mediawiki-extensions-MultimediaViewer/resources/mmv/ui/mmv.ui.canvasButtons.js

/*
 * This file is part of the MediaWiki extension MultimediaViewer.
 *
 * MultimediaViewer is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * MultimediaViewer 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with MultimediaViewer.  If not, see <http://www.gnu.org/licenses/>.
 */

const UiElement = require( './mmv.ui.js' );

/**
 * Represents the buttons which are displayed over the image - next, previous, close
 * and fullscreen.
 */
class CanvasButtons extends UiElement {
	/**
	 * @param {jQuery} $container The parent element we should put the buttons into.
	 * @param {jQuery} $closeButton The close button element from the parent class.
	 * @param {jQuery} $fullscreenButton The fullscreen button from the parent class.
	 * @fires MultimediaViewer#mmv-close
	 */
	constructor( $container, $closeButton, $fullscreenButton ) {
		super( $container );

		this.$close = $closeButton;
		this.$fullscreen = $fullscreenButton;

		this.$reuse = $( '<a>' )
			.attr( 'role', 'button' )
			.addClass( 'mw-mmv-reuse-button' )
			.text( '\u00A0' )
			.prop( 'title', mw.msg( 'multimediaviewer-reuse-link' ) );

		this.$options = $( '<button>' )
			.text( ' ' )
			.prop( 'title', mw.msg( 'multimediaviewer-options-tooltip' ) )
			.addClass( 'mw-mmv-options-button' );

		this.$download = $( '<a>' )
			.attr( 'role', 'button' )
			.addClass( 'mw-mmv-download-button' )
			.text( '\u00A0' )
			.prop( 'title', mw.msg( 'multimediaviewer-download-link' ) );

		this.$next = $( '<button>' )
			.prop( 'title', mw.msg( 'multimediaviewer-next-image-alt-text' ) )
			.addClass( 'mw-mmv-next-image disabled' )
			.text( '\u00A0' );

		this.$prev = $( '<button>' )
			.prop( 'title', mw.msg( 'multimediaviewer-prev-image-alt-text' ) )
			.addClass( 'mw-mmv-prev-image disabled' )
			.text( '\u00A0' );

		this.$nav = this.$next
			.add( this.$prev );

		this.$buttons = this.$close
			.add( this.$download )
			.add( this.$reuse )
			.add( this.$fullscreen )
			.add( this.$options )
			.add( this.$next )
			.add( this.$prev );

		this.$buttons.appendTo( this.$container );

		$( document ).on( 'mmv-close', () => {
			this.$nav.addClass( 'disabled' );
		} );

		this.$close.on( 'click', () => {
			$container.trigger( $.Event( 'mmv-close' ) );
		} );

		this.$next.on( 'click', () => {
			this.emit( 'next' );
		} );

		this.$prev.on( 'click', () => {
			this.emit( 'prev' );
		} );
	}

	/**
	 * Sets the top offset for the navigation buttons.
	 *
	 * @param {number} offset
	 */
	setOffset( offset ) {
		this.$nav.css( {
			top: offset
		} );
	}

	/**
	 * Stops the fading animation of the buttons and cancel any opacity value
	 */
	stopFade() {
		this.$buttons
			.stop( true )
			.removeClass( 'hidden' )
			.css( 'opacity', '' );

		this.$container.trigger( $.Event( 'mmv-fade-stopped' ) );
	}

	/**
	 * Toggles buttons being disabled or not
	 *
	 * @param {boolean} showPrevButton
	 * @param {boolean} showNextButton
	 */
	toggle( showPrevButton, showNextButton ) {
		this.$next.toggleClass( 'disabled', !showPrevButton );
		this.$prev.toggleClass( 'disabled', !showNextButton );
	}

	/**
	 * Fades out the active buttons
	 */
	fadeOut() {
		// We don't use animation chaining because delay() can't be stop()ed
		this.buttonsFadeTimeout = setTimeout( () => {
			// FIXME: Use CSS transition
			// eslint-disable-next-line no-jquery/no-animate
			this.$buttons.not( '.disabled' ).animate( { opacity: 0 }, 1000, 'swing',
				() => {
					this.$buttons.addClass( 'hidden' );
					this.$container.trigger( $.Event( 'mmv-faded-out' ) );
				} );
		}, 1500 );
	}

	/**
	 * Checks if any active buttons are currently hovered, given a position
	 *
	 * @param {number} x The horizontal coordinate of the position
	 * @param {number} y The vertical coordinate of the position
	 * @return {boolean}
	 */
	isAnyActiveButtonHovered( x, y ) {
		// We don't use mouseenter/mouseleave events because content is subject
		// to change underneath the cursor, eg. when entering fullscreen or
		// when going prev/next (the button can disappear when reaching ends)
		let hovered = false;

		this.$buttons.not( '.disabled' ).each( ( idx, e ) => {
			const $e = $( e );
			const offset = $e.offset();

			if ( y >= offset.top &&
				// using css( 'height' ) & css( 'width' ) instead of .height()
				// and .width() since those don't include padding, and as a
				// result can return a smaller size than is actually the button
				y <= offset.top + parseInt( $e.css( 'height' ) ) &&
				x >= offset.left &&
				x <= offset.left + parseInt( $e.css( 'width' ) ) ) {
				hovered = true;
			}
		} );

		return hovered;
	}

	/**
	 * Reveals all active buttons and schedule a fade out if needed
	 *
	 * @param {Object} [mousePosition] Mouse position containing 'x' and 'y' properties
	 */
	revealAndFade( mousePosition ) {
		if ( this.buttonsFadeTimeout ) {
			clearTimeout( this.buttonsFadeTimeout );
		}

		// Stop ongoing animations and make sure the buttons that need to be displayed are displayed
		this.stopFade();

		// mousePosition can be empty, for instance when we enter fullscreen and haven't
		// recorded a real mousemove event yet
		if ( !mousePosition ||
			!this.isAnyActiveButtonHovered( mousePosition.x, mousePosition.y ) ) {
			this.fadeOut();
		}
	}

	/**
	 * Registers listeners.
	 *
	 * @fires ReuseDialog#mmv-reuse-opened
	 * @fires ReuseDialog#mmv-reuse-closed
	 * @fires DownloadDialog#mmv-download-opened
	 * @fires DownloadDialog#mmv-download-closed
	 * @fires OptionsDialog#mmv-options-opened
	 * @fires OptionsDialog#mmv-options-closed
	 */
	attach() {
		this.$reuse.on( 'click.mmv-canvasButtons', ( e ) => {
			$( document ).trigger( 'mmv-reuse-open', e );
			return false;
		} );
		this.handleEvent( 'mmv-reuse-opened', () => this.$reuse.addClass( 'open' ) );
		this.handleEvent( 'mmv-reuse-closed', () => this.$reuse.removeClass( 'open' ) );

		this.$download.on( 'click.mmv-canvasButtons', ( e ) => {
			$( document ).trigger( 'mmv-download-open', e );
			return false;
		} );
		this.handleEvent( 'mmv-download-opened', () => this.$download.addClass( 'open' ) );
		this.handleEvent( 'mmv-download-closed', () => this.$download.removeClass( 'open' ) );

		this.$options.on( 'click.mmv-canvasButtons', ( e ) => {
			$( document ).trigger( 'mmv-options-open', e );
			e.stopPropagation();
		} );
		this.handleEvent( 'mmv-options-opened', () => this.$options.addClass( 'open' ) );
		this.handleEvent( 'mmv-options-closed', () => this.$options.removeClass( 'open' ) );

		this.$download
			.add( this.$reuse )
			.add( this.$options )
			.add( this.$close )
			.add( this.$fullscreen );
	}

	/**
	 * Removes all UI things from the DOM, or hides them
	 */
	unattach() {
		super.unattach();

		this.$download
			.add( this.$reuse )
			.add( this.$options )
			.add( this.$close )
			.add( this.$fullscreen )
			.off( 'click.mmv-canvasButtons' );
	}

	/**
	 * @param {ImageModel} image
	 */
	set( image ) {
		this.$reuse.prop( 'href', image.descriptionUrl );
		this.$download.prop( 'href', image.url );
	}

	empty() {
		this.$reuse
			.removeClass( 'open' )
			.prop( 'href', null );
		this.$download
			.prop( 'href', null );
	}
}

module.exports = CanvasButtons;