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110 lines
5.3 KiB
110 lines
5.3 KiB
/*
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Copyright (C) 2017 Milo Yip. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright notice, this
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list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions and the following disclaimer in the documentation
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and/or other materials provided with the distribution.
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* Neither the name of pngout nor the names of its
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contributors may be used to endorse or promote products derived from
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this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*! \file
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\brief svpng() is a minimalistic C function for saving RGB/RGBA image into uncompressed PNG.
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\author Milo Yip
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\version 0.1.1
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\copyright MIT license
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\sa http://github.com/miloyip/svpng
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*/
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#ifndef SVPNG_INC_
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#define SVPNG_INC_
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/*! \def SVPNG_LINKAGE
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\brief User customizable linkage for svpng() function.
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By default this macro is empty.
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User may define this macro as static for static linkage,
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and/or inline in C99/C++, etc.
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*/
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#ifndef SVPNG_LINKAGE
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#define SVPNG_LINKAGE
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#endif
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/*! \def SVPNG_OUTPUT
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\brief User customizable output stream.
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By default, it uses C file descriptor and fputc() to output bytes.
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In C++, for example, user may use std::ostream or std::vector instead.
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*/
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#ifndef SVPNG_OUTPUT
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#include <stdio.h>
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#define SVPNG_OUTPUT FILE* fp
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#endif
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/*! \def SVPNG_PUT
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\brief Write a byte
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*/
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#ifndef SVPNG_PUT
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#define SVPNG_PUT(u) fputc(u, fp)
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#endif
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/*!
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\brief Save a RGB/RGBA image in PNG format.
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\param SVPNG_OUTPUT Output stream (by default using file descriptor).
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\param w Width of the image. (<16383)
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\param h Height of the image.
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\param img Image pixel data in 24-bit RGB or 32-bit RGBA format.
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\param alpha Whether the image contains alpha channel.
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*/
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SVPNG_LINKAGE void svpng(SVPNG_OUTPUT, unsigned w, unsigned h, const unsigned char* img, int alpha) {
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static const unsigned t[] = { 0, 0x1db71064, 0x3b6e20c8, 0x26d930ac, 0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
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/* CRC32 Table */ 0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c, 0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c };
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unsigned a = 1, b = 0, c, p = w * (alpha ? 4 : 3) + 1, x, y, i; /* ADLER-a, ADLER-b, CRC, pitch */
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#define SVPNG_U8A(ua, l) for (i = 0; i < l; i++) SVPNG_PUT((ua)[i]);
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#define SVPNG_U32(u) do { SVPNG_PUT((u) >> 24); SVPNG_PUT(((u) >> 16) & 255); SVPNG_PUT(((u) >> 8) & 255); SVPNG_PUT((u) & 255); } while(0)
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#define SVPNG_U8C(u) do { SVPNG_PUT(u); c ^= (u); c = (c >> 4) ^ t[c & 15]; c = (c >> 4) ^ t[c & 15]; } while(0)
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#define SVPNG_U8AC(ua, l) for (i = 0; i < l; i++) SVPNG_U8C((ua)[i])
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#define SVPNG_U16LC(u) do { SVPNG_U8C((u) & 255); SVPNG_U8C(((u) >> 8) & 255); } while(0)
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#define SVPNG_U32C(u) do { SVPNG_U8C((u) >> 24); SVPNG_U8C(((u) >> 16) & 255); SVPNG_U8C(((u) >> 8) & 255); SVPNG_U8C((u) & 255); } while(0)
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#define SVPNG_U8ADLER(u) do { SVPNG_U8C(u); a = (a + (u)) % 65521; b = (b + a) % 65521; } while(0)
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#define SVPNG_BEGIN(s, l) do { SVPNG_U32(l); c = ~0U; SVPNG_U8AC(s, 4); } while(0)
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#define SVPNG_END() SVPNG_U32(~c)
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SVPNG_U8A("\x89PNG\r\n\32\n", 8); /* Magic */
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SVPNG_BEGIN("IHDR", 13); /* IHDR chunk { */
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SVPNG_U32C(w); SVPNG_U32C(h); /* Width & Height (8 bytes) */
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SVPNG_U8C(8); SVPNG_U8C(alpha ? 6 : 2); /* Depth=8, Color=True color with/without alpha (2 bytes) */
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SVPNG_U8AC("\0\0\0", 3); /* Compression=Deflate, Filter=No, Interlace=No (3 bytes) */
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SVPNG_END(); /* } */
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SVPNG_BEGIN("IDAT", 2 + h * (5 + p) + 4); /* IDAT chunk { */
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SVPNG_U8AC("\x78\1", 2); /* Deflate block begin (2 bytes) */
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for (y = 0; y < h; y++) { /* Each horizontal line makes a block for simplicity */
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SVPNG_U8C(y == h - 1); /* 1 for the last block, 0 for others (1 byte) */
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SVPNG_U16LC(p); SVPNG_U16LC(~p); /* Size of block in little endian and its 1's complement (4 bytes) */
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SVPNG_U8ADLER(0); /* No filter prefix (1 byte) */
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for (x = 0; x < p - 1; x++, img++)
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SVPNG_U8ADLER(*img); /* Image pixel data */
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}
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SVPNG_U32C((b << 16) | a); /* Deflate block end with adler (4 bytes) */
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SVPNG_END(); /* } */
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SVPNG_BEGIN("IEND", 0); SVPNG_END(); /* IEND chunk {} */
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}
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#endif /* SVPNG_INC_ */ |