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merge https://github.com/nothings/stb/pull/427 but I messed up the merge

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so you don't get the automatic info you normally do
This commit is contained in:
Sean Barrett 2017-03-18 18:31:06 -07:00
parent 6d60610348
commit 24fa816116
1 changed files with 51 additions and 6 deletions
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57
stb_image.h
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@ -2628,7 +2628,7 @@ static void stbi__jpeg_reset(stbi__jpeg *j)
j->code_bits = 0;
j->code_buffer = 0;
j->nomore = 0;
j->img_comp[0].dc_pred = j->img_comp[1].dc_pred = j->img_comp[2].dc_pred = 0;
j->img_comp[0].dc_pred = j->img_comp[1].dc_pred = j->img_comp[2].dc_pred = j->img_comp[3].dc_pred = 0;
j->marker = STBI__MARKER_none;
j->todo = j->restart_interval ? j->restart_interval : 0x7fffffff;
j->eob_run = 0;
@ -2959,7 +2959,7 @@ static int stbi__process_frame_header(stbi__jpeg *z, int scan)
s->img_y = stbi__get16be(s); if (s->img_y == 0) return stbi__err("no header height", "JPEG format not supported: delayed height"); // Legal, but we don't handle it--but neither does IJG
s->img_x = stbi__get16be(s); if (s->img_x == 0) return stbi__err("0 width","Corrupt JPEG"); // JPEG requires
c = stbi__get8(s);
if (c != 3 && c != 1) return stbi__err("bad component count","Corrupt JPEG"); // JFIF requires
if (c != 3 && c != 1 && c != 4) return stbi__err("bad component count","Corrupt JPEG");
s->img_n = c;
for (i=0; i < c; ++i) {
z->img_comp[i].data = NULL;
@ -2972,7 +2972,7 @@ static int stbi__process_frame_header(stbi__jpeg *z, int scan)
for (i=0; i < s->img_n; ++i) {
static unsigned char rgb[3] = { 'R', 'G', 'B' };
z->img_comp[i].id = stbi__get8(s);
if (z->img_comp[i].id == rgb[i])
if (s->img_n == 3 && z->img_comp[i].id == rgb[i])
++z->rgb;
q = stbi__get8(s);
z->img_comp[i].h = (q >> 4); if (!z->img_comp[i].h || z->img_comp[i].h > 4) return stbi__err("bad H","Corrupt JPEG");
@ -3516,6 +3516,13 @@ typedef struct
int ypos; // which pre-expansion row we're on
} stbi__resample;
// fast 0..255 * 0..255 => 0..255 rounded multiplication
static stbi_uc stbi__blinn_8x8(stbi_uc x, stbi_uc y)
{
unsigned int t = x*y + 128;
return (stbi_uc) ((t + (t >>8)) >> 8);
}
static stbi_uc *load_jpeg_image(stbi__jpeg *z, int *out_x, int *out_y, int *comp, int req_comp)
{
int n, decode_n, is_rgb;
@ -3528,7 +3535,7 @@ static stbi_uc *load_jpeg_image(stbi__jpeg *z, int *out_x, int *out_y, int *comp
if (!stbi__decode_jpeg_image(z)) { stbi__cleanup_jpeg(z); return NULL; }
// determine actual number of components to generate
n = req_comp ? req_comp : z->s->img_n;
n = req_comp ? req_comp : z->s->img_n >= 3 ? 3 : 1;
is_rgb = z->s->img_n == 3 && (z->rgb == 3 || (z->app14_color_transform == 0 && !z->jfif));
@ -3603,6 +3610,28 @@ static stbi_uc *load_jpeg_image(stbi__jpeg *z, int *out_x, int *out_y, int *comp
} else {
z->YCbCr_to_RGB_kernel(out, y, coutput[1], coutput[2], z->s->img_x, n);
}
} else if (z->s->img_n == 4) {
if (z->app14_color_transform == 0) { // CMYK
for (i=0; i < z->s->img_x; ++i) {
stbi_uc k = coutput[3][i];
out[0] = stbi__blinn_8x8(coutput[0][i], k);
out[1] = stbi__blinn_8x8(coutput[1][i], k);
out[2] = stbi__blinn_8x8(coutput[2][i], k);
out[3] = 255;
out += n;
}
} else if (z->app14_color_transform == 2) { // YCCK
z->YCbCr_to_RGB_kernel(out, y, coutput[1], coutput[2], z->s->img_x, n);
for (i=0; i < z->s->img_x; ++i) {
stbi_uc k = coutput[3][i];
out[0] = stbi__blinn_8x8(255 - out[0], k);
out[1] = stbi__blinn_8x8(255 - out[1], k);
out[2] = stbi__blinn_8x8(255 - out[2], k);
out += n;
}
} else { // YCbCr + alpha? Ignore the fourth channel for now
z->YCbCr_to_RGB_kernel(out, y, coutput[1], coutput[2], z->s->img_x, n);
}
} else
for (i=0; i < z->s->img_x; ++i) {
out[0] = out[1] = out[2] = y[i];
@ -3620,6 +3649,22 @@ static stbi_uc *load_jpeg_image(stbi__jpeg *z, int *out_x, int *out_y, int *comp
out[1] = 255;
}
}
} else if (z->s->img_n == 4 && z->app14_color_transform == 0) {
for (i=0; i < z->s->img_x; ++i) {
stbi_uc k = coutput[3][i];
stbi_uc r = stbi__blinn_8x8(coutput[0][i], k);
stbi_uc g = stbi__blinn_8x8(coutput[1][i], k);
stbi_uc b = stbi__blinn_8x8(coutput[2][i], k);
out[0] = stbi__compute_y(r, g, b);
out[1] = 255;
out += n;
}
} else if (z->s->img_n == 4 && z->app14_color_transform == 2) {
for (i=0; i < z->s->img_x; ++i) {
out[0] = stbi__blinn_8x8(255 - coutput[0][i], coutput[3][i]);
out[1] = 255;
out += n;
}
} else {
stbi_uc *y = coutput[0];
if (n == 1)
@ -3632,7 +3677,7 @@ static stbi_uc *load_jpeg_image(stbi__jpeg *z, int *out_x, int *out_y, int *comp
stbi__cleanup_jpeg(z);
*out_x = z->s->img_x;
*out_y = z->s->img_y;
if (comp) *comp = z->s->img_n; // report original components, not output
if (comp) *comp = z->s->img_n >= 3 ? 3 : 1; // report original components, not output
return output;
}
}
@ -3669,7 +3714,7 @@ static int stbi__jpeg_info_raw(stbi__jpeg *j, int *x, int *y, int *comp)
}
if (x) *x = j->s->img_x;
if (y) *y = j->s->img_y;
if (comp) *comp = j->s->img_n;
if (comp) *comp = j->s->img_n >= 3 ? 3 : 1;
return 1;
}