void ZDCPixmapDecoder_GIF::Imp_Read(const ZStreamR& iStream, ZDCPixmap& oPixmap)
{
oPixmap = ZDCPixmap();
if (fReadEnd)
return;
if (!fReadHeader)
{
fReadHeader = true;
if ('G' != iStream.ReadUInt8()
|| 'I' != iStream.ReadUInt8()
|| 'F' != iStream.ReadUInt8()
|| '8' != iStream.ReadUInt8())
{
sThrowBadFormat();
}
uint8 version = iStream.ReadUInt8();
if ('7' != version && '9' != version)
sThrowBadFormat();
if ('a' != iStream.ReadUInt8())
sThrowBadFormat();
fIs89a = version == '9';
fSize.h = iStream.ReadUInt16LE();
fSize.v = iStream.ReadUInt16LE();
uint8 strmFlags = iStream.ReadUInt8();
bool strmHasGlobalColorTable = (strmFlags & 0x80) != 0;
uint8 strmColorResolution = (strmFlags & 0x7) >> 4;
bool strmSortFlag = (strmFlags & 0x08) != 0;
uint8 strmGlobalColorTableSize = (strmFlags & 0x7);
uint8 strmBackgroundColorIndex = iStream.ReadUInt8();
uint8 strmPixelAspectRatio = iStream.ReadUInt8();
if (strmHasGlobalColorTable)
{
vector<ZRGBColorPOD> theColors;
sReadColorTable(iStream, 1 << (strmGlobalColorTableSize + 1), theColors);
fPixelDesc = ZDCPixmapNS::PixelDesc(&theColors[0], theColors.size());
}
static int sPhysicalDepths[] =
{
1, // 0
2, // 1
4, // 2
4, // 3
8, // 4
8, // 5
8, // 6
8, // 7
};
int rowBytes
= ZDCPixmapNS::sCalcRowBytes(sPhysicalDepths[strmGlobalColorTableSize], fSize.h);
ZDCPixmapNS::RasterDesc theRasterDesc(
ZDCPixmapNS::PixvalDesc(strmGlobalColorTableSize + 1, true),
rowBytes, fSize.v, false);
fRaster = new ZDCPixmapRaster_Simple(theRasterDesc);
fRaster->Fill(strmBackgroundColorIndex);
}
void ZDCPixmapDecoder_GIF::Imp_Read(const ZStreamR& iStream, ZDCPixmap& oPixmap)
{
oPixmap = ZDCPixmap();
if (fReadEnd)
return;
if (!fReadHeader)
{
fReadHeader = true;
if ('G' != iStream.ReadUInt8()
|| 'I' != iStream.ReadUInt8()
|| 'F' != iStream.ReadUInt8()
|| '8' != iStream.ReadUInt8())
{
spThrowBadFormat();
}
uint8 version = iStream.ReadUInt8();
if ('7' != version && '9' != version)
spThrowBadFormat();
if ('a' != iStream.ReadUInt8())
spThrowBadFormat();
fIs89a = version == '9';
fSize.h = iStream.ReadUInt16LE();
fSize.v = iStream.ReadUInt16LE();
uint8 strmFlags = iStream.ReadUInt8();
bool strmHasGlobalColorTable = (strmFlags & 0x80) != 0;
//uint8 strmColorResolution = (strmFlags & 0x7) >> 4;
//bool strmSortFlag = (strmFlags & 0x08) != 0;
uint8 strmGlobalColorTableSize = (strmFlags & 0x7);
uint8 strmBackgroundColorIndex = iStream.ReadUInt8();
/*uint8 strmPixelAspectRatio = */iStream.ReadUInt8();
if (strmHasGlobalColorTable)
{
vector<ZRGBA_POD> theColors;
spReadColorTable(iStream, 1 << (strmGlobalColorTableSize + 1), theColors);
fPixelDesc = PixelDesc(&theColors[0], theColors.size());
}
static int sPhysicalDepths[] =
{
1, // 0
2, // 1
4, // 2
4, // 3
8, // 4
8, // 5
8, // 6
8, // 7
};
int rowBytes =
sCalcRowBytes(sPhysicalDepths[strmGlobalColorTableSize], fSize.h, 4);
RasterDesc theRasterDesc(
PixvalDesc(strmGlobalColorTableSize + 1, true),
rowBytes, fSize.v, false);
fRaster = new ZDCPixmapRaster_Simple(theRasterDesc);
fRaster->Fill(strmBackgroundColorIndex);
}
else
{
// Clone our existing raster which contains the pixels
// making up the pixmap we last returned.
fRaster = new ZDCPixmapRaster_Simple(fRaster);
}
for (;;)
{
uint8 blockType = iStream.ReadUInt8();
if (blockType == ';')
{
// We've reached the end of the GIF stream.
fReadEnd = true;
return;
}
else if (blockType == '!')
{
// It's an extension.
// Ignore the extension type
iStream.ReadUInt8();
// Skip any data blocks.
StreamR_Chunk(iStream).SkipAll();
}
else if (blockType == ',')
{
// It's an image.
ZRectPOD curBounds;
curBounds.left = iStream.ReadUInt16LE();
curBounds.top = iStream.ReadUInt16LE();
curBounds.right = curBounds.left + iStream.ReadUInt16LE();
curBounds.bottom = curBounds.top + iStream.ReadUInt16LE();
uint8 strmFlags = iStream.ReadUInt8();
bool strmHasLocalColorTable = (strmFlags & 0x80) != 0;
bool strmIsInterlaced = (strmFlags & 0x40) != 0;
//bool strmSortFlag = (strmFlags & 0x20) != 0;
uint8 strmLocalColorTableSize = (strmFlags & 0x7);
PixelDesc thePixelDesc = fPixelDesc;
if (strmHasLocalColorTable)
{
vector<ZRGBA_POD> theColors;
spReadColorTable(iStream, 1 << (strmLocalColorTableSize + 1), theColors);
thePixelDesc = PixelDesc(&theColors[0], theColors.size());
}
spReadImageData(iStream, strmIsInterlaced, curBounds, fRaster);
oPixmap = new ZDCPixmapRep(fRaster, sRect(fSize), thePixelDesc);
return;
}
}
}
