Image captioning

src/converters.js

@@ -8,6 +8,8 @@
  */
 
 import ModelElement from '@ckeditor/ckeditor5-engine/src/model/element';
+import ModelPosition from '@ckeditor/ckeditor5-engine/src/model/position';
+import modelWriter from '@ckeditor/ckeditor5-engine/src/model/writer';
 import { isImageWidget } from './utils';
 
 /**
@@ -57,6 +59,14 @@ export function viewToModelImage() {
 			modelImage.setAttribute( 'alt', viewImg.getAttribute( 'alt' ) );
 		}
 
+		// Convert children of converted view element and append them to `modelImage`.
+		// TODO https://github.com/ckeditor/ckeditor5-engine/issues/736.
+		data.context.push( modelImage );
+		const modelChildren = conversionApi.convertChildren( viewFigureElement, consumable, data );
+		const insertPosition = ModelPosition.createAt( modelImage, 'end' );
+		modelWriter.insert( insertPosition, modelChildren );
+		data.context.pop();
+
 		data.output = modelImage;
 	};
 }

src/imagecaption/imagecaption.js

@@ -0,0 +1,26 @@
+/**
+ * @license Copyright (c) 2003-2017, CKSource - Frederico Knabben. All rights reserved.
+ * For licensing, see LICENSE.md.
+ */
+
+/**
+ * @module image/imagecaption/imagecaption
+ */
+
+import Plugin from '@ckeditor/ckeditor5-core/src/plugin';
+import ImageCaptionEngine from './imagecaptionengine';
+import '../../theme/imagecaption/theme.scss';
+
+/**
+ * The image caption plugin.
+ *
+ * @extends module:core/plugin~Plugin
+ */
+export default class ImageCaption extends Plugin {
+	/**
+	 * @inheritDoc
+	 */
+	static get requires() {
+		return [ ImageCaptionEngine ];
+	}
+}

src/imagecaption/imagecaptionengine.js

@@ -0,0 +1,225 @@
+/**
+ * @license Copyright (c) 2003-2017, CKSource - Frederico Knabben. All rights reserved.
+ * For licensing, see LICENSE.md.
+ */
+
+/**
+ * @module image/imagecaption/imagecaptionengine
+ */
+
+import Plugin from '@ckeditor/ckeditor5-core/src/plugin';
+import ModelTreeWalker from '@ckeditor/ckeditor5-engine/src/model/treewalker';
+import ModelElement from '@ckeditor/ckeditor5-engine/src/model/element';
+import ViewContainerElement from '@ckeditor/ckeditor5-engine/src/view/containerelement';
+import ViewElement from '@ckeditor/ckeditor5-engine/src/view/element';
+import ViewPosition from '@ckeditor/ckeditor5-engine/src/view/position';
+import ViewRange from '@ckeditor/ckeditor5-engine/src/view/range';
+import viewWriter from '@ckeditor/ckeditor5-engine/src/view/writer';
+import ModelPosition from '@ckeditor/ckeditor5-engine/src/model/position';
+import buildViewConverter from '@ckeditor/ckeditor5-engine/src/conversion/buildviewconverter';
+import ViewMatcher from '@ckeditor/ckeditor5-engine/src/view/matcher';
+import { isImage, isImageWidget } from '../utils';
+import { captionElementCreator, isCaption, getCaptionFromImage } from './utils';
+
+/**
+ * The image caption engine plugin.
+ *
+ * Registers proper converters. Takes care of adding caption element if image without it is inserted to model document.
+ *
+ * @extends module:core/plugin~Plugin
+ */
+export default class ImageCaptionEngine extends Plugin {
+	/**
+	 * @inheritDoc
+	 */
+	init() {
+		const editor = this.editor;
+		const document = editor.document;
+		const viewDocument = editor.editing.view;
+		const schema = document.schema;
+		const data = editor.data;
+		const editing = editor.editing;
+
+		/**
+		 * Last selected caption editable.
+		 * It is used for hiding editable when is empty and image widget is no longer selected.
+		 *
+		 * @member {module:image/imagecaption/imagecaptionengine~ImageCaptionEngine} #_lastSelectedEditable
+		 */
+
+		// Schema configuration.
+		schema.registerItem( 'caption' );
+		schema.allow( { name: '$inline', inside: 'caption' } );
+		schema.allow( { name: 'caption', inside: 'image' } );
+		schema.limits.add( 'caption' );
+
+		// Add caption element to each image inserted without it.
+		document.on( 'change', insertMissingCaptionElement );
+
+		// View to model converter for data pipeline.
+		const matcher = new ViewMatcher( ( element ) => {
+			const parent = element.parent;
+
+			// Convert only captions for images.
+			if ( element.name == 'figcaption' && parent && parent.name == 'figure' && parent.hasClass( 'image' ) ) {
+				return { name: true };
+			}
+
+			return null;
+		} );
+
+		buildViewConverter()
+			.for( data.viewToModel )
+			.from( matcher )
+			.toElement( 'caption' );
+
+		// Model to view converter for data pipeline.
+		data.modelToView.on(
+			'insert:caption',
+			captionModelToView( new ViewContainerElement( 'figcaption' ) )
+		);
+
+		// Model to view converter for editing pipeline.
+		editing.modelToView.on(
+			'insert:caption',
+			captionModelToView( captionElementCreator( viewDocument ) )
+		);
+
+		// Adding / removing caption element when there is no text in the model.
+		const selection = viewDocument.selection;
+
+		// Update view before each rendering.
+		this.listenTo( viewDocument, 'render', () => {
+			// Check if there is an empty caption view element to remove.
+			this._removeEmptyCaption();
+
+			// Check if image widget is selected and caption view element needs to be added.
+			this._addCaption();
+
+			// If selection is currently inside caption editable - store it to hide when empty.
+			const editableElement = selection.editableElement;
+
+			if ( editableElement && isCaption( selection.editableElement ) ) {
+				this._lastSelectedEditable = selection.editableElement;
+			}
+		}, { priority: 'high' } );
+	}
+
+	/**
+	 * Checks if there is an empty caption element to remove from view.
+	 *
+	 * @private
+	 */
+	_removeEmptyCaption() {
+		const viewSelection = this.editor.editing.view.selection;
+		const viewCaptionElement = this._lastSelectedEditable;
+
+		// No caption to hide.
+		if ( !viewCaptionElement ) {
+			return;
+		}
+
+		// If selection is placed inside caption - do not remove it.
+		if ( viewSelection.editableElement === viewCaptionElement ) {
+			return;
+		}
+
+		// Do not remove caption if selection is placed on image that contains that caption.
+		const selectedElement = viewSelection.getSelectedElement();
+
+		if ( selectedElement && isImageWidget( selectedElement ) ) {
+			const viewImage = viewCaptionElement.findAncestor( element => element == selectedElement );
+
+			if ( viewImage ) {
+				return;
+			}
+		}
+
+		// Remove image caption if its empty.
+		if ( viewCaptionElement.childCount === 0 ) {
+			const mapper = this.editor.editing.mapper;
+			viewWriter.remove( ViewRange.createOn( viewCaptionElement ) );
+			mapper.unbindViewElement( viewCaptionElement );
+		}
+	}
+
+	/**
+	 * Checks if selected image needs a new caption element inside.
+	 *
+	 * @private
+	 */
+	_addCaption() {
+		const editing = this.editor.editing;
+		const selection = editing.view.selection;
+		const imageFigure = selection.getSelectedElement();
+		const mapper = editing.mapper;
+		const editableCreator = captionElementCreator( editing.view );
+
+		if ( imageFigure && isImageWidget( imageFigure ) ) {
+			const modelImage = mapper.toModelElement( imageFigure );
+			const modelCaption = getCaptionFromImage( modelImage );
+			let viewCaption =  mapper.toViewElement( modelCaption );
+
+			if ( !viewCaption ) {
+				viewCaption = editableCreator();
+
+				const viewPosition = ViewPosition.createAt( imageFigure, 'end' );
+				mapper.bindElements( modelCaption, viewCaption );
+				viewWriter.insert( viewPosition, viewCaption );
+			}
+
+			this._lastSelectedEditable = viewCaption;
+		}
+	}
+}
+
+// Checks whether data inserted to the model document have image element that has no caption element inside it.
+// If there is none - adds it to the image element.
+//
+// @private
+function insertMissingCaptionElement( evt, changeType, data, batch ) {
+	if ( changeType !== 'insert' ) {
+		return;
+	}
+
+	const walker = new ModelTreeWalker( {
+		boundaries: data.range,
+		ignoreElementEnd: true
+	} );
+
+	for ( let value of walker ) {
+		const item = value.item;
+
+		if ( value.type == 'elementStart' && isImage( item ) && !getCaptionFromImage( item ) ) {
+			batch.document.enqueueChanges( () => {
+				batch.insert( ModelPosition.createAt( item, 'end' ), new ModelElement( 'caption' ) );
+			} );
+		}
+	}
+}
+
+// Creates a converter that converts image caption model element to view element.
+//
+// @private
+// @param {Function|module:engine/view/element~Element} elementCreator
+// @return {Function}
+function captionModelToView( elementCreator ) {
+	return ( evt, data, consumable, conversionApi ) => {
+		const captionElement = data.item;
+
+		if ( isImage( captionElement.parent ) && ( captionElement.childCount > 0 ) ) {
+			if ( !consumable.consume( data.item, 'insert' ) ) {
+				return;
+			}
+
+			const imageFigure = conversionApi.mapper.toViewElement( data.range.start.parent );
+			const viewElement = ( elementCreator instanceof ViewElement ) ?
+				elementCreator.clone( true ) :
+				elementCreator( data, consumable, conversionApi );
+
+			const viewPosition = ViewPosition.createAt( imageFigure, 'end' );
+			conversionApi.mapper.bindElements( data.item, viewElement );
+			viewWriter.insert( viewPosition, viewElement );
+		}
+	};
+}

src/imagecaption/utils.js

@@ -0,0 +1,63 @@
+/**
+ * @license Copyright (c) 2003-2017, CKSource - Frederico Knabben. All rights reserved.
+ * For licensing, see LICENSE.md.
+ */
+
+/**
+ * @module image/imagecaption/utils
+ */
+
+import ViewEditableElement from '@ckeditor/ckeditor5-engine/src/view/editableelement';
+import ModelElement from '@ckeditor/ckeditor5-engine/src/model/element';
+
+const captionSymbol = Symbol( 'imageCaption' );
+
+/**
+ * Returns a function that creates caption editable element for the given {@link module:engine/view/document~Document}.
+ *
+ * @param {module:engine/view/document~Document} viewDocument
+ * @return {Function}
+ */
+export function captionElementCreator( viewDocument ) {
+	return () => {
+		const editable = new ViewEditableElement( 'figcaption', { contenteditable: true } );
+		editable.document = viewDocument;
+		editable.setCustomProperty( captionSymbol, true );
+
+		editable.on( 'change:isFocused', ( evt, property, is ) => {
+			if ( is ) {
+				editable.addClass( 'focused' );
+			} else {
+				editable.removeClass( 'focused' );
+			}
+		} );
+
+		return editable;
+	};
+}
+
+/**
+ * Returns `true` if given view element is image's caption editable.
+ *
+ * @param {module:engine/view/element~Element} viewElement
+ * @return {Boolean}
+ */
+export function isCaption( viewElement ) {
+	return !!viewElement.getCustomProperty( captionSymbol );
+}
+
+/**
+ * Returns caption's model element from given image element. Returns `null` if no caption is found.
+ *
+ * @param {module:engine/model/element~Element} imageModelElement
+ * @return {module:engine/model/element~Element|null}
+ */
+export function getCaptionFromImage( imageModelElement ) {
+	for ( let node of imageModelElement.getChildren() ) {
+		if ( node instanceof ModelElement && node.name == 'caption' ) {
+			return node;
+		}
+	}
+
+	return null;
+}