bool GifDecoder::readBitmap(DataBlock* dataBlock)
{
uint8_t packed;
if (!dataBlock->read(&ix) || !dataBlock->read(&iy) || // (sub)image position & size
!dataBlock->read(&iw) || !dataBlock->read(&ih) || !dataBlock->read(&packed, 1)) {
return false;
}
bool lctFlag = (packed & 0x80) != 0; // 1 - local color table flag interlace
int32_t lctSize = 2 << (packed & 0x07);
// 3 - sort flag
// 4-5 - reserved lctSize = 2 << (packed & 7); // 6-8 - local color
// table size
interlace = (packed & 0x40) != 0;
uint32_t lct[256];
uint32_t* act;
if (lctFlag) {
if (!readColorTable(dataBlock, lct, lctSize)) { // read table
return false;
}
act = lct; // make local table active
} else {
act = gct; // make global table active
if (bgIndex == transIndex) {
bgColor = 0;
}
}
uint32_t save;
if (transparency) {
save = act[transIndex];
act[transIndex] = 0; // set transparent color if specified
}
if (!decodeBitmapData(dataBlock) || !skip(dataBlock)) { // decode pixel data
return false;
}
frameCount++;
// create new image to receive frame data
setPixels(act); // transfer pixel data to image
if (transparency) {
act[transIndex] = save;
}
resetFrame();
return true;
}
bool GifDecoder::readHeader(DataBlock* dataBlock)
{
uint8_t buffer[6];
if (!dataBlock->read(buffer, 6)) {
return false;
}
if (0 != memcmp("GIF", buffer, 3)) {
return false;
}
if (!readLSD(dataBlock)) {
return false;
}
if (gctFlag) {
if (!readColorTable(dataBlock, gct, gctSize)) {
return false;
}
bgColor = gct[bgIndex];
}
return true;
}
Sequence* ReaderWriterILDA::readFile(const QString& fileName)
{
QFile file(fileName);
if (file.open(QIODevice::ReadOnly))
{
bool eof = false;
QDataStream stream(&file);
stream.setByteOrder(QDataStream::BigEndian);
_sequence = new Sequence();
while (!stream.atEnd() && !eof)
{
char signature[4];
stream.readRawData(signature, 4);
if (memcmp(signature, "ILDA", 4))
{
file.close();
return 0L;
}
quint32 formatType;
stream >> formatType;
if (!_ildaVersion.contains(formatType))
_ildaVersion.append(formatType);
switch (formatType)
{
case 0:
// 3D Frame
eof = readFrameSection(stream, true);
break;
case 1:
// 2D Frame
eof = readFrameSection(stream, false);
break;
case 2:
// Color Table
eof = readColorTable(stream);
break;
case 3:
// True Color
eof = readTrueColorSection(stream);
break;
case 4:
eof = readFormat5(stream, true);
break;
case 5:
eof = readFormat5(stream, false);
break;
default:
// Unknow section type
{
qint32 dataLength;
qint32 numberOfPoints;
stream >> dataLength >> numberOfPoints;
stream.skipRawData(dataLength);
}
break;
}
}
file.close();
}