Add a block selection breadcrumb to the bottom of the editor

docs/designers-developers/developers/data/data-core-block-editor.md

@@ -189,6 +189,19 @@ _Returns_
 
 -   `Array`: Ordered client IDs of editor blocks.
 
+<a name="getBlockParents" href="#getBlockParents">#</a> **getBlockParents**
+
+Given a block client ID, returns the list of all its parents from top to bottom.
+
+_Parameters_
+
+-   _state_ `Object`: Editor state.
+-   _clientId_ `string`: Block from which to find root client ID.
+
+_Returns_
+
+-   `Array`: ClientIDs of the parent blocks.
+
 <a name="getBlockRootClientId" href="#getBlockRootClientId">#</a> **getBlockRootClientId**
 
 Given a block client ID, returns the root block from which the block is

packages/base-styles/_z-index.scss

@@ -24,6 +24,7 @@ $z-layers: (
 	".block-editor-warning": 5,
 	".block-library-gallery-item__inline-menu": 20,
 	".block-editor-url-input__suggestions": 30,
+	".edit-post-layout__footer": 30,
 	".edit-post-header": 30,
 	".edit-widgets-header": 30,
 	".block-library-button__inline-link .block-editor-url-input__suggestions": 6, // URL suggestions for button block above sibling inserter

packages/block-editor/README.md

@@ -82,6 +82,14 @@ _Related_
 
 Undocumented declaration.
 
+<a name="BlockBreadcrumb" href="#BlockBreadcrumb">#</a> **BlockBreadcrumb**
+
+Block breadcrumb component, displaying the hierarchy of the current block selection as a breadcrumb.
+
+_Returns_
+
+-   `WPElement`: Block Breadcrumb.
+
 <a name="BlockControls" href="#BlockControls">#</a> **BlockControls**
 
 Undocumented declaration.

packages/block-editor/src/components/block-breadcrumb/index.js

@@ -0,0 +1,77 @@
+/**
+ * WordPress dependencies
+ */
+import { Button } from '@wordpress/components';
+import { useSelect, useDispatch } from '@wordpress/data';
+import { __ } from '@wordpress/i18n';
+
+/**
+ * Internal dependencies
+ */
+import BlockTitle from '../block-title';
+
+/**
+ * Block breadcrumb component, displaying the hierarchy of the current block selection as a breadcrumb.
+ *
+ * @return {WPElement} Block Breadcrumb.
+ */
+const BlockBreadcrumb = function() {
+	const { selectBlock, clearSelectedBlock } = useDispatch( 'core/block-editor' );
+	const { clientId, parents, hasSelection } = useSelect( ( select ) => {
+		const {
+			getSelectionStart,
+			getSelectedBlockClientId,
+			getBlockParents,
+		} = select( 'core/block-editor' );
+		const selectedBlockClientId = getSelectedBlockClientId();
+		return {
+			parents: getBlockParents( selectedBlockClientId ),
+			clientId: selectedBlockClientId,
+			hasSelection: !! getSelectionStart().clientId,
+		};
+	}, [] );
+
+	/*
+	 * Disable reason: The `list` ARIA role is redundant but
+	 * Safari+VoiceOver won't announce the list otherwise.
+	 */
+	/* eslint-disable jsx-a11y/no-redundant-roles */
+	return (
+		<ul className="block-editor-block-breadcrumb" role="list" aria-label={ __( 'Block breadcrumb' ) }>
+			<li
+				className={ ! hasSelection ? 'block-editor-block-breadcrumb__current' : undefined }
+				aria-current={ ! hasSelection ? 'true' : undefined }
+			>
+				{ hasSelection && (
+					<Button
+						className="block-editor-block-breadcrumb__button"
+						isTertiary
+						onClick={ clearSelectedBlock }
+					>
+						{ __( 'Document' ) }
+					</Button>
+				) }
+				{ ! hasSelection && __( 'Document' ) }
+			</li>
+			{ parents.map( ( parentClientId ) => (
+				<li key={ parentClientId }>
+					<Button
+						className="block-editor-block-breadcrumb__button"
+						isTertiary
+						onClick={ () => selectBlock( parentClientId ) }
+					>
+						<BlockTitle clientId={ parentClientId } />
+					</Button>
+				</li>
+			) ) }
+			{ !! clientId && (
+				<li className="block-editor-block-breadcrumb__current" aria-current="true">
+					<BlockTitle clientId={ clientId } />
+				</li>
+			) }
+		</ul>
+		/* eslint-enable jsx-a11y/no-redundant-roles */
+	);
+};
+
+export default BlockBreadcrumb;

packages/block-editor/src/components/block-breadcrumb/style.scss

@@ -0,0 +1,41 @@
+.block-editor-block-breadcrumb {
+	list-style: none;
+	padding: 0;
+	margin: 0;
+
+	li {
+		display: inline-block;
+		margin: 0;
+
+		&:not(:last-child)::after {
+			content: "\2192"; // This becomes →.
+		}
+	}
+}
+
+.block-editor-block-breadcrumb__button.components-button {
+	height: $icon-button-size-small;
+	line-height: $icon-button-size-small;
+	padding: 0;
+
+	&:hover {
+		text-decoration: underline;
+	}
+
+	&:focus {
+		@include square-style__focus();
+		outline-offset: -2px;
+		box-shadow: none;
+	}
+}
+
+.block-editor-block-breadcrumb__current {
+	cursor: default;
+}
+
+.block-editor-block-breadcrumb__button.components-button,
+.block-editor-block-breadcrumb__current {
+	color: $dark-gray-500;
+	padding: 0 $grid-size;
+	font-size: inherit;
+}

packages/block-editor/src/components/index.js

@@ -7,6 +7,7 @@ export * from './font-sizes';
 export { default as AlignmentToolbar } from './alignment-toolbar';
 export { default as Autocomplete } from './autocomplete';
 export { default as BlockAlignmentToolbar } from './block-alignment-toolbar';
+export { default as BlockBreadcrumb } from './block-breadcrumb';
 export { default as BlockControls } from './block-controls';
 export { default as BlockEdit } from './block-edit';
 export { default as BlockFormatControls } from './block-format-controls';

packages/block-editor/src/store/selectors.js

@@ -420,6 +420,30 @@ export function getBlockRootClientId( state, clientId ) {
 		null;
 }
 
+/**
+ * Given a block client ID, returns the list of all its parents from top to bottom.
+ *
+ * @param {Object} state    Editor state.
+ * @param {string} clientId Block from which to find root client ID.
+ *
+ * @return {Array} ClientIDs of the parent blocks.
+ */
+export const getBlockParents = createSelector(
+	( state, clientId ) => {
+		const parents = [];
+		let current = clientId;
+		while ( !! state.blocks.parents[ current ] ) {
+			current = state.blocks.parents[ current ];
+			parents.push( current );
+		}
+
+		return parents.reverse();
+	},
+	( state ) => [
+		state.blocks.parents,
+	]
+);
+
 /**
  * Given a block client ID, returns the root of the hierarchy from which the block is nested, return the block itself for root level blocks.
  *

packages/block-editor/src/style.scss

@@ -3,6 +3,7 @@
 @import "./components/block-inspector/style.scss";
 @import "./components/block-list/style.scss";
 @import "./components/block-list-appender/style.scss";
+@import "./components/block-breadcrumb/style.scss";
 @import "./components/block-card/style.scss";
 @import "./components/block-compare/style.scss";
 @import "./components/block-mover/style.scss";

packages/e2e-tests/specs/editor/various/block-hierarchy-navigation.test.js

@@ -82,6 +82,7 @@ describe( 'Navigating the block hierarchy', () => {
 		await pressKeyWithModifier( 'ctrl', '`' );
 		await pressKeyWithModifier( 'ctrl', '`' );
 		await pressKeyWithModifier( 'ctrl', '`' );
+		await pressKeyWithModifier( 'ctrl', '`' );
 		await pressKeyTimes( 'Tab', 4 );
 
 		// Tweak the columns count by increasing it by one.

packages/e2e-tests/specs/editor/various/sidebar.test.js

@@ -91,6 +91,7 @@ describe( 'Sidebar', () => {
 		await pressKeyWithModifier( 'ctrl', '`' );
 		await pressKeyWithModifier( 'ctrl', '`' );
 		await pressKeyWithModifier( 'ctrl', '`' );
+		await pressKeyWithModifier( 'ctrl', '`' );
 
 		// Tab lands at first (presumed selected) option "Document".
 		await page.keyboard.press( 'Tab' );

packages/edit-post/src/components/layout/index.js

@@ -21,6 +21,7 @@ import {
 	EditorNotices,
 	PostPublishPanel,
 } from '@wordpress/editor';
+import { BlockBreadcrumb } from '@wordpress/block-editor';
 import { withDispatch, withSelect } from '@wordpress/data';
 import { PluginArea } from '@wordpress/plugins';
 import { withViewportMatch } from '@wordpress/viewport';
@@ -59,7 +60,7 @@ function Layout( {
 } ) {
 	const sidebarIsOpened = editorSidebarOpened || pluginSidebarOpened || publishSidebarOpened;
 
-	const className = classnames( 'edit-post-layout', {
+	const className = classnames( 'edit-post-layout', 'is-mode-' + mode, {
 		'is-sidebar-opened': sidebarIsOpened,
 		'has-fixed-toolbar': hasFixedToolbar,
 		'has-metaboxes': hasActiveMetaboxes,
@@ -80,7 +81,7 @@ function Layout( {
 			<LocalAutosaveMonitor />
 			<Header />
 			<div
-				className="edit-post-layout__content"
+				className="edit-post-layout__content edit-post-layout__scrollable-container"
 				role="region"
 				/* translators: accessibility text for the content landmark region. */
 				aria-label={ __( 'Editor content' ) }
@@ -99,7 +100,19 @@ function Layout( {
 				<div className="edit-post-layout__metaboxes">
 					<MetaBoxes location="advanced" />
 				</div>
+				{ isMobileViewport && sidebarIsOpened && <ScrollLock /> }
 			</div>
+			{ isRichEditingEnabled && mode === 'visual' && (
+				<div
+					className="edit-post-layout__footer"
+					role="region"
+					/* translators: accessibility text for the content landmark region. */
+					aria-label={ __( 'Editor footer' ) }
+					tabIndex="-1"
+				>
+					<BlockBreadcrumb />
+				</div>
+			) }
 			{ publishSidebarOpened ? (
 				<PostPublishPanel
 					{ ...publishLandmarkProps }
@@ -124,9 +137,6 @@ function Layout( {
 					</div>
 					<SettingsSidebar />
 					<Sidebar.Slot />
-					{
-						isMobileViewport && sidebarIsOpened && <ScrollLock />
-					}
 				</>
 			) }
 			<Popover.Slot />

packages/edit-post/src/components/layout/style.scss

@@ -54,7 +54,7 @@
 		// Because the body element scrolls the navigation sidebar, we have to use position fixed here.
 		// Otherwise you would scroll the editing canvas out of view when you scroll the sidebar.
 		position: fixed;
-		bottom: 0;
+		bottom: $footer-height;
 		left: 0;
 		right: 0;
 
@@ -70,6 +70,12 @@
 		// Because we are beyond the medium breakpoint, we only have to worry about folded, auto-folded, and default.
 		margin-left: $admin-sidebar-width;
 
+		// Make room for the footer
+		.edit-post-layout.is-mode-visual & {
+			bottom: $footer-height;
+			min-height: calc(100% - #{ $header-height + $admin-bar-height + $footer-height });
+		}
+
 		// Auto fold is when on smaller breakpoints, nav menu auto colllapses.
 		body.auto-fold & {
 			margin-left: $admin-sidebar-width-collapsed;
@@ -104,31 +110,6 @@
 		}
 	}
 
-	// Pad the scroll box so content on the bottom can be scrolled up.
-	padding-bottom: 50vh;
-	@include break-small {
-		padding-bottom: 0;
-	}
-
-	// On mobile the main content (html or body) area has to scroll.
-	// If, like we do on the desktop, scroll an element (.edit-post-layout__content) you can invoke
-	// the overscroll bounce on the non-scrolling container, causing for a frustrating scrolling experience.
-	// The following rule enables this scrolling beyond the mobile breakpoint, because on the desktop
-	// breakpoints scrolling an isolated element helps avoid scroll bleed.
-	@include break-small() {
-		overflow-y: auto;
-	}
-	-webkit-overflow-scrolling: touch;
-
-	// This rule ensures that if you've scrolled to the end of a container,
-	// then pause, then keep scrolling downwards, the browser doesn't try to scroll
-	// the parent element, usually invoking a "bounce" effect and then preventing you
-	// from scrolling upwards until you pause again.
-	// This is only necessary beyond the small breakpoint because that's when the scroll container changes.
-	@include break-small() {
-		overscroll-behavior-y: none;
-	}
-
 	.edit-post-visual-editor {
 		flex: 1 1 auto;
 
@@ -234,3 +215,51 @@
 		}
 	}
 }
+
+.edit-post-layout__footer {
+	display: none;
+	z-index: z-index(".edit-post-layout__footer");
+
+	// Stretch to mimic outline padding on desktop.
+	@include break-medium() {
+		display: flex;
+		position: fixed;
+		bottom: 0;
+		right: 0;
+		background: $white;
+		height: $footer-height;
+		padding: 0 $grid-size;
+		align-items: center;
+		border-top: $border-width solid $light-gray-500;
+		font-size: $default-font-size;
+		box-sizing: border-box;
+	}
+}
+@include editor-left(".edit-post-layout__footer");
+
+.edit-post-layout__scrollable-container {
+	// On mobile the main content (html or body) area has to scroll.
+	// If, like we do on the desktop, scroll an element (.edit-post-layout__content) you can invoke
+	// the overscroll bounce on the non-scrolling container, causing for a frustrating scrolling experience.
+	// The following rule enables this scrolling beyond the mobile breakpoint, because on the desktop
+	// breakpoints scrolling an isolated element helps avoid scroll bleed.
+	@include break-small() {
+		overflow-y: auto;
+	}
+	-webkit-overflow-scrolling: touch;
+
+	// This rule ensures that if you've scrolled to the end of a container,
+	// then pause, then keep scrolling downwards, the browser doesn't try to scroll
+	// the parent element, usually invoking a "bounce" effect and then preventing you
+	// from scrolling upwards until you pause again.
+	// This is only necessary beyond the small breakpoint because that's when the scroll container changes.
+	@include break-small() {
+		overscroll-behavior-y: none;
+	}
+
+	// Pad the scroll box so content on the bottom can be scrolled up.
+	padding-bottom: 50vh;
+	@include break-small {
+		padding-bottom: 0;
+	}
+}

packages/edit-post/src/components/sidebar/style.scss

@@ -22,6 +22,10 @@
 	@include break-medium() {
 		top: $admin-bar-height + $header-height;
 
+		.edit-post-layout.is-mode-visual & {
+			bottom: $footer-height;
+		}
+
 		body.is-fullscreen-mode & {
 			top: $header-height;
 		}