/**
* @param FileHandler $fh
*
* @throws Exception
*/
public function decode($fh)
{
if ($fh->getRemainingBytes() < 6) {
throw new Exception("Insufficient data. Need 6 bytes, got " . $fh->getRemainingBytes());
}
$this->signature = $fh->readData(3);
$this->version = $fh->readData(3);
}
/**
* @param FileHandler $fh
*
* @throws Exception
*/
public function decode($fh)
{
if ($fh->getRemainingBytes() < 7) {
throw new Exception("Insufficient data. Need 7 bytes, got " . $fh->getRemainingBytes());
}
$this->screenWidth = $fh->readUint16();
$this->screenHeight = $fh->readUint16();
$packedFields = ord($fh->readByte());
$this->colorTableFlag = ($packedFields & 0x80) > 0;
$this->colorResolution = ($packedFields & 0x70) >> 4;
$this->sortFlag = ($packedFields & 0x8) > 0;
// For just 8 possible values, the lookup table is faster.
// the commented lines below is the pedantic way of doing it.
// $v = ($packedFields & 0x07);
// $this->colorTableSize = pow(2, $v + 1);
$this->colorTableSize = $this->ctSizeListRev[$packedFields & 0x7];
$this->bgColorIndex = $fh->readByteUint();
$v = $fh->readByteUint();
$this->pixelAspectRatio = $v > 0 ? ($v + 15) / 64 : 0;
if ($this->colorTableFlag && $this->colorTableSize > 0) {
$this->colorTable = $fh->readData($this->colorTableSize * 3);
}
}
