Changeset 31040

Timestamp:

01/03/2015 10:01:54 PM (10 years ago)

Author:

wonderboymusic

Message:

Preserve alpha transparency when rotating a PNG while GD is the active image editor.

Adds unit tests.

Props frankpw, voldemortensen.
Fixes #30596.

Location:

trunk

Files:

• src/wp-includes/class-wp-image-editor-gd.php (modified) (1 diff)
• tests/phpunit/tests/image/editor_gd.php (modified) (1 diff)
• tests/phpunit/tests/image/editor_imagick.php (modified) (1 diff)

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

@@ -307 +307 @@
     public function rotate( $angle ) {
         if ( function_exists('imagerotate') ) {
-            $rotated = imagerotate( $this->image, $angle, 0 );
+            $transparency = imagecolorallocatealpha( $this->image, 255, 255, 255, 127 );
+            $rotated = imagerotate( $this->image, $angle, $transparency );
 
             if ( is_resource( $rotated ) ) {
+                imagealphablending( $rotated, true );
+                imagesavealpha( $rotated, true );
                 imagedestroy( $this->image );
                 $this->image = $rotated;

trunk/tests/phpunit/tests/image/editor_gd.php

@@ -500 +500 @@
         unlink( $save_to_file );
     }
+
+    /**
+     *
+     * @ticket 30596
+     */
+    public function test_image_preserves_alpha_on_rotate() {
+        $file = DIR_TESTDATA . '/images/transparent.png';
+
+        $image = imagecreatefrompng( $file );
+        $rgb = imagecolorat( $image, 0, 0 );
+        $expected = imagecolorsforindex( $image, $rgb );
+
+        $editor = new WP_Image_Editor_GD( $file );
+                $this->assertNotInstanceOf( 'WP_Error', $editor );
+                $editor->load();
+                $editor->rotate( 180 );
+                $save_to_file = tempnam( get_temp_dir(), '' ) . '.png';
+
+                $editor->save( $save_to_file );
+
+                $this->assertImageAlphaAtPointGD( $save_to_file, array( 0,0 ), $expected['alpha'] );
+                unlink( $save_to_file );
+
+    }
 }

trunk/tests/phpunit/tests/image/editor_imagick.php

@@ -508 +508 @@
         unlink( $save_to_file );
     }
+
+    /**
+     *
+     * @ticket 30596
+     */
+    public function test_image_peserves_alpha_on_rotate() {
+        $file = DIR_TESTDATA . '/images/transparent.png';
+
+        $pre_rotate_editor = new Imagick( $file );
+        $pre_rotate_pixel = $pre_rotate_editor->getImagePixelColor( 0, 0 );
+        $pre_rotate_alpha = $pre_rotate_pixel->getColorValue( imagick::COLOR_ALPHA );
+        $save_to_file = tempnam( get_temp_dir(),'' ) . '.png';
+        $pre_rotate_editor->writeImage( $save_to_file );
+        $pre_rotate_editor->destroy();
+
+        $image_editor = new WP_Image_Editor_Imagick( $save_to_file );
+        $image_editor->load();
+        $this->assertNotInstanceOf( 'WP_Error', $image_editor );
+        $image_editor->rotate( 180 );
+        $image_editor->save( $save_to_file );
+
+        $this->assertImageAlphaAtPointImagick( $save_to_file, array( 0, 0 ), $pre_rotate_alpha );
+        unlink( $save_to_file );
+    }
 }