Ticket #48202: 48202.diff

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

@@ -343 +343 @@
          */
         public function rotate( $angle ) {
                 if ( function_exists( 'imagerotate' ) ) {
-                        $transparency = imagecolorallocatealpha( $this->image, 255, 255, 255, 127 );
-                        $rotated      = imagerotate( $this->image, $angle, $transparency );
+                        // Set the background fill color when an image is partially rotated ($angle is not 90, 180, or 270).
+                        if ( 'image/png' === $this->mime_type || 'image/gif' === $this->mime_type ) {
+                                $bg_color = imagecolorallocatealpha( $this->image, 255, 255, 255, 127 );
+                        } else {
+                                $bg_color = imagecolorallocate( $this->image, 255, 255, 255 );
+                        }
 
+                        $rotated = imagerotate( $this->image, $angle, $bg_color );
+
                         if ( is_resource( $rotated ) ) {
-                                imagealphablending( $rotated, true );
-                                imagesavealpha( $rotated, true );
+                                // Disable blending mode for images that support transparency.
+                                // It "blends" the pixels and makes them opaque.
+                                if ( 'image/png' === $this->mime_type || 'image/gif' === $this->mime_type ) {
+                                        imagealphablending( $rotated, false );
+                                }
+
+                                // Preserve trnasparency for PNGs.
+                                if ( 'image/png' === $this->mime_type ) {
+                                        imagesavealpha( $rotated, true );
+                                }
+
                                 imagedestroy( $this->image );
                                 $this->image = $rotated;
                                 $this->update_size();
+
                                 return true;
                         }
                 }
+
                 return new WP_Error( 'image_rotate_error', __( 'Image rotate failed.' ), $this->file );
         }
 
@@ -384 +401 @@
                                 return true;
                         }
                 }
+
                 return new WP_Error( 'image_flip_error', __( 'Image flip failed.' ), $this->file );
         }