ckeditor/ckeditor5-heading

/**
 * @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 heading/headingbuttonsui
 */

import Plugin from '@ckeditor/ckeditor5-core/src/plugin';
import ButtonView from '@ckeditor/ckeditor5-ui/src/button/buttonview';

import { getLocalizedOptions } from './utils';
import iconHeading1 from '../theme/icons/heading1.svg';
import iconHeading2 from '../theme/icons/heading2.svg';
import iconHeading3 from '../theme/icons/heading3.svg';
import iconHeading4 from '../theme/icons/heading4.svg';
import iconHeading5 from '../theme/icons/heading5.svg';
import iconHeading6 from '../theme/icons/heading6.svg';

const defaultIcons = {
    heading1: iconHeading1,
    heading2: iconHeading2,
    heading3: iconHeading3,
    heading4: iconHeading4,
    heading5: iconHeading5,
    heading6: iconHeading6
};

/**
 * The `HeadingButtonsUI` plugin defines a set of UI buttons that can be used instead of the
 * standard drop down component.
 *
 * This feature is not enabled by default by the {@link module:heading/heading~Heading} plugin and needs to be
 * installed manually to the editor configuration.
 *
 * Plugin introduces button UI elements, which names are same as `model` property from {@link module:heading/heading~HeadingOption}.
 *
 *        ClassicEditor
 *            .create( {
 *                plugins: [ ..., Heading, Paragraph, HeadingButtonsUI, ParagraphButtonUI ]
 *                heading: {
 *                    options: [
 *                        { model: 'paragraph', title: 'Paragraph', class: 'ck-heading_paragraph' },
 *                        { model: 'heading1', view: 'h2', title: 'Heading 1', class: 'ck-heading_heading1' },
 *                        { model: 'heading2', view: 'h3', title: 'Heading 2', class: 'ck-heading_heading2' },
 *                        { model: 'heading3', view: 'h4', title: 'Heading 3', class: 'ck-heading_heading3' }
 *                    ]
 *                 },
 *                 toolbar: [ 'paragraph', 'heading1', 'heading2', 'heading3' ]
 *            } )
 *            .then( ... )
 *            .catch( ... );
 *
 * NOTE: The `'paragraph'` button is defined in by the {@link module:paragraph/paragraphbuttonui~ParagraphButtonUI} plugin
 * which needs to be loaded manually as well.
 *
 * It is possible to use custom icons by providing `icon` config option in {@link module:heading/heading~HeadingOption}.
 * For the default configuration standard icons are used.
 *
 * @extends module:core/plugin~Plugin
 */
export default class HeadingButtonsUI extends Plugin {
    /**
     * @inheritDoc
     */
    init() {
        const options = getLocalizedOptions( this.editor );

        options
            .filter( item => item.model !== 'paragraph' )
            .map( item => this._createButton( item ) );
    }

    /**
     * Creates single button view from provided configuration option.
     *
     * @private
     * @param {Object} option
     */
    _createButton( option ) {
        const editor = this.editor;

        editor.ui.componentFactory.add( option.model, locale => {
            const view = new ButtonView( locale );
            const command = editor.commands.get( 'heading' );

            view.label = option.title;
            view.icon = option.icon || defaultIcons[ option.model ];
            view.tooltip = true;
            view.isToggleable = true;
            view.bind( 'isEnabled' ).to( command );
            view.bind( 'isOn' ).to( command, 'value', value => value == option.model );

            view.on( 'execute', () => {
                editor.execute( 'heading', { value: option.model } );
                editor.editing.view.focus();
            } );

            return view;
        } );
    }
}