/**
* @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 $fh
*/
public function decode($fh)
{
$fh->seekForward(1);
// skip block label.
$this->readDataSubBlocks($fh);
while ($fh->peekByte() == "") {
$fh->seekForward(1);
}
}
/**
* @param FileHandler $fh
*/
public function readDataSubBlocks($fh)
{
$this->dataSubBlocks = "";
while (!$fh->compareByte("")) {
$subBlockLength = $fh->readByteUint();
if ($subBlockLength == 0) {
return;
}
$this->dataSubBlocks .= chr($subBlockLength) . $fh->readData($subBlockLength);
}
}
/**
* @param FileHandler $fh
*/
public function decode($fh)
{
$fh->seekForward(1);
// skip block label.
$this->blockLength = $fh->readByteUint();
// 11
$this->applicationIdentifier = $fh->readData(8);
$this->applicationAuthenticationCode = $fh->readData(3);
$this->readDataSubBlocks($fh);
while ($fh->peekByte() == "") {
$fh->seekForward(1);
}
}
/**
* @param FileHandler $fh
*/
public function decode($fh)
{
$fh->seekForward(1);
// skip block label.
$this->blockLength = $fh->readByteUint();
// 4
$packedFields = $fh->readByteUint();
$this->reserved = ($packedFields & 0x70) >> 5;
$this->disposalMethod = ($packedFields & 0x1c) >> 2;
$this->userInputFlag = ($packedFields & 0x2) > 0;
$this->transparentColorFlag = ($packedFields & 0x1) > 0;
$this->delayTime = $fh->readUint16();
$this->transparentColorIndex = $fh->readByteUint();
// Spool past the \x00 terminator byte. There *should* only be one.
while ($fh->compareByte("")) {
$fh->readByte();
}
// The GCE will always be followed by the Image Descriptor.
$this->imageDescriptor = new ImageDescriptor($fh);
$this->imageDescriptor->parentGCE = $this;
}
/**
* @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);
}
}
/**
* @param FileHandler $fh
* @param FileHandler $fhW
* @param float $ratio
* @param LogicalScreenDescriptor $lsd
*/
private static function readExtensionBlock($fh, $fhW, $ratio, $lsd)
{
$fh->seekForward(1);
$blockLabel = $fh->peekByte();
switch (ord($blockLabel)) {
case AbstractExtensionBlock::LABEL_APPLICATION:
$adb = new ApplicationExtension($fh);
$adb->encodeToFile($fhW);
break;
case AbstractExtensionBlock::LABEL_COMMENT:
$ceb = new CommentExtension($fh);
$ceb->encodeToFile($fhW);
break;
case AbstractExtensionBlock::LABEL_GRAPHICS_CONTROL:
$gce = new GraphicControlExtension($fh);
self::resizeGraphicControlExtensionBlock($gce, $ratio, $fhW, $lsd);
break;
case AbstractExtensionBlock::LABEL_PLAIN_TEXT:
$pte = new PlainTextExtension($fh);
$pte->encodeToFile($fhW);
break;
case AbstractExtensionBlock::CONTROL_TRAILER:
break;
default:
$fh->seekForward(1);
while (!$fh->compareByte("")) {
$fh->seekForward(1);
}
}
if ($fh->compareByte("")) {
$fh->readByte();
}
}
/**
* @param string $dstPath
* @param int $frameCount
* @param LogicalScreenDescriptor $lsd
* @param AbstractExtensionBlock $aeb
*
* @throws Exception
*/
private static function writeFrame($dstPath, &$frameCount, $lsd, $aeb)
{
$frameCount++;
if ($dstPath !== null) {
$dstFileName = $dstPath . str_pad(strval($frameCount), 3, "0", STR_PAD_LEFT) . ".gif";
$fhW = new FileHandler();
$fhW->openFile($dstFileName, true);
$fhW->writeData("GIF89a");
$lsd->encodeToFile($fhW);
$aeb->encodeToFile($fhW);
$fhW->writeData(";");
$fhW->closeFile();
}
}
/**
* @param FileHandler $fh
*/
public function decode($fh)
{
$fh->seekForward(1);
// skip block label.
$this->blockLength = $fh->readByteUint();
// 12
$this->textGridLeftPosition = $fh->readUint16();
$this->textGridTopPosition = $fh->readUint16();
$this->textGridWidth = $fh->readUint16();
$this->textGridHeight = $fh->readUint16();
$this->characterCellWidth = $fh->readByteUint();
$this->characterCellHeight = $fh->readByteUint();
$this->textFGColorIndex = $fh->readByteUint();
$this->textBGColorIndex = $fh->readByteUint();
$this->readDataSubBlocks($fh);
// Spool past the \x00 terminator byte. There *should* only be one.
while ($fh->peekByte() == "") {
$fh->seekForward(1);
}
}
/**
* @param FileHandler $fh
* @param GraphicControlExtension $gce
*
* @return ImageDescriptor|GraphicControlExtension
*/
public static function getFirstImageFrame($fh, $gce = null)
{
$nId = null;
while ($nId == null && !$fh->isEOF()) {
$blockLabel = $fh->peekByte();
if (ord($blockLabel) == AbstractExtensionBlock::CONTROL_IMAGE) {
$nId = new ImageDescriptor($fh);
if ($gce != null) {
$gce->transparentColorFlag = false;
$gce->transparentColorIndex = 0;
}
return $nId;
} else {
if (ord($blockLabel) == AbstractExtensionBlock::CONTROL_EXTENSION) {
$fh->seekForward(1);
$blockLabel = $fh->peekByte();
if (ord($blockLabel) == AbstractExtensionBlock::LABEL_GRAPHICS_CONTROL) {
$nGce = new GraphicControlExtension($fh);
if ($gce != null) {
$gce->transparentColorFlag = $nGce->transparentColorFlag;
$gce->transparentColorIndex = $nGce->transparentColorIndex;
}
return $nGce;
}
}
}
}
return null;
}
