import { HORIZONTAL_SLIDES_SELECTOR, VERTICAL_SLIDES_SELECTOR } from '../utils/constants.js' import { extend, toArray, closestParent } from '../utils/util.js' import { isMobile } from '../utils/device.js' /** * Handles loading, unloading and playback of slide * content such as images, videos and iframes. */ export default class SlideContent { constructor( Reveal ) { this.Reveal = Reveal; } /** * Should the given element be preloaded? * Decides based on local element attributes and global config. * * @param {HTMLElement} element */ shouldPreload( element ) { // Prefer an explicit global preload setting let preload = this.Reveal.getConfig().preloadIframes; // If no global setting is available, fall back on the element's // own preload setting if( typeof preload !== 'boolean' ) { preload = element.hasAttribute( 'data-preload' ); } return preload; } /** * Called when the given slide is within the configured view * distance. Shows the slide element and loads any content * that is set to load lazily (data-src). * * @param {HTMLElement} slide Slide to show */ load( slide, options = {} ) { // Show the slide element slide.style.display = this.Reveal.getConfig().display; // Media elements with data-src attributes toArray( slide.querySelectorAll( 'img[data-src], video[data-src], audio[data-src], iframe[data-src]' ) ).forEach( element => { if( element.tagName !== 'IFRAME' || this.shouldPreload( element ) ) { element.setAttribute( 'src', element.getAttribute( 'data-src' ) ); element.setAttribute( 'data-lazy-loaded', '' ); element.removeAttribute( 'data-src' ); } } ); // Media elements with children toArray( slide.querySelectorAll( 'video, audio' ) ).forEach( media => { let sources = 0; toArray( media.querySelectorAll( 'source[data-src]' ) ).forEach( source => { source.setAttribute( 'src', source.getAttribute( 'data-src' ) ); source.removeAttribute( 'data-src' ); source.setAttribute( 'data-lazy-loaded', '' ); sources += 1; } ); // If we rewrote sources for this video/audio element, we need // to manually tell it to load from its new origin if( sources > 0 ) { media.load(); } } ); // Show the corresponding background element let background = slide.slideBackgroundElement; if( background ) { background.style.display = 'block'; let backgroundContent = slide.slideBackgroundContentElement; let backgroundIframe = slide.getAttribute( 'data-background-iframe' ); // If the background contains media, load it if( background.hasAttribute( 'data-loaded' ) === false ) { background.setAttribute( 'data-loaded', 'true' ); let backgroundImage = slide.getAttribute( 'data-background-image' ), backgroundVideo = slide.getAttribute( 'data-background-video' ), backgroundVideoLoop = slide.hasAttribute( 'data-background-video-loop' ), backgroundVideoMuted = slide.hasAttribute( 'data-background-video-muted' ); // Images if( backgroundImage ) { backgroundContent.style.backgroundImage = 'url('+ encodeURI( backgroundImage ) +')'; } // Videos else if ( backgroundVideo && !this.Reveal.isSpeakerNotes() ) { let video = document.createElement( 'video' ); if( backgroundVideoLoop ) { video.setAttribute( 'loop', '' ); } if( backgroundVideoMuted ) { video.muted = true; } // Inline video playback works (at least in Mobile Safari) as // long as the video is muted and the `playsinline` attribute is // present if( isMobile ) { video.muted = true; video.autoplay = true; video.setAttribute( 'playsinline', '' ); } // Support comma separated lists of video sources backgroundVideo.split( ',' ).forEach( source => { video.innerHTML += ''; } ); backgroundContent.appendChild( video ); } // Iframes else if( backgroundIframe && options.excludeIframes !== true ) { let iframe = document.createElement( 'iframe' ); iframe.setAttribute( 'allowfullscreen', '' ); iframe.setAttribute( 'mozallowfullscreen', '' ); iframe.setAttribute( 'webkitallowfullscreen', '' ); iframe.setAttribute( 'allow', 'autoplay' ); iframe.setAttribute( 'data-src', backgroundIframe ); iframe.style.width = '100%'; iframe.style.height = '100%'; iframe.style.maxHeight = '100%'; iframe.style.maxWidth = '100%'; backgroundContent.appendChild( iframe ); } } // Start loading preloadable iframes let backgroundIframeElement = backgroundContent.querySelector( 'iframe[data-src]' ); if( backgroundIframeElement ) { // Check if this iframe is eligible to be preloaded if( this.shouldPreload( background ) && !/autoplay=(1|true|yes)/gi.test( backgroundIframe ) ) { if( backgroundIframeElement.getAttribute( 'src' ) !== backgroundIframe ) { backgroundIframeElement.setAttribute( 'src', backgroundIframe ); } } } } } /** * Unloads and hides the given slide. This is called when the * slide is moved outside of the configured view distance. * * @param {HTMLElement} slide */ unload( slide ) { // Hide the slide element slide.style.display = 'none'; // Hide the corresponding background element let background = this.Reveal.getSlideBackground( slide ); if( background ) { background.style.display = 'none'; // Unload any background iframes toArray( background.querySelectorAll( 'iframe[src]' ) ).forEach( element => { element.removeAttribute( 'src' ); } ); } // Reset lazy-loaded media elements with src attributes toArray( slide.querySelectorAll( 'video[data-lazy-loaded][src], audio[data-lazy-loaded][src], iframe[data-lazy-loaded][src]' ) ).forEach( element => { element.setAttribute( 'data-src', element.getAttribute( 'src' ) ); element.removeAttribute( 'src' ); } ); // Reset lazy-loaded media elements with children toArray( slide.querySelectorAll( 'video[data-lazy-loaded] source[src], audio source[src]' ) ).forEach( source => { source.setAttribute( 'data-src', source.getAttribute( 'src' ) ); source.removeAttribute( 'src' ); } ); } /** * Enforces origin-specific format rules for embedded media. */ formatEmbeddedContent() { let _appendParamToIframeSource = ( sourceAttribute, sourceURL, param ) => { toArray( this.Reveal.getSlidesElement().querySelectorAll( 'iframe['+ sourceAttribute +'*="'+ sourceURL +'"]' ) ).forEach( el => { let src = el.getAttribute( sourceAttribute ); if( src && src.indexOf( param ) === -1 ) { el.setAttribute( sourceAttribute, src + ( !/\?/.test( src ) ? '?' : '&' ) + param ); } }); }; // YouTube frames must include "?enablejsapi=1" _appendParamToIframeSource( 'src', 'youtube.com/embed/', 'enablejsapi=1' ); _appendParamToIframeSource( 'data-src', 'youtube.com/embed/', 'enablejsapi=1' ); // Vimeo frames must include "?api=1" _appendParamToIframeSource( 'src', 'player.vimeo.com/', 'api=1' ); _appendParamToIframeSource( 'data-src', 'player.vimeo.com/', 'api=1' ); } /** * Start playback of any embedded content inside of * the given element. * * @param {HTMLElement} element */ startEmbeddedContent( element ) { if( element && !this.Reveal.isSpeakerNotes() ) { // Restart GIFs toArray( element.querySelectorAll( 'img[src$=".gif"]' ) ).forEach( el => { // Setting the same unchanged source like this was confirmed // to work in Chrome, FF & Safari el.setAttribute( 'src', el.getAttribute( 'src' ) ); } ); // HTML5 media elements toArray( element.querySelectorAll( 'video, audio' ) ).forEach( el => { if( closestParent( el, '.fragment' ) && !closestParent( el, '.fragment.visible' ) ) { return; } // Prefer an explicit global autoplay setting let autoplay = this.Reveal.getConfig().autoPlayMedia; // If no global setting is available, fall back on the element's // own autoplay setting if( typeof autoplay !== 'boolean' ) { autoplay = el.hasAttribute( 'data-autoplay' ) || !!closestParent( el, '.slide-background' ); } if( autoplay && typeof el.play === 'function' ) { // If the media is ready, start playback if( el.readyState > 1 ) { this.startEmbeddedMedia( { target: el } ); } // Mobile devices never fire a loaded event so instead // of waiting, we initiate playback else if( isMobile ) { let promise = el.play(); // If autoplay does not work, ensure that the controls are visible so // that the viewer can start the media on their own if( promise && typeof promise.catch === 'function' && el.controls === false ) { promise.catch( () => { el.controls = true; // Once the video does start playing, hide the controls again el.addEventListener( 'play', () => { el.controls = false; } ); } ); } } // If the media isn't loaded, wait before playing else { el.removeEventListener( 'loadeddata', this.startEmbeddedMedia ); // remove first to avoid dupes el.addEventListener( 'loadeddata', this.startEmbeddedMedia ); } } } ); // Normal iframes toArray( element.querySelectorAll( 'iframe[src]' ) ).forEach( el => { if( closestParent( el, '.fragment' ) && !closestParent( el, '.fragment.visible' ) ) { return; } this.startEmbeddedIframe( { target: el } ); } ); // Lazy loading iframes toArray( element.querySelectorAll( 'iframe[data-src]' ) ).forEach( el => { if( closestParent( el, '.fragment' ) && !closestParent( el, '.fragment.visible' ) ) { return; } if( el.getAttribute( 'src' ) !== el.getAttribute( 'data-src' ) ) { el.removeEventListener( 'load', this.startEmbeddedIframe ); // remove first to avoid dupes el.addEventListener( 'load', this.startEmbeddedIframe ); el.setAttribute( 'src', el.getAttribute( 'data-src' ) ); } } ); } } /** * Starts playing an embedded video/audio element after * it has finished loading. * * @param {object} event */ startEmbeddedMedia( event ) { let isAttachedToDOM = !!closestParent( event.target, 'html' ), isVisible = !!closestParent( event.target, '.present' ); if( isAttachedToDOM && isVisible ) { event.target.currentTime = 0; event.target.play(); } event.target.removeEventListener( 'loadeddata', this.startEmbeddedMedia ); } /** * "Starts" the content of an embedded iframe using the * postMessage API. * * @param {object} event */ startEmbeddedIframe( event ) { let iframe = event.target; if( iframe && iframe.contentWindow ) { let isAttachedToDOM = !!closestParent( event.target, 'html' ), isVisible = !!closestParent( event.target, '.present' ); if( isAttachedToDOM && isVisible ) { // Prefer an explicit global autoplay setting let autoplay = this.Reveal.getConfig().autoPlayMedia; // If no global setting is available, fall back on the element's // own autoplay setting if( typeof autoplay !== 'boolean' ) { autoplay = iframe.hasAttribute( 'data-autoplay' ) || !!closestParent( iframe, '.slide-background' ); } // YouTube postMessage API if( /youtube\.com\/embed\//.test( iframe.getAttribute( 'src' ) ) && autoplay ) { iframe.contentWindow.postMessage( '{"event":"command","func":"playVideo","args":""}', '*' ); } // Vimeo postMessage API else if( /player\.vimeo\.com\//.test( iframe.getAttribute( 'src' ) ) && autoplay ) { iframe.contentWindow.postMessage( '{"method":"play"}', '*' ); } // Generic postMessage API else { iframe.contentWindow.postMessage( 'slide:start', '*' ); } } } } /** * Stop playback of any embedded content inside of * the targeted slide. * * @param {HTMLElement} element */ stopEmbeddedContent( element, options = {} ) { options = extend( { // Defaults unloadIframes: true }, options ); if( element && element.parentNode ) { // HTML5 media elements toArray( element.querySelectorAll( 'video, audio' ) ).forEach( el => { if( !el.hasAttribute( 'data-ignore' ) && typeof el.pause === 'function' ) { el.setAttribute('data-paused-by-reveal', ''); el.pause(); } } ); // Generic postMessage API for non-lazy loaded iframes toArray( element.querySelectorAll( 'iframe' ) ).forEach( el => { if( el.contentWindow ) el.contentWindow.postMessage( 'slide:stop', '*' ); el.removeEventListener( 'load', this.startEmbeddedIframe ); }); // YouTube postMessage API toArray( element.querySelectorAll( 'iframe[src*="youtube.com/embed/"]' ) ).forEach( el => { if( !el.hasAttribute( 'data-ignore' ) && el.contentWindow && typeof el.contentWindow.postMessage === 'function' ) { el.contentWindow.postMessage( '{"event":"command","func":"pauseVideo","args":""}', '*' ); } }); // Vimeo postMessage API toArray( element.querySelectorAll( 'iframe[src*="player.vimeo.com/"]' ) ).forEach( el => { if( !el.hasAttribute( 'data-ignore' ) && el.contentWindow && typeof el.contentWindow.postMessage === 'function' ) { el.contentWindow.postMessage( '{"method":"pause"}', '*' ); } }); if( options.unloadIframes === true ) { // Unload lazy-loaded iframes toArray( element.querySelectorAll( 'iframe[data-src]' ) ).forEach( el => { // Only removing the src doesn't actually unload the frame // in all browsers (Firefox) so we set it to blank first el.setAttribute( 'src', 'about:blank' ); el.removeAttribute( 'src' ); } ); } } } }