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Fix for interlaced and small images + cleanup

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This commit is contained in:
ocornut 2014-09-25 23:52:24 +01:00
parent 3b3e2996e7
commit 09a1ab87a0
1 changed files with 22 additions and 28 deletions
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50
stb_image.h
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@ -2500,10 +2500,7 @@ static int stbi__create_png_image_raw(stbi__png *a, stbi_uc *raw, stbi__uint32 r
a->out = (stbi_uc *) stbi__malloc(x * y * out_n);
if (!a->out) return stbi__err("outofmem", "Out of memory");
img_len = (img_n * x) * y;
if (depth<8) img_len /= (8/depth);
else if (depth>8) img_len *= depth>>3;
img_len += y;
img_len = ((((img_n * x * depth) + 7) >> 3) + 1) * y;
if (s->img_x == x && s->img_y == y) {
if (raw_len != img_len) return stbi__err("not enough pixels","Corrupt PNG");
} else { // interlaced:
@ -2511,7 +2508,7 @@ static int stbi__create_png_image_raw(stbi__png *a, stbi_uc *raw, stbi__uint32 r
}
if (depth != 8) {
line8 = (stbi_uc *) stbi__malloc((x+3) * out_n); // allocate buffer for one scanline
line8 = (stbi_uc *) stbi__malloc((x+7) * out_n); // allocate buffer for one scanline
if (!line8) return stbi__err("outofmem", "Out of memory");
}
@ -2533,35 +2530,31 @@ static int stbi__create_png_image_raw(stbi__png *a, stbi_uc *raw, stbi__uint32 r
// unpack 1/2/4-bit into a 8-bit buffer. allows us to keep the common 8-bit path optimal at minimal cost for 1/2/4-bit
// png guarante byte alignment, if width is not multiple of 8/4/2 we'll decode dummy trailing data that will be skipped in the later loop
in = line8;
stbi_uc* decode_in = raw;
stbi_uc* decode_out = line8;
stbi_uc scale = (color == 0) ? 0xFF/((1<<depth)-1) : 1; // scale grayscale values to 0..255 range
if (depth == 4) {
for (i=x*img_n; i >= 1; i-=2, decode_in++) {
*decode_out++ = scale * ((*decode_in >> 4) );
*decode_out++ = scale * ((*decode_in ) & 0x0f);
for (k=x*img_n; k >= 1; k-=2, raw++) {
*decode_out++ = scale * ((*raw >> 4) );
*decode_out++ = scale * ((*raw ) & 0x0f);
}
raw+=(x*img_n+1)>>1;
} else if (depth == 2) {
for (i=x*img_n; i >= 1; i-=4, decode_in++) {
*decode_out++ = scale * ((*decode_in >> 6) );
*decode_out++ = scale * ((*decode_in >> 4) & 0x03);
*decode_out++ = scale * ((*decode_in >> 2) & 0x03);
*decode_out++ = scale * ((*decode_in ) & 0x03);
for (k=x*img_n; k >= 1; k-=4, raw++) {
*decode_out++ = scale * ((*raw >> 6) );
*decode_out++ = scale * ((*raw >> 4) & 0x03);
*decode_out++ = scale * ((*raw >> 2) & 0x03);
*decode_out++ = scale * ((*raw ) & 0x03);
}
raw+=(x*img_n+3)>>2;
} else if (depth == 1) {
for (i=x*img_n; i >= 1; i-=8, decode_in++) {
*decode_out++ = scale * ((*decode_in >> 7) );
*decode_out++ = scale * ((*decode_in >> 6) & 0x01);
*decode_out++ = scale * ((*decode_in >> 5) & 0x01);
*decode_out++ = scale * ((*decode_in >> 4) & 0x01);
*decode_out++ = scale * ((*decode_in >> 3) & 0x01);
*decode_out++ = scale * ((*decode_in >> 2) & 0x01);
*decode_out++ = scale * ((*decode_in >> 1) & 0x01);
*decode_out++ = scale * ((*decode_in ) & 0x01);
for (k=x*img_n; k >= 1; k-=8, raw++) {
*decode_out++ = scale * ((*raw >> 7) );
*decode_out++ = scale * ((*raw >> 6) & 0x01);
*decode_out++ = scale * ((*raw >> 5) & 0x01);
*decode_out++ = scale * ((*raw >> 4) & 0x01);
*decode_out++ = scale * ((*raw >> 3) & 0x01);
*decode_out++ = scale * ((*raw >> 2) & 0x01);
*decode_out++ = scale * ((*raw >> 1) & 0x01);
*decode_out++ = scale * ((*raw ) & 0x01);
}
raw+=(x*img_n+7)>>3;
}
}
@ -2642,6 +2635,7 @@ static int stbi__create_png_image(stbi__png *a, stbi_uc *raw, stbi__uint32 raw_l
x = (a->s->img_x - xorig[p] + xspc[p]-1) / xspc[p];
y = (a->s->img_y - yorig[p] + yspc[p]-1) / yspc[p];
if (x && y) {
stbi__uint32 img_len = ((((out_n * x * depth) + 7) >> 3) + 1) * y;
if (!stbi__create_png_image_raw(a, raw, raw_len, out_n, x, y, depth, color)) {
free(final);
return 0;
@ -2651,8 +2645,8 @@ static int stbi__create_png_image(stbi__png *a, stbi_uc *raw, stbi__uint32 raw_l
memcpy(final + (j*yspc[p]+yorig[p])*a->s->img_x*out_n + (i*xspc[p]+xorig[p])*out_n,
a->out + (j*x+i)*out_n, out_n);
free(a->out);
raw += (x*out_n+1)*y;
raw_len -= (x*out_n+1)*y;
raw += img_len;
raw_len -= img_len;
}
}
a->out = final;