From 23dfb8c06b31cdf746561b727e3f2db43b57eb13 Mon Sep 17 00:00:00 2001 From: urraka Date: Mon, 3 Aug 2015 22:59:16 -0300 Subject: [PATCH] GIF loading improvements. - Fixed possible memory leak. - Fix for transparent backgrounds. - Adapted internal function to allow proper animation loading. --- stb_image.h | 81 +++++++++++++++++++++++++++++++++-------------------- 1 file changed, 50 insertions(+), 31 deletions(-) diff --git a/stb_image.h b/stb_image.h index d0fa9c2..d1333a1 100644 --- a/stb_image.h +++ b/stb_image.h @@ -5438,8 +5438,8 @@ typedef struct typedef struct { int w,h; - stbi_uc *out; // output buffer (always 4 components) - int flags, bgindex, ratio, transparent, eflags; + stbi_uc *out, *old_out; // output buffer (always 4 components) + int flags, bgindex, ratio, transparent, eflags, delay; stbi_uc pal[256][4]; stbi_uc lpal[256][4]; stbi__gif_lzw codes[4096]; @@ -5634,17 +5634,18 @@ static stbi_uc *stbi__process_gif_raster(stbi__context *s, stbi__gif *g) } } -static void stbi__fill_gif_background(stbi__gif *g) +static void stbi__fill_gif_background(stbi__gif *g, int x0, int y0, int x1, int y1) { - int i; + int x, y; stbi_uc *c = g->pal[g->bgindex]; - // @OPTIMIZE: write a dword at a time - for (i = 0; i < g->w * g->h * 4; i += 4) { - stbi_uc *p = &g->out[i]; - p[0] = c[2]; - p[1] = c[1]; - p[2] = c[0]; - p[3] = c[3]; + for (y = y0; y < y1; y += 4 * g->w) { + for (x = x0; x < x1; x += 4) { + stbi_uc *p = &g->out[y + x]; + p[0] = c[2]; + p[1] = c[1]; + p[2] = c[0]; + p[3] = 0; + } } } @@ -5652,27 +5653,40 @@ static void stbi__fill_gif_background(stbi__gif *g) static stbi_uc *stbi__gif_load_next(stbi__context *s, stbi__gif *g, int *comp, int req_comp) { int i; - stbi_uc *old_out = 0; + stbi_uc *prev_out = 0; - if (g->out == 0) { - if (!stbi__gif_header(s, g, comp,0)) return 0; // stbi__g_failure_reason set by stbi__gif_header - g->out = (stbi_uc *) stbi__malloc(4 * g->w * g->h); - if (g->out == 0) return stbi__errpuc("outofmem", "Out of memory"); - stbi__fill_gif_background(g); - } else { - // animated-gif-only path - if (((g->eflags & 0x1C) >> 2) == 3) { - old_out = g->out; - g->out = (stbi_uc *) stbi__malloc(4 * g->w * g->h); - if (g->out == 0) return stbi__errpuc("outofmem", "Out of memory"); - memcpy(g->out, old_out, g->w*g->h*4); - } + if (g->out == 0 && !stbi__gif_header(s, g, comp,0)) + return 0; // stbi__g_failure_reason set by stbi__gif_header + + prev_out = g->out; + g->out = (stbi_uc *) stbi__malloc(4 * g->w * g->h); + if (g->out == 0) return stbi__errpuc("outofmem", "Out of memory"); + + switch ((g->eflags & 0x1C) >> 2) { + case 0: // unspecified (also always used on 1st frame) + stbi__fill_gif_background(g, 0, 0, 4 * g->w, 4 * g->w * g->h); + break; + case 1: // do not dispose + if (prev_out) memcpy(g->out, prev_out, 4 * g->w * g->h); + g->old_out = prev_out; + break; + case 2: // dispose to background + if (prev_out) memcpy(g->out, prev_out, 4 * g->w * g->h); + stbi__fill_gif_background(g, g->start_x, g->start_y, g->max_x, g->max_y); + break; + case 3: // dispose to previous + if (g->old_out) { + for (i = g->start_y; i < g->max_y; i += 4 * g->w) + memcpy(&g->out[i + g->start_x], &g->old_out[i + g->start_x], g->max_x - g->start_x); + } + break; } for (;;) { switch (stbi__get8(s)) { case 0x2C: /* Image Descriptor */ { + int prev_trans = -1; stbi__int32 x, y, w, h; stbi_uc *o; @@ -5705,10 +5719,10 @@ static stbi_uc *stbi__gif_load_next(stbi__context *s, stbi__gif *g, int *comp, i stbi__gif_parse_colortable(s,g->lpal, 2 << (g->lflags & 7), g->eflags & 0x01 ? g->transparent : -1); g->color_table = (stbi_uc *) g->lpal; } else if (g->flags & 0x80) { - for (i=0; i < 256; ++i) // @OPTIMIZE: stbi__jpeg_reset only the previous transparent - g->pal[i][3] = 255; - if (g->transparent >= 0 && (g->eflags & 0x01)) + if (g->transparent >= 0 && (g->eflags & 0x01)) { + prev_trans = g->pal[g->transparent][3]; g->pal[g->transparent][3] = 0; + } g->color_table = (stbi_uc *) g->pal; } else return stbi__errpuc("missing color table", "Corrupt GIF"); @@ -5716,8 +5730,9 @@ static stbi_uc *stbi__gif_load_next(stbi__context *s, stbi__gif *g, int *comp, i o = stbi__process_gif_raster(s, g); if (o == NULL) return NULL; - if (req_comp && req_comp != 4) - o = stbi__convert_format(o, 4, req_comp, g->w, g->h); + if (prev_trans != -1) + g->pal[g->transparent][3] = prev_trans; + return o; } @@ -5728,7 +5743,7 @@ static stbi_uc *stbi__gif_load_next(stbi__context *s, stbi__gif *g, int *comp, i len = stbi__get8(s); if (len == 4) { g->eflags = stbi__get8(s); - stbi__get16le(s); // delay + g->delay = stbi__get16le(s); g->transparent = stbi__get8(s); } else { stbi__skip(s, len); @@ -5760,7 +5775,11 @@ static stbi_uc *stbi__gif_load(stbi__context *s, int *x, int *y, int *comp, int if (u) { *x = g.w; *y = g.h; + if (req_comp && req_comp != 4) + u = stbi__convert_format(u, 4, req_comp, g.w, g.h); } + else if (g.out) + STBI_FREE(g.out); return u; }