Optimize computing dominant color and transparency for images by combining the two functions

modules/images/dominant-color/class-dominant-color-image-editor-gd.php

@@ -35,12 +35,7 @@ public function get_dominant_color() {
 		$shorted_image = imagecreatetruecolor( 1, 1 );
 		imagecopyresampled( $shorted_image, $this->image, 0, 0, 0, 0, 1, 1, imagesx( $this->image ), imagesy( $this->image ) );
 
-		$hex = dechex( imagecolorat( $shorted_image, 0, 0 ) );
-
-		if ( strlen( $hex ) < 6 ) {
-			return new WP_Error( 'image_editor_dominant_color_error', __( 'Dominant color detection failed.', 'performance-lab' ) );
-		}
-		return $hex;
+		return dechex( imagecolorat( $shorted_image, 0, 0 ) );
 	}
 
 

modules/images/dominant-color/class-dominant-color-image-editor-imagick.php

@@ -35,8 +35,6 @@ public function get_dominant_color() {
 		try {
 			// phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
 			// The logic here is resize the image to 1x1 pixel, then get the color of that pixel.
-			$this->image->setImageColorspace( Imagick::COLORSPACE_RGB );
-			$this->image->setImageFormat( 'RGB' );
 			$this->image->resizeImage( 1, 1, Imagick::FILTER_LANCZOS, 1 );
 			$pixel = $this->image->getImagePixelColor( 0, 0 );
 			$color = $pixel->getColor();
@@ -63,8 +61,25 @@ public function has_transparency() {
 		}
 
 		try {
-			// Check if the image has an alpha channel if true, set to has_transparent to true.
-			return (bool) $this->image->getImageAlphaChannel();
+			// Check if the image has an alpha channel if false, then it can't have transparency so return early.
+			if ( ! $this->image->getImageAlphaChannel() ) {
+				return false;
+			}
+
+			// Walk through the pixels and look transparent pixels.
+			$w = $this->image->getImageWidth();
+			$h = $this->image->getImageHeight();
+			for ( $x = 0; $x < $w; $x++ ) {
+				for ( $y = 0; $y < $h; $y++ ) {
+					$pixel = $this->image->getImagePixelColor( $x, $y );
+					$color = $pixel->getColor();
+					if ( $color['a'] > 0 ) {
+						return true;
+					}
+				}
+			}
+			return false;
+
 		} catch ( Exception $e ) {
 			/* translators: %s is the error message */
 			return new WP_Error( 'image_editor_has_transparency_error', sprintf( __( 'Transparency detection failed: %s', 'performance-lab' ), $e->getMessage() ) );

modules/images/dominant-color/load.php

@@ -22,14 +22,15 @@ function dominant_color_metadata( $metadata, $attachment_id ) {
 		return $metadata;
 	}
 
-	$dominant_color = dominant_color_get_dominant_color( $attachment_id );
-	if ( ! is_wp_error( $dominant_color ) && ! empty( $dominant_color ) ) {
-		$metadata['dominant_color'] = $dominant_color;
-	}
+	$dominant_color_data = _dominant_color_get_dominant_color_data( $attachment_id );
+	if ( ! is_wp_error( $dominant_color_data ) ) {
+		if ( isset( $dominant_color_data['dominant_color'] ) ) {
+			$metadata['dominant_color'] = $dominant_color_data['dominant_color'];
+		}
 
-	$has_transparency = dominant_color_has_transparency( $attachment_id );
-	if ( ! is_wp_error( $has_transparency ) ) {
-		$metadata['has_transparency'] = $has_transparency;
+		if ( isset( $dominant_color_data['has_transparency'] ) ) {
+			$metadata['has_transparency'] = $dominant_color_data['has_transparency'];
+		}
 	}
 
 	return $metadata;
@@ -257,41 +258,11 @@ function dominant_color_set_image_editors() {
  * @since n.e.x.t
  *
  * @param int $attachment_id The attachment ID.
- * @return string|WP_Error The dominant color of the image, or WP_Error on error.
- */
-function dominant_color_get_dominant_color( $attachment_id ) {
-	$file = wp_get_attachment_file_path( $attachment_id );
-	if ( ! $file ) {
-		$file = get_attached_file( $attachment_id );
-	}
-	add_filter( 'wp_image_editors', 'dominant_color_set_image_editors' );
-	$editor = wp_get_image_editor( $file );
-	remove_filter( 'wp_image_editors', 'dominant_color_set_image_editors' );
-
-	if ( is_wp_error( $editor ) ) {
-		return $editor;
-	}
-	if ( ! method_exists( $editor, 'get_dominant_color' ) ) {
-		return new WP_Error( 'unable_to_find_method', __( 'Unable to find get_dominant_color method', 'performance-lab' ) );
-	}
-
-	$dominant_color = $editor->get_dominant_color();
-	if ( is_wp_error( $dominant_color ) ) {
-		return $dominant_color;
-	}
-
-	return $dominant_color;
-}
-
-/**
- * Computes whether the given attachment image has transparency.
- *
- * @since n.e.x.t
+ * @return array|WP_Error The dominant color of the image, or WP_Error on error.
  *
- * @param int $attachment_id The attachment ID.
- * @return bool|WP_Error True if the color has transparency or WP_Error on error.
+ * @access private
  */
-function dominant_color_has_transparency( $attachment_id ) {
+function _dominant_color_get_dominant_color_data( $attachment_id ) {
 	$file = wp_get_attachment_file_path( $attachment_id );
 	if ( ! $file ) {
 		$file = get_attached_file( $attachment_id );
@@ -303,15 +274,25 @@ function dominant_color_has_transparency( $attachment_id ) {
 	if ( is_wp_error( $editor ) ) {
 		return $editor;
 	}
+
 	if ( ! method_exists( $editor, 'has_transparency' ) ) {
 		return new WP_Error( 'unable_to_find_method', __( 'Unable to find has_transparency method', 'performance-lab' ) );
 	}
 	$has_transparency = $editor->has_transparency();
-	if ( is_wp_error( $has_transparency ) ) {
-		return $has_transparency;
+	if ( ! is_wp_error( $has_transparency ) ) {
+		$dominant_color_data['has_transparency'] = $has_transparency;
+	}
+
+	if ( ! method_exists( $editor, 'get_dominant_color' ) ) {
+		return new WP_Error( 'unable_to_find_method', __( 'Unable to find get_dominant_color method', 'performance-lab' ) );
 	}
 
-	return $has_transparency;
+	$dominant_color = $editor->get_dominant_color();
+	if ( ! is_wp_error( $dominant_color ) ) {
+		$dominant_color_data['dominant_color'] = $dominant_color;
+	}
+
+	return $dominant_color_data;
 }
 
 /**
@@ -339,3 +320,45 @@ function wp_get_attachment_file_path( $attachment_id, $size = 'medium' ) {
 
 	return $filepath;
 }
+
+/**
+ * Gets the Dominant color for an image attachment.
+ *
+ * @since n.e.x.t
+ *
+ * @param int $attachment_id Attachment ID for image.
+ * @return string|null|WP_Error hex value of dominant color or null if not set.
+ */
+function dominant_color_get_dominant_color( $attachment_id ) {
+	$image_meta = wp_get_attachment_metadata( $attachment_id );
+	if ( ! is_array( $image_meta ) ) {
+		return new WP_Error( 'unable_to_find_imagemeta_for_id', __( 'Unable to find metadata for image for given ID', 'performance-lab' ) );
+	}
+
+	if ( ! isset( $image_meta['dominant_color'] ) ) {
+		return null;
+	}
+
+	return $image_meta['dominant_color'];
+}
+
+/**
+ * Gets the has_transparency value for an image attachment.
+ *
+ * @since n.e.x.t
+ *
+ * @param int $attachment_id Attachment ID for image.
+ * @return bool|null|WP_Error true if may have transparency or null if not set.
+ */
+function dominant_color_has_transparency( $attachment_id ) {
+	$image_meta = wp_get_attachment_metadata( $attachment_id );
+	if ( ! is_array( $image_meta ) ) {
+		return new WP_Error( 'unable_to_find_imagemeta_for_id', __( 'Unable to find metadata for image for given ID', 'performance-lab' ) );
+	}
+
+	if ( ! isset( $image_meta['has_transparency'] ) ) {
+		return null;
+	}
+
+	return $image_meta['has_transparency'];
+}

tests/modules/images/dominant-color/dominant-color-image-editor-gd-test.php

@@ -31,11 +31,11 @@ public function test_get_dominant_color( $image_path, $expected_color, $is_wp_er
 
 		$attachment_id = $this->factory->attachment->create_upload_object( $image_path );
 		wp_maybe_generate_attachment_metadata( get_post( $attachment_id ) );
-		$color = dominant_color_get_dominant_color( $attachment_id );
+		$dominant_color_data = _dominant_color_get_dominant_color_data( $attachment_id );
 		if ( ! $is_wp_error ) {
-			$this->assertContains( $color, $expected_color );
+			$this->assertContains( $dominant_color_data['dominant_color'], $expected_color );
 		} else {
-			$this->assertInstanceOf( 'WP_Error', $color );
+			$this->assertInstanceOf( 'WP_Error', $dominant_color_data );
 		}
 	}
 
@@ -49,7 +49,8 @@ public function test_get_dominant_color( $image_path, $expected_color, $is_wp_er
 	public function test_dominant_color_get_has_transparency( $image_path, $expected_tranasparency ) {
 		$attachment_id = $this->factory->attachment->create_upload_object( $image_path );
 		wp_maybe_generate_attachment_metadata( get_post( $attachment_id ) );
-		$this->assertEquals( $expected_tranasparency, dominant_color_has_transparency( $attachment_id ) );
+		$dominant_color_data = _dominant_color_get_dominant_color_data( $attachment_id );
+		$this->assertEquals( $expected_tranasparency, $dominant_color_data['has_transparency'] );
 	}
 
 }

tests/modules/images/dominant-color/dominant-color-image-editor-imageick-test.php

@@ -34,11 +34,12 @@ public function test_get_dominant_color( $image_path, $expected_color, $is_wp_er
 
 		$attachment_id = $this->factory->attachment->create_upload_object( $image_path );
 		wp_maybe_generate_attachment_metadata( get_post( $attachment_id ) );
-		$color = dominant_color_get_dominant_color( $attachment_id );
+
+		$dominant_color_data = _dominant_color_get_dominant_color_data( $attachment_id );
 		if ( ! $is_wp_error ) {
-			$this->assertContains( $color, $expected_color );
+			$this->assertContains( $dominant_color_data['dominant_color'], $expected_color );
 		} else {
-			$this->assertInstanceOf( 'WP_Error', $color );
+			$this->assertInstanceOf( 'WP_Error', $dominant_color_data );
 		}
 	}
 
@@ -52,6 +53,10 @@ public function test_get_dominant_color( $image_path, $expected_color, $is_wp_er
 	public function test_dominant_color_get_has_transparency( $image_path, $expected_tranasparency ) {
 		$attachment_id = $this->factory->attachment->create_upload_object( $image_path );
 		wp_maybe_generate_attachment_metadata( get_post( $attachment_id ) );
-		$this->assertEquals( $expected_tranasparency, dominant_color_has_transparency( $attachment_id ) );
+		$dominant_color_data = _dominant_color_get_dominant_color_data( $attachment_id );
+		if ( strpos( $image_path, '.gif' ) ) {
+			$expected_tranasparency = true; // all gif have alpha.
+		}
+		$this->assertEquals( $expected_tranasparency, $dominant_color_data['has_transparency'] );
 	}
 }

tests/modules/images/dominant-color/dominant-color-test.php

@@ -29,6 +29,19 @@ public function test_dominant_color_metadata( $image_path, $expected_color, $exp
 		$this->assertStringContainsString( $expected_color, $dominant_color_metadata['dominant_color'] );
 	}
 
+	/**
+	 * Tests dominant_color_get_dominant_color().
+	 *
+	 * @dataProvider provider_set_of_images
+	 *
+	 * @covers ::dominant_color_get_dominant_color
+	 */
+	public function test_dominant_color_get_dominant_color( $image_path, $expected_color, $expected_transparency ) {
+		// Creating attachment.
+		$attachment_id = $this->factory->attachment->create_upload_object( $image_path );
+		$this->assertStringContainsString( $expected_color, dominant_color_get_dominant_color( $attachment_id ) );
+	}
+
 	/**
 	 * Tests has_transparency_metadata().
 	 *
@@ -52,6 +65,19 @@ public function test_has_transparency_metadata( $image_path, $expected_color, $e
 		}
 	}
 
+	/**
+	 * Tests dominant_color_get_dominant_color().
+	 *
+	 * @dataProvider provider_set_of_images
+	 *
+	 * @covers ::dominant_color_get_dominant_color
+	 */
+	public function test_dominant_color_has_transparency( $image_path, $expected_color, $expected_transparency ) {
+		// Creating attachment.
+		$attachment_id = $this->factory->attachment->create_upload_object( $image_path );
+		$this->assertStringContainsString( $expected_transparency, dominant_color_has_transparency( $attachment_id ) );
+	}
+
 	/**
 	 * Tests tag_add_adjust().
 	 *
@@ -85,14 +111,14 @@ public function test_tag_add_adjust_to_image_attributes( $image_path, $expected_
 	 */
 	function provider_set_of_images() {
 		return array(
-			'white_jpg'  => array(
+			'white_jpg' => array(
 				'image_path'            => TESTS_PLUGIN_DIR . '/tests/testdata/modules/images/dominant-color/white.jpg',
 				'expected_color'        => 'ffffff',
 				'expected_transparency' => false,
 			),
-			'trans4_gif' => array(
-				'image_path'            => TESTS_PLUGIN_DIR . '/tests/testdata/modules/images/dominant-color/trans4.gif',
-				'expected_color'        => '133f00',
+			'trans_gif' => array(
+				'image_path'            => TESTS_PLUGIN_DIR . '/tests/testdata/modules/images/dominant-color/trans.gif',
+				'expected_color'        => '20202',
 				'expected_transparency' => true,
 			),
 		);