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Code Issues Releases Activity

GIF loading improvements. 

- Fixed possible memory leak.
- Fix for transparent backgrounds.
- Adapted internal function to allow proper animation loading.
pull/157/head
urraka 2015-08-03 22:59:16 -03:00
parent 59c353962a
commit 23dfb8c06b
1 changed files with 50 additions and 31 deletions
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81
stb_image.h
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@ -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;
}