src/view/uielement.js
/**
* @license Copyright (c) 2003-2020, CKSource - Frederico Knabben. All rights reserved.
* For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license
*/
/**
* @module engine/view/uielement
*/
import Element from './element';
import CKEditorError from '@ckeditor/ckeditor5-utils/src/ckeditorerror';
import Node from './node';
import { keyCodes } from '@ckeditor/ckeditor5-utils/src/keyboard';
/**
* UI element class. It should be used to represent editing UI which needs to be injected into the editing view
* If possible, you should keep your UI outside the editing view. However, if that is not possible,
* UI elements can be used.
*
* How a UI element is rendered is in your control (you pass a callback to
* {@link module:engine/view/downcastwriter~DowncastWriter#createUIElement `downcastWriter#createUIElement()`}).
* The editor will ignore your UI element – the selection cannot be placed in it, it is skipped (invisible) when
* the user modifies the selection by using arrow keys and the editor does not listen to any mutations which
* happen inside your UI elements.
*
* The limitation is that you cannot convert a model element to a UI element. UI elements need to be
* created for {@link module:engine/model/markercollection~Marker markers} or as additinal elements
* inside normal {@link module:engine/view/containerelement~ContainerElement container elements}.
*
* To create a new UI element use the
* {@link module:engine/view/downcastwriter~DowncastWriter#createUIElement `downcastWriter#createUIElement()`} method.
*
* @extends module:engine/view/element~Element
*/
export default class UIElement extends Element {
/**
* Creates new instance of UIElement.
*
* Throws {@link module:utils/ckeditorerror~CKEditorError CKEditorError} `view-uielement-cannot-add` when third parameter is passed,
* to inform that usage of UIElement is incorrect (adding child nodes to UIElement is forbidden).
*
* @see module:engine/view/downcastwriter~DowncastWriter#createUIElement
* @protected
* @param {module:engine/view/document~Document} document The document instance to which this element belongs.
* @param {String} name Node name.
* @param {Object|Iterable} [attributes] Collection of attributes.
* @param {module:engine/view/node~Node|Iterable.<module:engine/view/node~Node>} [children]
* A list of nodes to be inserted into created element.
*/
constructor( document, name, attributes, children ) {
super( document, name, attributes, children );
/**
* Returns `null` because filler is not needed for UIElements.
*
* @method #getFillerOffset
* @returns {null} Always returns null.
*/
this.getFillerOffset = getFillerOffset;
}
/**
* Checks whether this object is of the given.
*
* uiElement.is( 'uiElement' ); // -> true
* uiElement.is( 'element' ); // -> true
* uiElement.is( 'node' ); // -> true
* uiElement.is( 'view:uiElement' ); // -> true
* uiElement.is( 'view:element' ); // -> true
* uiElement.is( 'view:node' ); // -> true
*
* uiElement.is( 'model:element' ); // -> false
* uiElement.is( 'documentFragment' ); // -> false
*
* Assuming that the object being checked is an ui element, you can also check its
* {@link module:engine/view/uielement~UIElement#name name}:
*
* uiElement.is( 'span' ); // -> true if this is a span ui element
* uiElement.is( 'uiElement', 'span' ); // -> same as above
* text.is( 'span' ); -> false
*
* {@link module:engine/view/node~Node#is Check the entire list of view objects} which implement the `is()` method.
*
* @param {String} type Type to check when `name` parameter is present.
* Otherwise, it acts like the `name` parameter.
* @param {String} [name] Element name.
* @returns {Boolean}
*/
is( type, name = null ) {
if ( !name ) {
return type === 'uiElement' || type === 'view:uiElement' ||
// From super.is(). This is highly utilised method and cannot call super. See ckeditor/ckeditor5#6529.
type === this.name || type === 'view:' + this.name ||
type === 'element' || type === 'view:element' ||
type === 'node' || type === 'view:node';
} else {
return name === this.name && (
type === 'uiElement' || type === 'view:uiElement' ||
type === 'element' || type === 'view:element'
);
}
}
/**
* Overrides {@link module:engine/view/element~Element#_insertChild} method.
* Throws {@link module:utils/ckeditorerror~CKEditorError CKEditorError} `view-uielement-cannot-add` to prevent adding any child nodes
* to UIElement.
*
* @protected
*/
_insertChild( index, nodes ) {
if ( nodes && ( nodes instanceof Node || Array.from( nodes ).length > 0 ) ) {
/**
* Cannot add children to {@link module:engine/view/uielement~UIElement}.
*
* @error view-uielement-cannot-add
*/
throw new CKEditorError( 'view-uielement-cannot-add: Cannot add child nodes to UIElement instance.', this );
}
}
/**
* Renders this {@link module:engine/view/uielement~UIElement} to DOM. This method is called by
* {@link module:engine/view/domconverter~DomConverter}.
* Do not use inheritance to create custom rendering method, replace `render()` method instead:
*
* const myUIElement = downcastWriter.createUIElement( 'span' );
* myUIElement.render = function( domDocument ) {
* const domElement = this.toDomElement( domDocument );
* domElement.innerHTML = '<b>this is ui element</b>';
*
* return domElement;
* };
*
* If changes in your UI element should trigger some editor UI update you should call
* the {@link module:core/editor/editorui~EditorUI#update `editor.ui.update()`} method
* after rendering your UI element.
*
* @param {Document} domDocument
* @returns {HTMLElement}
*/
render( domDocument ) {
return this.toDomElement( domDocument );
}
/**
* Creates DOM element based on this view UIElement.
* Note that each time this method is called new DOM element is created.
*
* @param {Document} domDocument
* @returns {HTMLElement}
*/
toDomElement( domDocument ) {
const domElement = domDocument.createElement( this.name );
for ( const key of this.getAttributeKeys() ) {
domElement.setAttribute( key, this.getAttribute( key ) );
}
return domElement;
}
}
/**
* This function injects UI element handling to the given {@link module:engine/view/document~Document document}.
*
* A callback is added to {@link module:engine/view/document~Document#event:keydown document keydown event}.
* The callback handles the situation when right arrow key is pressed and selection is collapsed before a UI element.
* Without this handler, it would be impossible to "jump over" UI element using right arrow key.
*
* @param {module:engine/view/view~View} view View controller to which the quirks handling will be injected.
*/
export function injectUiElementHandling( view ) {
view.document.on( 'keydown', ( evt, data ) => jumpOverUiElement( evt, data, view.domConverter ) );
}
// Returns `null` because block filler is not needed for UIElements.
//
// @returns {null}
function getFillerOffset() {
return null;
}
// Selection cannot be placed in a `UIElement`. Whenever it is placed there, it is moved before it. This
// causes a situation when it is impossible to jump over `UIElement` using right arrow key, because the selection
// ends up in ui element (in DOM) and is moved back to the left. This handler fixes this situation.
function jumpOverUiElement( evt, data, domConverter ) {
if ( data.keyCode == keyCodes.arrowright ) {
const domSelection = data.domTarget.ownerDocument.defaultView.getSelection();
const domSelectionCollapsed = domSelection.rangeCount == 1 && domSelection.getRangeAt( 0 ).collapsed;
// Jump over UI element if selection is collapsed or shift key is pressed. These are the cases when selection would extend.
if ( domSelectionCollapsed || data.shiftKey ) {
const domParent = domSelection.focusNode;
const domOffset = domSelection.focusOffset;
const viewPosition = domConverter.domPositionToView( domParent, domOffset );
// In case if dom element is not converted to view or is not mapped or something. Happens for example in some tests.
if ( viewPosition === null ) {
return;
}
// Skip all following ui elements.
let jumpedOverAnyUiElement = false;
const nextViewPosition = viewPosition.getLastMatchingPosition( value => {
if ( value.item.is( 'uiElement' ) ) {
// Remember that there was at least one ui element.
jumpedOverAnyUiElement = true;
}
// Jump over ui elements, jump over empty attribute elements, move up from inside of attribute element.
if ( value.item.is( 'uiElement' ) || value.item.is( 'attributeElement' ) ) {
return true;
}
// Don't jump over text or don't get out of container element.
return false;
} );
// If anything has been skipped, fix position.
// This `if` could be possibly omitted but maybe it is better not to mess with DOM selection if not needed.
if ( jumpedOverAnyUiElement ) {
const newDomPosition = domConverter.viewPositionToDom( nextViewPosition );
if ( domSelectionCollapsed ) {
// Selection was collapsed, so collapse it at further position.
domSelection.collapse( newDomPosition.parent, newDomPosition.offset );
} else {
// Selection was not collapse, so extend it instead of collapsing.
domSelection.extend( newDomPosition.parent, newDomPosition.offset );
}
}
}
}
}