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GRAPHICS: Generalized arbitrary bit depth images processing in PNG decoder.

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This fixes 1bpp image rengering.
This commit is contained in:
Eugene Sandulenko 2011-06-26 21:17:28 +03:00
parent 55a7bbf86a
commit d2962531cb
1 changed files with 16 additions and 14 deletions
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30
graphics/png.cpp
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@ -166,18 +166,26 @@ Graphics::Surface *PNG::getSurface(const PixelFormat &format) {
}
} else {
byte index, r, g, b;
uint32 mask = (0xff >> (8 - _header.bitDepth)) << (8 - _header.bitDepth);
// Convert the indexed surface to the target pixel format
for (uint16 i = 0; i < output->h; i++) {
bool otherPixel = false;
int data = 0;
int bitCount = 8;
byte *src1 = src;
for (uint16 j = 0; j < output->w; j++) {
if (_header.bitDepth != 4)
index = *src;
else if (!otherPixel)
index = (*src) >> 4;
else
index = (*src) & 0xf;
if (bitCount == 8) {
data = *src;
src++;
}
index = (data & mask) >> (8 - _header.bitDepth);
data = (data << _header.bitDepth) & 0xff;
bitCount -= _header.bitDepth;
if (bitCount == 0)
bitCount = 8;
r = _palette[index * 4 + 0];
g = _palette[index * 4 + 1];
@ -188,14 +196,8 @@ Graphics::Surface *PNG::getSurface(const PixelFormat &format) {
*((uint16 *)output->getBasePtr(j, i)) = format.ARGBToColor(a, r, g, b);
else
*((uint32 *)output->getBasePtr(j, i)) = format.ARGBToColor(a, r, g, b);
if (_header.bitDepth != 4 || otherPixel)
src++;
otherPixel = !otherPixel;
}
// The surface is a whole scanline wide, skip the rest of it.
if (_header.bitDepth == 4)
src += output->w / 2 + output->w % 2;
src = src1 + output->w;
}
}