Created public interface method gutenberg_style_engine_generate

lib/block-supports/colors.php

@@ -102,8 +102,7 @@ function gutenberg_apply_colors_support( $block_type, $block_attributes ) {
 	}
 
 	$attributes   = array();
-	$style_engine = gutenberg_get_style_engine();
-	$styles       = $style_engine->generate( array( 'color' => $color_block_styles ) );
+	$styles       = gutenberg_style_engine_generate( array( 'color' => $color_block_styles ) );
 
 	if ( ! empty( $styles['classnames'] ) ) {
 		$attributes['class'] = $styles['classnames'];

lib/block-supports/spacing.php

@@ -52,13 +52,12 @@ function gutenberg_apply_spacing_support( $block_type, $block_attributes ) {
 		return $attributes;
 	}
 
-	$style_engine                    = gutenberg_get_style_engine();
 	$skip_padding                    = gutenberg_should_skip_block_supports_serialization( $block_type, 'spacing', 'padding' );
 	$skip_margin                     = gutenberg_should_skip_block_supports_serialization( $block_type, 'spacing', 'margin' );
 	$spacing_block_styles            = array();
 	$spacing_block_styles['padding'] = $has_padding_support && ! $skip_padding ? _wp_array_get( $block_styles, array( 'spacing', 'padding' ), null ) : null;
 	$spacing_block_styles['margin']  = $has_margin_support && ! $skip_margin ? _wp_array_get( $block_styles, array( 'spacing', 'margin' ), null ) : null;
-	$styles                          = $style_engine->generate(
+	$styles                          = gutenberg_style_engine_generate(
 		array( 'spacing' => $spacing_block_styles )
 	);
 

lib/block-supports/typography.php

@@ -140,9 +140,8 @@ function gutenberg_apply_typography_support( $block_type, $block_attributes ) {
 			gutenberg_typography_get_preset_inline_style_value( $block_attributes['style']['typography']['letterSpacing'], 'letter-spacing' );
 	}
 
-	$attributes   = array();
-	$style_engine = gutenberg_get_style_engine();
-	$styles       = $style_engine->generate( array( 'typography' => $typography_block_styles ) );
+	$attributes = array();
+	$styles     = gutenberg_style_engine_generate( array( 'typography' => $typography_block_styles ) );
 
 	if ( ! empty( $styles['classnames'] ) ) {
 		$attributes['class'] = $styles['classnames'];

packages/style-engine/class-wp-style-engine.php

@@ -16,6 +16,11 @@
  *
  * Consolidates rendering block styles to reduce duplication and streamline
  * CSS styles generation.
+ *
+ * This class is for internal core usage and is not supposed to be used by extenders (plugins and/or themes).
+ * This is a low-level API that may need to do breaking changes. Please, use gutenberg_style_engine_get_styles instead.
+ *
+ * @access private
  */
 class WP_Style_Engine {
 	/**
@@ -169,10 +174,9 @@ protected static function get_classnames( $style_value, $style_definition ) {
 	 * @return array        An array of CSS rules.
 	 */
 	protected static function get_css( $style_value, $style_definition ) {
-		$css = array();
 		// Low-specificity check to see if the value is a CSS preset.
 		if ( is_string( $style_value ) && strpos( $style_value, 'var:' ) !== false ) {
-			return $css;
+			return array();
 		}
 
 		// If required in the future, style definitions could define a callable `value_func` to generate custom CSS rules.
@@ -269,12 +273,22 @@ protected static function get_css_rules( $style_value, $style_property ) {
 }
 
 /**
- * This function returns the Style Engine instance.
+ * Global public interface method to WP_Style_Engine->generate.
+ *
+ * Returns an CSS ruleset.
+ * Styles are bundled based on the instructions in BLOCK_STYLE_DEFINITIONS_METADATA.
+ *
+ * @param array $block_styles An array of styles from a block's attributes.
  *
- * @return WP_Style_Engine
+ * @return array|null array(
+ *     'styles'     => (string) A CSS ruleset formatted to be placed in an HTML `style` attribute or tag.
+ *     'classnames' => (string) Classnames separated by a space.
+ * );
  */
-function wp_get_style_engine() {
+function wp_style_engine_generate( $block_styles ) {
 	if ( class_exists( 'WP_Style_Engine' ) ) {
-		return WP_Style_Engine::get_instance();
+		$style_engine = WP_Style_Engine::get_instance();
+		return $style_engine->generate( $block_styles );
 	}
+	return null;
 }

packages/style-engine/phpunit/class-wp-style-engine-test.php

@@ -18,8 +18,7 @@ class WP_Style_Engine_Test extends WP_UnitTestCase {
 	 * @dataProvider data_generate_styles_fixtures
 	 */
 	function test_generate_styles( $block_styles, $expected_output ) {
-		$style_engine     = wp_get_style_engine();
-		$generated_styles = $style_engine->generate( $block_styles );
+		$generated_styles = wp_style_engine_generate( $block_styles );
 		$this->assertSame( $expected_output, $generated_styles );
 	}