Changeset 36700 for trunk/src/wp-includes/class-wp-image-editor-imagick.php

Timestamp:

02/24/2016 10:50:10 PM (9 years ago)

Author:

mikeschroder

Message:

Media: Optimize Imagick settings for quality and filesize

• Resamples and sharpens larger images before resize.
• Uses imagick::FILTER_TRIANGLE for a smoother resize.
• Introduces WP_Image_Editor_Imagick::thumbnail_image() protected method to efficiently resize images. Similar to the functionality of Imagick's thumbnailImage().
• Introduces WP_Image_Editor_Imagick::strip_meta() protected method and image_strip_meta filter that, by default, strip image profiles to reduce file size, while leaving color profiles intact.

See: #33642, #30402, #28634.
Props: joemcgill, dnewton, mikeschroder.

File:

• trunk/src/wp-includes/class-wp-image-editor-imagick.php (modified) (5 diffs)

trunk/src/wp-includes/class-wp-image-editor-imagick.php

@@ -63 +63 @@
             'getimageblob',
             'getimagegeometry',
+            'getimagedepth',
             'getimageformat',
             'setimageformat',
             'setimagecompression',
             'setimagecompressionquality',
+            'setimagedepth',
             'setimagepage',
+            'setimageproperty',
+            'setinterlacescheme',
             'scaleimage',
             'cropimage',
@@ -73 +77 @@
             'flipimage',
             'flopimage',
+            'unsharpmaskimage',
         );
 
         // Now, test for deep requirements within Imagick.
-        if ( ! defined( 'imagick::COMPRESSION_JPEG' ) )
+        if ( ! ( defined( 'imagick::COMPRESSION_JPEG' ) && defined( 'imagick::FILTER_TRIANGLE' ) ) )
             return false;
 
@@ -250 +255 @@
         }
 
-        try {
+        // Execute the resize
+        $thumb_result = $this->thumbnail_image( $dst_w, $dst_h );
+        if ( is_wp_error( $thumb_result ) ) {
+            return $thumb_result;
+        }
+
+        return $this->update_size( $dst_w, $dst_h );
+    }
+
+    /**
+     * Efficiently resize the current image
+     *
+     * This is a WordPress specific implementation of Imagick::thumbnailImage(),
+     * which resizes an image to given dimensions and removes any associated profiles.
+     *
+     * @since 4.5.0
+     * @access protected
+     *
+     * @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 bool|WP_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 our whitelist and the related
+         * Imagick constant is defined or fall back to our default filter.
+         */
+        if ( in_array( $filter_name, $allowed_filters ) && defined( 'Imagick::' . $filter_name ) ) {
+            $filter = constant( 'Imagick::' . $filter_name );
+        } else {
+            $filter = Imagick::FILTER_TRIANGLE;
+        }
+
+        /**
+         * Filter to override stripping 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.
+         */
+        $strip_meta = apply_filters( 'image_strip_meta', $strip_meta );
+
+        // Strip image meta.
+        if ( $strip_meta ) {
+            $strip_result = $this->strip_meta();
+
+            if ( is_wp_error( $strip_result ) ) {
+                return $strip_result;
+            }
+        }
+
+        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.
+             */
+            $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 );
+            }
+
+            // Resize to the final output size.
+            $this->image->setOption( 'filter:support', '2.0' );
+            $this->image->resizeImage( $dst_w, $dst_h, $filter, 1 );
+
+            // Set appropriate quality settings after resizing.
+            if ( 'image/jpeg' == $this->mime_type ) {
+                $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' );
+            }
+
             /**
-             * @TODO: Thumbnail is more efficient, given a newer version of Imagemagick.
-             * $this->image->thumbnailImage( $dst_w, $dst_h );
+             * 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.
              */
-            $this->image->scaleImage( $dst_w, $dst_h );
+            if ( method_exists( $this->image, 'getImageAlphaChannel') && $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 ( 8 < $this->image->getImageDepth() ) {
+                $this->image->setImageDepth( 8 );
+            }
+
+            $this->image->setInterlaceScheme( Imagick::INTERLACE_NO );
+
         }
         catch ( Exception $e ) {
             return new WP_Error( 'image_resize_error', $e->getMessage() );
         }
-
-        return $this->update_size( $dst_w, $dst_h );
     }
 
@@ -368 +486 @@
                     $dst_h = $src_h;
 
-                $this->image->scaleImage( $dst_w, $dst_h );
+                $thumb_result = $this->thumbnail_image( $dst_w, $dst_h );
+                if ( is_wp_error( $thumb_result ) ) {
+                    return $thumb_result;
+                }
+
                 return $this->update_size();
             }
@@ -531 +653 @@
         return true;
     }
+
+    /**
+     * Strip all image meta except color profiles from an image.
+     *
+     * @access protected
+     * @since 4.5.0
+     */
+    protected function strip_meta() {
+        try {
+            // Strip profiles.
+            foreach ( $this->image->getImageProfiles( '*', true ) as $key => $value ) {
+                if ( $key != 'icc' && $key != 'icm' ) {
+                    $this->image->removeImageProfile( $key );
+                }
+            }
+
+            // Strip image properties.
+            if ( method_exists( $this->image, 'deleteImageProperty' ) ) {
+                $this->image->deleteImageProperty( 'comment' );
+                $this->image->deleteImageProperty( 'Thumb::URI' );
+                $this->image->deleteImageProperty( 'Thumb::MTime' );
+                $this->image->deleteImageProperty( 'Thumb::Size' );
+                $this->image->deleteImageProperty( 'Thumb::Mimetype' );
+                $this->image->deleteImageProperty( 'software' );
+                $this->image->deleteImageProperty( 'Thumb::Image::Width' );
+                $this->image->deleteImageProperty( 'Thumb::Image::Height' );
+                $this->image->deleteImageProperty( 'Thumb::Document::Pages' );
+            } else {
+                $this->image->setImageProperty( 'comment', '' );
+                $this->image->setImageProperty( 'Thumb::URI', '' );
+                $this->image->setImageProperty( 'Thumb::MTime', '' );
+                $this->image->setImageProperty( 'Thumb::Size', '' );
+                $this->image->setImageProperty( 'Thumb::Mimetype', '' );
+                $this->image->setImageProperty( 'software', '' );
+                $this->image->setImageProperty( 'Thumb::Image::Width', '' );
+                $this->image->setImageProperty( 'Thumb::Image::Height', '' );
+                $this->image->setImageProperty( 'Thumb::Document::Pages', '' );
+            }
+        } catch ( Excpetion $e ) {
+            return new WP_Error( 'image_strip_meta_error', $e->getMessage() );
+        }
+
+        return true;
+    }
+
 }