Changeset 60667 for trunk/tests/phpunit/tests/image/editorImagick.php

Timestamp:

08/26/2025 08:55:24 PM (5 months ago)

Author:

adamsilverstein

Message:

Media: improve Imagick handling of indexed PNG images with transparency.

Fix an issue where certain transparent PNG images experienced noticeable quality degradation when resized by Imagick.

Follow up to [60246].

Props elvismdev, SirLouen, siliconforks, nosilver4u, iamshashank.

Fixes #63448.

File:

• trunk/tests/phpunit/tests/image/editorImagick.php (modified) (1 diff)

trunk/tests/phpunit/tests/image/editorImagick.php

@@ -874 +874 @@
         );
     }
+
+    /**
+     * Tests that alpha transparency is preserved after resizing.
+     *
+     * @ticket 63448
+     * @dataProvider data_alpha_transparency_is_preserved_after_resize
+     *
+     * @param string $file_path Path to the image file.
+     */
+    public function test_alpha_transparency_is_preserved_after_resize( $file_path ) {
+
+        $temp_file = DIR_TESTDATA . '/images/test-temp.png';
+
+        $imagick_image_editor = new WP_Image_Editor_Imagick( $file_path );
+        $imagick_image_editor->load();
+
+        $size = $imagick_image_editor->get_size();
+        $imagick_image_editor->resize( $size['width'] * 0.5, $size['height'] * 0.5 );
+        $imagick_image_editor->save( $temp_file );
+
+        $imagick             = new Imagick( $temp_file );
+        $alpha_channel_depth = $imagick->getImageChannelDepth( Imagick::CHANNEL_ALPHA );
+
+        unlink( $temp_file );
+
+        $this->assertGreaterThan( 1, $alpha_channel_depth, "Alpha transparency should be preserved after resize for {$file_path}." );
+    }
+
+    public static function data_alpha_transparency_is_preserved_after_resize() {
+        return array(
+            'oval-or8'                   => array(
+                DIR_TESTDATA . '/images/png-tests/oval-or8.png',
+            ),
+            'oval-or8-grayscale-indexed' => array(
+                DIR_TESTDATA . '/images/png-tests/oval-or8-grayscale-indexed.png',
+            ),
+        );
+    }
 }