Edit/create shadows in global styles

packages/block-editor/src/components/global-styles/shadow-panel-components.js

@@ -172,8 +172,11 @@ export function useShadowPresets( settings ) {
 		}
 
 		const defaultPresetsEnabled = settings?.shadow?.defaultPresets;
-		const { default: defaultShadows, theme: themeShadows } =
-			settings?.shadow?.presets ?? {};
+		const {
+			default: defaultShadows,
+			theme: themeShadows,
+			custom: customShadows,
+		} = settings?.shadow?.presets ?? {};
 		const unsetShadow = {
 			name: __( 'Unset' ),
 			slug: 'unset',
@@ -183,6 +186,7 @@ export function useShadowPresets( settings ) {
 		const shadowPresets = [
 			...( ( defaultPresetsEnabled && defaultShadows ) || EMPTY_ARRAY ),
 			...( themeShadows || EMPTY_ARRAY ),
+			...( customShadows || EMPTY_ARRAY ),
 		];
 		if ( shadowPresets.length ) {
 			shadowPresets.unshift( unsetShadow );

packages/edit-site/src/components/global-styles/root-menu.js

@@ -2,7 +2,13 @@
  * WordPress dependencies
  */
 import { __experimentalItemGroup as ItemGroup } from '@wordpress/components';
-import { typography, color, layout, image } from '@wordpress/icons';
+import {
+	typography,
+	color,
+	layout,
+	image,
+	shadow as shadowIcon,
+} from '@wordpress/icons';
 import { __ } from '@wordpress/i18n';
 import { privateApis as blockEditorPrivateApis } from '@wordpress/block-editor';
 
@@ -26,6 +32,7 @@ function RootMenu() {
 	const settings = useSettingsForBlockElement( rawSettings );
 	const hasTypographyPanel = useHasTypographyPanel( settings );
 	const hasColorPanel = useHasColorPanel( settings );
+	const hasShadowPanel = true; // useHasShadowPanel( settings );
 	const hasDimensionsPanel = useHasDimensionsPanel( settings );
 	const hasLayoutPanel = hasDimensionsPanel;
 	const hasBackgroundPanel = useHasBackgroundPanel( settings );
@@ -51,6 +58,15 @@ function RootMenu() {
 						{ __( 'Colors' ) }
 					</NavigationButtonAsItem>
 				) }
+				{ hasShadowPanel && (
+					<NavigationButtonAsItem
+						icon={ shadowIcon }
+						path="/shadows"
+						aria-label={ __( 'Shadow styles' ) }
+					>
+						{ __( 'Shadows' ) }
+					</NavigationButtonAsItem>
+				) }
 				{ hasLayoutPanel && (
 					<NavigationButtonAsItem
 						icon={ layout }

packages/edit-site/src/components/global-styles/screen-shadows.js

@@ -0,0 +1,13 @@
+/**
+ * Internal dependencies
+ */
+import ShadowsPanel from './shadows-panel';
+import ShadowsEditPanel from './shadows-edit-panel';
+
+export function ScreenShadows() {
+	return <ShadowsPanel />;
+}
+
+export function ScreenShadowsEdit() {
+	return <ShadowsEditPanel />;
+}

packages/edit-site/src/components/global-styles/shadow-utils.js

@@ -0,0 +1,158 @@
+export const CUSTOM_VALUE_SETTINGS = {
+	px: { max: 20, step: 1 },
+	'%': { max: 100, step: 1 },
+	vw: { max: 100, step: 1 },
+	vh: { max: 100, step: 1 },
+	em: { max: 10, step: 0.1 },
+	rm: { max: 10, step: 0.1 },
+	svw: { max: 100, step: 1 },
+	lvw: { max: 100, step: 1 },
+	dvw: { max: 100, step: 1 },
+	svh: { max: 100, step: 1 },
+	lvh: { max: 100, step: 1 },
+	dvh: { max: 100, step: 1 },
+	vi: { max: 100, step: 1 },
+	svi: { max: 100, step: 1 },
+	lvi: { max: 100, step: 1 },
+	dvi: { max: 100, step: 1 },
+	vb: { max: 100, step: 1 },
+	svb: { max: 100, step: 1 },
+	lvb: { max: 100, step: 1 },
+	dvb: { max: 100, step: 1 },
+	vmin: { max: 100, step: 1 },
+	svmin: { max: 100, step: 1 },
+	lvmin: { max: 100, step: 1 },
+	dvmin: { max: 100, step: 1 },
+	vmax: { max: 100, step: 1 },
+	svmax: { max: 100, step: 1 },
+	lvmax: { max: 100, step: 1 },
+	dvmax: { max: 100, step: 1 },
+};
+
+export function getShadowParts( shadow ) {
+	const shadowValues = shadow.match( /(?:[^,(]|\([^)]*\))+/g ) || [];
+	return shadowValues.map( ( value ) => value.trim() );
+}
+
+export function shadowStringToObject( shadowValue ) {
+	/*
+	 * Shadow spec: https://developer.mozilla.org/en-US/docs/Web/CSS/box-shadow
+	 * Shadow string format: <offset-x> <offset-y> <blur-radius> <spread-radius> <color> [inset]
+	 *
+	 * A shadow to be valid it must satisfy the following.
+	 *
+	 * 1. Should not contain "none" keyword.
+	 * 2. Values x, y, blur, spread should be in the order. Color and inset can be anywhere in the string except in between x, y, blur, spread values.
+	 * 3. Should not contain more than one set of x, y, blur, spread values.
+	 * 4. Should contain at least x and y values. Others are optional.
+	 * 5. Should not contain more than one "inset" (case insensitive) keyword.
+	 * 6. Should not contain more than one color value.
+	 */
+
+	const defaultShadow = {
+		x: '0',
+		y: '0',
+		blur: '0',
+		spread: '0',
+		color: '#000',
+		inset: false,
+	};
+
+	if ( ! shadowValue ) {
+		return defaultShadow;
+	}
+
+	// Rule 1: Should not contain "none" keyword.
+	// if the shadow has "none" keyword, it is not a valid shadow string
+	if ( shadowValue.includes( 'none' ) ) {
+		return defaultShadow;
+	}
+
+	// Rule 2: Values x, y, blur, spread should be in the order.
+	//		   Color and inset can be anywhere in the string except in between x, y, blur, spread values.
+	// Extract length values (x, y, blur, spread) from shadow string
+	// Regex match groups of 1 to 4 length values.
+	const lengthsRegex =
+		/((?:^|\s+)(-?\d*\.?\d+(?:px|%|in|cm|mm|em|rem|ex|pt|pc|vh|vw|vmin|vmax|ch|lh)?)(?=\s|$)(?![^(]*\))){1,4}/g;
+	const matches = shadowValue.match( lengthsRegex ) || [];
+
+	// Rule 3: Should not contain more than one set of x, y, blur, spread values.
+	// if the string doesn't contain exactly 1 set of x, y, blur, spread values,
+	// it is not a valid shadow string
+	if ( matches.length !== 1 ) {
+		return defaultShadow;
+	}
+
+	// Extract length values (x, y, blur, spread) from shadow string
+	const lengths = matches[ 0 ]
+		.split( ' ' )
+		.map( ( value ) => value.trim() )
+		.filter( ( value ) => value );
+
+	// Rule 4: Should contain at least x and y values. Others are optional.
+	if ( lengths.length < 2 ) {
+		return defaultShadow;
+	}
+
+	// Rule 5: Should not contain more than one "inset" (case insensitive) keyword.
+	// check if the shadow string contains "inset" keyword
+	const insets = shadowValue.match( /inset/gi ) || [];
+	if ( insets.length > 1 ) {
+		return defaultShadow;
+	}
+
+	// Strip lengths and inset from shadow string, leaving just color.
+	const hasInset = insets.length === 1;
+	let colorString = shadowValue.replace( lengthsRegex, '' ).trim();
+	if ( hasInset ) {
+		colorString = colorString
+			.replace( 'inset', '' )
+			.replace( 'INSET', '' )
+			.trim();
+	}
+
+	// Rule 6: Should not contain more than one color value.
+	// validate color string with regular expression
+	// check if color has matching hex, rgb or hsl values
+	const colorRegex =
+		/^#([0-9a-f]{3}){1,2}$|^#([0-9a-f]{4}){1,2}$|^(?:rgb|hsl)a?\(?[\d*\.?\d+%?,?\/?\s]*\)$/gi;
+	let colorMatches = ( colorString.match( colorRegex ) || [] )
+		.map( ( value ) => value?.trim() )
+		.filter( ( value ) => value );
+
+	// If color string has more than one color values, it is not a valid
+	if ( colorMatches.length > 1 ) {
+		return defaultShadow;
+	} else if ( colorMatches.length === 0 ) {
+		// check if color string has multiple named color values separated by space
+		colorMatches = colorString
+			.trim()
+			.split( ' ' )
+			.filter( ( value ) => value );
+		// If color string has more than one color values, it is not a valid
+		if ( colorMatches.length > 1 ) {
+			return defaultShadow;
+		}
+	}
+
+	// Return parsed shadow object.
+	const [ x, y, blur, spread ] = lengths;
+	return {
+		x,
+		y,
+		blur: blur || defaultShadow.blur,
+		spread: spread || defaultShadow.spread,
+		inset: hasInset,
+		color: colorString || defaultShadow.color,
+	};
+}
+
+export function shadowObjectToString( shadowObj ) {
+	const shadowString = `${ shadowObj.x || '0px' } ${ shadowObj.y || '0px' } ${
+		shadowObj.blur || '0px'
+	} ${ shadowObj.spread || '0px' }`;
+
+	return `${ shadowObj.inset ? 'inset' : '' } ${ shadowString } ${
+		shadowObj.color || ''
+	}`.trim();
+}