/**
* Returns an image manipulation library that is capable of handling the image file at $filePath -- will detect the image type and return the appropriate library from those available on the server
*
* @param string $filePath
* @param bool $setInstanceFilePath
* @return ISC_IMAGE_LIBRARY_INTERFACE
* @throws ISC_IMAGE_LIBRARY_FACTORY_INVALIDIMAGEFILE_EXCEPTION If the image file at $filePath is not a valid image
* @throws ISC_IMAGE_LIBRARY_FACTORY_NOPHPSUPPORT_EXCEPTION If there were no image libraries installed that could support the image
*/
public static function getImageLibraryInstance($filePath = null)
{
if ($filePath) {
if (!file_exists($filePath)) {
throw new ISC_IMAGE_LIBRARY_FACTORY_FILEDOESNTEXIST_EXCEPTION($filePath);
}
if (!self::isValidImageFile($filePath)) {
throw new ISC_IMAGE_LIBRARY_FACTORY_INVALIDIMAGEFILE_EXCEPTION($filePath);
}
}
// was going to use an array of classnames and call_user_func but it's a bit slow, and how often are libraries added? rarely
// use direct calls instead
try {
if (ISC_IMAGE_LIBRARY_IMAGICK::isLibrarySupported() && (!$filePath || ISC_IMAGE_LIBRARY_IMAGICK::isFileSupported($filePath))) {
$instance = new ISC_IMAGE_LIBRARY_IMAGICK($filePath);
} else if (ISC_IMAGE_LIBRARY_GD::isLibrarySupported() && (!$filePath || ISC_IMAGE_LIBRARY_GD::isFileSupported($filePath))) {
$instance = new ISC_IMAGE_LIBRARY_GD($filePath);
} else {
throw new ISC_IMAGE_LIBRARY_FACTORY_NOPHPSUPPORT_EXCEPTION($filePath);
}
} catch (ISC_IMAGE_BASECLASS_INVALIDIMAGE_EXCEPTION $exception) {
throw new ISC_IMAGE_LIBRARY_FACTORY_INVALIDIMAGEFILE_EXCEPTION($filePath);
}
return $instance;
}
/**
* Overlay another GD resource onto the current scratch at the given offset
*
* @param ISC_IMAGE_LIBRARY_GD $image
* @param mixed $offsetX
* @param mixed $offsetY
*/
public function overlayImage(ISC_IMAGE_LIBRARY_GD $image, $offsetX, $offsetY)
{
// when watermarking is implemented this may need to be re-examined for when gifs or 8bit pngs are used
$overlayResource = $image->getScratchResource();
$overlayWidth = $image->getWidth();
$overlayHeight = $image->getHeight();
if ($offsetX < 0) {
$offsetX = $this->getWidth() + $offsetX - $overlayWidth;
}
if ($offsetY < 0) {
$offsetY = $this->getHeight() + $offsetY - $overlayHeight;
}
imagecopyresampled($this->getScratchResource(), $overlayResource, $offsetX, $offsetY, 0, 0, $overlayWidth, $overlayHeight, $overlayWidth, $overlayHeight);
}