#define _POSIX_C_SOURCE 200809l #define STB_TRUETYPE_IMPLEMENTATION #define STBTT_STATIC #define STB_IMAGE_WRITE_IMPLEMENTATION #include #include #include "font.h" #include "stb_truetype.h" #include "stb_image_write.h" #include "util.h" #include "generic_cache.h" static inline unsigned int hash(unsigned int code) { // identity map the ascii range return code < 128 ? code : hash_u32(code); } CACHE_DECL(cache, struct font_glyph, hash, hash_cmp_u32) #define UTF8(c) (c&0x80) #define BDEPTH 1 #define BORDER 4 // FIXME: as of now only monospaced fonts work correctly since no kerning information // is stored struct priv { 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); ERROR(err == 0, -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(&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]; } } // FIXME: get the advance 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(&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); }