *   +-------------*---+ -
+ *   |       ^     |   | ^
+ *   |       |oy   |   | |
+ *   |       v     |   | |
+ *   |      .ii.   |   | |
+ *   |     @@@@@@. |   | |
+ *   |    V@Mio@@o |   | |
+ *   |    :i.  V@V |   | h
+ *   |      :oM@@M |   | |
+ *   |    :@@@MM@M |   | |
+ *   |    @@o  o@M |   | |
+ *   |<->:@@.  M@M |   | |
+ *   |ox  @@@o@@@@ |   | |
+ *   |    :M@@V:@@.|   | v
+ *   +-------------*---+ -
+ *   |<---- w ---->|
+ *   |<------ adv ---->|
+ */
+struct Glyph {
+	Codepoint code;
+	ushort u, v;
+	ushort w, h;
+	short adv, ox, oy;
+}
+
+const uint FONT_CACHED = 255;
+alias GlyphTable = map::HashMap{Codepoint, Glyph};
+
+faultdef TTF_LOAD_FAILED, MISSING_GLYPH, BAD_GLYPH_METRICS, RENDER_ERROR;
+
+struct Font {
+	schrift::Sft sft;
+	String path;
+	Id id; // font id, same as atlas id
+	GlyphTable table;
+
+	float size;
+	float ascender, descender, linegap; // Line Metrics
+	Atlas atlas;
+	bool should_update; // should send update_atlas command, resets at frame_end()
+}
+
+macro Rect Glyph.bounds(&g) => {.x = g.ox, .y = g.oy, .w = g.w, .h = g.h};
+macro Rect Glyph.uv(&g) => {.x = g.u, .y = g.v, .w = g.w, .h = g.h};
+
+<*
+@param [&inout] font
+@param [in] name
+@param [&in] path
+@require height > 0, scale > 0: "height and scale must be positive non-zero"
+*>
+fn void? Font.load(&font, Allocator allocator, String name, ZString path, uint height, float scale)
+{
+	font.table.init(allocator, capacity: FONT_CACHED);
+	font.id = name.hash();
+
+	font.size = height*scale;
+
+	font.sft = {
+		.xScale = (double)font.size,
+		.yScale = (double)font.size,
+		.flags = schrift::SFT_DOWNWARD_Y,
+	};
+
+	font.sft.font = schrift::loadfile(path);
+	if (font.sft.font == null) {
+		font.table.free();
+		return TTF_LOAD_FAILED?;
+	}
+
+	schrift::SftLMetrics lmetrics;
+	schrift::lmetrics(&font.sft, &lmetrics);
+	font.ascender  = (float)lmetrics.ascender;
+	font.descender = (float)lmetrics.descender;
+	font.linegap   = (float)lmetrics.lineGap;
+	//io::printfn("ascender:%d, descender:%d, linegap:%d", font.ascender, font.descender, font.linegap);
+
+	// TODO: allocate buffer based on FONT_CACHED and the size of a sample letter
+	//       like the letter 'A'
+	ushort size = (ushort)font.size*(ushort)($$sqrt((float)FONT_CACHED));
+	font.atlas.new(font.id, ATLAS_GRAYSCALE, size, size)!;
+
+	// preallocate the ASCII range
+	for (char c = ' '; c < '~'; c++) {
+		// FIXME: without @inline, this crashes with O1 or greater
+		font.get_glyph((Codepoint)c) @inline!;
+	}
+}
+
+<*
+@param [&inout] font
+*>
+fn Glyph*? Font.get_glyph(&font, Codepoint code)
+{
+	Glyph*? gp;
+	gp = font.table.get_ref(code);
+
+	if (catch excuse = gp) {
+		if (excuse != NOT_FOUND) {
+			return excuse?;
+		}
+	} else {
+		return gp;
+	}
+
+
+	// missing glyph, render and place into an atlas
+	Glyph glyph;
+
+	schrift::SftGlyph gid;
+	schrift::SftGMetrics gmtx;
+
+	if (schrift::lookup(&font.sft, (SftUChar)code, &gid) < 0) {
+		return MISSING_GLYPH?;
+	}
+
+	if (schrift::gmetrics(&font.sft, gid, &gmtx) < 0) {
+		return BAD_GLYPH_METRICS?;
+	}
+
+	schrift::SftImage img = {
+		.width = gmtx.minWidth,
+		.height = gmtx.minHeight,
+	};
+	char[] pixels = mem::new_array(char, (usz)img.width * img.height);
+	img.pixels = pixels;
+	if (schrift::render(&font.sft, gid, img) < 0) {
+		return RENDER_ERROR?;
+	}
+
+	glyph.code = code;
+	glyph.w = (ushort)img.width;
+	glyph.h = (ushort)img.height;
+	glyph.ox = (short)gmtx.leftSideBearing;
+	glyph.oy = (short)gmtx.yOffset;
+	glyph.adv = (short)gmtx.advanceWidth;
+	//io::printfn("code=%c, w=%d, h=%d, ox=%d, oy=%d, adv=%d",
+	//    glyph.code, glyph.w, glyph.h, glyph.ox, glyph.oy, glyph.adv);
+
+	Point uv = font.atlas.place(pixels, glyph.w, glyph.h, (ushort)img.width)!;
+	glyph.u = uv.x;
+	glyph.v = uv.y;
+
+	mem::free(pixels);
+
+	font.table.set(code, glyph);
+
+	font.should_update = true;
+	return font.table.get_ref(code);
+}
+
+<*
+@param [&inout] font
+*>
+fn void Font.free(&font)
+{
+	font.atlas.free();
+	font.table.free();
+	schrift::freefont(font.sft.font);
+}
+
+
+// ---------------------------------------------------------------------------------- //
+//                           FONT LOAD AND QUERY                                      //
+// ---------------------------------------------------------------------------------- //
+
+module ugui;
+
+<*
+@param [&inout] ctx
+@param [in] name
+@param [&in] path
+@require height > 0, scale > 0: "height and scale must be positive non-zero"
+*>
+fn void? Ctx.load_font(&ctx, Allocator allocator, String name, ZString path, uint height, float scale = 1.0)
+{
+	return ctx.font.load(allocator, name, path, height, scale);
+}
+
+<*
+@param [&in] ctx
+@param [in] label
+*>
+// TODO: check if the font is present in the context
+fn Id Ctx.get_font_id(&ctx, String label) => (Id)label.hash();
+
+<*
+@param [&in] ctx
+@param [in] name
+*>
+fn Atlas*? Ctx.get_font_atlas(&ctx, String name)
+{
+	// TODO: use the font name, for now there is only one font
+	if (name.hash() != ctx.font.id) {
+		return WRONG_ID?;
+	}
+
+	return &ctx.font.atlas;
+}
+
+<* @param [&in] font *>
+fn int Font.line_height(&font) => (int)(font.ascender - font.descender + (float)0.5);

src/input.c3

@@ -0,0 +1,237 @@
+module ugui;
+
+import std::io;
+import std::math;
+import std::core::string;
+
+
+bitstruct InputEvents : uint {
+	bool resize       : 0; // window size was changed
+	bool change_focus : 1; // window focus changed
+	bool mouse_move   : 2; // mouse was moved
+	bool mouse_btn    : 3; // mouse button pressed or released
+	bool mouse_scroll : 4; // mouse scroll wheel. x or y
+	bool text_input   : 5;
+	bool mod_key      : 6;
+	bool key_press    : 7;
+	bool key_release  : 8;
+	bool key_repeat   : 9;
+}
+
+bitstruct MouseButtons : uint {
+	bool btn_left   : 0;
+	bool btn_middle : 1;
+	bool btn_right  : 2;
+	bool btn_4      : 3;
+	bool btn_5      : 4;
+}
+
+// FIXME: all of these names were prefixed with key_ idk if this is better,
+//        if it is remove the prefix on MouseButtons as well
+// Modifier Keys, intended as any key that is not text
+bitstruct ModKeys : uint {
+	bool lshift :  0;
+	bool rshift :  1;
+	bool lctrl  :  2;
+	bool rctrl  :  3;
+	bool lalt   :  4;
+	bool ralt   :  5;
+	bool lgui   :  6;
+	bool rgui   :  7;
+	bool num    :  8;
+	bool caps   :  9;
+	bool mode   : 10;
+	bool scroll : 11;
+	bool bkspc  : 12;
+	bool del    : 13;
+	bool home   : 14;
+	bool end    : 15;
+	// arrow keys
+	bool up     : 16;
+	bool down   : 17;
+	bool left   : 18;
+	bool right  : 19;
+}
+
+const ModKeys KMOD_CTRL  = {.lctrl  = true, .rctrl  = true};
+const ModKeys KMOD_SHIFT = {.lshift = true, .rshift = true};
+const ModKeys KMOD_ALT   = {.lalt   = true, .ralt   = true};
+const ModKeys KMOD_GUI   = {.lgui   = true, .rgui   = true};
+const ModKeys KMOD_TXT   = {.bkspc  = true, .del    = true}; // modkeys that act like text input
+const ModKeys KMOD_NONE  = {};
+const ModKeys KMOD_ANY   = (ModKeys)(ModKeys.inner.max);
+
+const MouseButtons BTN_NONE   = {};
+const MouseButtons BTN_ANY    = (MouseButtons)(MouseButtons.inner.max);
+const MouseButtons BTN_LEFT   = {.btn_left   = true};
+const MouseButtons BTN_MIDDLE = {.btn_middle = true};
+const MouseButtons BTN_RIGHT  = {.btn_right  = true};
+const MouseButtons BTN_4      = {.btn_4      = true};
+const MouseButtons BTN_5      = {.btn_5      = true};
+
+const ModKeys KEY_ANY = (ModKeys)(ModKeys.inner.max);
+
+<* @param [&inout] ctx *>
+fn bool Ctx.check_key_combo(&ctx, ModKeys mod, String ...keys)
+{
+	bool is_mod = (bool)(ctx.current_input.keyboard.modkeys & mod);
+	bool is_keys = true;
+	String haystack = (String)ctx.get_keys();
+	foreach (needle: keys) {
+		is_keys = is_keys && haystack.contains(needle);
+	}
+	return is_mod && is_keys;
+}
+
+// Window size was changed
+<* @param [&inout] ctx *>
+fn void? Ctx.input_window_size(&ctx, short width, short height)
+{
+	if (width <= 0 || height <= 0) {
+		return INVALID_SIZE?;
+	}
+	ctx.current_input.events.resize = ctx.width != width || ctx.height != height;
+	ctx.width = width;
+	ctx.height = height;
+	if (ctx.current_input.events.resize) ctx.skip_frame = true;
+}
+
+// Window gained/lost focus
+<* @param [&inout] ctx *>
+fn void Ctx.input_changefocus(&ctx, bool has_focus)
+{
+	// FIXME: raylib only has an API to query the focus status so we have to
+	//        update the input flag only if the focus changed
+	ctx.current_input.events.change_focus = ctx.has_focus != has_focus;
+	ctx.has_focus = has_focus;
+}
+
+// NOTE: all of these refer to the previous frame's data
+macro Ctx.mouse_pressed(&ctx) => ctx.input.mouse.updated & ctx.input.mouse.down;
+macro Ctx.mouse_released(&ctx) => ctx.input.mouse.updated & ~ctx.input.mouse.down;
+macro Ctx.mouse_down(&ctx) => ctx.input.mouse.down;
+macro Ctx.is_mouse_pressed(&ctx, MouseButtons btn) => (ctx.mouse_pressed() & btn) != BTN_NONE;
+macro Ctx.is_mouse_released(&ctx, MouseButtons btn) => (ctx.mouse_released() & btn) != BTN_NONE;
+macro Ctx.is_mouse_down(&ctx, MouseButtons btn) => (ctx.mouse_down() & btn) != BTN_NONE;
+
+// Mouse Buttons down
+<* @param [&inout] ctx *>
+fn void Ctx.input_mouse_button(&ctx, MouseButtons buttons)
+{
+	ctx.current_input.mouse.updated = ctx.current_input.mouse.down ^ buttons;
+	ctx.current_input.mouse.down = buttons;
+	ctx.current_input.events.mouse_btn = ctx.current_input.mouse.down != BTN_NONE || ctx.current_input.mouse.updated != BTN_NONE;
+}
+
+// Mouse was moved, report absolute position
+<* @param [&inout] ctx *>
+fn void Ctx.input_mouse_abs(&ctx, short x, short y)
+{
+	ctx.current_input.mouse.pos.x = math::clamp(x, (short)0, ctx.width);
+	ctx.current_input.mouse.pos.y = math::clamp(y, (short)0, ctx.height);
+
+	short dx, dy;
+	dx = x - ctx.current_input.mouse.pos.x;
+	dy = y - ctx.current_input.mouse.pos.y;
+
+	ctx.current_input.mouse.delta.x = dx;
+	ctx.current_input.mouse.delta.y = dy;
+
+	ctx.current_input.events.mouse_move = dx != 0 || dy != 0;
+}
+
+// Mouse was moved, report relative motion
+<* @param [&inout] ctx *>
+fn void Ctx.input_mouse_delta(&ctx, short dx, short dy)
+{
+	ctx.current_input.mouse.delta.x = dx;
+	ctx.current_input.mouse.delta.y = dy;
+
+	short mx, my;
+	mx = ctx.current_input.mouse.pos.x + dx;
+	my = ctx.current_input.mouse.pos.y + dy;
+
+	ctx.current_input.mouse.pos.x = math::clamp(mx, (short)0, ctx.width);
+	ctx.current_input.mouse.pos.y = math::clamp(my, (short)0, ctx.height);
+
+	ctx.current_input.events.mouse_move = dx != 0 || dy != 0;
+}
+
+<* @param [&inout] ctx *>
+fn void Ctx.input_mouse_wheel(&ctx, short x, short y, float scale = 1.0)
+{
+	ctx.current_input.mouse.scroll.x = (short)((float)-x*scale);
+	ctx.current_input.mouse.scroll.y = (short)((float)-y*scale);
+	ctx.current_input.events.mouse_scroll = x !=0 || y != 0;
+}
+
+<* @param [&inout] ctx *>
+fn void Ctx.input_key_press(&ctx)
+{
+	ctx.current_input.events.key_press = true;
+}
+
+<* @param [&inout] ctx *>
+fn void Ctx.input_key_release(&ctx)
+{
+	ctx.current_input.events.key_release = true;
+}
+
+<* @param [&inout] ctx *>
+fn void Ctx.input_key_repeat(&ctx)
+{
+	ctx.current_input.events.key_repeat = true;
+}
+
+// append utf-8 encoded text to the context text input
+<* @param [&inout] ctx *>
+fn void Ctx.input_text_utf8(&ctx, char[] text)
+{
+	if (text == "") return;
+
+	usz remaining = ctx.current_input.keyboard.text.len - ctx.current_input.keyboard.text_len;
+	usz len = text.len > remaining ? remaining : text.len;
+	char[] s = ctx.current_input.keyboard.text[ctx.current_input.keyboard.text_len ..];
+	s[..len-1] = text[..len-1];
+	ctx.current_input.keyboard.text_len += len;
+	ctx.current_input.events.text_input = true;
+}
+
+<*
+@param [&inout] ctx
+@param [in] text
+*>
+fn void? Ctx.input_text_unicode(&ctx, uint[] text)
+{
+	if (text.len == 0) return;
+
+	usz remaining = ctx.current_input.keyboard.text.len - ctx.current_input.keyboard.text_len;
+	char[] s = ctx.current_input.keyboard.text[ctx.current_input.keyboard.text_len ..];
+
+	usz off = conv::utf32to8(text, s)!;
+	ctx.current_input.keyboard.text_len += off;
+
+	ctx.current_input.events.text_input = true;
+}
+
+<* @param [&inout] ctx *>
+fn void Ctx.input_char(&ctx, char c)
+{
+	char[1] b = {c};
+	ctx.input_text_utf8(b[..]);
+}
+
+fn String Ctx.get_keys(&ctx) => (String)ctx.input.keyboard.text[:ctx.input.keyboard.text_len];
+fn ModKeys Ctx.get_mod(&ctx) => ctx.input.keyboard.modkeys;
+
+// Modifier keys, like control or backspace
+<* @param [&inout] ctx *>
+fn void Ctx.input_mod_keys(&ctx, ModKeys modkeys, bool set)
+{
+	if (set) {
+		ctx.current_input.keyboard.modkeys |= modkeys;
+	} else {
+		ctx.current_input.keyboard.modkeys &= ~modkeys;
+	}
+	ctx.current_input.events.mod_key = (uint)ctx.current_input.keyboard.modkeys != 0;
+}

src/layout.c3

@@ -0,0 +1,353 @@
+module ugui;
+
+import std::math;
+import std::io;
+
+enum LayoutDirection {
+	ROW,
+	COLUMN,
+}
+
+enum Anchor {
+	TOP_LEFT,
+	LEFT,
+	BOTTOM_LEFT,
+	BOTTOM,
+	BOTTOM_RIGHT,
+	RIGHT,
+	TOP_RIGHT,
+	TOP,
+	CENTER
+}
+
+struct Layout {
+	Size w, h; // size of the CONTENT, does not include margin, border and padding
+	struct children { // the children size includes the children's margin/border/pading
+		Size w, h;
+	}
+	TextSize text;
+	ushort grow_children;
+	short occupied;
+	Point origin;
+	Point scroll_offset;
+	// false: the element is laid out according to the parent
+	// true: the element is laid out separate from all other children and the relative position to
+	//       the parent is the .origin field
+	bool absolute;
+	LayoutDirection dir; // the direction the children are laid out
+	Anchor anchor;       // how the children are positioned
+	Rect content_offset; // combined effect of margin, border and padding
+}
+
+// Returns the width and height of a @FIT() element based on it's wanted size (min/max)
+// and the content size, this function is used to both update the parent's children size and
+// give the dimensions of a fit element
+// TODO: test and cleanup this function
+macro Point Layout.get_dimensions(&el)
+{
+	Point dim;
+	// if the direction is ROW then the text is placed horizontally with the children
+	if (el.dir == ROW) {
+		Size content_width = el.children.w + el.text.width;
+		Size width = el.w.combine(content_width);
+		short final_width = width.greater();
+
+		short text_height;
+		if (el.text.area != 0) {
+			short text_width = (@exact(final_width) - el.children.w).combine(el.text.width).min;
+			text_height = @exact((short)(el.text.area / text_width)).combine(el.text.height).min;
+		}
+
+		Size content_height = el.children.h.comb_max(@exact(text_height));
+		Size height = el.h.combine(content_height);
+		short final_height = height.greater();
+
+		dim = {
+			.x = final_width + el.content_offset.x + el.content_offset.w,
+			.y = final_height + el.content_offset.y + el.content_offset.h,
+		};
+	} else {
+	// if the direction is COLUMN the text and children are one on top of the other
+		Size content_width = el.children.w.comb_max(el.text.width);
+		Size width = el.w.combine(content_width);
+		short final_width = width.greater();
+
+		short text_height;
+		if (el.text.area != 0) {
+			short text_width = @exact(final_width).combine(el.text.width).min;
+			text_height = @exact((short)(el.text.area / text_width)).combine(el.text.height).min;
+		}
+
+		Size content_height = el.children.h + @exact(text_height);
+		Size height = el.h.combine(content_height);
+		short final_height = height.greater();
+
+		dim = {
+			.x = final_width + el.content_offset.x + el.content_offset.w,
+			.y = final_height + el.content_offset.y + el.content_offset.h,
+		};
+	}
+
+	// GROSS HACK FOR EXACT DIMENSIONS
+	if (el.w.@is_exact()) dim.x = el.w.min + el.content_offset.x + el.content_offset.w;
+	if (el.h.@is_exact()) dim.y = el.h.min + el.content_offset.y + el.content_offset.h;
+
+	// GROSS HACK FOR GROW DIMENSIONS
+	// FIXME: does this always work?
+	if (el.w.@is_grow()) dim.x = 0;
+	if (el.h.@is_grow()) dim.y = 0;
+
+	return dim;
+}
+
+// The content space of the element
+macro Point Elem.content_space(&e)
+{
+	return {
+		.x = (short)max(e.bounds.w - e.layout.content_offset.x - e.layout.content_offset.w, 0),
+		.y = (short)max(e.bounds.h - e.layout.content_offset.y - e.layout.content_offset.h, 0),
+	};
+}
+
+// Update the parent element's children size
+fn void update_parent_size(Elem* child, Elem* parent)
+{
+	Layout* cl = &child.layout;
+	Layout* pl = &parent.layout;
+
+	// if the element has absolute position do not update the parent
+	if (cl.absolute) return;
+
+	Point child_size = cl.get_dimensions();
+
+	switch (pl.dir) {
+	case ROW: // on rows grow the ch width by the child width and only grow ch height if it exceeds
+		pl.children.w += @exact(child_size.x);
+		pl.children.h = pl.children.h.comb_max(@exact(child_size.y));
+		if (child.layout.w.@is_grow()) parent.layout.grow_children++;
+	case COLUMN: // do the opposite on column
+		pl.children.w = pl.children.w.comb_max(@exact(child_size.x));
+		pl.children.h += @exact(child_size.y);
+		if (child.layout.h.@is_grow()) parent.layout.grow_children++;
+	}
+}
+
+macro Rect Elem.content_bounds(&elem) => elem.bounds.pad(elem.layout.content_offset);
+
+// Assign the width and height of an element in the directions that it doesn't need to grow
+fn void resolve_dimensions(Elem* e, Elem* p)
+{
+	Layout* el = &e.layout;
+	Layout* pl = &p.layout;
+
+	Point elem_dimensions = el.get_dimensions();
+	e.bounds.w = elem_dimensions.x;
+	e.bounds.h = elem_dimensions.y;
+
+	// if the element has absolute position do not update the parent
+	if (el.absolute) return;
+
+	switch (pl.dir) {
+	case ROW:
+		if (!el.w.@is_grow()) pl.occupied += e.bounds.w;
+	case COLUMN:
+		if (!el.h.@is_grow()) pl.occupied += e.bounds.h;
+	}
+}
+
+fn void resolve_grow_elements(Elem* e, Elem* p)
+{
+	// WIDTH
+	if (e.layout.w.@is_grow()) {
+		if (e.layout.absolute) { // absolute children do not need to share space
+			e.bounds.w = p.content_space().x;
+		} else if (p.layout.dir == ROW) { // grow along the axis, divide the parent size
+			short slot = (short)max(((p.content_space().x - p.layout.occupied) / p.layout.grow_children), 0);
+			e.bounds.w = slot;
+			p.layout.grow_children--;
+			p.layout.occupied += slot;
+		} else if (p.layout.dir == COLUMN) { // grow across the layout axis, inherit width of the parent
+			e.bounds.w = p.content_space().x;
+		}
+	}
+
+	// HEIGHT
+	if (e.layout.h.@is_grow()) {
+		if (e.layout.absolute) { // absolute children do not need to share space
+			e.bounds.h = p.content_space().y;
+		} else if (p.layout.dir == COLUMN) { // grow along the axis, divide the parent size
+			short slot = (short)max(((p.content_space().y - p.layout.occupied) / p.layout.grow_children), 0);
+			e.bounds.h = slot;
+			p.layout.grow_children--;
+			p.layout.occupied += slot;
+		} else if (p.layout.dir == ROW) { // grow across the layout axis, inherit width of the parent
+			e.bounds.h = p.content_space().y;
+		}
+	}
+}
+
+fn void resolve_placement(Elem* c, Elem* p)
+{
+	Layout* pl = &p.layout;
+	Layout* cl = &c.layout;
+
+	Point off = {
+		.x = p.bounds.x + pl.origin.x + pl.content_offset.x,
+		.y = p.bounds.y + pl.origin.y + pl.content_offset.y,
+	};
+
+	// if the element has absolute position assign the origin and do not update the parent
+	if (cl.absolute) {
+		c.bounds.x = p.bounds.x + pl.content_offset.x + cl.origin.x;
+		c.bounds.y = p.bounds.y + pl.content_offset.y + cl.origin.y;
+		return;
+	}
+
+	switch (pl.anchor) {
+	case TOP_LEFT:
+		c.bounds.x = off.x;
+		c.bounds.y = off.y;
+	case LEFT:
+		c.bounds.x = off.x;
+		c.bounds.y = off.y + p.content_space().y/2;
+		if (pl.dir == COLUMN) {
+			c.bounds.y -= pl.occupied/2;
+		} else if (pl.dir == ROW) {
+			c.bounds.y -= c.bounds.h/2;
+		}
+	case BOTTOM_LEFT:
+		c.bounds.x = off.x;
+		c.bounds.y = off.y + p.content_space().y ;
+		if (pl.dir == COLUMN) {
+			c.bounds.y -= pl.occupied;
+		} else if (pl.dir == ROW) {
+			c.bounds.y -= c.bounds.h;
+		}
+	case BOTTOM:
+		c.bounds.x = off.x + p.content_space().x/2;
+		c.bounds.y = off.y + p.content_space().y;
+		if (pl.dir == COLUMN) {
+			c.bounds.y -= pl.occupied;
+			c.bounds.x -= c.bounds.w/2;
+		} else if (pl.dir == ROW) {
+			c.bounds.y -= c.bounds.h;
+			c.bounds.x -= pl.occupied/2;
+		}
+	case BOTTOM_RIGHT:
+		c.bounds.x = off.x + p.content_space().x;
+		c.bounds.y = off.y + p.content_space().y;
+		if (pl.dir == COLUMN) {
+			c.bounds.y -= pl.occupied;
+			c.bounds.x -= c.bounds.w;
+		} else if (pl.dir == ROW) {
+			c.bounds.y -= c.bounds.h;
+			c.bounds.x -= pl.occupied;
+		}
+	case RIGHT:
+		c.bounds.x = off.x + p.content_space().x;
+		c.bounds.y = off.y + p.content_space().y/2;
+		if (pl.dir == COLUMN) {
+			c.bounds.y -= pl.occupied/2;
+			c.bounds.x -= c.bounds.w;
+		} else if (pl.dir == ROW) {
+			c.bounds.y -= c.bounds.h/2;
+			c.bounds.x -= pl.occupied;
+		}
+	case TOP_RIGHT:
+		c.bounds.x = off.x + p.content_space().x;
+		c.bounds.y = off.y;
+		if (pl.dir == COLUMN) {
+			c.bounds.x -= c.bounds.w;
+		} else if (pl.dir == ROW) {
+			c.bounds.x -= pl.occupied;
+		}
+	case TOP:
+		c.bounds.x = off.x + p.content_space().x/2;
+		c.bounds.y = off.y;
+		if (pl.dir == COLUMN) {
+			c.bounds.x -= c.bounds.w/2;
+		} else if (pl.dir == ROW) {
+			c.bounds.x -= pl.occupied/2;
+		}
+	case CENTER:
+		c.bounds.x = off.x + p.content_space().x/2;
+		c.bounds.y = off.y + p.content_space().y/2;
+		if (pl.dir == COLUMN) {
+			c.bounds.x -= c.bounds.w/2;
+			c.bounds.y -= pl.occupied/2;
+		} else if (pl.dir == ROW) {
+			c.bounds.x -= pl.occupied/2;
+			c.bounds.y -= c.bounds.h/2;
+		}
+		break;
+	}
+
+	switch (pl.dir) {
+	case ROW:
+		pl.origin.x += c.bounds.w;
+	case COLUMN:
+		pl.origin.y += c.bounds.h;
+	default: unreachable("unknown layout direction");
+	}
+
+	// update the parent children_bounds
+	// FIXME: this causes scollbars to flicker in/out during resize because the current frames children_bounds are updated
+	//        with the previous' frame child bounds. It would be better to implement another pass during layout.
+	// FIXME: this long way around to compute the children bounds works and reduces flickering, but it is very ugly 
+	Rect ncb = c.children_bounds;
+	ncb.x = c.bounds.x;
+	ncb.y = c.bounds.y;
+	Rect cb = containing_rect(c.bounds, ncb);
+	Point o = p.layout.scroll_offset;
+	p.children_bounds = containing_rect(cb + o, p.children_bounds);
+
+	// reset the children bounds
+	c.children_bounds = {
+		.x = c.bounds.x,
+		.y = c.bounds.y
+	};
+}
+
+fn void? Ctx.layout_element_tree(&ctx)
+{
+	int current;
+	for (int n; (current = ctx.tree.level_order_it(0, n)) >= 0; n++) {
+		Elem* p = ctx.find_elem(ctx.tree.get(current))!;
+		p.layout.origin = -p.layout.scroll_offset;
+
+		int ch;
+		// RESOLVE KNOWN DIMENSIONS
+		for (int i; (ch = ctx.tree.children_it(current, i)) >= 0; i++) {
+			Elem* c = ctx.find_elem(ctx.tree.get(ch))!;
+			if (ctx.tree.is_root(ch)) {
+				resolve_dimensions(p, &&{});
+			} else {
+				resolve_dimensions(c, p);
+			}
+		}
+
+		// RESOLVE GROW CHILDREN
+		for (int i; (ch = ctx.tree.children_it(current, i)) >= 0; i++) {
+			Elem* c = ctx.find_elem(ctx.tree.get(ch))!;
+			if (ctx.tree.is_root(ch)) {
+				resolve_grow_elements(p, &&{});
+			} else {
+				resolve_grow_elements(c, p);
+			}
+		}
+
+		// RESOLVE CHILDREN PLACEMENT
+		for (int i; (ch = ctx.tree.children_it(current, i)) >= 0; i++) {
+			Elem* c = ctx.find_elem(ctx.tree.get(ch))!;
+			if (ctx.tree.is_root(ch)) {
+				resolve_placement(p, &&{});
+			} else {
+				resolve_placement(c, p);
+			}
+
+			// FIXME: this stuff would be better elsewhere but we are already iteraring through all
+			//        elements so here it fits really well
+			ctx.update_hover_and_focus(c);
+		}
+	}
+}

src/main.c3

@@ -1,238 +0,0 @@
-import std::io;
-import vtree;
-import cache;
-import ugui;
-import rl;
-import std::time;
-import std::collections::ringbuffer;
-
-def Times = ringbuffer::RingBuffer(<time::NanoDuration, 128>);
-
-fn void Times.print_stats(&times)
-{
-	time::NanoDuration min, max, avg, x;
-	min = times.get(0);
-	for (usz i = 0; i < times.written; i++) {
-		x = times.get(i);
-		if (x < min) { min = x; }
-		if (x > max) { max = x; }
-		avg += x;
-	}
-	avg = (NanoDuration)((ulong)avg/128.0);
-
-	io::printfn("min=%s, max=%s, avg=%s", min, max, avg);
-}
-
-fn int main(String[] args)
-{
-	ugui::Ctx ui;
-	ui.init()!!;
-	ui.font.load("/usr/share/fonts/TTF/HackNerdFontMono-Regular.ttf", 16)!!;
-
-	short width = 800;
-	short height = 450;
-	rl::set_config_flags(rl::FLAG_WINDOW_RESIZABLE);
-	rl::init_window(width, height, "Ugui Test");
-	ui.input_window_size(width, height)!!;
-	rl::set_target_fps(60);
-	rl::enable_event_waiting();
-
-	isz frame;
-	bool toggle = true;
-	time::Clock clock;
-	Times ui_times;
-	Times draw_times;
-
-	// Main loop
-	while (!rl::window_should_close()) {
-		clock.mark();
-
-		/* Start Input Handling */
-		if (rl::is_window_resized()) {
-			width  = (short)rl::get_screen_width();
-			height = (short)rl::get_screen_height();
-			ui.input_window_size(width, height)!!;
-		}
-
-		ui.input_changefocus(rl::is_window_focused());
-
-		rl::Vector2 mpos = rl::get_mouse_position();
-		ui.input_mouse_abs((short)mpos.x, (short)mpos.y);
-
-		ugui::MouseButtons buttons;
-		buttons.btn_left = rl::is_mouse_button_down(rl::MOUSE_BUTTON_LEFT);
-		buttons.btn_right = rl::is_mouse_button_down(rl::MOUSE_BUTTON_RIGHT);
-		buttons.btn_middle = rl::is_mouse_button_down(rl::MOUSE_BUTTON_MIDDLE);
-		ui.input_mouse_button(buttons);
-		/* End Input Handling */
-
-		/* Start UI Handling */
-		ui.frame_begin()!!;
-
-		// main div, fill the whole window
-		ui.div_begin("main", ugui::Rect{.w=ui.width/2})!!;
-		{|
-
-			ui.layout_set_row()!!;
-			if (ui.button("button0", ugui::Rect{0,0,30,30})!!.mouse_press) {
-				io::printn("press button0");
-				toggle = !toggle;
-				ui.force_update()!!;
-			}
-			//ui.layout_next_column()!!;
-			if (ui.button("button1", ugui::Rect{0,0,30,30})!!.mouse_press) {
-				io::printn("press button1");
-			}
-			//ui.layout_next_column()!!;
-			if (toggle) {
-				if (ui.button("button2", ugui::Rect{0,0,30,30})!!.mouse_release) {
-					io::printn("release button2");
-				}
-			}
-			if (ui.slider_ver("slider", ugui::Rect{0,0,30,100})!!.update) {
-				ugui::Elem* e = ui.get_elem_by_label("slider")!!;
-				io::printfn("slider: %f", e.slider.value);
-			}
-
-			ui.text_unbounded("text1", "Ciao Mamma\nAbilità ⚡")!!;
-		|};
-		ui.div_end()!!;
-
-		ui.div_begin("second", ugui::DIV_FILL)!!;
-		ugui::Elem* de = ui.get_elem_by_label("second")!!;
-		de.div.scroll.can_y = true;
-		{|
-			ui.layout_set_column()!!;
-			if (ui.slider_ver("slider_other", ugui::Rect{0,0,30,100})!!.update) {
-				ugui::Elem* e = ui.get_elem_by_label("slider_other")!!;
-				io::printfn("other slider: %f", e.slider.value);
-			}
-			ui.button("button10", ugui::Rect{0,0,50,50})!!;
-			ui.button("button11", ugui::Rect{0,0,50,50})!!;
-			ui.button("button12", ugui::Rect{0,0,50,50})!!;
-			ui.button("button13", ugui::Rect{0,0,50,50})!!;
-			ui.button("button14", ugui::Rect{0,0,50,50})!!;
-			ui.button("button15", ugui::Rect{0,0,50,50})!!;
-			ui.button("button16", ugui::Rect{0,0,50,50})!!;
-			ui.button("button17", ugui::Rect{0,0,50,50})!!;
-		|};
-		ui.div_end()!!;
-
-		ui.frame_end()!!;
-		/* End UI Handling */
-		ui_times.push(clock.mark());
-		ui_times.print_stats();
-
-		/* Start UI Drawing */
-		rl::begin_drawing();
-		// ClearBackground(BLACK);
-
-		rl::Color c;
-		rl::Rectangle r;
-		static rl::Image font_atlas;
-		static rl::Texture2D font_texture;
-		for (Cmd* cmd; (cmd = ui.cmd_queue.dequeue() ?? null) != null;) {
-			switch (cmd.type) {
-			case ugui::CmdType.CMD_RECT:
-				c = rl::Color{
-				    .r = cmd.rect.color.r,
-				    .g = cmd.rect.color.g,
-				    .b = cmd.rect.color.b,
-				    .a = cmd.rect.color.a,
-				};
-				r = rl::Rectangle{
-					.x = cmd.rect.rect.x,
-					.y = cmd.rect.rect.y,
-					.height = cmd.rect.rect.h,
-					.width = cmd.rect.rect.w,
-				};
-			    float rad = cmd.rect.radius;
-				// for some weird-ass reason the straight forward inverse formula does not work
-			    float roundness = r.width > r.height ? (2.1*rad)/r.height : (2.1*rad)/r.width;
-				rl::draw_rectangle_rounded(r, roundness, 0, c);
-			case ugui::CmdType.CMD_UPDATE_ATLAS:
-				rl::unload_image(font_atlas);
-				font_atlas.data = cmd.update_atlas.raw_buffer;
-				font_atlas.width = cmd.update_atlas.width;
-				font_atlas.height = cmd.update_atlas.height;
-				font_atlas.mipmaps = 1;
-				//font_atlas.format = rl::PixelFormat.PIXELFORMAT_UNCOMPRESSED_GRAYSCALE;
-				font_atlas.format = 1;
-				if (rl::is_texture_ready(font_texture)) {
-					rl::unload_texture(font_texture);
-				}
-				font_texture = rl::load_texture_from_image(font_atlas);
-				//rl::draw_texture(font_texture, 0, 0, rl::WHITE);
-			case ugui::CmdType.CMD_SPRITE:
-				rl::Rectangle source = {
-					.x = cmd.sprite.texture_rect.x,
-					.y = cmd.sprite.texture_rect.y,
-					.width = cmd.sprite.texture_rect.w,
-					.height = cmd.sprite.texture_rect.h,
-				};
-				rl::Vector2 position = {
-					.x = cmd.sprite.rect.x,
-					.y = cmd.sprite.rect.y,
-				};
-
-				rl::draw_texture_rec(font_texture, source, position, rl::WHITE);
-				//rl::draw_rectangle(cmd.sprite.rect.x,
-				//    cmd.sprite.rect.y,
-				//    cmd.sprite.rect.w,
-				//    cmd.sprite.rect.h,
-				//    rl::WHITE
-				//);
-			default:
-				io::printfn("Unknown cmd type: %s", cmd.type);
-			}
-		}
-		draw_times.push(clock.mark());
-		draw_times.print_stats();
-		rl::end_drawing();
-		/* End Drawing */
-
-	}
-
-	rl::close_window();
-
-	ui.font.free();
-	ui.free();
-	return 0;
-}
-
-/*
-fn void! test_vtree() @test
-{
-	vtree::VTree(<String>) vt;
-	vt.init(10)!!;
-	defer vt.free();
-
-	assert(vt.size() == 10, "Size is incorrect");
-
-	isz ref = vt.add("Ciao Mamma", 0)!!;
-	String s = vt.get(ref)!!;
-	assert(s == "Ciao Mamma", "String is incorrect");
-	isz par = vt.parentof(0)!!;
-	assert(ref == par, "Not Root");
-
-	vt.print();
-}
-
-def StrCache = cache::Cache(<int, String, 256>);
-fn void! test_cache() @test
-{
-	StrCache cc;
-	cc.init()!!;
-	defer cc.free();
-
-	String*! r = cc.search(1);
-	if (catch ex = r) {
-		if (ex != SearchResult.MISSING) {
-			return ex?;
-		}
-	}
-
-	r = cc.get_or_insert(&&"Ciao Mamma", 1)!;
-	assert(*r!! == "Ciao Mamma", "incorrect string");
-}
-*/

src/mtree.c3

@@ -0,0 +1,367 @@
+module mtree{Type};
+
+/* ================================================================================================
+ * MTree, Bitmap-based tree
+ * ================================================================================================
+ *
+ *  Overview
+ *  --------
+ *  The MTree is a bitmap-based tree structure composed of three core elements:
+ *    - Element Vector: Stores user data.
+ *    - Reference Node Vector: Manages node relationships.
+ *    - Bitmap: Marks used indices.
+ *
+ *  The name "MTree" originates from "Matrix Tree," where the vector is divided into
+ *  sectors of power-of-two sizes. Each node's bitmap marks the positions of its
+ *  children within the same sector.
+ *
+ *  If a parent and its children are in different sectors, a new node is created.
+ *  The parent's "next" field points to this new node, forming a chain that must
+ *  be traversed during iteration.
+ *
+ *
+ *  Example (sector size = 8)
+ *  -------------------------
+ *
+ *             _________________________________
+ *            |__ __ _______________________    |
+ *            |  |  |                       | _ |
+ *            |  v  v                       vv |v
+ *           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+ *  refs_vec:| 0| 1| 2| 3| 4| 5| 6| 7| 8| 9|10|11|12|13|14|15|16|...
+ *           +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+ *            \__________ __________/ \__________ __________/ \__
+ *                       V                       V
+ *                    sector 0                sector 1
+ *
+ *
+ *  Node Relationships:
+ *  -------------------
+ *    - Root (Element 0) has three direct children: 1, 2, and 10.
+ *    - Node 10 is in a different sector than the root, so root.next points to Node 11.
+ *    - Node 11 has Node 10 as a direct child and Node 0 (root) as its parent.
+ *
+ *  Bitmap Representation:
+ *  ---------------------
+ *
+ *       root = {
+ *         .parent = -1;           // Root has no parent
+ *         .next    = 11;          // Points to Node 11
+ *         .children = 0b00000110; // [0|1|1|0|0|0|0|0] (Children: 1, 2)
+ *       }
+ *
+ *       node11 = {
+ *         .parent   = 0;          // Parent is root (Node 0)
+ *         .next     = -1;         // Last in the chain
+ *         .children = 0b00000100; // [0|0|1|0|0|0|0|0] (Child: 10)
+ *       }
+ *
+ * ================================================================================================
+ */
+
+import std::core::mem;
+import std::core::mem::allocator;
+import std::io;
+import std::bits;
+import std::collections::list;
+
+
+alias Bitmap = ulong;
+const BITS = Bitmap.sizeof*8;
+
+alias IdxList = List{int};
+
+// next: if positive it contains the index of the next node that contains the children information
+struct RefNode {
+	int next;
+	int parent;
+	Bitmap children;
+}
+
+struct MTree {
+	usz elements;
+	Allocator allocator;
+	IdxList  queue;
+	Bitmap[]  used;
+	Type[]    elem_vec; // element vector
+	RefNode[] refs_vec; // relationship vector
+}
+
+
+<* @param [&inout] tree *>
+fn void MTree.init(&tree, usz size, Allocator allocator = mem)
+{
+	// round size to the nearest multiple of BITS
+	size = size + size%BITS;
+
+	tree.elements = 0;
+	tree.allocator = allocator;
+	tree.queue.init(tree.allocator, size);
+	tree.used     = allocator::new_array(tree.allocator, Bitmap, size/BITS);
+	tree.elem_vec = allocator::new_array(tree.allocator, Type, size);
+	tree.refs_vec = allocator::new_array(tree.allocator, RefNode, size);
+
+	foreach (&r: tree.refs_vec) {
+		r.next = -1;
+	}
+}
+
+
+<* @param [&inout] tree *>
+fn void MTree.free(&tree)
+{
+	tree.elements = 0;
+	tree.queue.free();
+	(void)allocator::free(tree.allocator, tree.used);
+	(void)allocator::free(tree.allocator, tree.elem_vec);
+	(void)allocator::free(tree.allocator, tree.refs_vec);
+}
+
+
+<* @param [&inout] tree *>
+fn int? MTree.get_free_spot(&tree)
+{
+	foreach (idx, d: tree.used) {
+		if (d != $typeof(d).max) {
+			int spot = (int)idx*BITS + BITS-(int)d.clz();
+			return spot;
+		}
+	}
+	return CAPACITY_EXCEEDED?;
+}
+
+<* @require idx >= 0 *>
+macro void MTree.set_used(&tree, int idx)
+{
+	int r = idx % BITS;
+	int q = idx / BITS;
+	tree.used[q] |= (1l << r);
+}
+
+<* @require idx >= 0 *>
+macro void MTree.unset_used(&tree, int idx)
+{
+	int r = idx % BITS;
+	int q = idx / BITS;
+	tree.used[q] &= ~(1l << r);
+}
+
+<* @require idx >= 0 *>
+macro bool MTree.is_used(&tree, int idx)
+{
+	int r = idx % BITS;
+	int q = idx / BITS;
+	return !!(tree.used[q] & (1l << r));
+}
+
+
+// get the last node in the "next" chain
+<* @require tree.is_used(parent) == true *>
+fn int MTree.last_node(&tree, int parent)
+{
+	while(tree.refs_vec[parent].next >= 0) {
+		parent = tree.refs_vec[parent].next;
+	}
+	return parent;
+}
+
+
+<*
+@require tree.elements == 0 || tree.is_used(parent) == true
+@param [&inout] tree
+*>
+fn int? MTree.add(&tree, int parent, Type t)
+{
+	int idx = tree.get_free_spot()!;
+	int subtree = idx / BITS;
+
+	tree.set_used(idx);
+	tree.elem_vec[idx] = t;
+	tree.refs_vec[idx] = (RefNode){
+		.parent = parent,
+		.next = -1,
+	};
+
+	tree.elements++;
+	// root element, has no parent
+	if (tree.elements == 1) {
+		tree.refs_vec[idx].parent = -1;
+		return idx;
+	}
+
+
+	// if the parent already has a node in the same subtree as the child then update that node's
+	// children bitmap
+	bool done;
+	for (int p = parent; p >= 0; p = tree.refs_vec[p].next) {
+		int ps = p/BITS;
+		if (ps == subtree) {
+			tree.refs_vec[p].children |= (1l << (idx%BITS));
+			done = true;
+			break;
+		}
+	}
+	// on fail we need to create another parent node
+	if (!done) {
+		int new_next = tree.get_free_spot()!;
+		// if the new node does not land in the same subtree as the child we cannot do
+		// anything since the references are immutable
+		if (new_next/BITS != subtree) {
+			return CAPACITY_EXCEEDED?;
+		}
+		tree.set_used(new_next);
+		tree.elements++;
+		// update the "next" chain
+		int last_link = tree.last_node(parent);
+		tree.refs_vec[last_link].next = new_next;
+		tree.refs_vec[new_next].next = -1;
+		tree.refs_vec[new_next].children |= (long)(1 << (idx%BITS));
+		tree.refs_vec[new_next].parent = last_link;
+		// FIXME: the elem_vec is not updated, do we need to?
+	}
+
+	return idx;
+}
+
+
+// get the index of the n-th children of parent, -1 otherwise
+// usage: for (int i, c; (c = tree.children_it(parent, i)) >= 0; i++) { ... }
+<* @param [&in] tree *>
+fn int MTree.children_it(&tree, int parent, int n)
+{
+	int tot_children;
+	int child;
+	for (int p = parent; p >= 0; p = tree.refs_vec[p].next) {
+		int cn = (int)tree.refs_vec[p].children.popcount();
+		tot_children += cn;
+
+		// we are in the right subtree
+		if (tot_children > n) {
+			child = (p/BITS) * BITS; // start at the parent's subtree index
+			int j = cn - (tot_children - n); // we need the j-th children of this node
+			Bitmap u = tree.refs_vec[p].children;
+
+			child += j; // add the children number
+			do {
+				child += (int)u.ctz(); // increment by the skipped zeroes
+				u >>= u.ctz() + 1;
+				j--;
+			} while (j >= 0);
+
+			return child;
+		}
+	}
+	return -1;
+}
+
+<* @param [&in] tree *>
+fn int MTree.children_num(&tree, int parent)
+{
+	int n;
+	for (int p = parent; p >= 0; p = tree.refs_vec[p].next) {
+		n += (int)tree.refs_vec[p].children.popcount();
+	}
+	return n;
+}
+
+<* @param [&in] tree *>
+fn int MTree.subtree_size(&tree, int parent)
+{
+	int x = tree.children_num(parent);
+	int c;
+	for (int n; (c = tree.children_it(parent, n)) >= 0; n++) {
+		x += tree.subtree_size(c);
+	}
+	return x;
+}
+
+<* @param [&inout] tree *>
+fn int MTree.level_order_it(&tree, int parent, int i)
+{
+	if (i == 0) {
+		tree.queue.clear();
+		tree.queue.push(parent);
+	}
+
+	if (tree.queue.len() == 0) return -1;
+
+	int p = tree.queue.pop_first()!!;
+	int c;
+	for (int n; (c = tree.children_it(p, n)) >= 0; n++) {
+		tree.queue.push(c);
+	}
+	return p;
+}
+
+<* @param [&inout] tree *>
+fn void MTree.prune(&tree, int parent)
+{
+	if (!tree.is_used(parent)) return;
+
+	int c;
+	for (int i = 0; (c = tree.children_it(parent, i)) >= 0; i++) {
+		tree.prune(c); // prune the subtree
+
+		// delete all children including their next chain
+		for (int p = c; p >= 0;) {
+			int next = tree.refs_vec[p].next;
+			tree.unset_used(p);
+			tree.refs_vec[p] = {.next = -1};
+			p = next;
+		}
+
+	}
+
+	// finally delete the parent
+	for (int p = parent; p >= 0;) {
+		int next = tree.refs_vec[p].next;
+		tree.unset_used(p);
+		tree.elements--;
+		tree.refs_vec[p] = {.next = -1};
+		p = next;
+	}
+
+}
+
+<*
+@require ref >= 0 , ref < tree.elem_vec.len
+@param [&inout] tree
+*>
+fn Type? MTree.get(&tree, int ref) @operator([])
+{
+	if (tree.is_used(ref)) return tree.elem_vec[ref];
+	return NOT_FOUND?;
+}
+
+<* @param [&in] tree *>
+fn Type? MTree.parentof(&tree, int ref)
+{
+	if (!tree.is_used(ref)) return NOT_FOUND?;
+	return tree.refs_vec[ref].parent;
+}
+
+<* @param [&inout] tree *>
+fn void MTree.nuke(&tree)
+{
+	foreach (idx, &b: tree.used) {
+		*b = 0;
+		tree.refs_vec[idx] = {.next = -1};
+	}
+	tree.elements = 0;
+}
+
+<* @param [&in] t *>
+macro bool MTree.is_root(&t, int i) => t.is_used(i) && t.refs_vec[i].parent == -1;
+
+<* @param [&in] tree *>
+fn void MTree.print(&tree)
+{
+	foreach (idx, c: tree.elem_vec) {
+		if (tree.is_used((int)idx)) {
+			io::printfn("[%d](%s) parent:%d next:%d children:%b",
+			             idx, c, tree.refs_vec[idx].parent, tree.refs_vec[idx].next,
+			             tree.refs_vec[idx].children
+			           );
+		}
+	}
+}

src/shapes.c3

@@ -0,0 +1,268 @@
+module ugui;
+
+
+// ---------------------------------------------------------------------------------- //
+//                                  RECTANGLE                                         //
+// ---------------------------------------------------------------------------------- //
+
+// Rect and it's methods
+struct Rect {
+	short x, y, w, h;
+}
+
+// TODO: find another name
+const Rect RECT_MAX = {0, 0, short.max, short.max};
+
+// return true if rect a contains b
+macro bool Rect.contains(Rect a, Rect b)
+{
+	return (a.x <= b.x && a.y <= b.y && a.x+a.w >= b.x+b.w && a.y+a.h >= b.y+b.h);
+}
+
+// returns the intersection of a and b
+macro Rect Rect.intersection(Rect a, Rect b)
+{
+	return {
+		.x = (short)max(a.x, b.x),
+		.y = (short)max(a.y, b.y),
+		.w = (short)min(a.x+a.w, b.x+b.w) - (short)max(a.x, b.x),
+		.h = (short)min(a.y+a.h, b.y+b.h) - (short)max(a.y, b.y),
+	};
+}
+
+// returns true if the intersection not null
+macro bool Rect.collides(Rect a, Rect b)
+{
+	return !(a.x > b.x+b.w || a.x+a.w < b.x || a.y > b.y+b.h || a.y+a.h < b.y);
+}
+
+// return a rect that contains both rects, a bounding box of both
+macro Rect containing_rect(Rect a, Rect b)
+{
+	short min_x = (short)min(a.x, b.x);
+	short min_y = (short)min(a.y, b.y);
+	short max_x = (short)max(a.x + a.w, b.x + b.w);
+	short max_y = (short)max(a.y + a.h, b.y + b.h);
+	return {
+		.x = min_x,
+		.y = min_y,
+		.w = (short)(max_x - min_x),
+		.h = (short)(max_y - min_y)
+	};
+}
+
+// check for empty rect
+macro bool Rect.is_null(Rect r) => r.x == 0 && r.y == 0 && r.x == 0 && r.w == 0;
+
+// returns the element-wise addition of r1 and r2
+macro Rect Rect.add(Rect r1, Rect r2) @operator_s(+)
+{
+	return {
+		.x = r1.x + r2.x,
+		.y = r1.y + r2.y,
+		.w = r1.w + r2.w,
+		.h = r1.h + r2.h,
+	};
+}
+
+// returns the element-wise subtraction of r1 and r2
+macro Rect Rect.sub(Rect r1, Rect r2) @operator_s(-)
+{
+	return {
+		.x = r1.x - r2.x,
+		.y = r1.y - r2.y,
+		.w = r1.w - r2.w,
+		.h = r1.h - r2.h,
+	};
+}
+
+// returns the element-wise multiplication of r1 and r2
+macro Rect Rect.mul(Rect r1, Rect r2) @operator_s(*)
+{
+	return {
+		.x = r1.x * r2.x,
+		.y = r1.y * r2.y,
+		.w = r1.w * r2.w,
+		.h = r1.h * r2.h,
+	};
+}
+
+macro Point Rect.position(Rect r)
+{
+	return {
+		.x = r.x,
+		.y = r.y,
+	};
+}
+
+macro Point Rect.size(Rect r)
+{
+	return {
+		.x = r.w,
+		.y = r.h,
+	};
+}
+
+macro Rect Rect.max(Rect a, Rect b)
+{
+	return {
+		.x = max(a.x, b.x),
+		.y = max(a.y, b.y),
+		.w = max(a.w, b.w),
+		.h = max(a.h, b.h),
+	};
+}
+
+macro Rect Rect.min(Rect a, Rect b)
+{
+	return {
+		.x = min(a.x, b.x),
+		.y = min(a.y, b.y),
+		.w = min(a.w, b.w),
+		.h = min(a.h, b.h),
+	};
+}
+
+// Offset a rect by a point
+macro Rect Rect.off(Rect r, Point p) @operator_s(+)
+{
+	return {
+		.x = r.x + p.x,
+		.y = r.y + p.y,
+		.w = r.w,
+		.h = r.h,
+	};
+}
+
+// Resize a rect width and height
+macro Rect Rect.grow(Rect r, Point p)
+{
+	return {
+		.x = r.x,
+		.y = r.y,
+		.w = r.w + p.x,
+		.h = r.h + p.y,
+	};
+}
+
+// Return the bottom-right corner of a rectangle
+macro Point Rect.bottom_right(Rect r)
+{
+	return {
+		.x = r.x + r.w,
+		.y = r.y + r.h,
+	};
+}
+
+macro Rect Rect.center_to(Rect a, Rect b)
+{
+	return {
+		.x = b.x + (b.w - a.w)/2,
+		.y = b.y + (b.h - a.h)/2,
+		.w = a.w,
+		.h = a.h,
+	};
+}
+
+macro Rect Rect.pad(Rect a, Rect b)
+{
+	return {
+		.x = a.x + b.x,
+		.y = a.y + b.y,
+		.w = a.w - b.x - b.w,
+		.h = a.h - b.y - b.h,
+	};
+}
+
+macro Rect Rect.expand(Rect a, Rect b)
+{
+	return {
+		.x = a.x - b.x,
+		.y = a.y - b.y,
+		.w = a.w + b.x + b.w,
+		.h = a.h + b.y + b.h,
+	};
+}
+
+// ---------------------------------------------------------------------------------- //
+//                                    POINT                                           //
+// ---------------------------------------------------------------------------------- //
+
+struct Point {
+	short x, y;
+}
+
+// returns true if a point is inside the rectangle
+macro bool Point.in_rect(Point p, Rect r)
+{
+	return (p.x >= r.x && p.x <= r.x + r.w) && (p.y >= r.y && p.y <= r.y + r.h);
+}
+
+macro bool Point.outside(Point p, Rect r) => !p.in_rect(r);
+
+macro Point Point.add(Point a, Point b) @operator_s(+) => {.x = a.x+b.x, .y = a.y+b.y};
+macro Point Point.sub(Point a, Point b) @operator_s(-) => {.x = a.x-b.x, .y = a.y-b.y};
+macro Point Point.neg(Point p) @operator_s(-) => {-p.x, -p.y};
+
+macro Point Point.max(Point a, Point b) => {.x = max(a.x, b.x), .y = max(a.y, b.y)};
+macro Point Point.min(Point a, Point b) => {.x = min(a.x, b.x), .y = min(a.y, b.y)};
+
+macro bool Point.equals(Point a, Point b) @operator_s(==) => a.x == b.x && a.y == b.y;
+
+// ---------------------------------------------------------------------------------- //
+//                                    COLOR                                           //
+// ---------------------------------------------------------------------------------- //
+
+struct Color{
+	char r, g, b, a;
+}
+
+macro Color uint.to_rgba(u)
+{
+	return {
+		.r = (char)((u >> 24) & 0xff),
+		.g = (char)((u >> 16) & 0xff),
+		.b = (char)((u >> 8) & 0xff),
+		.a = (char)((u >> 0) & 0xff)
+	};
+}
+
+
+macro Color uint.@to_rgba($u)
+{
+	return {
+		.r = (char)(($u >> 24) & 0xff),
+		.g = (char)(($u >> 16) & 0xff),
+		.b = (char)(($u >> 8) & 0xff),
+		.a = (char)(($u >> 0) & 0xff)
+	};
+}
+
+macro uint Color.to_uint(c) => c.r | (c.g << 8) | (c.b << 16) | (c.a << 24);
+
+// ---------------------------------------------------------------------------------- //
+//                                    SIZE                                            //
+// ---------------------------------------------------------------------------------- //
+
+macro short short.add_no_of(short a, short b) => (short)max(min((int)a + (int)b, short.max), short.min) @inline;
+
+struct Size {
+	short min, max;
+}
+
+macro Size @grow() => {.min = 0, .max = 0};
+macro Size @exact(short s) => {.min = s, .max = s};
+macro Size @fit(short min = 0, short max = short.max) => {.min = min, .max = max};
+
+macro bool Size.@is_grow(s) => (s.min == 0 && s.max == 0);
+macro bool Size.@is_exact(s) => (s.min == s.max && s.min != 0);
+macro bool Size.@is_fit(s) => (s.min != s.max);
+
+macro Size Size.add(a, Size b) @operator_s(+) => {.min = a.min.add_no_of(b.min), .max = a.max.add_no_of(b.max)};
+macro Size Size.sub(a, Size b) @operator_s(-) => {.min = a.min.add_no_of(-b.min), .max = a.max.add_no_of(-b.max)};
+
+macro Size Size.combine(a, Size b) => {.min = max(a.min, b.min), .max = min(a.max, b.max)};
+macro Size Size.comb_max(a, Size b) => {.min = max(a.min, b.min), .max = max(a.max, b.max)};
+macro Size Size.comb_min(a, Size b) => {.min = min(a.min, b.min), .max = min(a.max, b.max)};
+
+macro short Size.greater(a) => a.min > a.max ? a.min : a.max;

src/sprite.c3

@@ -0,0 +1,107 @@
+module ugui;
+
+import std::core::mem::allocator;
+import std::collections::map;
+import std::io;
+import std::compression::qoi;
+
+const usz SRITES_PER_ATLAS = 64;
+
+enum SpriteType {
+	SPRITE_NORMAL,
+	SPRITE_SDF,
+	SPRITE_MSDF,
+	SPRITE_ANIMATED,
+}
+
+struct Sprite {
+	Id id;
+	SpriteType type;
+	ushort u, v;
+	ushort w, h;
+}
+
+alias SpriteMap = map::HashMap{Id, Sprite};
+
+struct SpriteAtlas {
+	Id id;
+	Atlas atlas;
+	SpriteMap sprites;
+	bool should_update;
+}
+
+// name: some examples are "icons" or "images"
+fn void? SpriteAtlas.init(&this, String name, AtlasType type, ushort width, ushort height)
+{
+	// FIXME: for now only R8G8B8A8 format is supported
+	if (type != ATLAS_R8G8B8A8) {
+		return INVALID_TYPE?;
+	}
+
+	this.id = name.hash();
+	this.atlas.new(this.id, AtlasType.ATLAS_R8G8B8A8, width, height)!;
+	this.sprites.init(allocator::mem, capacity: SRITES_PER_ATLAS);
+	this.should_update = false;
+}
+
+fn void? SpriteAtlas.free(&this)
+{
+	this.atlas.free();
+	this.sprites.free();
+}
+
+// FIXME: this should throw an error when a different pixel format than the atlas' is used
+//        or convert from the source's pixel format to the atlas'
+fn Sprite*? SpriteAtlas.insert(&this, String name, SpriteType type, char[] pixels, ushort w, ushort h, ushort stride)
+{
+	Sprite s;
+	s.id = name.hash();
+	s.type = type;
+	Point uv = this.atlas.place(pixels, w, h, stride)!;
+	s.w = w;
+	s.h = h;
+	s.u = uv.x;
+	s.v = uv.y;
+	this.sprites.set(s.id, s);
+	this.should_update = true;
+	return this.sprites.get_ref(s.id);
+}
+
+fn Sprite*? SpriteAtlas.get(&this, String name)
+{
+	Id id = name.hash();
+	return this.sprites.get_ref(id);
+}
+
+fn Sprite*? SpriteAtlas.get_by_id(&this, Id id)
+{
+	return this.sprites.get_ref(id);
+}
+
+macro Rect Sprite.rect(s) => {0,0,s.w,s.h};
+macro Rect Sprite.uv(s) => {s.u,s.v,s.w,s.h};
+
+fn void? Ctx.sprite_atlas_create(&ctx, String name, AtlasType type, ushort w, ushort h)
+{
+	ctx.sprite_atlas.init(name, type, w, h)!;
+}
+
+fn Id Ctx.get_sprite_atlas_id(&ctx, String name)
+{
+	return name.hash();
+}
+
+fn void? Ctx.import_sprite_memory(&ctx, String name, char[] pixels, ushort w, ushort h, ushort stride, SpriteType type = SPRITE_NORMAL)
+{
+	ctx.sprite_atlas.insert(name, type, pixels, w, h, stride)!;
+}
+
+fn void? Ctx.import_sprite_file_qoi(&ctx, String name, String path, SpriteType type = SPRITE_NORMAL)
+{
+	QOIDesc desc;
+
+	char[] pixels = qoi::read(allocator::mem, path, &desc, QOIChannels.RGBA)!;
+	defer mem::free(pixels);
+
+	ctx.sprite_atlas.insert(name, type, pixels, (ushort)desc.width, (ushort)desc.height, (ushort)desc.width)!;
+}

src/string.c3

@@ -0,0 +1,588 @@
+module ugui;
+
+import std::collections::list;
+import std::core::string;
+
+struct LineInfo @local {
+	usz start, end;
+	short width, height;
+	short first_off; // first character offset
+}
+
+macro usz LineInfo.len(li) => li.end-li.start;
+
+alias LineStack @local = list::List{LineInfo};
+
+fn short Rect.y_off(Rect bounds, short height, Anchor anchor) @local
+{
+	short off;
+
+	switch (anchor) {
+	case TOP_LEFT: nextcase;
+	case TOP: nextcase;
+	case TOP_RIGHT:
+		off = 0;
+	case LEFT: nextcase;
+	case CENTER: nextcase;
+	case RIGHT:
+		off = (short)(bounds.h - height)/2;
+	case BOTTOM_LEFT: nextcase;
+	case BOTTOM: nextcase;
+	case BOTTOM_RIGHT:
+		off = (short)(bounds.h - height);
+	}
+	return off;
+}
+
+fn short Rect.x_off(Rect bounds, short width, Anchor anchor) @local
+{
+	short off;
+
+	switch (anchor) {
+	case TOP_LEFT: nextcase;
+	case LEFT: nextcase;
+	case BOTTOM_LEFT:
+		off = 0;
+	case TOP: nextcase;
+	case CENTER: nextcase;
+	case BOTTOM:
+		off = (short)(bounds.w - width)/2;
+	case TOP_RIGHT: nextcase;
+	case RIGHT: nextcase;
+	case BOTTOM_RIGHT:
+		off = (short)(bounds.w - width);
+	}
+	
+	return off;
+}
+
+
+// ---------------------------------------------------------------------------------- //
+//                                STRING LAYOUT                                       //
+// ---------------------------------------------------------------------------------- //
+
+
+struct GlyphIterator {
+	short baseline;
+	short line_height;
+	short line_gap;
+	short space_width;
+	short tab_width;
+	Rect bounds;
+	Anchor anchor;
+	bool reflow;
+	Font* font;
+
+	LineStack lines;
+	usz line_off, line_idx;
+	String text;
+
+	Codepoint cp;
+	Glyph* gp;
+	short adv; // prev advance
+	Point o;
+	Rect str_bounds;
+}
+
+<*
+@param [&inout] self
+@param [in] text
+@param [&inout] font
+*>
+fn void? GlyphIterator.init(&self, Allocator allocator, String text, Rect bounds, Font* font, Anchor anchor, bool reflow, uint tab_size)
+{
+	self.font = font;
+
+	self.line_height = (short)font.line_height();
+	self.baseline = (short)font.ascender;
+	self.line_gap = (short)font.linegap;
+	self.space_width = font.get_glyph(' ').adv!;
+	self.tab_width = self.space_width * (short)tab_size;
+
+	self.bounds = bounds;
+	self.o = bounds.position();
+	self.reflow = reflow;
+	self.text = text;
+	self.anchor = anchor;
+
+	// if the anchor is top_left we can skip dividing the string line by line, in GlyphIterator.next
+	// this has to be accounted for
+	if (anchor != TOP_LEFT) {
+		self.lines.init(allocator, 4);
+		self.populate_lines_stack()!;
+		self.line_off = 0;
+		self.line_idx = 0;
+	
+		if (self.lines.len() > 0) {
+			self.o.y += bounds.y_off(self.str_bounds.h, anchor);
+			self.o.x += bounds.x_off(self.lines[0].width, anchor) - self.lines[0].first_off;
+		}
+	}
+}
+
+
+fn void? GlyphIterator.populate_lines_stack(&self)
+{
+	usz line_start;
+	LineInfo li;
+	Point o = self.o;
+	StringIterator ti = self.text.iterator();
+
+	usz prev_off;
+	for (Codepoint cp; ti.has_next();) {
+		cp = ti.next()!;
+		usz off = ti.current;
+		bool push = false;
+
+		li.height = self.line_height;
+		switch {
+		case cp == '\n':
+			push = true;
+		case cp == '\t':
+			o.x += self.tab_width;
+		case ascii::is_cntrl((char)cp):
+			break;
+		default:
+			Glyph* gp = self.font.get_glyph(cp)!;
+
+			if (off == line_start) {
+				li.first_off = gp.ox;
+				o.x -= gp.ox;
+			}
+
+			Rect b = gp.bounds().off(o);
+			b.y += self.baseline;
+			
+			if (self.reflow && b.x + b.w > self.bounds.x + self.bounds.w) {
+				push = true;
+				// roll back this character since it is on the next line
+				ti.current = prev_off;
+				off = prev_off;
+			} else {
+				o.x += gp.adv;
+				li.width += gp.adv;
+			}
+		}
+		
+		if (push) {
+			li.start = line_start;
+			li.end = off;
+			self.lines.push(li);
+			self.str_bounds.w = max(self.str_bounds.w, li.width);
+			self.str_bounds.h += li.height;
+
+			o.x = self.bounds.x;
+			o.y += self.line_height;
+			line_start = off;
+
+			li.height = 0;
+			li.width = 0;
+		}
+		
+		prev_off = off;
+	}
+	if (line_start != ti.current) {
+		// FIXME: crap, can we not repeat this code?
+		li.start = line_start;
+		li.end = ti.current;
+		self.lines.push(li);
+		self.str_bounds.w = max(self.str_bounds.w, li.width);
+		self.str_bounds.h += li.height;
+	}
+	
+	self.str_bounds.h += (short)(self.lines.len()-1) * self.line_gap;
+}
+
+fn String GlyphIterator.current_line(&self)
+{
+	LineInfo li = self.lines[self.line_idx];
+	return self.text[li.start:li.len()];
+}
+
+
+fn Rect? GlyphIterator.next(&self)
+{
+	// check if there is a next glyph and maybe update the line and offset indices
+	if (self.anchor != TOP_LEFT) {
+		if (self.line_idx >= self.lines.len()) {
+			return NO_MORE_ELEMENT?;
+		}
+	
+		LineInfo li = self.lines[self.line_idx];
+		if (self.line_off >= li.len()) {
+			self.line_idx++;
+			
+			if (self.line_idx >= self.lines.len()) {
+				return NO_MORE_ELEMENT?;
+			}
+			
+			self.line_off = 0;
+			li = self.lines[self.line_idx];
+	
+			self.o.y += self.line_height + self.line_gap;
+			self.o.x = self.bounds.x + self.bounds.x_off(li.width, self.anchor) - li.first_off;
+		}
+	} else if (self.line_off >= self.text.len) {
+		return NO_MORE_ELEMENT?;
+	}
+
+	String t;
+	if (self.anchor != TOP_LEFT) {
+		t = self.current_line()[self.line_off..];
+	} else {
+		t = self.text[self.line_off..];
+	}
+	
+	usz read = t.len < 4 ? t.len : 4;
+	self.cp = conv::utf8_to_char32(&t[0], &read)!;
+	self.line_off += read;
+	self.gp = self.font.get_glyph(self.cp)!;
+	
+	Rect b = {.x = self.o.x, .y = self.o.y};
+
+	Point prev_o = self.o;
+	self.adv = 0;
+	switch {
+	case self.cp == '\n':
+		if (self.anchor == TOP_LEFT) {
+			self.o.x = self.bounds.x;
+			self.o.y += self.line_height + self.line_gap;
+			self.line_idx++;
+		}
+		break;
+	case self.cp == '\t':
+		self.o.x += self.tab_width;
+	case ascii::is_cntrl((char)self.cp):
+		break;
+	default:
+		b = self.gp.bounds().off(self.o);
+		b.y += self.baseline;
+		if (self.anchor == TOP_LEFT) {
+			//if (self.o.x == self.bounds.x) self.bounds.x -= self.gp.ox;
+			if (self.reflow && b.bottom_right().x > self.bounds.bottom_right().x) {
+				self.o.x = self.bounds.x - self.gp.ox;
+				self.o.y += self.line_height + self.line_gap;
+				self.line_idx++;
+				b = self.gp.bounds().off(self.o);
+				b.y += self.baseline;
+			}
+		}
+		self.o.x += self.gp.adv;
+		self.adv = self.o.x - prev_o.x;
+	}
+
+	return b;
+}
+
+fn bool GlyphIterator.has_next(&self)
+{
+	if (self.anchor == TOP_LEFT) {
+		return self.line_off < self.text.len;
+	}
+
+	if (self.line_idx >= self.lines.len()) {
+		return false;
+	}
+	
+	LineInfo li = self.lines[self.line_idx];
+	if (self.line_idx == self.lines.len() - 1 && self.line_off >= li.len()) {
+		return false;
+	}
+
+	return true;
+}
+
+fn usz GlyphIterator.current_offset(&self)
+{
+	if (self.anchor == TOP_LEFT) return self.line_off;
+	return self.lines[self.line_idx].start + self.line_off;
+}
+
+
+// layout a string inside a bounding box, following the given alignment (anchor).
+<*
+@param [&in] ctx
+@param [in] text
+*>
+fn void? Ctx.layout_string(&ctx, String text, Rect bounds, Anchor anchor, int z_index, Color hue, bool reflow = false)
+{
+	if (text == "") return;
+	if (bounds.w <= 0 || bounds.h <= 0) return;
+	ctx.push_scissor(bounds, z_index)!;
+
+	Font* font = &ctx.font;
+	Id texture_id = font.id;
+	
+	GlyphIterator gi;
+	gi.init(tmem, text, bounds, font, anchor, reflow, TAB_SIZE)!;
+	while (gi.has_next()) {
+		Rect b = gi.next()!;
+		Rect uv = gi.gp.uv();
+		ctx.push_sprite(b, uv, texture_id, z_index, hue)!;
+	}
+
+	ctx.reset_scissor(z_index)!;
+//	ctx.dbg_rect(str_bounds.off(bounds.position()));
+}
+
+
+// ---------------------------------------------------------------------------------- //
+//                              CURSOR AND MOUSE                                      //
+// ---------------------------------------------------------------------------------- //
+
+
+fn Rect? Ctx.get_cursor_position(&ctx, String text, Rect bounds, Anchor anchor, usz cursor, bool reflow = false)
+{
+	if (bounds.w <= 0 || bounds.h <= 0) return {};
+
+	Font* font = &ctx.font;
+	Id texture_id = font.id;
+	
+	if (text == "") text = "\f";
+
+	GlyphIterator gi;
+	gi.init(tmem, text, bounds, font, anchor, reflow, TAB_SIZE)!;
+	Rect cursor_rect;
+	cursor_rect.x = gi.o.x;
+	cursor_rect.y = gi.o.y;
+	cursor_rect.h = (short)font.line_height();
+	if (cursor == 0) return cursor_rect;
+
+	while (gi.has_next()) {
+		Rect b = gi.next()!;
+		if (gi.current_offset() == cursor) {
+			if (gi.cp == '\n') {
+				if (!gi.has_next()) {
+					cursor_rect.x = bounds.x + bounds.x_off(0, anchor);
+					cursor_rect.y = b.y + gi.line_height + gi.line_gap;
+				} else {
+					gi.next()!;
+					cursor_rect.x = gi.o.x - gi.gp.adv;
+					cursor_rect.y = gi.o.y;
+				}
+			} else {
+				// Use the updated origin position instead of glyph bounds
+				cursor_rect.x = gi.o.x;
+				cursor_rect.y = gi.o.y;
+			}
+			return cursor_rect;
+		}
+	}
+
+	return {};
+}
+
+<*
+@param [&in] ctx
+@param [in] text
+*>
+fn usz? Ctx.hit_test_string(&ctx, String text, Rect bounds, Anchor anchor, Point p, bool reflow = false)
+{
+	if (text == "") return 0;
+	if (bounds.w <= 0 || bounds.h <= 0) return 0;
+
+	Font* font = &ctx.font;
+	
+	GlyphIterator gi;
+	gi.init(tmem, text, bounds, font, anchor, reflow, TAB_SIZE)!;
+	
+	usz prev_offset = 0;
+	Point prev_o = gi.o;
+	
+	while (gi.has_next()) {
+		Point o_before = gi.o;
+		usz offset_before = gi.current_offset();
+		Rect b = gi.next()!;
+		
+		switch {
+		case gi.cp == '\n':
+			// Check if point is on this line before the newline
+			Rect line_rect = {
+				.x = prev_o.x,
+				.y = prev_o.y,
+				.w = (short)(o_before.x - prev_o.x),
+				.h = gi.line_height
+			};
+			if (p.in_rect(line_rect)) return offset_before;
+			prev_o = gi.o;
+			break;
+		case gi.cp == '\t':
+			// Check if point is in the tab space
+			Rect tab_rect = {
+				.x = o_before.x,
+				.y = o_before.y,
+				.w = gi.tab_width,
+				.h = gi.line_height
+			};
+			if (p.in_rect(tab_rect)) return offset_before;
+			break;
+		case ascii::is_cntrl((char)gi.cp):
+			break;
+		default:
+			// Create a hit test rect for this character
+			Rect hit_rect = {
+				.x = o_before.x,
+				.y = o_before.y,
+				.w = gi.gp.adv,
+				.h = gi.line_height
+			};
+
+			if (p.in_rect(hit_rect)) {
+				// Check if cursor should be before or after this character
+				// by checking which half of the character was clicked
+				short mid_x = o_before.x + gi.gp.adv / 2;
+				if (p.x < mid_x) {
+					return offset_before;
+				} else {
+					return gi.current_offset();
+				}
+			}
+		}
+		
+		prev_offset = gi.current_offset();
+	}
+	
+	// Point is after all text
+	return text.len;
+}
+
+// TODO: implement a function `layout_string_with_selection` to avoid iterating over the string twice
+fn void? Ctx.draw_string_selection(&ctx, String text, Rect bounds, Anchor anchor, usz start, usz end, int z_index, Color hue, bool reflow = false)
+{
+	if (text == "") return;
+	if (bounds.w <= 0 || bounds.h <= 0) return;
+
+	if (start > end) @swap(start, end);
+
+	// Ensure start < end
+	if (start > end) {
+		usz temp = start;
+		start = end;
+		end = temp;
+	}
+	
+	ctx.push_scissor(bounds, z_index)!;
+
+	Font* font = &ctx.font;
+	
+	GlyphIterator gi;
+	gi.init(tmem, text, bounds, font, anchor, reflow, TAB_SIZE)!;
+
+	Rect sel_rect = { .h = gi.line_height }; // selection rect
+	isz sel_line = -1; // selection line
+	while (gi.has_next()) {
+		Rect b = gi.next()!;
+		usz off = gi.current_offset()-1;
+		isz line = gi.line_idx;
+		bool in_selection = start <= off && off <= end;
+
+		if  (in_selection && line != sel_line) {
+			if (sel_line != -1) {
+				ctx.push_rect(sel_rect, z_index, &&{.bg = hue})!;
+			}
+			sel_rect = {.x = gi.o.x - gi.adv, .y = gi.o.y, .w = 0, .h = gi.line_height};
+			sel_line = line;
+		}
+		if (in_selection) {
+			sel_rect.w = gi.o.x - sel_rect.x;
+			if (gi.cp == '\n') sel_rect.w += gi.space_width;
+		}
+		
+		if (off > end) break;
+	}
+	ctx.push_rect(sel_rect, z_index, &&{.bg = hue})!;
+	
+	ctx.reset_scissor(z_index)!;
+}
+
+
+// ---------------------------------------------------------------------------------- //
+//                              TEXT MEASUREMENT                                      //
+// ---------------------------------------------------------------------------------- //
+
+
+const uint TAB_SIZE = 4;
+
+struct TextSize {
+	Size width, height;
+	int area;
+}
+
+// Measeure the size of a string.
+// width.min: as if each word is broken up by a new line
+// width.max: the width of the string left as-is
+// height.min: the height of the string left as-is
+// height.max: the height of the string with each word broken up by a new line
+<*
+@param [&in] ctx
+@param [in] text
+*>
+fn TextSize? Ctx.measure_string(&ctx, String text)
+{
+	if (text == "") return (TextSize){};
+
+	Font* font = &ctx.font;
+	short baseline = (short)font.ascender;
+	short line_height = (short)font.line_height();
+	short line_gap = (short)font.linegap;
+	short space_width = font.get_glyph(' ').adv!;
+	short tab_width = space_width * TAB_SIZE;
+
+	isz off;
+	usz x;
+
+	TextSize ts;
+
+	short word_width;
+	short words = 1;
+	Rect bounds; // unaltered text bounds;
+	Point origin;
+
+	StringIterator it = text.iterator();
+	for (Codepoint cp; it.has_next();) {
+		cp = it.next()!;
+		Glyph* gp = font.get_glyph(cp)!;
+
+		// update the text bounds
+		switch {
+		case cp == '\n':
+			origin.x = 0;
+			origin.y += line_height + line_gap;
+		case cp == '\t':
+			origin.x += tab_width;
+		case ascii::is_cntrl((char)cp):
+			break;
+		default:
+			Rect b = gp.bounds().off(origin);
+			b.y += baseline;
+			bounds = containing_rect(bounds, b);
+			origin.x += gp.adv;
+		}
+
+		// update the word width
+		switch {
+		case ascii::is_space((char)cp):
+			if (word_width > ts.width.min) ts.width.min = word_width;
+			word_width = 0;
+			words++;
+		default:
+			//word_width += gp.w + gp.ox;
+			if (off < text.len) {
+				word_width += gp.adv;
+			} else {
+				word_width += gp.w + gp.ox;
+			}
+		}
+	}
+	// end of string is also end of word
+	if (word_width > ts.width.min) ts.width.min = word_width;
+
+	ts.width.max = bounds.w;
+	ts.height.min = bounds.h;
+	ts.height.max = words * line_height + line_gap * (words-1);
+	ts.area = bounds.w * bounds.h;
+
+	return ts;
+}
+
+

src/style.c3

@@ -0,0 +1,461 @@
+module ugui;
+
+import std::collections::map;
+import std::core::mem::allocator;
+import std::io;
+
+// global style, similar to the css box model
+struct Style { // css box model
+	Rect  padding;
+	Rect  border;
+	Rect  margin;
+
+	Color bg;        // background color
+	Color fg;        // foreground color
+	Color primary;   // primary color
+	Color secondary; // secondary color
+	Color accent;    // accent color
+
+	ushort radius;
+	short  size;
+}
+
+const Style DEFAULT_STYLE = {
+	.margin  = {2, 2, 2, 2},
+	.border  = {2, 2, 2, 2},
+	.padding = {1, 1, 1, 1},
+	.radius  = 0,
+	.size    = 16,
+
+	.bg        = 0x282828ffu.@to_rgba(),
+	.fg        = 0xfbf1c7ffu.@to_rgba(),
+	.primary   = 0xcc241dffu.@to_rgba(),
+	.secondary = 0x458588ffu.@to_rgba(),
+	.accent    = 0xfabd2fffu.@to_rgba(),
+};
+
+// style is stored in a hashmap, each style has an Id that can be generated by a string or whatever
+alias StyleMap = map::HashMap{Id, Style};
+
+// push or update a new style into the map
+fn void StyleMap.register_style(&map, Style* style, Id id)
+{
+	if (style == null) return;
+	map.set(id, *style);
+}
+
+// get a style from the map, if the style is not found then use a default style.
+fn Style* StyleMap.get_style(&map, Id id)
+{
+	Style*? s = map.get_ref(id);
+	if (catch s) {
+//		io::eprintfn("WARNING: style %x not found, using default style", id);
+		return &DEFAULT_STYLE;
+	}
+	return s;
+}
+
+fn int StyleMap.import_style_string(&map, String text)
+{
+	Parser p;
+	p.lex.text = text;
+	int added;
+
+	while (p.parse_style() == true) {
+		added++;
+		// set the default style correctly
+		map.register_style(&p.style, p.style_id);
+		if (p.lex.peep_token().type == EOF) break;
+	}
+
+	return added;
+}
+
+fn int Ctx.import_style_from_string(&ctx, String text) => ctx.styles.import_style_string(text);
+fn int Ctx.import_style_from_file(&ctx, String path)
+{
+	char[] text;
+	usz size = file::get_size(path)!!;
+	text = mem::new_array(char, size);
+	file::load_buffer(path, text)!!;
+	defer mem::free(text);
+
+	int added = ctx.import_style_from_string((String)text);
+	return added;
+}
+
+
+/*
+ * Style can be serialized and deserialized with a subset of CSS
+ * <style name> {
+ *     padding: left right top bottom;
+ *     border: left right top bottom;
+ *     margin: left right top bottom;
+ *     radius: uint;
+ *     size: uint;
+ *     Color: #RRGGBBAA;
+ *     Color: #RRGGBBAA;
+ *     Color: #RRGGBBAA;
+ *     Color: #RRGGBBAA;
+ *     Color: #RRGGBBAA;
+ * }
+ * The field "style name" will be hashed and the hash used as the id int the style map.
+ * Fields may be excluded, each excluded field is set to zero.
+ * The default unit is pixels, but millimeters is also available. The parser function accepts a scale
+ * factor that has to be obtained with the window manager functions.
+*/
+// TODO: implement <style name> : <another style> to easily inherit all properties
+//       of a previously defined style
+
+module ugui::css;
+
+import std::ascii;
+import std::io;
+
+// CSS parser module
+
+enum TokenType {
+	INVALID,
+	IDENTIFIER,
+	RCURLY,
+	LCURLY,
+	SEMICOLON,
+	COLON,
+	NUMBER,
+	COLOR,
+	EOF,
+}
+
+enum Unit {
+	PIXELS,
+	MILLIMETERS
+}
+
+struct Token {
+	TokenType type;
+	usz line, col, off;
+	String text;
+	union {
+		struct {
+			float value;
+			Unit unit;
+		}
+		Color color;
+	}
+}
+
+fn short Token.to_px(&t, float mm_to_px)
+{
+	if (t.type != NUMBER) {
+		unreachable("WFT you cannot convert to pixels a non-number");
+	}
+	if (t.unit == PIXELS) return (short)(t.value);
+	return (short)(t.value * mm_to_px);
+}
+
+
+// ---------------------------------------------------------------------------------- //
+//                                    LEXER                                           //
+// ---------------------------------------------------------------------------------- //
+
+
+struct Lexer {
+	String text;
+	usz line, col, off;
+}
+
+macro char Lexer.peep(&lex) => lex.text[lex.off];
+
+fn char Lexer.advance(&lex)
+{
+	if (lex.off >= lex.text.len) return '\0';
+
+	char c = lex.text[lex.off];
+	if (c == '\n') {
+		lex.col = 0;
+		lex.line++;
+	} else {
+		lex.col++;
+	}
+	lex.off++;
+	return c;
+}
+
+fn Token Lexer.next_token(&lex)
+{
+	Token t;
+	t.type = INVALID;
+	t.off = lex.off;
+	t.col = lex.col;
+	t.line = lex.line;
+
+	if (lex.off >= lex.text.len) {
+		return {.type = EOF};
+	}
+
+	// skip whitespace
+	while (ascii::is_space_m(lex.peep())) {
+		if (lex.advance() == 0) return {.type = EOF};
+		if (lex.off >= lex.text.len) return {.type = EOF};
+	}
+	t.off = lex.off;
+
+	switch (true) {
+	case ascii::is_punct_m(lex.peep()) && lex.peep() != '#': // punctuation
+		t.text = lex.text[lex.off:1];
+		if (lex.advance() == 0) { t.type = INVALID; break; }
+		switch (t.text[0]) {
+		case ':': t.type = COLON;
+		case ';': t.type = SEMICOLON;
+		case '{': t.type = LCURLY;
+		case '}': t.type = RCURLY;
+		default:  t.type = INVALID;
+		}
+
+	case lex.peep() == '#': // color
+		t.type = COLOR;
+		if (lex.advance() == 0) { t.type = INVALID; break; }
+		usz hex_start = t.off+1;
+		while (ascii::is_alnum_m(lex.peep())) {
+			if (lex.advance() == 0) { t.type = INVALID; break; }
+		}
+		usz h_len = lex.off - hex_start;
+		if (h_len != 8 && h_len != 6) {
+			io::eprintfn("CSS lexing error at %d:%d: the only suppported color formats are #RRGGBBAA or #RRGGBB", t.line, t.col);
+			t.type = INVALID;
+			break;
+		}
+
+		char[10] hex_str = (char[])"0x";
+		hex_str[2:h_len] = lex.text[hex_start:h_len];
+		if (h_len == 6) hex_str[8..9] = "ff"[..];
+		uint? color_hex = ((String)hex_str[..]).to_uint();
+		if (catch color_hex) {
+			t.type = INVALID;
+			break;
+		}
+		t.color = color_hex.to_rgba();
+
+	case ascii::is_alpha_m(lex.peep()): // identifier
+		t.type = IDENTIFIER;
+		while (ascii::is_alnum_m(lex.peep()) || lex.peep() == '-' || lex.peep() == '_') {
+			if (lex.advance() == 0) { t.type = INVALID; break; }
+		}
+		t.text = lex.text[t.off..lex.off-1];
+
+	case ascii::is_digit_m(lex.peep()): // number
+		t.type = NUMBER;
+		t.unit = PIXELS;
+		// find the end of the number
+		usz end;
+		while (ascii::is_alnum_m(lex.peep()) || lex.peep() == '+' || lex.peep() == '-' || lex.peep() == '.') {
+			if (lex.advance() == 0) { t.type = INVALID; break; }
+		}
+		end = lex.off;
+		if (end - t.off > 2) {
+			if (lex.text[end-2:2] == "px") {
+				t.unit = PIXELS;
+				end -= 2;
+			} else if (lex.text[end-2:2] == "mm") {
+				t.unit = MILLIMETERS;
+				end -= 2;
+			} else if (lex.text[end-2:2] == "pt" || lex.text[end-2:2] == "em") {
+				io::eprintn("units 'em' or 'pt' are not supported at the moment");
+				t.type = INVALID;
+				break;
+			}
+		}
+		String number_str = lex.text[t.off..end-1];
+		float? value = number_str.to_float();
+		if (catch value) { t.type = INVALID; break; }
+		t.value = value;
+		t.text = lex.text[t.off..lex.off-1];
+	}
+
+	if (t.type == INVALID) {
+		io::eprintfn("CSS Lexing ERROR at %d:%d: '%s' is not a valid token", t.line, t.col, lex.text[t.off..lex.off]);
+	}
+	return t;
+}
+
+fn Token Lexer.peep_token(&lex)
+{
+	Lexer start_state = *lex;
+	Token t;
+	t = lex.next_token();
+	*lex = start_state;
+	return t;
+}
+
+
+// ---------------------------------------------------------------------------------- //
+//                                    PARSER                                          //
+// ---------------------------------------------------------------------------------- //
+
+
+struct Parser {
+	Lexer lex;
+	Style style;
+	Id style_id;
+	float mm_to_px;
+}
+
+macro bool Parser.expect(&p, Token* t, TokenType type)
+{
+	*t = p.lex.next_token();
+	if (t.type == type) return true;
+	io::eprintfn("CSS parsing error at %d:%d: expected %s but got %s", t.line, t.col, type, t.type);
+	return false;
+}
+
+// style := ( IDENTIFIER "{" property_list "}" )
+// property_list := property property_list
+fn bool Parser.parse_style(&p)
+{
+	Token t;
+	p.style = {};
+	p.style_id = 0;
+
+	// style name
+	if (p.expect(&t, IDENTIFIER) == false) return false;
+	p.style_id = t.text.hash();
+
+	// style body
+	if (p.expect(&t, LCURLY) == false) return false;
+
+	while (true) {
+		if (p.parse_property() == false) return false;
+		t = p.lex.peep_token();
+		if (t.type != IDENTIFIER) break;
+	}
+
+	if (p.expect(&t, RCURLY) == false) return false;
+
+	return true;
+}
+
+// property        := ( number_property | color_property | size_property ) ";"
+// number_property := ( "radius" | "size" ) "=" number
+// color_property  := ( "bg" | "fg" | "primary" | "secondary" | "accent" ) "=" color
+// size_property   := ( "padding" | "border" | "margin" ) "=" size
+fn bool Parser.parse_property(&p)
+{
+	Token t, prop;
+	if (p.expect(&prop, IDENTIFIER) == false) return false;
+	if (p.expect(&t, COLON) == false) return false;
+
+	switch (prop.text) {
+	case "padding":
+		Rect padding;
+		if (p.parse_size(&padding) == false) return false;
+		p.style.padding = padding;
+
+	case "border":
+		Rect border;
+		if (p.parse_size(&border) == false) return false;
+		p.style.border = border;
+
+	case "margin":
+		Rect margin;
+		if (p.parse_size(&margin) == false) return false;
+		p.style.margin = margin;
+
+	case "bg":
+		Color bg;
+		if (p.parse_color(&bg) == false) return false;
+		p.style.bg = bg;
+
+	case "fg":
+		Color fg;
+		if (p.parse_color(&fg) == false) return false;
+		p.style.fg = fg;
+
+	case "primary":
+		Color primary;
+		if (p.parse_color(&primary) == false) return false;
+		p.style.primary = primary;
+
+	case "secondary":
+		Color secondary;
+		if (p.parse_color(&secondary) == false) return false;
+		p.style.secondary = secondary;
+
+	case "accent":
+		Color accent;
+		if (p.parse_color(&accent) == false) return false;
+		p.style.accent = accent;
+
+	case "radius":
+		short r;
+		if (p.parse_number(&r) == false) return false;
+		if (r < 0) {
+			io::eprintfn("CSS parsing error at %d:%d: 'radius' must be a positive number, got %d", t.line, t.col, r);
+			return false;
+		}
+		p.style.radius = (ushort)r;
+
+	case "size":
+		short s;
+		if (p.parse_number(&s) == false) return false;
+		if (s < 0) {
+			io::eprintfn("CSS parsing error at %d:%d: 'size' must be a positive number, got %d", t.line, t.col, s);
+			return false;
+		}
+		p.style.size = (ushort)s;
+
+
+	default:
+		io::eprintfn("CSS parsing error at %d:%d: '%s' is not a valid property", prop.line, prop.col, prop.text);
+		return false;
+	}
+	if (p.expect(&t, SEMICOLON) == false) return false;
+	return true;
+}
+
+// number := NUMBER
+fn bool Parser.parse_number(&p, short* n)
+{
+	Token t;
+	if (p.expect(&t, NUMBER) == false) return false;
+	*n = t.to_px(p.mm_to_px);
+	return true;
+}
+
+// color := COLOR
+// FIXME: since '#' is punctuation this cannot be done in parsing but it has to be done in lexing
+fn bool Parser.parse_color(&p, Color* c)
+{
+	Token t;
+	if (p.expect(&t, COLOR) == false) return false;
+	*c = t.color;
+	return true;
+}
+
+// size := number | number_list
+// number_list := number number number number
+fn bool Parser.parse_size(&p, Rect* r)
+{
+	short x;
+	Token t;
+
+	if (p.parse_number(&x) == false) return false;
+
+	t = p.lex.peep_token();
+	if (t.type == NUMBER) {
+		// we got another number so we expect three more
+		r.x = x;
+		if (p.parse_number(&x) == false) return false;
+		r.y = x;
+		if (p.parse_number(&x) == false) return false;
+		r.w = x;
+		if (p.parse_number(&x) == false) return false;
+		r.h = x;
+		return true;
+	} else if (t.type == SEMICOLON) {
+		// just one number, all dimensions are the same
+		r.x = r.y = r.w = r.h = x;
+		return true;
+	}
+
+	return false;
+}

src/textedit.c3

@@ -0,0 +1,288 @@
+module ugui;
+
+import ugui::textedit::te;
+
+struct TextEdit {
+	char[] buffer;
+	usz chars;
+	usz cursor;
+	isz sel_len;
+}
+
+fn String TextEdit.to_string(&te) => (String)te.buffer[:te.chars];
+fn String TextEdit.until_cursor(&te) => (String)te.buffer[..te.cursor];
+fn String TextEdit.from_cursor(&te) => (String)te.buffer[te.cursor..te.chars];
+fn String TextEdit.until(&te, usz off) => (String)te.buffer[..min(te.chars, off)];
+fn String TextEdit.from(&te, usz off) => (String)te.buffer[off..te.chars];
+
+// implement text editing operations on the buffer
+// returns true if the buffer is full
+fn bool Ctx.text_edit(&ctx, TextEdit* te)
+{
+	String in = ctx.get_keys();
+	ModKeys mod = ctx.get_mod();
+
+	te.insert_utf8(in);
+
+	bool select = !!(mod & KMOD_SHIFT);
+	bool ctrl = !!(mod & KMOD_CTRL);
+
+	// handle backspace and delete
+	if (mod.bkspc) {
+		if (ctrl) {
+			te.remove_word(false);
+		} else {
+			te.remove_character(false);
+		}
+	}
+	if (mod.del) {
+		if (ctrl) {
+			te.remove_word(true);
+		} else {
+			te.remove_character(true);
+		}
+	}
+
+	// handle arrow keys
+	if (mod.left) {
+		if (ctrl) {
+			te.move_cursor_word(false, select);
+		} else {
+			te.move_cursor(false, select);
+		}
+	}
+	if (mod.right) {
+		if (ctrl) {
+			te.move_cursor_word(true, select);
+		} else {
+			te.move_cursor(true, select);
+		}
+	}
+
+	if (mod.home) {
+		te.set_cursor(te.search_lines(false).first, select);
+	}
+
+	if (mod.end) {
+		te.set_cursor(te.search_lines(true).first, select);
+	}
+
+	// TODO: up, down
+
+	return te.chars < te.buffer.len;
+}
+
+module ugui::textedit::te;
+
+import std::core::string;
+import std::ascii;
+import std::collections::pair;
+
+alias OffPair = pair::Pair{usz, usz};
+
+// returns the offset of the next codepoint in the buffer from the cursor
+fn usz TextEdit.next_char_off(&te)
+{
+	usz len = min(te.chars - te.cursor, 4);
+	if (len == 0) return len;
+	conv::utf8_to_char32(&te.buffer[te.cursor], &len)!!;
+	return len;
+}
+
+// returns the offset of the previous codepoint in the buffer from the cursor
+fn usz TextEdit.prev_char_off(&te)
+{
+	if (te.cursor == 0) return 0;
+	String b = (String)te.buffer[..te.cursor];
+	usz len;
+	foreach_r (off, c: b) {
+		if (c & 0xC0 == 0x80) continue;
+		len = b.len - off;
+		break;
+	}
+	// verify the utf8 character
+	conv::utf8_to_char32(&b[te.cursor - len], &len)!!;
+	return len;
+}
+
+// moves the cursor forwards or backwards by one codepoint without exiting the bounds, if select is
+// true also change the selection width
+fn void TextEdit.move_cursor(&te, bool forward, bool select)
+{
+	// in selection but trying to move without selecting, snap the cursor and reset selection
+	if (te.sel_len != 0 && !select) {
+		if (te.sel_len > 0 && forward) {
+			// selection is in front of the cursor and trying to move right, snap the cursor to the
+			// end of selection
+			te.cursor += te.sel_len;
+		} else if (te.sel_len < 0 && !forward) {
+			// selection is behind the cursor and trying to move left, snap the cursor to the start
+			// of selection
+			te.cursor += te.sel_len;
+		}
+		te.sel_len = 0;
+
+	} else {
+		isz off = forward ? te.next_char_off() : -te.prev_char_off();
+		if (te.cursor + off < 0 || te.cursor + off > te.chars) return;
+		te.cursor += off;
+		// if trying to select increment selection width
+		if (select) {
+			te.sel_len -= off;
+		}
+	}
+}
+
+// set the cursor to the exact offset provided, the selection flags controls wether the selection has
+// expanded or rese
+fn void TextEdit.set_cursor(&te, usz cur, bool select)
+{
+	if (!select) te.sel_len = 0;
+	if (cur == te.cursor) return;
+
+	usz prev_cur = te.cursor;
+	te.cursor = cur;
+	if (select) {
+		te.sel_len += prev_cur - cur;
+	}
+}
+
+fn void TextEdit.move_cursor_word(&te, bool forward, bool select)
+{
+	// moving out of selection, snap to the end
+	if (!select && te.sel_len != 0) {
+		te.move_cursor(forward, select);
+		return;
+	}
+
+	usz prev_cur = te.cursor;
+	while (te.cursor <= te.chars) {
+		char c;
+		if (forward) {
+			if (te.cursor == te.chars) break;
+			c = te.buffer[te.cursor];
+		} else {
+			if (te.cursor == 0) break;
+			c = te.buffer[te.cursor-1];
+		}
+		if (ascii::is_space(c) || ascii::is_punct(c)) break;
+		te.move_cursor(forward, select);
+	}
+
+	// move at least one character
+	if (prev_cur == te.cursor) te.move_cursor(forward, select);
+}
+
+// get the offset of the current line start and the previous line start from the cursor
+fn OffPair TextEdit.search_lines(&te, bool forward)
+{
+	// look for the current line start
+	OffPair p;
+
+	if (forward) {
+		// if searching forwards look for the end of the current line and the end of the next line
+		p.first = te.cursor + (te.from_cursor().index_of_char('\n') ?? (te.chars - te.cursor));
+		if (p.first < te.chars) {
+			p.second = p.first + 1 + (te.from(p.first + 1).index_of_char('\n') ?? (te.chars - p.first - 1));
+		} else {
+			p.second = te.chars;
+		}
+	} else {
+		// if searching backwards, look for the start of the current and previous line
+		if (te.cursor > 0) {
+			p.first = te.until(te.cursor-1).rindex_of_char('\n') ?? 0;
+			if (p.first != 0 && te.chars) p.first++;
+		}
+		p.second = te.until(p.first).rindex_of_char('\n') ?? 0;
+	}
+
+	return p;
+}
+
+fn void TextEdit.delete_selection(&te)
+{
+	if (te.sel_len == 0) return;
+
+	usz start = te.sel_len > 0 ? te.cursor : te.cursor + te.sel_len;
+	usz end   = te.sel_len > 0 ? te.cursor + te.sel_len : te.cursor;
+	usz len = te.chars - end;
+
+	te.buffer[start:len] = te.buffer[end:len];
+	te.cursor -= te.sel_len < 0 ? -te.sel_len : 0;
+	te.chars -= te.sel_len < 0 ? -te.sel_len : te.sel_len;
+	te.sel_len = 0;
+}
+
+// removes the character before or after the cursor
+fn void TextEdit.remove_character(&te, bool forward)
+{
+	// if there is a selection active then delete that selection
+	if (te.sel_len) {
+		te.delete_selection();
+		return;
+	}
+
+	if (te.chars == 0) return;
+	if (forward) {
+		usz rem = te.chars - te.cursor;
+		if (rem > 0) {
+			usz len = te.next_char_off();
+			te.buffer[te.cursor:rem-len] = te.buffer[te.cursor+len:rem-len];
+			te.chars -= len;
+		}
+	} else {
+		if (te.cursor > 0) {
+			usz len = te.prev_char_off();
+			te.buffer[te.cursor-len:te.chars-te.cursor] = te.buffer[te.cursor:te.chars-te.cursor];
+			te.chars -= len;
+			te.cursor -= len;
+		}
+	}
+}
+
+// remove the word before or after the cursor up until the next punctuation or space
+fn void TextEdit.remove_word(&te, bool forward)
+{
+	// if there is a selection active then delete that selection
+	if (te.sel_len) {
+		te.delete_selection();
+		return;
+	}
+
+	usz prev_cur = te.cursor;
+	while (te.chars > 0) {
+		char c;
+		if (forward) {
+			if (te.cursor == te.chars) break;
+			c = te.buffer[te.cursor];
+		} else {
+			if (te.cursor == 0) break;
+			c = te.buffer[te.cursor-1];
+		}
+		if (ascii::is_space(c) || ascii::is_punct(c)) break;
+		te.remove_character(forward);
+	}
+
+	// delete at least one character
+	if (prev_cur == te.cursor) te.remove_character(forward);
+}
+
+// insert a character at the cursor and update the cursor
+fn void TextEdit.insert_character(&te, uint cp)
+{
+	char[4] b;
+	usz len = conv::char32_to_utf8(cp, b[..])!!;
+	te.insert_utf8((String)b[:len]);
+}
+
+fn void TextEdit.insert_utf8(&te, String s)
+{
+	if (s.len == 0) return;
+	if (s.len + te.chars > te.buffer.len) return;
+
+	te.delete_selection();
+	te.buffer[te.cursor+s.len : te.chars-te.cursor] = te.buffer[te.cursor : te.chars-te.cursor];
+	te.buffer[te.cursor : s.len] = s[..];
+	te.chars += s.len;
+	te.cursor += s.len;
+}

src/ugui_button.c3

@@ -1,40 +0,0 @@
-module ugui;
-
-import std::io;
-
-// draw a button, return the events on that button
-fn ElemEvents! Ctx.button(&ctx, String label, Rect size)
-{
-	Id id = label.hash();
-
-	Elem *parent = ctx.get_parent()!;
-	Elem *c_elem = ctx.get_elem(id)!;
-	// add it to the tree
-	ctx.tree.add(id, ctx.active_div)!;
-
-	// 1. Fill the element fields
-	// this resets the flags
-	c_elem.type     = ETYPE_BUTTON;
-	Color bg_color = uint_to_rgba(0x0000ffff);
-
-	// if the element is new or the parent was updated then redo layout
-	if (c_elem.flags.is_new || parent.flags.updated) {
-		// 2. Layout
-		c_elem.bounds = ctx.position_element(parent, size, true);
-
-		// TODO: 3. Fill the button specific fields
-	}
-
-	c_elem.events = ctx.get_elem_events(c_elem);
-	if (parent.flags.has_focus) {
-		if (c_elem.events.mouse_hover) {
-			c_elem.flags.has_focus = true;
-			bg_color = uint_to_rgba(0x00ff00ff);
-		}
-	}
-
-	// Draw the button
-	ctx.push_rect(c_elem.bounds, bg_color, do_border: true, do_radius: true)!;
-
-	return c_elem.events;
-}

src/ugui_cmd.c3

@@ -1,99 +0,0 @@
-module ugui;
-
-import std::ascii;
-
-// FIXME: is this really the best solution?
-// "rect" is the bounding box of the element, which includes the border and the padding (so not just the content)
-fn void! Ctx.push_rect(&ctx, Rect rect, Color color, bool do_border = false, bool do_padding = false, bool do_radius = false)
-{
-	// FIXME: this should be culled higher up, maybe
-	if (rect.w <= 0 || rect.h <= 0) {
-		return;
-	}
-
-	Rect border = ctx.style.border;
-	Rect padding = ctx.style.padding;
-	ushort radius = ctx.style.radius;
-	Color border_color = ctx.style.brcolor;
-
-	if (do_border) {
-		Cmd cmd = {
-			.type = CMD_RECT,
-			.rect.rect = rect,
-			.rect.color = border_color,
-			.rect.radius = do_radius ? radius : 0,
-		};
-		ctx.cmd_queue.enqueue(&cmd)!;
-	}
-
-	Cmd cmd = {
-		.type = CMD_RECT,
-		.rect.rect = {
-			.x = rect.x + (do_border ? border.x : 0) + (do_padding ? padding.x : 0),
-			.y = rect.y + (do_border ? border.y : 0) + (do_padding ? padding.y : 0),
-			.w = rect.w - (do_border ? border.x+border.w : 0) - (do_padding ? padding.x+padding.w : 0),
-			.h = rect.h - (do_border ? border.y+border.h : 0) - (do_padding ? padding.y+padding.h : 0),
-		},
-		.rect.color = color,
-		.rect.radius = do_radius ? radius : 0,
-	};
-	ctx.cmd_queue.enqueue(&cmd)!;
-}
-
-// TODO: add texture id
-fn void! Ctx.push_sprite(&ctx, Rect bounds, Rect texture)
-{
-	Cmd cmd = {
-		.type = CMD_SPRITE,
-		.sprite.rect = bounds,
-		.sprite.texture_rect = texture,
-	};
-	ctx.cmd_queue.enqueue(&cmd)!;
-}
-
-fn void! Ctx.push_string(&ctx, Rect bounds, String text)
-{
-	if (text.len == 0) {
-		return;
-	}
-
-	short baseline = (short)ctx.font.ascender;
-	short line_height = (short)ctx.font.ascender - (short)ctx.font.descender;
-	short line_gap = (short)ctx.font.linegap;
-	Point orig = {
-		.x = bounds.x,
-		.y = bounds.y,
-	};
-
-	short line_len;
-	Codepoint cp;
-	usz off, x;
-	while ((cp = str_to_codepoint(text[off..], &x)) != 0) {
-		off += x;
-		Glyph* gp;
-		if (!ascii::is_cntrl((char)cp)) {
-			gp = ctx.font.get_glyph(cp)!;
-			Rect gb = {
-			.x = orig.x + line_len + gp.ox,
-			.y = orig.y + gp.oy + baseline,
-			.w = gp.w,
-			.h = gp.h,
-			};
-			Rect gt = {
-			.x = gp.u,
-			.y = gp.v,
-			.w = gp.w,
-			.h = gp.h,
-			};
-			if (rect_collision(gb, bounds)) {
-				ctx.push_sprite(gb, gt)!;
-			}
-			line_len += gp.adv;
-		} else if (cp == '\n'){
-			orig.y += line_height + line_gap;
-			line_len = 0;
-		} else {
-			continue;
-		}
-	}
-}

src/ugui_data.c3

@@ -1,240 +0,0 @@
-module ugui;
-
-import std::core::string;
-
-import vtree;
-import cache;
-import fifo;
-
-
-struct Rect {
-	short x, y, w, h;
-}
-
-struct Point {
-	short x, y;
-}
-
-struct Color{
-	char r, g, b, a;
-}
-
-// element ids are just long ints
-def Id = usz;
-
-enum ElemType {
-	ETYPE_NONE,
-	ETYPE_DIV,
-	ETYPE_BUTTON,
-	ETYPE_SLIDER,
-	ETYPE_TEXT,
-}
-
-bitstruct ElemFlags : uint {
-	bool updated : 0;
-	bool has_focus : 1;
-	bool is_new : 2;
-}
-
-bitstruct ElemEvents : uint {
-	bool key_press     : 0;
-	bool key_release   : 1;
-	bool key_hold      : 2;
-	bool mouse_hover   : 3;
-	bool mouse_press   : 4;
-	bool mouse_release : 5;
-	bool mouse_hold    : 6;
-	bool update        : 7;
-}
-
-enum DivLayout {
-	LAYOUT_ROW,
-	LAYOUT_COLUMN,
-	LAYOUT_FLOATING,
-}
-
-// div element
-struct Div {
-	DivLayout layout;
-	struct scroll {
-		bool can_x;
-		bool can_y;
-		bool on_x;
-		bool on_y;
-		float value_x;
-		float value_y;
-	}
-	Rect children_bounds;
-	Point origin_r, origin_c;
-	Color color_bg;
-}
-
-// slider element
-struct Slider {
-	float value;
-	Rect handle;
-}
-
-struct Text {
-	char* str;
-}
-
-// element structure
-struct Elem {
-	Id id;
-	ElemFlags flags;
-	ElemEvents events;
-	Rect bounds;
-	ElemType type;
-	union {
-		Div div;
-		Slider slider;
-		Text text;
-	}
-}
-
-
-// relationships between elements are stored in a tree, it stores just the ids
-def IdTree = vtree::VTree(<Id>) @private;
-
-// elements themselves are kept in a cache
-const uint MAX_ELEMENTS = 1024;
-def ElemCache = cache::Cache(<Id, Elem, MAX_ELEMENTS>) @private;
-
-def CmdQueue = fifo::Fifo(<Cmd>);
-
-fault UgError {
-	INVALID_SIZE,
-	EVENT_UNSUPPORTED,
-	UNEXPECTED_ELEMENT,
-}
-
-macro uint_to_rgba(uint u) {
-	return Color{
-		.r = (char)((u >> 24) & 0xff),
-		.g = (char)((u >> 16) & 0xff),
-		.b = (char)((u >> 8) & 0xff),
-		.a = (char)((u >> 0) & 0xff)
-	};
-}
-
-const Rect DIV_FILL = { .x = 0, .y = 0, .w = 0, .h = 0 };
-
-macro abs(a) { return a < 0 ? -a : a; }
-macro clamp(x, min, max) { return x < min ? min : (x > max ? max : x); }
-
-const uint STACK_STEP = 10;
-const uint MAX_ELEMS  = 128;
-const uint MAX_CMDS   = 256;
-const uint ROOT_ID    = 1;
-
-// command type
-enum CmdType {
-	CMD_RECT,
-	CMD_UPDATE_ATLAS,
-	CMD_SPRITE,
-}
-
-// command to draw a rect
-// TODO: implement radius
-struct CmdRect {
-	Rect rect;
-	ushort radius;
-	Color color;
-}
-
-// FIXME: For now only support black and white atlas, so PIXELFORMAT_UNCOMPRESSED_GRAYSCALE
-struct CmdUpdateAtlas {
-	char* raw_buffer;
-	short width, height;
-}
-
-// TODO:
-//    1. Add atlases as a data type
-//    2. Each atlas has an id
-struct CmdSprite {
-	Rect rect;
-	Rect texture_rect;
-}
-
-// command structure
-struct Cmd {
-	CmdType type;
-	union {
-		CmdRect rect;
-		CmdUpdateAtlas update_atlas;
-		CmdSprite sprite;
-	}
-}
-
-enum Layout {
-	ROW,
-	COLUMN,
-	FLOATING
-}
-
-// global style, similar to the css box model
-struct Style { // css box model
-	Rect  padding;
-	Rect  border;
-	Rect  margin;
-	Color bgcolor; // background color
-	Color fgcolor; // foreground color
-	Color brcolor; // border color
-	ushort radius;
-}
-
-
-struct Ctx {
-	Layout layout;
-	IdTree tree;
-	ElemCache cache;
-	CmdQueue cmd_queue;
-	// total size in pixels of the context
-	ushort width, height;
-	Style style;
-	Font font;
-
-	bool has_focus;
-	struct input {
-		InputEvents events;
-		struct mouse {
-			Point pos, delta;
-			// mouse_down:      bitmap of mouse buttons that are held
-			// mouse_updated:   bitmap of mouse buttons that have been updated
-			// mouse_released = mouse_updated & ~mouse_down
-			// mouse_pressed  = mouse_updated & mouse_down
-			MouseButtons down;
-			MouseButtons updated;
-		}
-	}
-
-	isz active_div; // tree node indicating the current active div
-}
-
-macro point_in_rect(Point p, Rect r)
-{
-	return (p.x >= r.x && p.x <= r.x + r.w) && (p.y >= r.y && p.y <= r.y + r.h);
-}
-
-// return true if rect a contains b
-macro rect_contains(Rect a, Rect b)
-{
-	return (a.x <= b.x && a.y <= b.y && a.x+a.w >= b.x+b.w && a.y+a.h >= b.y+b.h);
-}
-
-macro rect_intersection(Rect a, Rect b)
-{
-	return Rect{
-		.x = (short)max(a.x, b.x),
-		.y = (short)max(a.y, b.y),
-		.w = (short)min(a.x+a.w, b.x+b.w) - (short)max(a.x, b.x),
-		.h = (short)min(a.y+a.h, b.y+b.h) - (short)max(a.y, b.y),
-	};
-}
-
-// rect intersection not null
-macro rect_collision(Rect a, Rect b)
-{
-	return !(a.x > b.x+b.w || a.x+a.w < b.x || a.y > b.y+b.h || a.y+a.h < b.y);
-}

src/ugui_div.c3

@@ -1,115 +0,0 @@
-module ugui;
-
-import std::io;
-
-fn void! Ctx.div_begin(&ctx, String label, Rect size)
-{
-	Id id = label.hash();
-
-	Elem *parent = ctx.get_parent()!;
-	Elem* c_elem = ctx.get_elem(id)!;
-	isz div_node = ctx.tree.add(id, ctx.active_div)!;
-	ctx.active_div = div_node;
-
-	// 1. Fill the element fields
-	c_elem.type = ETYPE_DIV;
-
-	// do layout and update flags only if the element was updated
-	if (c_elem.flags.is_new || parent.flags.updated) {
-		// 2. layout the element
-		c_elem.bounds = ctx.position_element(parent, size);
-		if (c_elem.flags.is_new) {
-			c_elem.div.children_bounds = c_elem.bounds;
-			c_elem.div.color_bg = ctx.style.bgcolor;
-			c_elem.div.scroll.can_x = false;
-			c_elem.div.scroll.can_y = false;
-			c_elem.div.scroll.value_x = 0;
-			c_elem.div.scroll.value_y = 0;
-		}
-
-		// 3. Mark the element as updated
-		c_elem.flags.updated = true;
-		// 4. Fill the div fields
-		c_elem.div.origin_c = Point{
-			.x = c_elem.bounds.x,
-			.y = c_elem.bounds.y,
-		};
-		c_elem.div.origin_r = c_elem.div.origin_c;
-		c_elem.div.layout   = parent.div.layout;
-	}
-
-	// Add the background to the draw stack
-	ctx.push_rect(c_elem.bounds, c_elem.div.color_bg)!;
-
-	// TODO: check active
-	// TODO: check resizeable
-
-	// check and draw scroll bars
-	if (!rect_contains(c_elem.bounds, c_elem.div.children_bounds)) {
-		Point cbc = {
-			.x = c_elem.div.children_bounds.x + c_elem.div.children_bounds.w,
-			.y = c_elem.div.children_bounds.y + c_elem.div.children_bounds.h,
-		};
-		Point bc = {
-			.x = c_elem.bounds.x + c_elem.bounds.w,
-			.y = c_elem.bounds.y + c_elem.bounds.h,
-		};
-		// vertical overflow, check and draw scroll bar
-		if (cbc.y > bc.y && c_elem.div.scroll.can_y) {
-			// set the scrollbar flag, is used in layout
-			c_elem.div.scroll.on_y = true;
-
-			Rect vslider = {
-				.x = c_elem.bounds.x + c_elem.bounds.w - 10,
-				.y = c_elem.bounds.y,
-				.w = 10,
-				.h = c_elem.bounds.h,
-			};
-
-			float vh = max((float)bc.y / cbc.y, (float)0.15);
-			Rect vhandle = {
-				.x = c_elem.bounds.x + c_elem.bounds.w - 10,
-				.y = (short)(c_elem.bounds.y + (int)(c_elem.bounds.h*(1-vh) * c_elem.div.scroll.value_y)),
-				.w = 10,
-				.h = (short)(c_elem.bounds.h * vh),
-			};
-
-			c_elem.events = ctx.get_elem_events(c_elem);
-			if (parent.flags.has_focus && c_elem.events.mouse_hover && c_elem.events.mouse_hold && point_in_rect(ctx.input.mouse.pos, vhandle)) {
-				short y = (short)clamp(ctx.input.mouse.pos.y - vhandle.h/2, vslider.y, vslider.y + vslider.h - vhandle.h);
-				vhandle.y = y;
-				float v = (float)(vhandle.y-vslider.y) / (float)(vslider.h-vhandle.h);
-				c_elem.div.scroll.value_y = v;
-				c_elem.flags.updated = true;
-				c_elem.div.origin_c = Point{
-					.x = c_elem.bounds.x,
-					.y = c_elem.bounds.y,
-				};
-				c_elem.div.origin_r = c_elem.div.origin_c;
-			}
-
-			ctx.push_rect(vslider, uint_to_rgba(0x999999ff))!;
-			ctx.push_rect(vhandle, uint_to_rgba(0x9999ffff))!;
-		} else {
-			c_elem.div.scroll.on_y = false;
-		}
-	}
-
-	// if the bounds are outside of the view then allocate space for scrollbars
-	DivLayout old_layout = c_elem.div.layout;
-	c_elem.div.layout = LAYOUT_FLOATING;
-	c_elem.div.layout = old_layout;
-
-	if (parent.flags.has_focus) {
-		if (point_in_rect(ctx.input.mouse.pos, c_elem.bounds)) {
-			c_elem.flags.has_focus = true;
-		}
-	}
-
-}
-
-fn void! Ctx.div_end(&ctx)
-{
-	// the active_div returns to the parent of the current one
-	ctx.active_div = ctx.tree.parentof(ctx.active_div)!;
-}

src/ugui_font.c3

@@ -1,221 +0,0 @@
-module ugui;
-
-import schrift;
-import std::collections::map;
-import std::core::mem;
-import std::io;
-
-// unicode code point, different type for a different hash
-def Codepoint = uint;
-
-
-/* width and height of a glyph contain the kering advance
- * (u,v)
- *   +-------------*---+ -
- *   |       ^     |   | ^
- *   |       |oy   |   | |
- *   |       v     |   | |
- *   |      .ii.   |   | |
- *   |     @@@@@@. |   | |
- *   |    V@Mio@@o |   | |
- *   |    :i.  V@V |   | h
- *   |      :oM@@M |   | |
- *   |    :@@@MM@M |   | |
- *   |    @@o  o@M |   | |
- *   |<->:@@.  M@M |   | |
- *   |ox  @@@o@@@@ |   | |
- *   |    :M@@V:@@.|   | v
- *   +-------------*---+ -
- *   |<---- w ---->|
- *   |<------ adv ---->|
- */
-struct Glyph {
-	Codepoint code;
-	ushort u, v;
-	ushort w, h;
-	short adv, ox, oy;
-	short idx; // atlas index
-}
-
-const uint FONT_CACHED = 512;
-def GlyphTable = map::HashMap(<Codepoint, Glyph>) @private;
-
-fault UgFontError {
-	TTF_LOAD_FAILED,
-	MISSING_GLYPH,
-	BAD_GLYPH_METRICS,
-	RENDER_ERROR,
-}
-
-fault UgAtlasError {
-	CANNOT_PLACE,
-}
-
-// black and white atlas
-struct AtlasBW {
-	ushort width, height;
-	char[] buffer;
-
-	Point row;
-	ushort row_h;
-}
-
-struct Font {
-	schrift::Sft sft;
-	String path;
-	GlyphTable table;
-
-	float size;
-	float ascender, descender, linegap; // Line Metrics
-	AtlasBW[] atlas;
-}
-
-fn void! AtlasBW.new(&atlas, ushort width, ushort height)
-{
-	atlas.width = width;
-	atlas.height = height;
-	atlas.buffer = mem::new_array(char, (usz)atlas.width*atlas.height);
-}
-
-fn void AtlasBW.free(&atlas)
-{
-	free(atlas.buffer);
-}
-
-// place a rect inside the atlas
-// uses a row first algorithm
-// TODO: use a skyline algorithm https://jvernay.fr/en/blog/skyline-2d-packer/implementation/
-fn Point! AtlasBW.place(&atlas, char[] pixels, ushort w, ushort h)
-{
-	Point p;
-
-	if (atlas.row.x + w <= atlas.width && atlas.row.y + h <= atlas.height) {
-		p = atlas.row;
-	} else {
-		atlas.row.x = 0;
-		atlas.row.y = atlas.row.y + atlas.row_h;
-		atlas.row_h = 0;
-		if (atlas.row.x + w <= atlas.width && atlas.row.y + h <= atlas.height) {
-			p = atlas.row;
-		} else {
-			return UgAtlasError.CANNOT_PLACE?;
-		}
-	}
-
-	for (usz y = 0; y < h; y++) {
-		for (usz x = 0; x < w; x++) {
-			atlas.buffer[(usz)(p.y+y)*atlas.width + (p.x+x)] = pixels[y*w + x];
-		}
-	}
-
-	atlas.row.x += w;
-	if (h > atlas.row_h) {
-		atlas.row_h = h;
-	}
-
-	return p;
-}
-
-fn void! Font.load(&font, String path, uint height, float scale = 1)
-{
-	font.table.new_init(capacity: FONT_CACHED);
-	
-	font.size = height*scale;
-
-	font.sft = schrift::Sft{
-		.xScale = (double)font.size,
-		.yScale = (double)font.size,
-		.flags = schrift::SFT_DOWNWARD_Y,
-	};
-
-	font.sft.font = schrift::loadfile(path);
-	if (font.sft.font == null) {
-		return UgFontError.TTF_LOAD_FAILED?;
-	}
-
-	schrift::SftLMetrics lmetrics;
-	schrift::lmetrics(&font.sft, &lmetrics);
-	font.ascender  = (float)lmetrics.ascender;
-	font.descender = (float)lmetrics.descender;
-	font.linegap   = (float)lmetrics.lineGap;
-	//io::printfn("ascender:%d, descender:%d, linegap:%d", font.ascender, font.descender, font.linegap);
-
-	// TODO: allocate buffer based on FONT_CACHED and the size of a sample letter
-	//       like the letter 'A'
-	font.atlas = mem::new_array(AtlasBW, 1);
-	ushort size = (ushort)font.size*256;
-	font.atlas[0].new(size, size)!;
-	
-	// preallocate the ASCII range
-//	for (char c = ' '; c < '~'; c++) {
-//		font.get_glyph((Codepoint)c)!;
-//	}
-}
-
-fn Glyph*! Font.get_glyph(&font, Codepoint code, bool* is_new = null)
-{
-	Glyph*! gp;
-	gp = font.table.get_ref(code);
-	
-	if (catch excuse = gp) {
-		if (excuse != SearchResult.MISSING) {
-			return excuse?;
-		}
-	} else {
-		if (is_new) { *is_new = false; }
-		return gp;
-	}
-
-	// missing glyph, render and place into an atlas
-	Glyph glyph;
-
-	schrift::SftGlyph gid;
-	schrift::SftGMetrics gmtx;
-	
-	if (schrift::lookup(&font.sft, code, &gid) < 0) {
-		return UgFontError.MISSING_GLYPH?;
-	}
-
-	if (schrift::gmetrics(&font.sft, gid, &gmtx) < 0) {
-		return UgFontError.BAD_GLYPH_METRICS?;
-	}
-
-	schrift::SftImage img = {
-		.width = gmtx.minWidth,
-		.height = gmtx.minHeight,
-	};
-	char[] pixels = mem::new_array(char, (usz)img.width * img.height);
-	img.pixels = pixels;
-	if (schrift::render(&font.sft, gid, img) < 0) {
-		return UgFontError.RENDER_ERROR?;
-	}
-
-	glyph.code = code;
-	glyph.w = (ushort)img.width;
-	glyph.h = (ushort)img.height;
-	glyph.ox = (short)gmtx.leftSideBearing;
-	glyph.oy = (short)gmtx.yOffset;
-	glyph.adv = (short)gmtx.advanceWidth;
-	//io::printfn("code=%c, w=%d, h=%d, ox=%d, oy=%d, adv=%d",
-	//    glyph.code, glyph.w, glyph.h, glyph.ox, glyph.oy, glyph.adv);
-
-	Point uv = font.atlas[0].place(pixels, glyph.w, glyph.h)!;
-	glyph.idx = 0;
-	glyph.u = uv.x;
-	glyph.v = uv.y;
-
-	mem::free(pixels);
-
-	font.table.set(code, glyph);
-
-	if (is_new) { *is_new = true; }
-	return font.table.get_ref(code);
-}
-
-fn void Font.free(&font)
-{
-	foreach (atlas: font.atlas) {
-		atlas.free();
-	}
-	schrift::freefont(font.sft.font);
-}

src/ugui_impl.c3

@@ -1,152 +0,0 @@
-module ugui;
-
-import std::io;
-
-// return a pointer to the parent of the current active div
-fn Elem*! Ctx.get_parent(&ctx)
-{
-	// FIXME: if the tree held pointers to the elements then no more
-	//        redundant cache search
-	Id parent_id = ctx.tree.get(ctx.active_div)!;
-	return ctx.cache.search(parent_id);
-}
-
-// get or push an element from the cache, return a pointer to it
-// resets all flags except is_new which is set accordingly
-macro Ctx.get_elem(&ctx, Id id)
-{
-	Elem empty_elem;
-	bool is_new;
-	Elem* c_elem;
-	c_elem = ctx.cache.get_or_insert(&empty_elem, id, &is_new)!;
-	c_elem.flags = (ElemFlags)0;
-	c_elem.flags.is_new = is_new;
-	return c_elem;
-}
-
-// this searches an element in the cache by label, it does not create a new element
-// if it does't find one
-macro Ctx.get_elem_by_label(&ctx, String label)
-{
-	Id id = label.hash();
-	return ctx.cache.search(id);
-}
-
-macro Ctx.get_elem_by_tree_idx(&ctx, isz idx) @private
-{
-	Id id = ctx.tree.get(ctx.active_div)!;
-	return ctx.cache.search(id);
-}
-
-fn void! Ctx.init(&ctx)
-{
-	ctx.tree.init(MAX_ELEMENTS)!;
-	defer catch { (void)ctx.tree.free(); }
-
-	ctx.cache.init()!;
-	defer catch { (void)ctx.cache.free(); }
-
-	ctx.cmd_queue.init(MAX_ELEMENTS)!;
-	defer catch { (void)ctx.cmd_queue.free(); }
-
-	ctx.layout = Layout.ROW;
-	ctx.active_div = 0;
-
-	// TODO: add style config
-	ctx.style.margin  = Rect{2, 2, 2, 2};
-	ctx.style.border  = Rect{2, 2, 2, 2};
-	ctx.style.padding = Rect{1, 1, 1, 1};
-	ctx.style.radius  = 5;
-	ctx.style.bgcolor = uint_to_rgba(0x282828ff);
-	ctx.style.fgcolor = uint_to_rgba(0xfbf1c7ff);
-	ctx.style.brcolor = uint_to_rgba(0xd79921ff);
-}
-
-fn void Ctx.free(&ctx)
-{
-	(void)ctx.tree.free();
-	(void)ctx.cache.free();
-	(void)ctx.cmd_queue.free();
-}
-
-fn void! Ctx.frame_begin(&ctx)
-{
-
-	// 2. Get the root element from the cache and update it
-	Elem* c_elem = ctx.get_elem(ROOT_ID)!;
-	// The root should have the updated flag only if the size of the window
-	// was changed between frames, this propagates an element size recalculation
-	// down the element tree
-	c_elem.flags.updated = ctx.input.events.resize | ctx.input.events.force_update;
-	ctx.input.events.force_update = false;
-	// if the window has focus then the root element also has focus, no other
-	// computation needed, child elements need to check the mouse positon and
-	// other stuff
-	c_elem.flags.has_focus = ctx.has_focus;
-
-	if (c_elem.flags.is_new || c_elem.flags.updated) {
-		Elem def_root = {
-			.id = ROOT_ID,
-			.type = ETYPE_DIV,
-			.bounds = {
-				.w = ctx.width,
-				.h = ctx.height,
-			},
-			.div = {
-				.layout = LAYOUT_ROW,
-				.children_bounds = {
-					.w = ctx.width,
-					.h = ctx.height,
-				}
-			},
-			.flags = c_elem.flags,
-		};
-
-		*c_elem = def_root;
-	}
-
-	// 3. Push the root element into the element tree
-	ctx.active_div = ctx.tree.add(ROOT_ID, 0)!;
-
-	// The root element does not push anything to the stack
-	// TODO: add a background color taken from a theme or config
-}
-
-fn void! Ctx.force_update(&ctx)
-{
-	ctx.input.events.force_update = true;
-}
-
-fn void! Ctx.frame_end(&ctx)
-{
-	// 1. clear the tree
-	ctx.tree.prune(0)!;
-
-	// 2. clear input fields
-	bool f = ctx.input.events.force_update;
-	ctx.input.events = (InputEvents)0;
-	ctx.input.events.force_update = f;
-
-	// draw mouse position
-$if 1:
-	Cmd cmd = {
-		.type = CMD_RECT,
-		.rect.rect = {
-			.x = ctx.input.mouse.pos.x - 2,
-			.y = ctx.input.mouse.pos.y - 2,
-			.w = 4,
-			.h = 4,
-		},
-		.rect.color = uint_to_rgba(0xff00ffff)
-	};
-	ctx.cmd_queue.enqueue(&cmd)!;
-$endif
-}
-
-<*
- * @ensure elem != null
- *>
-fn bool Ctx.is_hovered(&ctx, Elem *elem)
-{
-	return point_in_rect(ctx.input.mouse.pos, elem.bounds);
-}

src/ugui_input.c3

@@ -1,114 +0,0 @@
-module ugui;
-
-import std::io;
-
-// TODO: this could be a bitstruct
-bitstruct InputEvents : uint {
-	bool resize : 0; // window size was changed
-	bool change_focus : 1; // window focus changed
-	bool mouse_move : 2; // mouse was moved
-	bool mouse_btn : 3; // mouse button pressed or released
-	bool force_update : 4;
-}
-
-// Window size was changed
-fn void! Ctx.input_window_size(&ctx, short width, short height)
-{
-	if (width <= 0 || height <= 0) {
-		return UgError.INVALID_SIZE?;
-	}
-	ctx.width = width;
-	ctx.height = height;
-	ctx.input.events.resize = true;
-}
-
-// Window gained/lost focus
-fn void Ctx.input_changefocus(&ctx, bool has_focus)
-{
-	// FIXME: raylib only has an API to query the focus status so we have to
-	//        update the input flag only if the focus changed
-	if (ctx.has_focus != has_focus) {
-		ctx.input.events.change_focus = true;
-	}
-	ctx.has_focus = has_focus;
-}
-
-bitstruct MouseButtons : uint {
-	bool btn_left : 0;
-	bool btn_middle : 1;
-	bool btn_right : 2;
-	bool btn_4 : 3;
-	bool btn_5 : 4;
-}
-
-macro Ctx.mouse_pressed(&ctx) => ctx.input.mouse.updated & ctx.input.mouse.down;
-macro Ctx.mouse_released(&ctx) => ctx.input.mouse.updated & ~ctx.input.mouse.down;
-macro Ctx.mouse_down(&ctx) => ctx.input.mouse.down;
-
-const MouseButtons BTN_NONE = (MouseButtons)0u;
-const MouseButtons BTN_ANY = (MouseButtons)(uint.max);
-const MouseButtons BTN_LEFT = {.btn_left = true};
-const MouseButtons BTN_MIDDLE = {.btn_middle = true};
-const MouseButtons BTN_RIGHT = {.btn_right = true};
-const MouseButtons BTN_4 = {.btn_4 = true};
-const MouseButtons BTN_5 = {.btn_5 = true};
-
-// FIXME: hthis compairson could be done with a cast using MouseButtons.inner
-// property but I could not figure out how
-macro Ctx.is_mouse_pressed(&ctx, MouseButtons btn) => (ctx.mouse_pressed() & btn) != BTN_NONE;
-macro Ctx.is_mouse_released(&ctx, MouseButtons btn) => (ctx.mouse_released() & btn) != BTN_NONE;
-macro Ctx.is_mouse_down(&ctx, MouseButtons btn) => (ctx.mouse_down() & btn) != BTN_NONE;
-
-macro ElemEvents Ctx.get_elem_events(&ctx, Elem *elem)
-{
-	// TODO: add the other events
-	// FIXME: active should be elsewhere
-	bool active = elem.events.mouse_hold || ctx.is_hovered(elem);
-	ElemEvents ev = {
-		.mouse_hover = ctx.is_hovered(elem),
-		.mouse_press = active & ctx.is_mouse_pressed(BTN_ANY),
-		.mouse_release = active & ctx.is_mouse_released(BTN_ANY),
-		.mouse_hold = active & ctx.is_mouse_down(BTN_ANY),
-	};
-	return ev;
-}
-
-// Mouse Button moved
-fn void Ctx.input_mouse_button(&ctx, MouseButtons buttons)
-{
-	ctx.input.mouse.updated = ctx.input.mouse.down ^ buttons;
-	ctx.input.mouse.down = buttons;
-	ctx.input.events.mouse_btn = true;
-}
-
-// Mouse was moved, report absolute position
-fn void Ctx.input_mouse_abs(&ctx, short x, short y)
-{
-	ctx.input.mouse.pos.x = clamp(x, 0u16, ctx.width);
-	ctx.input.mouse.pos.y = clamp(y, 0u16, ctx.height);
-
-	short dx, dy;
-	dx = x - ctx.input.mouse.pos.x;
-	dy = y - ctx.input.mouse.pos.y;
-
-	ctx.input.mouse.delta.x = dx;
-	ctx.input.mouse.delta.y = dy;
-
-	ctx.input.events.mouse_move = true;
-}
-
-// Mouse was moved, report relative motion
-fn void Ctx.input_mouse_delta(&ctx, short dx, short dy)
-{
-	ctx.input.mouse.delta.x = dx;
-	ctx.input.mouse.delta.y = dy;
-
-	short mx, my;
-	mx = ctx.input.mouse.pos.x + dx;
-	my = ctx.input.mouse.pos.y + dy;
-
-	ctx.input.mouse.pos.x = clamp(mx, 0u16, ctx.width);
-	ctx.input.mouse.pos.y = clamp(my, 0u16, ctx.height);
-
-	ctx.input.events.mouse_move = true;
-}

src/ugui_layout.c3

@@ -1,177 +0,0 @@
-module ugui;
-
-
-fn void! Ctx.layout_set_row(&ctx)
-{
-	Id parent_id = ctx.tree.get(ctx.active_div)!;
-	Elem *parent = ctx.cache.search(parent_id)!;
-
-	if (parent.type != ETYPE_DIV) {
-		// what?
-		return UgError.UNEXPECTED_ELEMENT?;
-	}
-
-	parent.div.layout = LAYOUT_ROW;
-}
-
-fn void! Ctx.layout_set_column(&ctx)
-{
-	Id parent_id = ctx.tree.get(ctx.active_div)!;
-	Elem *parent = ctx.cache.search(parent_id)!;
-
-	if (parent.type != ETYPE_DIV) {
-		// what?
-		return UgError.UNEXPECTED_ELEMENT?;
-	}
-
-	parent.div.layout = LAYOUT_COLUMN;
-}
-
-fn void! Ctx.layout_set_floating(&ctx)
-{
-	Id parent_id = ctx.tree.get(ctx.active_div)!;
-	Elem *parent = ctx.cache.search(parent_id)!;
-
-	if (parent.type != ETYPE_DIV) {
-		// what?
-		return UgError.UNEXPECTED_ELEMENT?;
-	}
-
-	parent.div.layout = LAYOUT_FLOATING;
-}
-
-fn void! Ctx.layout_next_row(&ctx)
-{
-	Id parent_id = ctx.tree.get(ctx.active_div)!;
-	Elem *parent = ctx.cache.search(parent_id)!;
-
-	if (parent.type != ETYPE_DIV) {
-		// what?
-		return UgError.UNEXPECTED_ELEMENT?;
-	}
-
-	parent.div.origin_r = Point{
-		.x = parent.bounds.x,
-		.y = parent.div.origin_c.y,
-	};
-	parent.div.origin_c = parent.div.origin_r;
-}
-
-fn void! Ctx.layout_next_column(&ctx)
-{
-	Id parent_id = ctx.tree.get(ctx.active_div)!;
-	Elem *parent = ctx.cache.search(parent_id)!;
-
-	if (parent.type != ETYPE_DIV) {
-		// what?
-		return UgError.UNEXPECTED_ELEMENT?;
-	}
-
-	parent.div.origin_c = Point{
-		.x = parent.div.origin_r.x,
-		.y = parent.bounds.y,
-	};
-	parent.div.origin_r = parent.div.origin_c;
-}
-
-// position the rectangle inside the parent according to the layout
-// parent: parent div
-// rect: the requested size
-// style: apply style
-<*
-@require ctx != null
-@require parent.type == ETYPE_DIV
-*>
-fn Rect Ctx.position_element(&ctx, Elem *parent, Rect rect, bool style = false)
-{
-	Rect placement;
-	Point origin;
-	Div* div = &parent.div;
-
-	// 1. Select the right origin
-	switch (div.layout) {
-	case LAYOUT_ROW:
-		origin = div.origin_r;
-	case LAYOUT_COLUMN:
-		origin = div.origin_c;
-	case LAYOUT_FLOATING: // none
-	default:
-		// Error
-	}
-
-	// the bottom-right border of the element box
-	Point pl_corner;
-
-	// 2. Calculate the placement
-	placement.x = (short)max(origin.x + rect.x, 0);
-	placement.y = (short)max(origin.y + rect.y, 0);
-	placement.w = rect.w > 0 ? rect.w : (short)max(parent.bounds.w - (placement.x - parent.bounds.x), 0);
-	placement.h = rect.h > 0 ? rect.h : (short)max(parent.bounds.h - (placement.y - parent.bounds.y), 0);
-
-	pl_corner.x = placement.x + placement.w;
-	pl_corner.y = placement.y + placement.h;
-
-	// 2.1 apply style, css box model
-	if (style) {
-		Rect margin = ctx.style.margin;
-		Rect border = ctx.style.border;
-		Rect padding = ctx.style.padding;
-
-		placement.x += margin.x;
-		placement.y += margin.y;
-		if (rect.w != 0) { placement.w += border.x+border.w + padding.x+padding.w; }
-		if (rect.h != 0) { placement.h += border.y+border.h + padding.y+padding.h; }
-
-		pl_corner.x = placement.x + placement.w + margin.w;
-		pl_corner.y = placement.y + placement.h + margin.h;
-	}
-
-	// 3. Update the origins of the parent
-	div.origin_r = Point{
-		.x = pl_corner.x,
-		.y = origin.y,
-	};
-	div.origin_c = Point{
-		.x = origin.x,
-		.y = pl_corner.y,
-	};
-
-	// 4. Calculate the "scrolled" view
-	Point off;
-	Rect* cb = &div.children_bounds;
-	if (div.scroll.can_x && div.scroll.on_x) {
-		off.x = (short)(cb.w * div.scroll.value_x);
-	}
-	if (div.scroll.can_y && div.scroll.on_y) {
-		off.y = (short)((float)(cb.h - parent.bounds.h) * div.scroll.value_y);
-	}
-	Rect view = {
-		.x = parent.bounds.x + off.x,
-		.y = parent.bounds.y + off.y,
-		.w = parent.bounds.w,
-		.h = parent.bounds.h,
-	};
-
-	// 5. check if the placement overflows the children ounds, if so update them
-	if (!point_in_rect(pl_corner, *cb)) {
-		if (pl_corner.y > cb.y+cb.h) {
-			cb.h = pl_corner.y - cb.y;
-		}
-		if (pl_corner.x > cb.x+cb.w) {
-			cb.w += pl_corner.x - (cb.x + cb.w);
-		}
-	}
-
-	// 6. check if the placement is inside the view
-	if (rect_collision(placement, view)) {
-		return Rect{
-			.x = placement.x - off.x,
-			.y = placement.y - off.y,
-			.w = placement.w,
-			.h = placement.h,
-		};
-	} else {
-		return Rect{};
-	}
-}
-

src/ugui_slider.c3

@@ -1,108 +0,0 @@
-module ugui;
-
-import std::io;
-
-/*       handle
- * +----+-----+---------------------+
- * |    |#####|                     |
- * +----+-----+---------------------+
- */
-fn ElemEvents! Ctx.slider_hor(&ctx, String label, Rect size)
-{
-    Id id = label.hash();
-
-	Elem *parent = ctx.get_parent()!;
-	Elem *c_elem = ctx.get_elem(id)!;
-	// add it to the tree
-	ctx.tree.add(id, ctx.active_div)!;
-
-	// 1. Fill the element fields
-	c_elem.type = ETYPE_SLIDER;
-
-	// if the element is new or the parent was updated then redo layout
-	if (c_elem.flags.is_new || parent.flags.updated) {
-		// 2. Layout
-		c_elem.bounds = ctx.position_element(parent, size, true);
-		c_elem.slider.handle = Rect{
-			.x = (short)(c_elem.bounds.x + (int)(c_elem.bounds.w*(1.0-0.25) * c_elem.slider.value)),
-			.y = c_elem.bounds.y,
-			.w = (short)(c_elem.bounds.w * 0.25),
-			.h = c_elem.bounds.h,
-		};
-	}
-
-	c_elem.events = ctx.get_elem_events(c_elem);
-	if (parent.flags.has_focus && c_elem.events.mouse_hover) {
-		if (point_in_rect(ctx.input.mouse.pos, c_elem.slider.handle) && c_elem.events.mouse_hold) {
-			short x = (short)clamp(ctx.input.mouse.pos.x - c_elem.slider.handle.w/2, c_elem.bounds.x, c_elem.bounds.x + c_elem.bounds.w - c_elem.slider.handle.w);
-			float v = (float)(c_elem.slider.handle.x-c_elem.bounds.x) / (float)(c_elem.bounds.w-c_elem.slider.handle.w);
-			c_elem.slider.handle.x = x;
-			c_elem.slider.value = v;
-			c_elem.events.update = true;
-		}
-	}
-
-	// Draw the slider background and handle
-	Color bg_color = uint_to_rgba(0x0000ffff);
-	Color handle_color = uint_to_rgba(0x0ff000ff);
-	ctx.push_rect(c_elem.bounds, bg_color)!;
-	ctx.push_rect(c_elem.slider.handle, handle_color)!;
-
-	return c_elem.events;
-}
-
-/*
- * +-+
- * | |
- * | |
- * +-+
- * |#| handle
- * |#|
- * +-+
- * | |
- * | |
- * +-+
- */
-fn ElemEvents! Ctx.slider_ver(&ctx, String label, Rect size)
-{
-	Id id = label.hash();
-
-	Elem *parent = ctx.get_parent()!;
-	Elem *c_elem = ctx.get_elem(id)!;
-	// add it to the tree
-	ctx.tree.add(id, ctx.active_div)!;
-
-	// 1. Fill the element fields
-	c_elem.type = ETYPE_SLIDER;
-
-	// if the element is new or the parent was updated then redo layout
-	if (c_elem.flags.is_new || parent.flags.updated) {
-		// 2. Layout
-		c_elem.bounds = ctx.position_element(parent, size, true);
-		c_elem.slider.handle = Rect{
-			.x = c_elem.bounds.x,
-			.y = (short)(c_elem.bounds.y + (int)(c_elem.bounds.h*(1.0-0.25) * c_elem.slider.value)),
-			.w = c_elem.bounds.w,
-			.h = (short)(c_elem.bounds.h * 0.25),
-		};
-	}
-
-	c_elem.events = ctx.get_elem_events(c_elem);
-	if (parent.flags.has_focus && c_elem.events.mouse_hover) {
-		if (point_in_rect(ctx.input.mouse.pos, c_elem.slider.handle) && c_elem.events.mouse_hold) {
-			short y = (short)clamp(ctx.input.mouse.pos.y - c_elem.slider.handle.h/2, c_elem.bounds.y, c_elem.bounds.y + c_elem.bounds.h - c_elem.slider.handle.h);
-			float v = (float)(c_elem.slider.handle.y-c_elem.bounds.y) / (float)(c_elem.bounds.h-c_elem.slider.handle.h);
-			c_elem.slider.handle.y = y;
-			c_elem.slider.value = v;
-			c_elem.events.update = true;
-		}
-	}
-
-	// Draw the slider background and handle
-	Color bg_color = uint_to_rgba(0x0000ffff);
-	Color handle_color = uint_to_rgba(0x0ff000ff);
-	ctx.push_rect(c_elem.bounds, bg_color)!;
-	ctx.push_rect(c_elem.slider.handle, handle_color)!;
-
-	return c_elem.events;
-}

src/ugui_text.c3

@@ -1,103 +0,0 @@
-module ugui;
-
-import std::io;
-import std::ascii;
-import grapheme;
-
-<*
-@require off != null
-*>
-fn Codepoint str_to_codepoint(char[] str, usz* off)
-{
-	Codepoint cp;
-	isz b = grapheme::decode_utf8(str, str.len, &cp);
-	if (b == 0 || b > str.len) {
-		return 0;
-	}
-	*off = b;
-	return cp;
-}
-
-fn Rect! Ctx.get_text_bounds(&ctx, String text, bool* update_atlas)
-{
-	Rect text_bounds;
-	short line_height = (short)ctx.font.ascender - (short)ctx.font.descender;
-	short line_gap = (short)ctx.font.linegap;
-	text_bounds.h = line_height;
-	Glyph* gp;
-
-	// TODO: account for unicode codepoints
-	short line_len;
-	Codepoint cp;
-	usz off, x;
-	while ((cp = str_to_codepoint(text[off..], &x)) != 0) {
-		off += x;
-		bool n;
-		if (!ascii::is_cntrl((char)cp)) {
-			gp = ctx.font.get_glyph(cp, &n)!;
-			line_len += gp.adv;
-			if (n) { *update_atlas = true; }
-		} else if (cp == '\n'){
-			text_bounds.h += line_height + line_gap;
-			line_len = 0;
-		} else {
-			continue;
-		}
-		if (line_len > text_bounds.w) {
-			text_bounds.w = line_len;
-		}
-	}
-
-	return text_bounds;
-}
-
-fn void! Ctx.text_unbounded(&ctx, String label, String text)
-{
-	Id id = label.hash();
-
-	Elem *parent = ctx.get_parent()!;
-	Elem *c_elem = ctx.get_elem(id)!;
-	// add it to the tree
-	ctx.tree.add(id, ctx.active_div)!;
-
-	// 1. Fill the element fields
-	// this resets the flags
-	c_elem.type = ETYPE_TEXT;
-
-	short baseline = (short)ctx.font.ascender;
-	short line_height = (short)ctx.font.ascender - (short)ctx.font.descender;
-	short line_gap = (short)ctx.font.linegap;
-	bool update_atlas;
-	// if the element is new or the parent was updated then redo layout
-	if (c_elem.flags.is_new || parent.flags.updated) {
-		Rect text_size = ctx.get_text_bounds(text, &update_atlas)!;
-
-		// 2. Layout
-		c_elem.bounds = ctx.position_element(parent, text_size, true);
-
-		// 3. Fill the button specific fields
-		c_elem.text.str = text;
-	}
-
-	if (update_atlas) {
-		// FIXME: atlas here is hardcoded, look at the todo in ugui_data
-		Cmd up = {
-			.type = CMD_UPDATE_ATLAS,
-			.update_atlas = {
-				.raw_buffer = ctx.font.atlas[0].buffer,
-				.width = ctx.font.atlas[0].width,
-				.height = ctx.font.atlas[0].height,
-			},
-		};
-		ctx.cmd_queue.enqueue(&up)!;
-	}
-
-	Cmd bounds = {
-		.type = CMD_RECT,
-		.rect.rect = c_elem.bounds,
-		.rect.color = uint_to_rgba(0x000000ff),
-	};
-	ctx.cmd_queue.enqueue(&bounds)!;
-
-	ctx.push_string(c_elem.bounds, text)!;
-}

src/vtree.c3

@@ -1,333 +0,0 @@
-module vtree(<ElemType>);
-
-import std::core::mem;
-import std::io;
-
-struct VTree {
-	usz elements;
-	ElemType[] vector; // vector of element ids
-	isz[] refs, ordered_refs;
-}
-
-fault VTreeError {
-	CANNOT_SHRINK,
-	INVALID_REFERENCE,
-	TREE_FULL,
-	REFERENCE_NOT_PRESENT,
-	INVALID_ARGUMENT,
-}
-
-macro VTree.ref_is_valid(&tree, isz ref) { return (ref >= 0 && ref < tree.refs.len); }
-macro VTree.ref_is_present(&tree, isz ref) { return tree.refs[ref] >= 0; }
-macro VTree.size(&tree) { return tree.refs.len; }
-
-// macro to zero an elemen
-macro @zero()
-{
-	$if $assignable(0, ElemType):
-		return 0;
-	$else
-		return ElemType{0};
-	$endif
-}
-
-fn void! VTree.init(&tree, usz size)
-{
-	tree.vector = mem::new_array(ElemType, size);
-	defer catch { (void)mem::free(tree.vector); }
-
-	tree.refs = mem::new_array(isz, size);
-	defer catch { (void)mem::free(tree.refs); }
-
-	tree.ordered_refs = mem::new_array(isz, size);
-	defer catch { (void)mem::free(tree.ordered_refs); }
-
-	// set all refs to -1, meaning invalid (free) element
-	tree.refs[..] = -1;
-
-	tree.elements = 0;
-}
-
-fn void VTree.free(&tree)
-{
-	(void)mem::free(tree.vector);
-	(void)mem::free(tree.refs);
-	(void)mem::free(tree.ordered_refs);
-}
-
-fn void VTree.pack(&tree)
-{
-	// TODO: add a PACKED flag to skip this
-
-	isz free_spot = -1;
-	for (usz i = 0; i < tree.size(); i++) {
-		if (tree.refs[i] == -1) {
-			free_spot = i;
-			continue;
-		}
-
-		// find a item that can be packed
-		if (free_spot >= 0 && tree.refs[i] >= 0) {
-			isz old_ref = i;
-
-			// move the item
-			tree.vector[free_spot] = tree.vector[i];
-			tree.refs[free_spot]   = tree.refs[i];
-
-			tree.vector[i] = @zero();
-			tree.refs[i]   = -1;
-
-			// and move all references
-			for (usz j = 0; j < tree.size(); j++) {
-				if (tree.refs[j] == old_ref) {
-				    tree.refs[j] = free_spot;
-				}
-			}
-
-			// mark the free spot as used
-			free_spot = -1;
-		}
-	}
-}
-
-fn void! VTree.resize(&tree, usz newsize)
-{
-	// return error when shrinking with too many elements
-	if (newsize < tree.elements) {
-		return VTreeError.CANNOT_SHRINK?;
-	}
-
-	// pack the vector when shrinking to avoid data loss
-	if ((int)newsize < tree.size()) {
-		// FIXME: packing destroys all references to elements of vec
-		//        so shrinking may cause dangling pointers
-		return VTreeError.CANNOT_SHRINK?;
-	}
-
-	usz old_size = tree.size();
-
-	tree.vector = ((ElemType*)mem::realloc(tree.vector, newsize*ElemType.sizeof))[:newsize];
-	defer catch { (void)mem::free(tree.vector); }
-
-	tree.refs = ((isz*)mem::realloc(tree.refs, newsize*isz.sizeof))[:newsize];
-	defer catch { (void)mem::free(tree.refs); }
-
-	tree.ordered_refs = ((isz*)mem::realloc(tree.ordered_refs, newsize*isz.sizeof))[:newsize];
-	defer catch { (void)mem::free(tree.ordered_refs); }
-
-	if (newsize > tree.size()) {
-		tree.vector[old_size..newsize-1] = @zero();
-		tree.refs[old_size..newsize-1] = -1;
-	}
-}
-
-// add an element to the tree, return it's ref
-fn isz! VTree.add(&tree, ElemType elem, isz parent)
-{
-	// invalid parent
-	if (!tree.ref_is_valid(parent)) {
-		return VTreeError.INVALID_REFERENCE?;
-	}
-
-	// no space left
-	if (tree.elements >= tree.size()) {
-		return VTreeError.TREE_FULL?;
-	}
-
-	// check if the parent exists
-	// if there are no elements in the tree the first add will set the root
-	if (!tree.ref_is_present(parent) && tree.elements != 0) {
-		return VTreeError.REFERENCE_NOT_PRESENT?;
-	}
-
-	// get the first free spot
-	isz free_spot = -1;
-	for (usz i = 0; i < tree.size(); i++) {
-		if (tree.refs[i] == -1) {
-			free_spot = i;
-			break;
-		}
-	}
-	if (free_spot < 0) {
-		return VTreeError.TREE_FULL?;
-	}
-
-	// finally add the element
-	tree.vector[free_spot] = elem;
-	tree.refs[free_spot]   = parent;
-	tree.elements++;
-
-	return free_spot;
-}
-
-// prune the tree starting from the ref
-// returns the number of pruned elements
-fn usz! VTree.prune(&tree, isz ref)
-{
-	if (!tree.ref_is_valid(ref)) {
-		return VTreeError.INVALID_REFERENCE?;
-	}
-
-	if (!tree.ref_is_present(ref)) {
-		return 0;
-	}
-
-	tree.vector[ref] = @zero();
-	tree.refs[ref]   = -1;
-	tree.elements--;
-
-	usz count = 1;
-	for (usz i = 0; tree.elements > 0 && i < tree.size(); i++) {
-		if (tree.refs[i] == ref) {
-			count += tree.prune(i)!;
-		}
-	}
-
-	return count;
-}
-
-// find the size of the subtree starting from ref
-fn usz! VTree.subtree_size(&tree, isz ref)
-{
-	if (!tree.ref_is_valid(ref)) {
-		return VTreeError.INVALID_REFERENCE?;
-	}
-
-	if (!tree.ref_is_present(ref)) {
-		return 0;
-	}
-
-	usz count = 1;
-	for (usz i = 0; i < tree.size(); i++) {
-		// only root has the reference to itself
-		if (tree.refs[i] == ref && ref != i) {
-			count += tree.subtree_size(i)!;
-		}
-	}
-
-	return count;
-}
-
-// iterate through the first level children, use a cursor like strtok_r
-fn isz! VTree.children_it(&tree, isz parent, isz *cursor)
-{
-	if (cursor == null) {
-		return VTreeError.INVALID_ARGUMENT?;
-	}
-
-	// if the cursor is out of bounds then we are done for sure
-	if (!tree.ref_is_valid(*cursor)) {
-		return VTreeError.INVALID_REFERENCE?;
-	}
-
-	// same for the parent, if it's invalid it can't have children
-	if (!tree.ref_is_valid(parent) || !tree.ref_is_present(parent)) {
-		return VTreeError.INVALID_REFERENCE?;
-	}
-
-	// find the first child, update the cursor and return the ref
-	for (isz i = *cursor; i < tree.size(); i++) {
-		if (tree.refs[i] == parent) {
-			*cursor = i + 1;
-			return i;
-		}
-	}
-
-	// if no children are found return -1
-	*cursor = -1;
-	return -1;
-}
-
-/* iterates trough every leaf of the subtree in the following manner
- * node [x], x: visit order
- *              [0]
- *             / | \
- *            / [2] [3]
- *          [1]      |
- *         /   \    [6]
- *       [4]   [5]
- */
-fn isz! VTree.level_order_it(&tree, isz ref, isz *cursor)
-{
-	if (cursor == null) {
-		return VTreeError.INVALID_ARGUMENT?;
-	}
-
-	isz[] queue = tree.ordered_refs;
-
-	// TODO: this could also be done when adding or removing elements
-	// first call, create a ref array ordered like we desire
-	if (*cursor == -1) {
-		*cursor = 0;
-		queue[..] = -1;
-
-		// iterate through the queue appending found children
-		isz pos, off;
-		do {
-			// printf ("ref=%d\n", ref);
-			for (isz i = 0; i < tree.size(); i++) {
-				if (tree.refs[i] == ref) {
-					queue[pos++] = i;
-				}
-			}
-
-			for (; ref == queue[off] && off < tree.size(); off++);
-			ref = queue[off];
-
-		} while (tree.ref_is_valid(ref));
-		// This line is why tree.ordered_refs has to be size+1
-		queue[off + 1] = -1;
-	}
-
-	// PRINT_ARR(queue, tree.size());
-	// return -1;
-
-	// on successive calls just iterate through the queue until we find an
-	// invalid ref, if the user set the cursor to -1 it means it has found what
-	// he needed, so free
-	if (*cursor < 0) {
-		return -1;
-	} else if (tree.ref_is_valid(*cursor)) {
-		return queue[(*cursor)++];
-	}
-
-	return -1;
-}
-
-fn isz! VTree.parentof(&tree, isz ref)
-{
-	if (!tree.ref_is_valid(ref)) {
-		return VTreeError.INVALID_REFERENCE?;
-	}
-
-	if (!tree.ref_is_present(ref)) {
-		return VTreeError.REFERENCE_NOT_PRESENT?;
-	}
-
-	return tree.refs[ref];
-}
-
-fn ElemType! VTree.get(&tree, isz ref)
-{
-	if (!tree.ref_is_valid(ref)) {
-		return VTreeError.INVALID_REFERENCE?;
-	}
-
-	if (!tree.ref_is_present(ref)) {
-		return VTreeError.REFERENCE_NOT_PRESENT?;
-	}
-
-	return tree.vector[ref];
-}
-
-fn void VTree.print(&tree)
-{
-	for (isz i = 0; i < tree.size(); i++) {
-		if (tree.refs[i] == -1) {
-			continue;
-		}
-		io::printf("[%d] {parent=%d, data=", i, tree.refs[i]);
-		io::print(tree.vector[i]);
-		io::printn("}");
-	}
-}

src/widgets/button.c3

@@ -0,0 +1,226 @@
+module ugui;
+
+import std::io;
+
+// button element
+struct ElemButton {
+	int filler;
+}
+
+
+macro Ctx.button(&ctx, String label = "", String icon = "", ...)
+	=> ctx.button_id(@compute_id($vasplat), label, icon);
+fn ElemEvents? Ctx.button_id(&ctx, Id id, String label, String icon)
+{
+	id = ctx.gen_id(id)!;
+	Elem* parent, elem;
+	ctx.get_elem(id, ETYPE_BUTTON)!.unpack(&elem, &parent);
+	Style* style = ctx.styles.get_style(@str_hash("button"));
+
+	Sprite* sprite = icon != "" ? ctx.sprite_atlas.get(icon)! : &&(Sprite){};
+	Rect icon_size = sprite.rect();
+
+	ushort min_size = style.size;
+	ushort half_lh = (ushort)(ctx.font.line_height() / 2);
+	ushort inner_pad = label != "" && icon != "" ? half_lh : 0;
+	/*
+	 * +--------------------------------------+
+	 * |   +--------+                         |
+	 * |   |        |   +-----------------+   |
+	 * |   |  icon  |   |     label       |   |
+	 * |   |        |   +-----------------+   |
+	 * |   +--------+<->|                     |
+	 * +-------------^------------------------+
+	 *               |inner_pad
+	 */
+	Point content_size = {
+		.x = icon_size.w + inner_pad, // text sizing is handled differently
+		.y = icon_size.h + inner_pad,
+	};
+	elem.layout.w = @fit(min_size);
+	elem.layout.h = @fit(min_size);
+	elem.layout.children.w = @exact(content_size.x);
+	elem.layout.children.h = @exact(content_size.y);
+	elem.layout.text = ctx.measure_string(label)!;
+	elem.layout.content_offset = style.margin + style.border + style.padding;
+
+	update_parent_size(elem, parent);
+
+	//elem.events = ctx.get_elem_events(elem);
+//	if (ctx.input.z_index == elem.z_index) println("true ", elem.z_index);
+	Rect content_bounds = elem.content_bounds();
+
+	Rect icon_bounds = {
+		.x = content_bounds.x,
+		.y = content_bounds.y,
+		.w = icon_size.w,
+		.h = icon_size.h
+	};
+	icon_bounds = icon_size.center_to(icon_bounds);
+
+	Rect text_bounds = {
+		.x = content_bounds.x + icon_bounds.w + inner_pad,
+		.y = content_bounds.y,
+		.w = content_bounds.w - icon_bounds.w - inner_pad,
+		.h = content_bounds.h,
+	};
+	//text_bounds = text_size.center_to(text_bounds);
+
+	bool is_active = elem.events.has_focus || elem.events.mouse_hover;
+	Style s = *style;
+	if (is_active) {
+		s.secondary = s.primary;
+		s.bg = s.accent;
+	}
+
+	ctx.push_rect(elem.bounds.pad(style.margin), parent.z_index, &s)!;
+	if (icon != "") {
+		ctx.push_sprite(icon_bounds, sprite.uv(), ctx.sprite_atlas.id, parent.z_index, type: sprite.type)!;
+	}
+	if (label != "") {
+		ctx.layout_string(label, text_bounds, CENTER, parent.z_index, style.fg)!;
+	}
+	return elem.events;
+}
+
+
+macro Ctx.checkbox(&ctx, String desc, bool* active, String tick_sprite = "", ...)
+	=> ctx.checkbox_id(@compute_id($vasplat), desc, active, tick_sprite);
+fn void? Ctx.checkbox_id(&ctx, Id id, String description, bool* active, String tick_sprite)
+{
+	id = ctx.gen_id(id)!;
+	Elem* parent, elem;
+	ctx.get_elem(id, ETYPE_BUTTON)!.unpack(&elem, &parent);
+	Style* style = ctx.styles.get_style(@str_hash("checkbox"));
+
+	short inner_pad = description != "" ? style.size/2 : 0;
+	/*
+	 *                       |< >| style.size/2
+	 * +---------------------|---|-----------+
+	 * |                     |    .-----. ---|--
+	 * |   +-----------------+   '  ###  '   | ^
+	 * |   |   description   |   | ##### |   | style.size
+	 * |   +-----------------+   .  ###  .   | v
+	 * |                          '-----' ---|--
+	 * +-------------------------|-------|---+
+	 *                           |<----->| style.size
+	 */
+
+	elem.layout.w = @fit(style.size);
+	elem.layout.h = @fit(style.size);
+	elem.layout.children.w = @exact(style.size + inner_pad);
+	elem.layout.children.h = @exact(style.size);
+	elem.layout.text = ctx.measure_string(description)!;
+	elem.layout.content_offset = style.margin + style.border + style.padding;
+
+	update_parent_size(elem, parent);
+
+	//elem.events = ctx.get_elem_events(elem);
+	if (elem.events.mouse_hover && elem.events.mouse_release) *active = !(*active);
+
+
+	Rect content_bounds = elem.bounds.pad(elem.layout.content_offset);
+	Rect text_bounds = {
+		.x = content_bounds.x,
+		.y = content_bounds.y,
+		.w = content_bounds.w - inner_pad - style.size,
+		.h = content_bounds.h
+	};
+	Rect check_bounds = {
+		.x = content_bounds.x + text_bounds.w + inner_pad,
+		.y = content_bounds.y + (content_bounds.h - style.size)/2,
+		.w = style.size,
+		.h = style.size,
+	};
+
+	Style s;
+	s.bg = style.bg;
+	s.secondary = style.secondary;
+	s.border = style.border;
+	s.radius = style.radius;
+
+	ctx.layout_string(description, text_bounds, CENTER, parent.z_index, style.fg)!;
+	if (tick_sprite != "") {
+		ctx.push_rect(check_bounds, parent.z_index, &s)!;
+		if (*active) {
+			Sprite* sprite = ctx.sprite_atlas.get(tick_sprite)!;
+			Id tex_id = ctx.sprite_atlas.id;
+			ctx.push_sprite(check_bounds, sprite.uv(), tex_id, parent.z_index, type: sprite.type)!;
+		}
+	} else {
+		if (*active) {
+			s.bg = style.primary;
+			ctx.push_rect(check_bounds, parent.z_index, &s)!;
+		} else {
+			ctx.push_rect(check_bounds, parent.z_index, &s)!;
+		}
+	}
+}
+
+macro Ctx.toggle(&ctx, String desc, bool* active)
+	=> ctx.toggle_id(@compute_id($vasplat), desc, active);
+fn void? Ctx.toggle_id(&ctx, Id id, String description, bool* active)
+{
+	id = ctx.gen_id(id)!;
+
+	Elem* parent, elem;
+	ctx.get_elem(id, ETYPE_BUTTON)!.unpack(&elem, &parent);
+	Style* style = ctx.styles.get_style(@str_hash("toggle"));
+
+	short inner_pad = description != "" ? style.size/2 : 0;
+	/*
+	 *                       |< >| style.size/2
+	 * +---------------------|---|-----------------+
+	 * |                     |    .-----------. ---|--
+	 * |   +-----------------+   ' #####       '   | ^
+	 * |   |   description   |   | #####       |   | style.size
+	 * |   +-----------------+   . #####       .   | v
+	 * |                          '-----------' ---|--
+	 * +-------------------------|-------------|---+
+	 *                           |<----->| style.size*2
+	 */
+
+	elem.layout.w = @fit(style.size*2);
+	elem.layout.h = @fit(style.size);
+	elem.layout.children.w = @exact(style.size*2 + inner_pad);
+	elem.layout.children.h = @exact(style.size);
+	elem.layout.text = ctx.measure_string(description)!;
+	elem.layout.content_offset = style.margin + style.border + style.padding;
+
+	update_parent_size(elem, parent);
+
+	//elem.events = ctx.get_elem_events(elem);
+	if (elem.events.mouse_hover && elem.events.mouse_release) *active = !(*active);
+
+	Rect content_bounds = elem.bounds.pad(elem.layout.content_offset);
+	Rect text_bounds = {
+		.x = content_bounds.x,
+		.y = content_bounds.y,
+		.w = content_bounds.w - inner_pad - style.size*2,
+		.h = content_bounds.h
+	};
+	Rect toggle_bounds = {
+		.x = content_bounds.x + text_bounds.w + inner_pad,
+		.y = content_bounds.y + (content_bounds.h - style.size)/2,
+		.w = style.size*2,
+		.h = style.size,
+	};
+	Rect toggle = {
+		.x = toggle_bounds.x + (*active ? style.size : 0),
+		.y = toggle_bounds.y,
+		.w = style.size,
+		.h = style.size
+	};
+
+	Style s;
+	s.bg = style.bg;
+	s.secondary = style.secondary;
+	s.border = style.border;
+	s.radius = style.radius;
+	ctx.layout_string(description, text_bounds, CENTER, parent.z_index, style.fg)!;
+	ctx.push_rect(toggle_bounds, parent.z_index, &s)!;
+	s.bg = style.primary;
+	s.border = {};
+	ctx.push_rect(toggle.pad(style.border), parent.z_index, &s)!;
+
+}

src/widgets/div.c3

@@ -0,0 +1,252 @@
+module ugui;
+
+import std::io;
+import std::math;
+
+// div element
+struct ElemDiv {
+	struct scroll_x {
+		bool enabled;
+		bool on;
+		float value;
+	}
+	struct scroll_y {
+		bool enabled;
+		bool on;
+		float value;
+	}
+}
+
+
+macro Ctx.@center(&ctx, LayoutDirection dir = ROW, ...; @body())
+{
+	return ctx.@div(@grow(), @grow(), dir, CENTER) {
+		@body();
+	}!;
+}
+
+macro Ctx.@row(&ctx, Anchor anchor = TOP_LEFT, ...; @body())
+{
+	return ctx.@div(@fit(), @fit(), ROW, anchor: anchor) {
+		@body();
+	}!;
+}
+
+macro Ctx.@column(&ctx, Anchor anchor = TOP_LEFT, ...; @body())
+{
+	return ctx.@div(@fit(), @fit(), COLUMN, anchor: anchor) {
+		@body();
+	}!;
+}
+
+
+// useful macro to start and end a div, capturing the trailing block
+macro Ctx.@div(&ctx,
+               Size width = @grow, Size height = @grow,
+               LayoutDirection dir = ROW,
+               Anchor anchor = TOP_LEFT,
+               bool absolute = false, Point off = {},
+               bool scroll_x = false, bool scroll_y = false,
+               ...;
+               @body()
+              )
+{
+	ctx.div_begin(width, height, dir, anchor, absolute, off, scroll_x, scroll_y, $vasplat)!;
+	@body();
+	return ctx.div_end()!;
+}
+
+macro Ctx.div_begin(&ctx,
+                    Size width = @grow(), Size height = @grow(),
+                    LayoutDirection dir = ROW,
+                    Anchor anchor = TOP_LEFT,
+                    bool absolute = false, Point off = {},
+                    bool scroll_x = false, bool scroll_y = false,
+                    ...
+                   )
+{
+	return ctx.div_begin_id(@compute_id($vasplat), width, height, dir, anchor, absolute, off, scroll_x, scroll_y);
+}
+
+fn void? Ctx.div_begin_id(&ctx,
+                          Id id,
+                          Size width, Size height,
+                          LayoutDirection dir,
+                          Anchor anchor,
+                          bool absolute, Point off,
+                          bool scroll_x, bool scroll_y
+                         )
+{
+	id = ctx.gen_id(id)!;
+
+	Elem* parent, elem;
+	ctx.get_elem(id, ETYPE_DIV)!.unpack(&elem, &parent);
+	ctx.active_div = elem.tree_idx;
+
+	Style* style = ctx.styles.get_style(@str_hash("div"));
+
+	elem.div.scroll_x.enabled = scroll_x;
+	elem.div.scroll_y.enabled = scroll_y;
+	
+	// update layout with correct info
+	elem.layout = {
+		.w = width,
+		.h = height,
+		.dir = dir,
+		.anchor = anchor,
+		.content_offset = style.margin + style.border + style.padding,
+		.absolute = absolute,
+	};
+	if (absolute) {
+		elem.layout.origin.x = off.x;
+		elem.layout.origin.y = off.y;
+	}
+
+	ctx.push_rect(elem.bounds.pad(style.margin), elem.z_index, style)!;
+
+	// update the ctx scissor, it HAS to be after drawing the background
+	ctx.div_scissor = elem.bounds.pad(elem.layout.content_offset).max({0,0,0,0});
+	ctx.push_scissor(ctx.div_scissor, elem.z_index)!;
+
+	//elem.events = ctx.get_elem_events(elem);
+
+	// TODO: check active
+	// TODO: check resizeable
+}
+
+fn Id? Ctx.div_end(&ctx)
+{
+	Elem* elem = ctx.get_active_div()!;
+	Style* style = ctx.styles.get_style(@str_hash("div"));
+	Rect bounds = elem.bounds.pad(style.margin + style.border);
+
+	// set the scrollbar flag, is used in layout
+	Point cbc = elem.children_bounds.bottom_right();
+	Point bc = elem.bounds.bottom_right();
+	// horizontal overflow
+	elem.div.scroll_x.on = cbc.x > bc.x && elem.div.scroll_x.enabled;
+	// vertical overflow
+	elem.div.scroll_y.on = cbc.y > bc.y && elem.div.scroll_y.enabled;
+
+	Id hsid_raw = @str_hash("div_scrollbar_horizontal");
+	Id vsid_raw = @str_hash("div_scrollbar_vertical");
+	Id hsid_real = ctx.gen_id(hsid_raw)!;
+	Id vsid_real = ctx.gen_id(vsid_raw)!;
+
+	if (elem.div.scroll_y.on) {
+		if (ctx.input.events.mouse_scroll && ctx.hover_id == elem.id && !(ctx.get_mod() & KMOD_SHIFT)) {
+			elem.div.scroll_y.value += ctx.input.mouse.scroll.y * 0.07f;
+			elem.div.scroll_y.value = math::clamp(elem.div.scroll_y.value, 0.0f, 1.0f);
+		}
+		ctx.scrollbar(vsid_raw, &elem.div.scroll_y.value, max((float)bc.y / cbc.y, (float)0.15))!;
+		elem.layout.scroll_offset.y = (short)(elem.div.scroll_y.value*(float)(elem.children_bounds.h-elem.bounds.h));
+	} else {
+		elem.div.scroll_y.value = 0;
+	}
+
+
+	if (elem.div.scroll_x.on) {
+		if (ctx.input.events.mouse_scroll && ctx.hover_id == elem.id) {
+			if (ctx.get_mod() & KMOD_SHIFT) { // horizontal scroll with shift
+				elem.div.scroll_x.value += ctx.input.mouse.scroll.y * 0.07f;
+				elem.div.scroll_x.value = math::clamp(elem.div.scroll_x.value, 0.0f, 1.0f);
+			} else {
+				elem.div.scroll_x.value += ctx.input.mouse.scroll.x * 0.07f;
+				elem.div.scroll_x.value = math::clamp(elem.div.scroll_x.value, 0.0f, 1.0f);
+			}
+		}
+		ctx.scrollbar(hsid_raw, &elem.div.scroll_x.value, max((float)bc.x / cbc.x, (float)0.15), false)!;
+		elem.layout.scroll_offset.x = (short)(elem.div.scroll_x.value*(float)(elem.children_bounds.w-elem.bounds.w));
+	} else {
+		elem.div.scroll_x.value = 0;
+	}
+
+	// the active_div returns to the parent of the current one
+	ctx.active_div = ctx.tree.parentof(ctx.active_div)!;
+	Elem* parent = ctx.get_parent()!;
+	ctx.div_scissor = parent.bounds.pad(parent.layout.content_offset).max({0,0,0,0});
+	ctx.reset_scissor(elem.z_index)!;
+
+	update_parent_size(elem, parent);
+
+	return elem.id;
+}
+
+<* @param[&inout] state *>
+macro Ctx.@popup(&ctx, bool* state,
+             Point pos,
+             Size width, Size height,
+             LayoutDirection dir = ROW, Anchor anchor = TOP_LEFT, 
+             bool scroll_x = false, bool scroll_y = false,
+             ...; @body())
+{
+	if (*state) {
+		*state = ctx.popup_begin(pos, width, height, dir, anchor, scroll_x, scroll_y)!;
+		@body();
+		ctx.div_end()!;
+	}
+}
+
+macro bool? Ctx.popup_begin(&ctx, Point pos,
+                      Size width, Size height,
+                      LayoutDirection dir = ROW, Anchor anchor = TOP_LEFT, 
+                      bool scroll_x = false, bool scroll_y = false,
+                      ...
+                     )
+	=> ctx.popup_begin_id(@compute_id($vasplat), pos, width, height, dir, anchor, scroll_x, scroll_y);
+fn bool? Ctx.popup_begin_id(&ctx, 
+                       Id id, 
+                       Point pos, 
+                       Size width, Size height,
+                       LayoutDirection dir, Anchor anchor, 
+                       bool scroll_x, bool scroll_y
+                      )
+{
+	id = ctx.gen_id(id)!;
+
+	Elem* parent, elem;
+	ctx.get_elem(id, ETYPE_DIV)!.unpack(&elem, &parent);
+	ctx.active_div = elem.tree_idx;
+
+	Style* style = ctx.styles.get_style(@str_hash("popup"));
+
+	elem.div.scroll_x.enabled = scroll_x;
+	elem.div.scroll_y.enabled = scroll_y;
+	elem.z_index++;
+
+	// update layout with correct info
+	elem.layout = {
+		.w = width,
+		.h = height,
+		.dir = dir,
+		.anchor = anchor,
+		.content_offset = style.margin + style.border + style.padding,
+		.absolute = true,
+		.origin.x = pos.x - parent.bounds.x,
+		.origin.y = pos.y - parent.bounds.y,
+	};
+
+	// if the position is not the one expected then request a frame-skip to not flash appear in the
+	// wrong position for one frame
+	if (elem.bounds.position() != pos) {
+		ctx.skip_frame = true;
+		return true;
+	}
+
+	ctx.push_rect(elem.bounds.pad(style.margin), elem.z_index, style)!;
+
+	// update the ctx scissor, it HAS to be after drawing the background
+	ctx.div_scissor = elem.bounds.pad(elem.layout.content_offset).max({0,0,0,0});
+	ctx.push_scissor(ctx.div_scissor, elem.z_index)!;
+
+	//elem.events = ctx.get_elem_events(elem);
+	
+	// check close condition, mouse release anywhere outside the div bounds
+	if ((ctx.mouse_released() & BTN_ANY) && ctx.input.mouse.pos.outside(elem.bounds)) {
+		return false;
+	}
+
+	// TODO: check active
+	// TODO: check resizeable
+	return true;
+}

src/widgets/separator.c3

@@ -0,0 +1,56 @@
+module ugui;
+
+
+macro Ctx.separator(&ctx, Size width, Size height, ...)
+	=> ctx.separator_id(@compute_id($vasplat), width, height);
+fn void? Ctx.separator_id(&ctx, Id id, Size width, Size height)
+{
+	id = ctx.gen_id(id)!;
+	Elem* parent, elem;
+	ctx.get_elem(id, ETYPE_NONE)!.unpack(&elem, &parent);
+
+	elem.layout.w = width;
+	elem.layout.h = height;
+
+	update_parent_size(elem, parent);
+}
+
+
+macro Ctx.hor_line(&ctx, ...)
+	=> ctx.hor_line_id(@compute_id($vasplat));
+fn void? Ctx.hor_line_id(&ctx, Id id)
+{
+	id = ctx.gen_id(id)!;
+	Elem* parent, elem;
+	ctx.get_elem(id, ETYPE_NONE)!.unpack(&elem, &parent);
+	Style* style = ctx.styles.get_style(@str_hash("separator"));
+
+	elem.layout.w = @grow();
+	elem.layout.h = @exact(style.size);
+	elem.layout.content_offset = style.margin + style.border + style.padding;
+
+	update_parent_size(elem, parent);
+
+	Rect r = elem.bounds.pad(elem.layout.content_offset);
+	ctx.push_rect(r, elem.z_index, style)!;
+}
+
+
+macro Ctx.ver_line(&ctx, ...)
+	=> ctx.ver_line_id(@compute_id($vasplat));
+fn void? Ctx.ver_line_id(&ctx, Id id)
+{
+	id = ctx.gen_id(id)!;
+	Elem* parent, elem;
+	ctx.get_elem(id, ETYPE_NONE)!.unpack(&elem, &parent);
+	Style* style = ctx.styles.get_style(@str_hash("separator"));
+
+	elem.layout.w = @exact(style.size);
+	elem.layout.h = @grow();
+	elem.layout.content_offset = style.margin + style.border + style.padding;
+
+	update_parent_size(elem, parent);
+
+	Rect r = elem.bounds.pad(elem.layout.content_offset);
+	ctx.push_rect(r, elem.z_index, style)!;
+}

src/widgets/slider.c3

@@ -0,0 +1,185 @@
+module ugui;
+
+import std::io;
+import std::math;
+
+// slider element
+struct ElemSlider {
+	Rect handle;
+}
+
+/*       handle
+ * +----+-----+---------------------+
+ * |    |#####|                     |
+ * +----+-----+---------------------+
+ */
+macro Ctx.slider_hor(&ctx, Size w, Size h, float* value, float hpercent = 0.25, ...)
+	=> ctx.slider_hor_id(@compute_id($vasplat), w, h, value, hpercent);
+<*
+@require value != null
+*>
+fn ElemEvents? Ctx.slider_hor_id(&ctx, Id id, Size w, Size h, float* value, float hpercent = 0.25)
+{
+	id = ctx.gen_id(id)!;
+
+	Elem* parent, elem;
+	ctx.get_elem(id, ETYPE_SLIDER)!.unpack(&elem, &parent);
+	Style* style = ctx.styles.get_style(@str_hash("slider"));
+
+	elem.layout.w = w;
+	elem.layout.h = h;
+	elem.layout.content_offset = style.margin + style.border + style.padding;
+	update_parent_size(elem, parent);
+
+	Rect bg_bounds = elem.bounds.pad(style.margin);
+	Rect content_bounds = elem.bounds.pad(style.margin + style.border + style.padding);
+
+	// handle width
+	short hw = (short)(content_bounds.w * hpercent);
+	Rect handle = {
+		.x = calc_slider(content_bounds.x, content_bounds.w-hw, *value),
+		.y = content_bounds.y,
+		.w = hw,
+		.h = content_bounds.h,
+	};
+	elem.slider.handle = handle;
+
+	Point m = ctx.input.mouse.pos;
+	//elem.events = ctx.get_elem_events(elem);
+
+	if (elem.events.has_focus && ctx.is_mouse_down(BTN_LEFT)) {
+		*value = calc_value(content_bounds.x, m.x, content_bounds.w, hw);
+		elem.slider.handle.x = calc_slider(content_bounds.x, content_bounds.w-hw, *value);
+		elem.events.update = true;
+	}
+
+	// Draw the slider background and handle
+	Style s = *style;
+	Rect padding = s.padding;
+	s.padding = {};
+	ctx.push_rect(bg_bounds, parent.z_index, &s)!;
+	s.bg = s.primary;
+	s.padding = padding;
+	s.border = {};
+	ctx.push_rect(elem.slider.handle, parent.z_index, &s)!;
+
+	return elem.events;
+}
+
+
+/*
+ * +--+
+ * |  |
+ * |  |
+ * +--+
+ * |##| handle
+ * |##|
+ * +--+
+ * |  |
+ * |  |
+ * +--+
+ */
+macro Ctx.slider_ver(&ctx, Size w, Size h, float* value, float hpercent = 0.25, ...)
+	=> ctx.slider_ver_id(@compute_id($vasplat), w, h, value, hpercent);
+fn ElemEvents? Ctx.slider_ver_id(&ctx, Id id, Size w, Size h, float* value, float hpercent = 0.25)
+{
+	id = ctx.gen_id(id)!;
+
+	Elem* parent, elem;
+	ctx.get_elem(id, ETYPE_SLIDER)!.unpack(&elem, &parent);
+	Style* style = ctx.styles.get_style(@str_hash("slider"));
+
+	elem.layout.w = w;
+	elem.layout.h = h;
+	elem.layout.content_offset = style.margin + style.border + style.padding;
+	update_parent_size(elem, parent);
+
+	// 2. Layout
+	Rect bg_bounds = elem.bounds.pad(style.margin);
+	Rect content_bounds = elem.bounds.pad(style.margin + style.border + style.padding);
+
+	// handle height
+	short hh = (short)(content_bounds.h * hpercent);
+	Rect handle = {
+		.x = content_bounds.x,
+		.y = calc_slider(content_bounds.y, content_bounds.h-hh, *value),
+		.w = content_bounds.w,
+		.h = hh,
+	};
+	elem.slider.handle = handle;
+
+	Point m = ctx.input.mouse.pos;
+	//elem.events = ctx.get_elem_events(elem);
+
+	if (elem.events.has_focus && ctx.is_mouse_down(BTN_LEFT)) {
+		*value = calc_value(content_bounds.y, m.y, content_bounds.h, hh);
+		elem.slider.handle.y = calc_slider(content_bounds.y, content_bounds.h-hh, *value);
+		elem.events.update = true;
+	}
+
+	// Draw the slider background and handle
+	Style s = *style;
+	Rect padding = s.padding;
+	s.padding = {};
+	ctx.push_rect(bg_bounds, parent.z_index, &s)!;
+	s.bg = s.primary;
+	s.padding = padding;
+	s.border = {};
+	ctx.push_rect(elem.slider.handle, parent.z_index, &s)!;
+
+	return elem.events;
+}
+
+
+fn void? Ctx.scrollbar(&ctx, Id id, float *value, float handle_percent, bool vertical = true)
+{
+	id = ctx.gen_id(id)!;
+
+	Elem* parent, elem;
+	ctx.get_elem(id, ETYPE_SLIDER)!.unpack(&elem, &parent);
+	Style* style = ctx.styles.get_style(@str_hash("scrollbar"));
+
+	Rect pb = parent.bounds.pad(parent.layout.content_offset);
+	if (vertical) {
+		elem.layout.w = @exact(style.size);
+		elem.layout.h = @grow();
+		elem.layout.origin.x = pb.w - style.size;
+		elem.layout.origin.y = 0;
+	} else {
+		elem.layout.w = @grow();
+		elem.layout.h = @exact(style.size);
+		elem.layout.origin.x = 0;
+		elem.layout.origin.y = pb.h - style.size;
+	}
+	elem.layout.content_offset = style.margin + style.border + style.padding;
+	elem.layout.absolute = true;
+	update_parent_size(elem, parent);
+
+	Rect content_bounds = elem.bounds.pad(elem.layout.content_offset);
+
+	short o = vertical ? content_bounds.y : content_bounds.x;
+	short m = vertical ? ctx.input.mouse.pos.y : ctx.input.mouse.pos.x;
+	short s = vertical ? content_bounds.h : content_bounds.w;
+	short h = (short)((float)s * handle_percent);
+	if (elem.events.has_focus && ctx.is_mouse_down(BTN_LEFT)) {
+		*value = calc_value(o, m, s, h);
+		elem.events.update = true;
+	}
+	short handle_pos = calc_slider(o, s-h, *value);
+
+	elem.slider.handle = {
+		.x = vertical ? content_bounds.x : handle_pos,
+		.y = vertical ? handle_pos : content_bounds.y,
+		.w = vertical ? content_bounds.w : h,
+		.h = vertical ? h : content_bounds.h,
+	};
+
+
+	Rect bg_bounds = elem.bounds.pad(style.margin);
+	ctx.push_rect(bg_bounds, parent.z_index, style)!;
+	ctx.push_rect(elem.slider.handle, parent.z_index, &&(Style){.bg = style.primary, .radius = style.radius})!;
+}
+
+macro short calc_slider(short off, short dim, float value) => (short)off + (short)(dim * value);
+macro float calc_value(short off, short mouse, short dim, short slider)
+	=> math::clamp((float)(mouse-off-slider/2)/(float)(dim-slider), 0.0f, 1.0f);

src/widgets/sprite.c3

@@ -0,0 +1,41 @@
+module ugui;
+
+struct ElemSprite {
+	Id id;
+}
+
+macro Ctx.sprite(&ctx, String name, short size = 0, ...)
+	=> ctx.sprite_id(@compute_id($vasplat), name, size);
+fn void? Ctx.sprite_id(&ctx, Id id, String name, short size = 0)
+{
+	id = ctx.gen_id(id)!;
+	Elem* parent, elem;
+	ctx.get_elem(id, ETYPE_SPRITE)!.unpack(&elem, &parent);
+
+	Style* style = ctx.styles.get_style(@str_hash("sprite"));
+	Sprite* sprite = ctx.sprite_atlas.get(name)!;
+	elem.sprite.id = ctx.get_sprite_atlas_id(name);
+
+	// scale the sprite so that the biggest dimension becomes "size"
+	short width = sprite.w;
+	short height = sprite.h;
+	if (size > 0) {
+		if (sprite.w >= sprite.h) {
+			height = (short)(size * (float)height/width);
+			width = size;
+		} else {
+			width = (short)(size * (float)width/height);
+			height = size;
+		}
+	}
+
+	elem.layout.w = elem.layout.children.w = @exact(width);
+	elem.layout.h = elem.layout.children.h = @exact(height);
+	elem.layout.content_offset = style.margin + style.border + style.padding;
+
+	update_parent_size(elem, parent);
+
+	Id tex_id = ctx.sprite_atlas.id;
+	Rect content_bounds = elem.bounds.pad(elem.layout.content_offset);
+	return ctx.push_sprite(content_bounds, sprite.uv(), tex_id, parent.z_index, type: sprite.type)!;
+}

src/widgets/text.c3

@@ -0,0 +1,97 @@
+module ugui;
+
+import std::io;
+
+struct ElemText {
+	Id hash;
+	TextSize size;
+	TextEdit* te;
+}
+
+/* Layout some text without bounds.
+ * There is a limitation where the current frame bounds are based on the last frame, this is usually
+ * not a problem but it is in the situation where the text changes almost all frames.
+ */
+macro Ctx.text(&ctx, String text, ...)
+	=> ctx.text_id(@compute_id($vasplat), text);
+fn void? Ctx.text_id(&ctx, Id id, String text)
+{
+	id = ctx.gen_id(id)!;
+
+	Elem* parent, elem;
+	ctx.get_elem(id, ETYPE_TEXT)!.unpack(&elem, &parent);
+	Style* style = ctx.styles.get_style(@str_hash("text"));
+
+	Id text_hash = text.hash();
+	if (elem.flags.is_new || elem.text.hash != text_hash) {
+		elem.text.size = ctx.measure_string(text)!;
+	}
+	elem.text.hash = text_hash;
+
+	elem.layout.w = @fit(style.size);
+	elem.layout.h = @fit(style.size);
+	elem.layout.text = elem.text.size;
+	elem.layout.content_offset = style.margin + style.border + style.padding;
+
+	update_parent_size(elem, parent);
+
+	ctx.layout_string(text, elem.bounds.pad(elem.layout.content_offset), TOP_LEFT, parent.z_index, style.fg)!;
+}
+
+
+macro Ctx.text_box(&ctx, Size w, Size h, TextEdit* te, Anchor text_alignment = TOP_LEFT, bool reflow = true, ...)
+	=> ctx.text_box_id(@compute_id($vasplat), w, h, te, text_alignment, reflow);
+fn ElemEvents? Ctx.text_box_id(&ctx, Id id, Size w, Size h, TextEdit* te, Anchor text_alignment, bool reflow)
+{
+	id = ctx.gen_id(id)!;
+
+	Elem* parent, elem;
+	ctx.get_elem(id, ETYPE_TEXT)!.unpack(&elem, &parent);
+	Style* style = ctx.styles.get_style(@str_hash("text-box"));
+
+	elem.text.te = te;
+
+	Id text_hash = te.to_string().hash();
+	if (elem.flags.is_new || elem.text.hash != text_hash) {
+		elem.text.size = ctx.measure_string(te.to_string())!;
+	}
+	elem.text.hash = text_hash;
+
+	elem.layout.w = w;
+	elem.layout.h = h;
+	elem.layout.text = elem.text.size;
+	elem.layout.content_offset = style.margin + style.border + style.padding;
+
+	update_parent_size(elem, parent);
+
+	// check input and update the text
+	//elem.events = ctx.get_elem_events(elem);
+
+	if (elem.events.text_input || elem.events.key_press) {
+		ctx.text_edit(elem.text.te);
+	}
+
+	Rect bg_bounds = elem.bounds.pad(style.margin);
+	Rect text_bounds = elem.bounds.pad(elem.layout.content_offset);
+	ctx.push_rect(bg_bounds, parent.z_index, style)!;
+	String s = elem.text.te.to_string();
+	if (te.sel_len) {
+		usz start = te.sel_len > 0 ? te.cursor : te.cursor + te.sel_len;
+		usz end = (te.sel_len > 0 ? te.cursor + te.sel_len : te.cursor) - 1;
+		ctx.draw_string_selection(s, text_bounds, text_alignment, start, end, parent.z_index, style.accent, reflow)!;
+	}
+	ctx.layout_string(s, text_bounds, text_alignment, parent.z_index, style.fg, reflow)!;
+
+	// draw the cursor if the element has focus
+	if (elem.events.has_focus) {
+		if (elem.events.mouse_press || elem.events.mouse_hold) {
+			usz cur = ctx.hit_test_string(s, text_bounds, text_alignment, ctx.input.mouse.pos, reflow)!;
+			bool select = (elem.events.mouse_hold && !elem.events.mouse_press) || (ctx.get_mod() & KMOD_SHIFT);
+			te.set_cursor(cur, select);
+		}
+		Rect cur = ctx.get_cursor_position(s, text_bounds, text_alignment, te.cursor, reflow)!;
+		cur.w = 2;
+		ctx.push_rect(cur, parent.z_index, &&(Style){.bg = style.fg})!;
+	}
+	return elem.events;
+}

test/test_bitsruct.c3

@@ -1,14 +0,0 @@
-bitstruct Bits : uint {
-	bool a : 0;
-	bool b : 1;
-	bool c : 2;
-}
-
-fn int main()
-{
-	Bits a = {false, true, false};
-	Bits b = {true, true, false};
-	Bits c = a | b;
-
-	return 0;
-}

test/test_bittype.c3

@@ -1,10 +0,0 @@
-import std::io;
-import std::collections::bitset;
-
-def Bits = bitset::BitSet(<128>);
-
-fn void main()
-{
-    Bits b;
-	io::printn($typeof(b.data[0]).sizeof);
-}

test/test_custom_hash.c3

@@ -1,14 +0,0 @@
-import std::collections::map;
-
-def Codepoint = uint;
-fn uint Codepoint.hash(Codepoint code) => code < 128 ? code : ((uint)code).hash();
-def CodeMap = map::HashMap(<Codepoint, Codepoint>);
-
-
-fn int main()
-{
-    CodeMap m;
-    m.new_init();
-    m.free();
-    return 0;
-}

test/test_font.c3

@@ -1,6 +0,0 @@
-import rl;
-
-fn int main(void)
-{
-	return 0;
-}

test/test_union.c3

@@ -1,26 +0,0 @@
-
-struct CmdA {
-	int a, b;
-}
-
-struct CmdB {
-	float a, b;
-}
-
-union AnyCmd {
-	CmdA a;
-	CmdB b;
-}
-
-struct Cmd {
-	int type;
-	AnyCmd cmd;
-}
-
-fn int main()
-{
-	Cmd c;
-	c.type = 1;
-	c.cmd.a = {.a = 1, .b = 2};
-	return 0;
-}

test/test_vtree.c3

@@ -1,7 +0,0 @@
-import std::io;
-import vtree;
-
-fn int main()
-{
-    return 0;
-}

test/ugui_font.c3

@@ -1,226 +0,0 @@
-module ugui;
-
-import cache;
-//#include <grapheme.h>
-//#include <assert.h>
-
-//#include "stb_truetype.h"
-//#include "stbimage_write.h"
-
-// unicode code point, different type for a different hash
-def Codepoint = uint;
-
-/* width and height of a glyph contain the kering advance
- * (u,v)
- *   +-------------*---+ -
- *   |       ^     |   | ^
- *   |       |oy   |   | |
- *   |       v     |   | |
- *   |      .ii.   |   | |
- *   |     @@@@@@. |<->| |
- *   |    V@Mio@@o |adv| |h
- *   |    :i.  V@V |   | |
- *   |      :oM@@M |   | |
- *   |    :@@@MM@M |   | |
- *   |    @@o  o@M |   | |
- *   |<->:@@.  M@M |   | |
- *   |ox  @@@o@@@@ |   | |
- *   |    :M@@V:@@.|   | v
- *   +-------------*---+ -
- *   |<------------->|
- *           w
- */
-struct Glyph {
-    Codepoint code;
-	uint u, v;
-	ushort w, h, a, x, y;
-}
-
-def GlyphCache = cache::Cache(<Codepoint, Glyph, 1024>);
-
-// identity map the ASCII range
-fn uint Codepoint.hash(Codepoint code) => code < 128 ? code : ((uint)code).hash();
-
-struct FontAtlas {
-	uint width, height;
-	char* atlas;
-	uint glyph_max_w, glyph_max_h;
-	int size;
-	int file_size;
-	char *file;
-	void *priv;
-}
-
-
-macro is_utf8(char c) => c & 0x80;
-const uint BDEPTH = 1;
-const uint BORDER = 4;
-
-// FIXME: as of now only monospaced fonts look decent since no
-//        kerning information is stored
-
-struct Priv @private {
-	stbtt_fontinfo stb;
-	float scale;
-	int baseline;
-	unsigned char *bitmap;
-	struct cache c;
-}
-//#define PRIV(x) ((struct priv *)x->priv)
-
-
-struct font_atlas * font_init(void)
-{
-	struct font_atlas *p = emalloc(sizeof(struct font_atlas));
-	memset(p, 0, sizeof(struct font_atlas));
-	p->priv = emalloc(sizeof(struct priv));
-	memset(p->priv, 0, sizeof(struct priv));
-	PRIV(p)->c = cache_init();
-	return p;
-}
-
-
-// loads a font into memory, storing all the ASCII characters in the atlas, each font
-// atlas structure holds glyphs of a specific size in pixels
-// NOTE: size includes ascend and descend (so 12 does not mean that 'A' is 12px tall)
-int font_load(struct font_atlas *atlas, const char *path, int size)
-{
-	if (!atlas || !path)
-		return -1;
-
-	int err;
-
-	dump_file(path, &(atlas->file), &(atlas->file_size));
-
-	err = stbtt_InitFont(&(PRIV(atlas)->stb), (unsigned char *)atlas->file, 0);
-	if (err == 0) return -1;
-
-	int ascent, descent, linegap, baseline;
-	int x0,y0,x1,y1;
-	float scale;
-	stbtt_GetFontVMetrics(&(PRIV(atlas)->stb), &ascent, &descent, &linegap);
-	stbtt_GetFontBoundingBox(&(PRIV(atlas)->stb), &x0, &y0, &x1, &y1);
-	scale = stbtt_ScaleForPixelHeight(&(PRIV(atlas)->stb), size);
-	baseline = scale * -y0;
-	atlas->glyph_max_w = (scale*x1) - (scale*x0);
-	atlas->glyph_max_h = (baseline+scale*y1) - (baseline+scale*y0);
-	atlas->atlas = emalloc(CACHE_SIZE*BDEPTH*atlas->glyph_max_w*atlas->glyph_max_h);
-	memset(atlas->atlas, 0, CACHE_SIZE*BDEPTH*atlas->glyph_max_w*atlas->glyph_max_h);
-	PRIV(atlas)->baseline = atlas->glyph_max_h - baseline;
-	PRIV(atlas)->scale = scale;
-	PRIV(atlas)->bitmap = emalloc(BDEPTH*atlas->glyph_max_w*atlas->glyph_max_h);
-	// FIXME: make this a square atlas
-	atlas->width  = atlas->glyph_max_w*CACHE_SIZE/4;
-	atlas->height = atlas->glyph_max_h*4;
-	atlas->size = size;
-
-	// preallocate all ascii characters
-	for (char c = ' '; c <= '~'; c++) {
-		if (!font_get_glyph_texture(atlas, c, NULL))
-			return -1;
-	}
-
-	return 0;
-}
-
-
-int font_free(struct font_atlas *atlas)
-{
-	efree(atlas->atlas);
-	efree(atlas->file);
-	efree(PRIV(atlas)->bitmap);
-	cache_free(&PRIV(atlas)->c);
-	efree(atlas->priv);
-	efree(atlas);
-	return 0;
-}
-
-
-// TODO: time and take the median of the time it takes to generate the cache and
-//       the time it takes to draw the glyph
-const struct font_glyph * font_get_glyph_texture(struct font_atlas *atlas, unsigned int code, int *updated)
-{
-	int _u = 0;
-	if (!updated) updated = &_u;
-
-	const struct font_glyph *r;
-	if ((r = cache_search(&PRIV(atlas)->c, code)) != NULL) {
-		*updated = 0;
-		return r;
-	}
-
-	*updated = 1;
-	// generate the sdf and put it into the cache
-	// TODO: generate the whole block at once
-	int idx = stbtt_FindGlyphIndex(&PRIV(atlas)->stb, code);
-	int x0,y0,x1,y1,gw,gh,l,off_x,off_y,adv,base;
-	base = atlas->glyph_max_h - PRIV(atlas)->baseline;
-	stbtt_GetGlyphBitmapBoxSubpixel(
-		&PRIV(atlas)->stb,
-		idx,
-		PRIV(atlas)->scale,
-		PRIV(atlas)->scale,
-		0,0,
-		&x0,&y0,
-		&x1, &y1);
-	gw = x1 - x0;
-	gh = y1 - y0;
-	stbtt_GetGlyphHMetrics(&PRIV(atlas)->stb, idx, &adv, &l);
-	adv *= PRIV(atlas)->scale;
-	off_x = PRIV(atlas)->scale*l;
-	off_y = atlas->glyph_max_h+y0;
-	stbtt_MakeGlyphBitmapSubpixel(
-		&PRIV(atlas)->stb,
-		PRIV(atlas)->bitmap,
-		atlas->glyph_max_w,
-		atlas->glyph_max_h,
-		atlas->glyph_max_w,
-		PRIV(atlas)->scale,
-		PRIV(atlas)->scale,
-		0, 0,
-		idx);
-
-	// TODO: bounds check usign atlas height
-	// TODO: clear spot area in the atlas before writing on it
-	unsigned int spot = cache_get_free_spot(&PRIV(atlas)->c);
-	unsigned int ty   = ((atlas->glyph_max_w * spot) / atlas->width) * atlas->glyph_max_h;
-	unsigned int tx   = (atlas->glyph_max_w * spot) % atlas->width;
-	unsigned int w    = atlas->width;
-
-	unsigned char *a = (void *)atlas->atlas;
-
-	//printf("max:%d %d spot:%d : %d %d %d %d\n", atlas->glyph_max_w, atlas->glyph_max_h, spot, tx, ty, off_x, off_y);
-
-	for (int y = 0; y < gh; y++) {
-		for (int x = 0; x < gw; x++) {
-			int c, r;
-			r = (ty+y)*w;
-			c = tx+x;
-			a[r+c] = PRIV(atlas)->bitmap[y*atlas->glyph_max_w+x];
-		}
-	}
-
-	struct font_glyph g = {
-		.codepoint = code,
-		.u = tx,
-		.v = ty,
-		.w = gw,
-		.h = gh,
-		.x = off_x,
-		.y = off_y-base,
-		.a = adv,
-	};
-	return cache_insert_at(&PRIV(atlas)->c, &g, g.codepoint, spot);
-}
-
-
-void font_dump(const struct font_atlas *atlas, const char *path)
-{
-	stbi_write_png(
-		path,
-		atlas->width,
-		atlas->height,
-		BDEPTH,
-		atlas->atlas,
-		BDEPTH*atlas->width);
-}