List View: Add media previews to list view for gallery and image bloc…

…ks (#53381)

* List View: Add images

* Add some styling and a max number of images

* Tweak styling

* Add image count

* Reduce to 3 images, remove image count

packages/block-editor/src/components/list-view/block-select-button.js

@@ -28,6 +28,7 @@ import useBlockDisplayTitle from '../block-title/use-block-display-title';
 import ListViewExpander from './expander';
 import { useBlockLock } from '../block-lock';
 import { store as blockEditorStore } from '../../store';
+import useListViewImages from './use-list-view-images';
 
 function ListViewBlockSelectButton(
 	{
@@ -63,6 +64,7 @@ function ListViewBlockSelectButton(
 	const { removeBlocks } = useDispatch( blockEditorStore );
 	const isMatch = useShortcutEventMatch();
 	const isSticky = blockInformation?.positionType === 'sticky';
+	const images = useListViewImages( { clientId, isExpanded } );
 
 	const positionLabel = blockInformation?.positionLabel
 		? sprintf(
@@ -184,6 +186,23 @@ function ListViewBlockSelectButton(
 							</span>
 						</Tooltip>
 					) }
+					{ images.length ? (
+						<span
+							className="block-editor-list-view-block-select-button__images"
+							aria-hidden
+						>
+							{ images.map( ( image, index ) => (
+								<span
+									className="block-editor-list-view-block-select-button__image"
+									key={ `img-${ image.url }` }
+									style={ {
+										backgroundImage: `url(${ image.url })`,
+										zIndex: images.length - index, // Ensure the first image is on top, and subsequent images are behind.
+									} }
+								/>
+							) ) }
+						</span>
+					) : null }
 					{ isLocked && (
 						<span className="block-editor-list-view-block-select-button__lock">
 							<Icon icon={ lock } />

packages/block-editor/src/components/list-view/style.scss

@@ -339,6 +339,31 @@
 	.block-editor-list-view-block-select-button__sticky {
 		line-height: 0;
 	}
+
+	.block-editor-list-view-block-select-button__images {
+		display: flex;
+	}
+
+	.block-editor-list-view-block-select-button__image {
+		background-size: cover;
+		width: 20px;
+		height: 20px;
+		border-radius: $radius-block-ui;
+
+		&:not(:only-child) {
+			box-shadow: 0 0 0 $radius-block-ui $white;
+		}
+
+		&:not(:first-child) {
+			margin-left: -5px;
+		}
+	}
+
+	&.is-selected .block-editor-list-view-block-select-button__image {
+		&:not(:only-child) {
+			box-shadow: 0 0 0 $radius-block-ui var(--wp-admin-theme-color);
+		}
+	}
 }
 
 .block-editor-list-view-block__contents-cell,

packages/block-editor/src/components/list-view/use-list-view-images.js

@@ -0,0 +1,79 @@
+/**
+ * WordPress dependencies
+ */
+import { useMemo } from '@wordpress/element';
+import { useSelect } from '@wordpress/data';
+
+/**
+ * Internal dependencies
+ */
+import { store as blockEditorStore } from '../../store';
+
+// Maximum number of images to display in a list view row.
+const MAX_IMAGES = 3;
+
+function getImageUrl( block ) {
+	if ( block.name !== 'core/image' ) {
+		return;
+	}
+
+	if ( block.attributes?.url ) {
+		return { url: block.attributes.url, alt: block.attributes.alt };
+	}
+}
+
+function getImagesFromGallery( block ) {
+	if ( block.name !== 'core/gallery' || ! block.innerBlocks ) {
+		return [];
+	}
+
+	const images = [];
+
+	for ( const innerBlock of block.innerBlocks ) {
+		const img = getImageUrl( innerBlock );
+		if ( img ) {
+			images.push( img );
+		}
+		if ( images.length >= MAX_IMAGES ) {
+			return images;
+		}
+	}
+
+	return images;
+}
+
+function getImagesFromBlock( block, isExpanded ) {
+	const img = getImageUrl( block );
+	if ( img ) {
+		return [ img ];
+	}
+	return isExpanded ? [] : getImagesFromGallery( block );
+}
+
+/**
+ * Get a block's preview images for display within a list view row.
+ *
+ * TODO: Currently only supports images from the core/image and core/gallery
+ * blocks. This should be expanded to support other blocks that have images,
+ * potentially via an API that blocks can opt into / provide their own logic.
+ *
+ * @param {Object}  props            Hook properties.
+ * @param {string}  props.clientId   The block's clientId.
+ * @param {boolean} props.isExpanded Whether or not the block is expanded in the list view.
+ * @return {Array} Images.
+ */
+export default function useListViewImages( { clientId, isExpanded } ) {
+	const { block } = useSelect(
+		( select ) => {
+			const _block = select( blockEditorStore ).getBlock( clientId );
+			return { block: _block };
+		},
+		[ clientId ]
+	);
+
+	const images = useMemo( () => {
+		return getImagesFromBlock( block, isExpanded );
+	}, [ block, isExpanded ] );
+
+	return images;
+}