Make images block elements

Use markdown-it-image-figures to render standalone images inside
`<figure>` elements instead of `<p>` when markdown source gets parsed
into HTML. This allows to treat images as block elements by TipTap.

Also keep support for inline images to not break markdown files that
have inline images.

Fixes: #2873

Signed-off-by: Jonas <jonas@freesources.org>

src/extensions/RichText.js

@@ -37,6 +37,7 @@ import HardBreak from './HardBreak.js'
 import Heading from '../nodes/Heading/index.js'
 import HorizontalRule from '@tiptap/extension-horizontal-rule'
 import Image from './../nodes/Image.js'
+import ImageInline from './../nodes/ImageInline.js'
 import KeepSyntax from './KeepSyntax.js'
 import ListItem from '@tiptap/extension-list-item'
 import Mention from './../extensions/Mention.js'
@@ -82,9 +83,8 @@ export default Extension.create({
 			TaskItem,
 			Callout,
 			Underline,
-			Image.configure({
-				inline: true,
-			}),
+			Image,
+			ImageInline,
 			Dropcursor,
 			KeepSyntax,
 			FrontMatter,

src/markdownit/index.js

@@ -5,6 +5,7 @@ import underline from './underline.js'
 import splitMixedLists from './splitMixedLists.js'
 import callouts from './callouts.js'
 import keepSyntax from './keepSyntax.js'
+import implicitFigures from 'markdown-it-image-figures'
 
 const markdownit = MarkdownIt('commonmark', { html: false, breaks: false })
 	.enable('strikethrough')
@@ -15,6 +16,7 @@ const markdownit = MarkdownIt('commonmark', { html: false, breaks: false })
 	.use(callouts)
 	.use(keepSyntax)
 	.use(markdownitMentions)
+	.use(implicitFigures)
 
 // Issue #3370: To preserve softbreaks within md files we preserve all whitespaces, so we must not introduce additional new lines after a <br> element
 markdownit.renderer.rules.hardbreak = (tokens, idx, options) => (options.xhtmlOut ? '<br />' : '<br>')

src/nodes/Image.js

@@ -29,6 +29,16 @@ const Image = TiptapImage.extend({
 
 	selectable: false,
 
+	parseHTML() {
+		return [
+			{
+				tag: this.options.allowBase64
+					? 'figure img[src]'
+					: 'figure img[src]:not([src^="data:"])',
+			},
+		]
+	},
+
 	renderHTML() {
 		// Avoid the prosemirror node creation to trigger image loading as we use a custom node view anyways
 		// Otherwise it would attempt to load the image from the current location before the node view is even initialized

src/nodes/ImageInline.js

@@ -0,0 +1,74 @@
+/*
+ * @copyright Copyright (c) 2022 Jonas <jonas@freesources.org>
+ *
+ * @author Jonas <jonas@freesources.org>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+import TiptapImage from '@tiptap/extension-image'
+import ImageView from './ImageView.vue'
+import { VueNodeViewRenderer } from '@tiptap/vue-2'
+
+// Inline image extension. Needed if markdown contains inline images.
+// Not supported to be created from our UI (we default to block images).
+const ImageInline = TiptapImage.extend({
+	name: 'image-inline',
+
+	// Lower priority than (block) Image extension
+	priority: 99,
+
+	selectable: false,
+
+	parseHTML() {
+		return [
+			{
+				tag: this.options.allowBase64
+					? 'img[src]'
+					: 'img[src]:not([src^="data:"])',
+			},
+		]
+	},
+
+	addOptions() {
+		return {
+			...this.parent?.(),
+			inline: true,
+		}
+	},
+
+	// Empty commands, we want only those from (block) Image extension
+	addCommands() {
+		return {}
+	},
+
+	// Empty input rules, we want only those from (block) Image extension
+	addInputRules() {
+		return []
+	},
+
+	addNodeView() {
+		return VueNodeViewRenderer(ImageView)
+	},
+
+	toMarkdown(state, node) {
+		state.write('![' + state.esc(node.attrs.alt || '') + '](' + node.attrs.src.replace(/[()]/g, '\\$&')
+			+ (node.attrs.title ? ' "' + node.attrs.title.replace(/"/g, '\\"') + '"' : '') + ')')
+	},
+})
+
+export default ImageInline