block_core_gallery_render( array $attributes, string $content ): string

46function block_core_gallery_render( $attributes, $content ) {47	// Adds a style tag for the --wp--style--unstable-gallery-gap var.48	// The Gallery block needs to recalculate Image block width based on49	// the current gap setting in order to maintain the number of flex columns50	// so a css var is added to allow this.51 52	$gap = $attributes['style']['spacing']['blockGap'] ?? null;53	// Skip if gap value contains unsupported characters.54	// Regex for CSS value borrowed from `safecss_filter_attr`, and used here55	// because we only want to match against the value, not the CSS attribute.56	if ( is_array( $gap ) ) {57		foreach ( $gap as $key => $value ) {58			// Make sure $value is a string to avoid PHP 8.1 deprecation error in preg_match() when the value is null.59			$value = is_string( $value ) ? $value : '';60			$value = $value && preg_match( '%[\\\(&=}]|/\*%', $value ) ? null : $value;61 62			// Get spacing CSS variable from preset value if provided.63			if ( is_string( $value ) && str_contains( $value, 'var:preset|spacing|' ) ) {64				$index_to_splice = strrpos( $value, '|' ) + 1;65				$slug            = _wp_to_kebab_case( substr( $value, $index_to_splice ) );66				$value           = "var(--wp--preset--spacing--$slug)";67			}68 69			$gap[ $key ] = $value;70		}71	} else {72		// Make sure $gap is a string to avoid PHP 8.1 deprecation error in preg_match() when the value is null.73		$gap = is_string( $gap ) ? $gap : '';74		$gap = $gap && preg_match( '%[\\\(&=}]|/\*%', $gap ) ? null : $gap;75 76		// Get spacing CSS variable from preset value if provided.77		if ( is_string( $gap ) && str_contains( $gap, 'var:preset|spacing|' ) ) {78			$index_to_splice = strrpos( $gap, '|' ) + 1;79			$slug            = _wp_to_kebab_case( substr( $gap, $index_to_splice ) );80			$gap             = "var(--wp--preset--spacing--$slug)";81		}82	}83 84	$unique_gallery_classname = wp_unique_id( 'wp-block-gallery-' );85	$processed_content        = new WP_HTML_Tag_Processor( $content );86	$processed_content->next_tag();87	$processed_content->add_class( $unique_gallery_classname );88 89	// --gallery-block--gutter-size is deprecated. --wp--style--gallery-gap-default should be used by themes that want to set a default90	// gap on the gallery.91	$fallback_gap = 'var( --wp--style--gallery-gap-default, var( --gallery-block--gutter-size, var( --wp--style--block-gap, 0.5em ) ) )';92	$gap_value    = $gap ? $gap : $fallback_gap;93	$gap_column   = $gap_value;94 95	if ( is_array( $gap_value ) ) {96		$gap_row    = isset( $gap_value['top'] ) ? $gap_value['top'] : $fallback_gap;97		$gap_column = isset( $gap_value['left'] ) ? $gap_value['left'] : $fallback_gap;98		$gap_value  = $gap_row === $gap_column ? $gap_row : $gap_row . ' ' . $gap_column;99	}100 101	// The unstable gallery gap calculation requires a real value (such as `0px`) and not `0`.102	if ( '0' === $gap_column ) {103		$gap_column = '0px';104	}105 106	// Set the CSS variable to the column value, and the `gap` property to the combined gap value.107	$gallery_styles = array(108		array(109			'selector'     => ".wp-block-gallery.{$unique_gallery_classname}",110			'declarations' => array(111				'--wp--style--unstable-gallery-gap' => $gap_column,112				'gap'                               => $gap_value,113			),114		),115	);116 117	wp_style_engine_get_stylesheet_from_css_rules(118		$gallery_styles,119		array(120			'context' => 'block-supports',121		)122	);123 124	// The WP_HTML_Tag_Processor class calls get_updated_html() internally125	// when the instance is treated as a string, but here we explicitly