GC_Image_Editor_Imagick
最后更新于：2021-11-25 20:36:59
GC_Image_Editor_ImagickGeChiUI Image Editor Class for Image Manipulation through Imagick PHP Module
源文件
文件: gc-includes/class-gc-image-editor-imagick.php
class GC_Image_Editor_Imagick extends GC_Image_Editor {
/**
* Imagick object.
*
* @var Imagick
*/
protected $image;
public function __destruct() {
if ( $this->image instanceof Imagick ) {
// We don't need the original in memory anymore.
$this->image->clear();
$this->image->destroy();
}
}
/**
* Checks to see if current environment supports Imagick.
*
* We require Imagick 2.2.0 or greater, based on whether the queryFormats()
* method can be called statically.
*
* @since 3.5.0
*
* @param array $args
* @return bool
*/
public static function test( $args = array() ) {
// First, test Imagick's extension and classes.
if ( ! extension_loaded( 'imagick' ) || ! class_exists( 'Imagick', false ) || ! class_exists( 'ImagickPixel', false ) ) {
return false;
}
if ( version_compare( phpversion( 'imagick' ), '2.2.0', '<' ) ) {
return false;
}
$required_methods = array(
'clear',
'destroy',
'valid',
'getimage',
'writeimage',
'getimageblob',
'getimagegeometry',
'getimageformat',
'setimageformat',
'setimagecompression',
'setimagecompressionquality',
'setimagepage',
'setoption',
'scaleimage',
'cropimage',
'rotateimage',
'flipimage',
'flopimage',
'readimage',
'readimageblob',
);
// Now, test for deep requirements within Imagick.
if ( ! defined( 'imagick::COMPRESSION_JPEG' ) ) {
return false;
}
$class_methods = array_map( 'strtolower', get_class_methods( 'Imagick' ) );
if ( array_diff( $required_methods, $class_methods ) ) {
return false;
}
return true;
}
/**
* Checks to see if editor supports the mime-type specified.
*
* @since 3.5.0
*
* @param string $mime_type
* @return bool
*/
public static function supports_mime_type( $mime_type ) {
$imagick_extension = strtoupper( self::get_extension( $mime_type ) );
if ( ! $imagick_extension ) {
return false;
}
// setIteratorIndex is optional unless mime is an animated format.
// Here, we just say no if you are missing it and aren't loading a jpeg.
if ( ! method_exists( 'Imagick', 'setIteratorIndex' ) && 'image/jpeg' !== $mime_type ) {
return false;
}
try {
// phpcs:ignore GeChiUI.PHP.NoSilencedErrors.Discouraged
return ( (bool) @Imagick::queryFormats( $imagick_extension ) );
} catch ( Exception $e ) {
return false;
}
}
/**
* Loads image from $this->file into new Imagick Object.
*
* @since 3.5.0
*
* @return true|GC_Error True if loaded; GC_Error on failure.
*/
public function load() {
if ( $this->image instanceof Imagick ) {
return true;
}
if ( ! is_file( $this->file ) && ! gc_is_stream( $this->file ) ) {
return new GC_Error( 'error_loading_image', __( 'File doesn’t exist?' ), $this->file );
}
/*
* Even though Imagick uses less PHP memory than GD, set higher limit
* for users that have low PHP.ini limits.
*/
gc_raise_memory_limit( 'image' );
try {
$this->image = new Imagick();
$file_extension = strtolower( pathinfo( $this->file, PATHINFO_EXTENSION ) );
if ( 'pdf' === $file_extension ) {
$pdf_loaded = $this->pdf_load_source();
if ( is_gc_error( $pdf_loaded ) ) {
return $pdf_loaded;
}
} else {
if ( gc_is_stream( $this->file ) ) {
// Due to reports of issues with streams with `Imagick::readImageFile()`, uses `Imagick::readImageBlob()` instead.
$this->image->readImageBlob( file_get_contents( $this->file ), $this->file );
} else {
$this->image->readImage( $this->file );
}
}
if ( ! $this->image->valid() ) {
return new GC_Error( 'invalid_image', __( 'File is not an image.' ), $this->file );
}
// Select the first frame to handle animated images properly.
if ( is_callable( array( $this->image, 'setIteratorIndex' ) ) ) {
$this->image->setIteratorIndex( 0 );
}
$this->mime_type = $this->get_mime_type( $this->image->getImageFormat() );
} catch ( Exception $e ) {
return new GC_Error( 'invalid_image', $e->getMessage(), $this->file );
}
$updated_size = $this->update_size();
if ( is_gc_error( $updated_size ) ) {
return $updated_size;
}
return $this->set_quality();
}
/**
* Sets Image Compression quality on a 1-100% scale.
*
* @since 3.5.0
*
* @param int $quality Compression Quality. Range: [1,100]
* @return true|GC_Error True if set successfully; GC_Error on failure.
*/
public function set_quality( $quality = null ) {
$quality_result = parent::set_quality( $quality );
if ( is_gc_error( $quality_result ) ) {
return $quality_result;
} else {
$quality = $this->get_quality();
}
try {
switch ( $this->mime_type ) {
case 'image/jpeg':
$this->image->setImageCompressionQuality( $quality );
$this->image->setImageCompression( imagick::COMPRESSION_JPEG );
break;
case 'image/webp':
$webp_info = gc_get_webp_info( $this->file );
if ( 'lossless' === $webp_info['type'] ) {
// Use WebP lossless settings.
$this->image->setImageCompressionQuality( 100 );
$this->image->setOption( 'webp:lossless', 'true' );
} else {
$this->image->setImageCompressionQuality( $quality );
}
break;
default:
$this->image->setImageCompressionQuality( $quality );
}
} catch ( Exception $e ) {
return new GC_Error( 'image_quality_error', $e->getMessage() );
}
return true;
}
/**
* Sets or updates current image size.
*
* @since 3.5.0
*
* @param int $width
* @param int $height
* @return true|GC_Error
*/
protected function update_size( $width = null, $height = null ) {
$size = null;
if ( ! $width || ! $height ) {
try {
$size = $this->image->getImageGeometry();
} catch ( Exception $e ) {
return new GC_Error( 'invalid_image', __( 'Could not read image size.' ), $this->file );
}
}
if ( ! $width ) {
$width = $size['width'];
}
if ( ! $height ) {
$height = $size['height'];
}
return parent::update_size( $width, $height );
}
/**
* Resizes current image.
*
* At minimum, either a height or width must be provided.
* If one of the two is set to null, the resize will
* maintain aspect ratio according to the provided dimension.
*
* @since 3.5.0
*
* @param int|null $max_w Image width.
* @param int|null $max_h Image height.
* @param bool $crop
* @return true|GC_Error
*/
public function resize( $max_w, $max_h, $crop = false ) {
if ( ( $this->size['width'] == $max_w ) && ( $this->size['height'] == $max_h ) ) {
return true;
}
$dims = image_resize_dimensions( $this->size['width'], $this->size['height'], $max_w, $max_h, $crop );
if ( ! $dims ) {
return new GC_Error( 'error_getting_dimensions', __( 'Could not calculate resized image dimensions' ) );
}
list( $dst_x, $dst_y, $src_x, $src_y, $dst_w, $dst_h, $src_w, $src_h ) = $dims;
if ( $crop ) {
return $this->crop( $src_x, $src_y, $src_w, $src_h, $dst_w, $dst_h );
}
// Execute the resize.
$thumb_result = $this->thumbnail_image( $dst_w, $dst_h );
if ( is_gc_error( $thumb_result ) ) {
return $thumb_result;
}
return $this->update_size( $dst_w, $dst_h );
}
/**
* Efficiently resize the current image
*
* This is a GeChiUI specific implementation of Imagick::thumbnailImage(),
* which resizes an image to given dimensions and removes any associated profiles.
*
* @since 4.5.0
*
* @param int $dst_w The destination width.
* @param int $dst_h The destination height.
* @param string $filter_name Optional. The Imagick filter to use when resizing. Default 'FILTER_TRIANGLE'.
* @param bool $strip_meta Optional. Strip all profiles, excluding color profiles, from the image. Default true.
* @return void|GC_Error
*/
protected function thumbnail_image( $dst_w, $dst_h, $filter_name = 'FILTER_TRIANGLE', $strip_meta = true ) {
$allowed_filters = array(
'FILTER_POINT',
'FILTER_BOX',
'FILTER_TRIANGLE',
'FILTER_HERMITE',
'FILTER_HANNING',
'FILTER_HAMMING',
'FILTER_BLACKMAN',
'FILTER_GAUSSIAN',
'FILTER_QUADRATIC',
'FILTER_CUBIC',
'FILTER_CATROM',
'FILTER_MITCHELL',
'FILTER_LANCZOS',
'FILTER_BESSEL',
'FILTER_SINC',
);
/**
* Set the filter value if '$filter_name' name is in the allowed list and the related
* Imagick constant is defined or fall back to the default filter.
*/
if ( in_array( $filter_name, $allowed_filters, true ) && defined( 'Imagick::' . $filter_name ) ) {
$filter = constant( 'Imagick::' . $filter_name );
} else {
$filter = defined( 'Imagick::FILTER_TRIANGLE' ) ? Imagick::FILTER_TRIANGLE : false;
}
/**
* Filters whether to strip metadata from images when they're resized.
*
* This filter only applies when resizing using the Imagick editor since GD
* always strips profiles by default.
*
* @since 4.5.0
*
* @param bool $strip_meta Whether to strip image metadata during resizing. Default true.
*/
if ( apply_filters( 'image_strip_meta', $strip_meta ) ) {
$this->strip_meta(); // Fail silently if not supported.
}
try {
/*
* To be more efficient, resample large images to 5x the destination size before resizing
* whenever the output size is less that 1/3 of the original image size (1/3^2 ~= .111),
* unless we would be resampling to a scale smaller than 128x128.
*/
if ( is_callable( array( $this->image, 'sampleImage' ) ) ) {
$resize_ratio = ( $dst_w / $this->size['width'] ) * ( $dst_h / $this->size['height'] );
$sample_factor = 5;
if ( $resize_ratio < .111 && ( $dst_w * $sample_factor > 128 && $dst_h * $sample_factor > 128 ) ) {
$this->image->sampleImage( $dst_w * $sample_factor, $dst_h * $sample_factor );
}
}
/*
* Use resizeImage() when it's available and a valid filter value is set.
* Otherwise, fall back to the scaleImage() method for resizing, which
* results in better image quality over resizeImage() with default filter
* settings and retains backward compatibility with pre 4.5 functionality.
*/
if ( is_callable( array( $this->image, 'resizeImage' ) ) && $filter ) {
$this->image->setOption( 'filter:support', '2.0' );
$this->image->resizeImage( $dst_w, $dst_h, $filter, 1 );
} else {
$this->image->scaleImage( $dst_w, $dst_h );
}
// Set appropriate quality settings after resizing.
if ( 'image/jpeg' === $this->mime_type ) {
if ( is_callable( array( $this->image, 'unsharpMaskImage' ) ) ) {
$this->image->unsharpMaskImage( 0.25, 0.25, 8, 0.065 );
}
$this->image->setOption( 'jpeg:fancy-upsampling', 'off' );
}
if ( 'image/png' === $this->mime_type ) {
$this->image->setOption( 'png:compression-filter', '5' );
$this->image->setOption( 'png:compression-level', '9' );
$this->image->setOption( 'png:compression-strategy', '1' );
$this->image->setOption( 'png:exclude-chunk', 'all' );
}
/*
* If alpha channel is not defined, set it opaque.
*
* Note that Imagick::getImageAlphaChannel() is only available if Imagick
* has been compiled against ImageMagick version 6.4.0 or newer.
*/
if ( is_callable( array( $this->image, 'getImageAlphaChannel' ) )
&& is_callable( array( $this->image, 'setImageAlphaChannel' ) )
&& defined( 'Imagick::ALPHACHANNEL_UNDEFINED' )
&& defined( 'Imagick::ALPHACHANNEL_OPAQUE' )
) {
if ( $this->image->getImageAlphaChannel() === Imagick::ALPHACHANNEL_UNDEFINED ) {
$this->image->setImageAlphaChannel( Imagick::ALPHACHANNEL_OPAQUE );
}
}
// Limit the bit depth of resized images to 8 bits per channel.
if ( is_callable( array( $this->image, 'getImageDepth' ) ) && is_callable( array( $this->image, 'setImageDepth' ) ) ) {
if ( 8 < $this->image->getImageDepth() ) {
$this->image->setImageDepth( 8 );
}
}
if ( is_callable( array( $this->image, 'setInterlaceScheme' ) ) && defined( 'Imagick::INTERLACE_NO' ) ) {
$this->image->setInterlaceScheme( Imagick::INTERLACE_NO );
}
} catch ( Exception $e ) {
return new GC_Error( 'image_resize_error', $e->getMessage() );
}
}
/**
* Create multiple smaller images from a single source.
*
* Attempts to create all sub-sizes and returns the meta data at the end. This
* may result in the server running out of resources. When it fails there may be few
* "orphaned" images left over as the meta data is never returned and saved.
*
* As of 5.3.0 the preferred way to do this is with `make_subsize()`. It creates
* the new images one at a time and allows for the meta data to be saved after
* each new image is created.
*
* @since 3.5.0
*
* @param array $sizes {
* An array of image size data arrays.
*
* Either a height or width must be provided.
* If one of the two is set to null, the resize will
* maintain aspect ratio according to the provided dimension.
*
* @type array $size {
* Array of height, width values, and whether to crop.
*
* @type int $width Image width. Optional if `$height` is specified.
* @type int $height Image height. Optional if `$width` is specified.
* @type bool $crop Optional. Whether to crop the image. Default false.
* }
* }
* @return array An array of resized images' metadata by size.
*/
public function multi_resize( $sizes ) {
$metadata = array();
foreach ( $sizes as $size => $size_data ) {
$meta = $this->make_subsize( $size_data );
if ( ! is_gc_error( $meta ) ) {
$metadata[ $size ] = $meta;
}
}
return $metadata;
}
/**
* Create an image sub-size and return the image meta data value for it.
*
* @since 5.3.0
*
* @param array $size_data {
* Array of size data.
*
* @type int $width The maximum width in pixels.
* @type int $height The maximum height in pixels.
* @type bool $crop Whether to crop the image to exact dimensions.
* }
* @return array|GC_Error The image data array for inclusion in the `sizes` array in the image meta,
* GC_Error object on error.
*/
public function make_subsize( $size_data ) {
if ( ! isset( $size_data['width'] ) && ! isset( $size_data['height'] ) ) {
return new GC_Error( 'image_subsize_create_error', __( 'Cannot resize the image. Both width and height are not set.' ) );
}
$orig_size = $this->size;
$orig_image = $this->image->getImage();
if ( ! isset( $size_data['width'] ) ) {
$size_data['width'] = null;
}
if ( ! isset( $size_data['height'] ) ) {
$size_data['height'] = null;
}
if ( ! isset( $size_data['crop'] ) ) {
$size_data['crop'] = false;
}
$resized = $this->resize( $size_data['width'], $size_data['height'], $size_data['crop'] );
if ( is_gc_error( $resized ) ) {
$saved = $resized;
} else {
$saved = $this->_save( $this->image );
$this->image->clear();
$this->image->destroy();
$this->image = null;
}
$this->size = $orig_size;
$this->image = $orig_image;
if ( ! is_gc_error( $saved ) ) {
unset( $saved['path'] );
}
return $saved;
}
/**
* Crops Image.
*
* @since 3.5.0
*
* @param int $src_x The start x position to crop from.
* @param int $src_y The start y position to crop from.
* @param int $src_w The width to crop.
* @param int $src_h The height to crop.
* @param int $dst_w Optional. The destination width.
* @param int $dst_h Optional. The destination height.
* @param bool $src_abs Optional. If the source crop points are absolute.
* @return true|GC_Error
*/
public function crop( $src_x, $src_y, $src_w, $src_h, $dst_w = null, $dst_h = null, $src_abs = false ) {
if ( $src_abs ) {
$src_w -= $src_x;
$src_h -= $src_y;
}
try {
$this->image->cropImage( $src_w, $src_h, $src_x, $src_y );
$this->image->setImagePage( $src_w, $src_h, 0, 0 );
if ( $dst_w || $dst_h ) {
// If destination width/height isn't specified,
// use same as width/height from source.
if ( ! $dst_w ) {
$dst_w = $src_w;
}
if ( ! $dst_h ) {
$dst_h = $src_h;
}
$thumb_result = $this->thumbnail_image( $dst_w, $dst_h );
if ( is_gc_error( $thumb_result ) ) {
return $thumb_result;
}
return $this->update_size();
}
} catch ( Exception $e ) {
return new GC_Error( 'image_crop_error', $e->getMessage() );
}
return $this->update_size();
}
/**
* Rotates current image counter-clockwise by $angle.
*
* @since 3.5.0
*
* @param float $angle
* @return true|GC_Error
*/
public function rotate( $angle ) {
/**
* $angle is 360-$angle because Imagick rotates clockwise
* (GD rotates counter-clockwise)
*/
try {
$this->image->rotateImage( new ImagickPixel( 'none' ), 360 - $angle );
// Normalise EXIF orientation data so that display is consistent across devices.
if ( is_callable( array( $this->image, 'setImageOrientation' ) ) && defined( 'Imagick::ORIENTATION_TOPLEFT' ) ) {
$this->image->setImageOrientation( Imagick::ORIENTATION_TOPLEFT );
}
// Since this changes the dimensions of the image, update the size.
$result = $this->update_size();
if ( is_gc_error( $result ) ) {
return $result;
}
$this->image->setImagePage( $this->size['width'], $this->size['height'], 0, 0 );
} catch ( Exception $e ) {
return new GC_Error( 'image_rotate_error', $e->getMessage() );
}
return true;
}
/**
* Flips current image.
*
* @since 3.5.0
*
* @param bool $horz Flip along Horizontal Axis
* @param bool $vert Flip along Vertical Axis
* @return true|GC_Error
*/
public function flip( $horz, $vert ) {
try {
if ( $horz ) {
$this->image->flipImage();
}
if ( $vert ) {
$this->image->flopImage();
}
// Normalise EXIF orientation data so that display is consistent across devices.
if ( is_callable( array( $this->image, 'setImageOrientation' ) ) && defined( 'Imagick::ORIENTATION_TOPLEFT' ) ) {
$this->image->setImageOrientation( Imagick::ORIENTATION_TOPLEFT );
}
} catch ( Exception $e ) {
return new GC_Error( 'image_flip_error', $e->getMessage() );
}
return true;
}
/**
* Check if a JPEG image has EXIF Orientation tag and rotate it if needed.
*
* As ImageMagick copies the EXIF data to the flipped/rotated image, proceed only
* if EXIF Orientation can be reset afterwards.
*
* @since 5.3.0
*
* @return bool|GC_Error True if the image was rotated. False if no EXIF data or if the image doesn't need rotation.
* GC_Error if error while rotating.
*/
public function maybe_exif_rotate() {
if ( is_callable( array( $this->image, 'setImageOrientation' ) ) && defined( 'Imagick::ORIENTATION_TOPLEFT' ) ) {
return parent::maybe_exif_rotate();
} else {
return new GC_Error( 'write_exif_error', __( 'The image cannot be rotated because the embedded meta data cannot be updated.' ) );
}
}
/**
* Saves current image to file.
*
* @since 3.5.0
*
* @param string $destfilename
* @param string $mime_type
* @return array|GC_Error {'path'=>string, 'file'=>string, 'width'=>int, 'height'=>int, 'mime-type'=>string}
*/
public function save( $destfilename = null, $mime_type = null ) {
$saved = $this->_save( $this->image, $destfilename, $mime_type );
if ( ! is_gc_error( $saved ) ) {
$this->file = $saved['path'];
$this->mime_type = $saved['mime-type'];
try {
$this->image->setImageFormat( strtoupper( $this->get_extension( $this->mime_type ) ) );
} catch ( Exception $e ) {
return new GC_Error( 'image_save_error', $e->getMessage(), $this->file );
}
}
return $saved;
}
/**
* @param Imagick $image
* @param string $filename
* @param string $mime_type
* @return array|GC_Error
*/
protected function _save( $image, $filename = null, $mime_type = null ) {
list( $filename, $extension, $mime_type ) = $this->get_output_format( $filename, $mime_type );
if ( ! $filename ) {
$filename = $this->generate_filename( null, null, $extension );
}
try {
// Store initial format.
$orig_format = $this->image->getImageFormat();
$this->image->setImageFormat( strtoupper( $this->get_extension( $mime_type ) ) );
} catch ( Exception $e ) {
return new GC_Error( 'image_save_error', $e->getMessage(), $filename );
}
$write_image_result = $this->write_image( $this->image, $filename );
if ( is_gc_error( $write_image_result ) ) {
return $write_image_result;
}
try {
// Reset original format.
$this->image->setImageFormat( $orig_format );
} catch ( Exception $e ) {
return new GC_Error( 'image_save_error', $e->getMessage(), $filename );
}
// Set correct file permissions.
$stat = stat( dirname( $filename ) );
$perms = $stat['mode'] & 0000666; // Same permissions as parent folder, strip off the executable bits.
chmod( $filename, $perms );
return array(
'path' => $filename,
/** This filter is documented in gc-includes/class-gc-image-editor-gd.php */
'file' => gc_basename( apply_filters( 'image_make_intermediate_size', $filename ) ),
'width' => $this->size['width'],
'height' => $this->size['height'],
'mime-type' => $mime_type,
);
}
/**
* Writes an image to a file or stream.
*
* @since 5.6.0
*
* @param Imagick $image
* @param string $filename The destination filename or stream URL.
* @return true|GC_Error
*/
private function write_image( $image, $filename ) {
if ( gc_is_stream( $filename ) ) {
/*
* Due to reports of issues with streams with `Imagick::writeImageFile()` and `Imagick::writeImage()`, copies the blob instead.
* Checks for exact type due to: https://www.php.net/manual/en/function.file-put-contents.php
*/
if ( file_put_contents( $filename, $image->getImageBlob() ) === false ) {
return new GC_Error(
'image_save_error',
sprintf(
/* translators: %s: PHP function name. */
__( '%s failed while writing image to stream.' ),
'<code>file_put_contents()</code>'
),
$filename
);
} else {
return true;
}
} else {
$dirname = dirname( $filename );
if ( ! gc_mkdir_p( $dirname ) ) {
return new GC_Error(
'image_save_error',
sprintf(
/* translators: %s: Directory path. */
__( 'Unable to create directory %s. Is its parent directory writable by the server?' ),
esc_html( $dirname )
)
);
}
try {
return $image->writeImage( $filename );
} catch ( Exception $e ) {
return new GC_Error( 'image_save_error', $e->getMessage(), $filename );
}
}
}
/**
* Streams current image to browser.
*
* @since 3.5.0
*
* @param string $mime_type The mime type of the image.
* @return true|GC_Error True on success, GC_Error object on failure.
*/
public function stream( $mime_type = null ) {
list( $filename, $extension, $mime_type ) = $this->get_output_format( null, $mime_type );
try {
// Temporarily change format for stream.
$this->image->setImageFormat( strtoupper( $extension ) );
// Output stream of image content.
header( "Content-Type: $mime_type" );
print $this->image->getImageBlob();
// Reset image to original format.
$this->image->setImageFormat( $this->get_extension( $this->mime_type ) );
} catch ( Exception $e ) {
return new GC_Error( 'image_stream_error', $e->getMessage() );
}
return true;
}
/**
* Strips all image meta except color profiles from an image.
*
* @since 4.5.0
*
* @return true|GC_Error True if stripping metadata was successful. GC_Error object on error.
*/
protected function strip_meta() {
if ( ! is_callable( array( $this->image, 'getImageProfiles' ) ) ) {
return new GC_Error(
'image_strip_meta_error',
sprintf(
/* translators: %s: ImageMagick method name. */
__( '%s is required to strip image meta.' ),
'<code>Imagick::getImageProfiles()</code>'
)
);
}
if ( ! is_callable( array( $this->image, 'removeImageProfile' ) ) ) {
return new GC_Error(
'image_strip_meta_error',
sprintf(
/* translators: %s: ImageMagick method name. */
__( '%s is required to strip image meta.' ),
'<code>Imagick::removeImageProfile()</code>'
)
);
}
/*
* Protect a few profiles from being stripped for the following reasons:
*
* - icc: Color profile information
* - icm: Color profile information
* - iptc: Copyright data
* - exif: Orientation data
* - xmp: Rights usage data
*/
$protected_profiles = array(
'icc',
'icm',
'iptc',
'exif',
'xmp',
);
try {
// Strip profiles.
foreach ( $this->image->getImageProfiles( '*', true ) as $key => $value ) {
if ( ! in_array( $key, $protected_profiles, true ) ) {
$this->image->removeImageProfile( $key );
}
}
} catch ( Exception $e ) {
return new GC_Error( 'image_strip_meta_error', $e->getMessage() );
}
return true;
}
/**
* Sets up Imagick for PDF processing.
* Increases rendering DPI and only loads first page.
*
* @since 4.7.0
*
* @return string|GC_Error File to load or GC_Error on failure.
*/
protected function pdf_setup() {
try {
// By default, PDFs are rendered in a very low resolution.
// We want the thumbnail to be readable, so increase the rendering DPI.
$this->image->setResolution( 128, 128 );
// Only load the first page.
return $this->file . '[0]';
} catch ( Exception $e ) {
return new GC_Error( 'pdf_setup_failed', $e->getMessage(), $this->file );
}
}
/**
* Load the image produced by Ghostscript.
*
* Includes a workaround for a bug in Ghostscript 8.70 that prevents processing of some PDF files
* when `use-cropbox` is set.
*
* @since 5.6.0
*
* @return true|GC_error
*/
protected function pdf_load_source() {
$filename = $this->pdf_setup();
if ( is_gc_error( $filename ) ) {
return $filename;
}
try {
// When generating thumbnails from cropped PDF pages, Imagemagick uses the uncropped
// area (resulting in unnecessary whitespace) unless the following option is set.
$this->image->setOption( 'pdf:use-cropbox', true );
// Reading image after Imagick instantiation because `setResolution`
// only applies correctly before the image is read.
$this->image->readImage( $filename );
} catch ( Exception $e ) {
// Attempt to run `gs` without the `use-cropbox` option. See #48853.
$this->image->setOption( 'pdf:use-cropbox', false );
$this->image->readImage( $filename );
}
return true;
}
}