Ticket #39331: 39331.2.patch

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

@@ -368 +368 @@
                         // 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 );
+                                        // Not compatible with CMYK color spaces for ImageMagick versions 6.8.4-0 to 6.9.6-4 (https://github.com/ImageMagick/ImageMagick/issues/299).
+                                        $do_unsharp = true;
+                                        if ( Imagick::COLORSPACE_CMYK === $this->image->getImageColorspace() ) {
+                                                $imagick_version = Imagick::getVersion();
+                                                if ( preg_match( '/[0-9]+\.[0-9]+\.[0-9]+-[0-9]+/', $imagick_version['versionString'], $matches ) ) {
+                                                        $do_unsharp = version_compare( $matches[0], '6.8.4-0', '<' ) || version_compare( $matches[0], '6.9.6-4', '>' );
+                                                }
+                                        }
+                                        if ( $do_unsharp ) {
+                                                $this->image->unsharpMaskImage( 0.25, 0.25, 8, 0.065 );
+                                        }
                                 }
 
                                 $this->image->setOption( 'jpeg:fancy-upsampling', 'off' );

tests/phpunit/tests/image/editor_imagick.php

@@ -572 +572 @@
                 unlink( $ret['path'] );
         }
 
+        /**
+         * @ticket 39331
+         * Note affects only ImageMagick versions 6.8.4-0 to 6.9.6-4.
+         */
+        public function test_cmyk_jpg_resize() {
+                $test_file = DIR_TESTDATA . '/images/test_cmyk.jpg';
+                $save_to_file = tempnam( get_temp_dir(), '' ) . '.jpg';
+
+                $editor = new WP_Image_Editor_Imagick( $test_file );
+                $editor->load();
+                $editor->resize( 106, 150 ); // Default thumbnail size.
+                $editor->save( $save_to_file );
+
+                // Use GD as Imagick seems to do some color mapping of CMYK images.
+                $gd_image = imagecreatefromjpeg( $save_to_file );
+                // Pixel (15, 10) should be white.
+                $output = dechex( imagecolorat( $gd_image, 15, 10 ) );
+                imagedestroy( $gd_image );
+                $this->assertSame( 'ffffff', $output );
+
+                unlink( $save_to_file );
+        }
 }