js/controllers/slidecontent.js
import { extend, queryAll, closest, getMimeTypeFromFile, encodeRFC3986URI } from '../utils/util.js'
import { isMobile } from '../utils/device.js'
import fitty from 'fitty';
/**
* Handles loading, unloading and playback of slide
* content such as images, videos and iframes.
*/
export default class SlideContent {
constructor( Reveal ) {
this.Reveal = Reveal;
this.startEmbeddedIframe = this.startEmbeddedIframe.bind( this );
}
/**
* Should the given element be preloaded?
* Decides based on local element attributes and global config.
*
* @param {HTMLElement} element
*/
shouldPreload( element ) {
if( this.Reveal.isScrollView() ) {
return true;
}
// 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
queryAll( slide, '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 <source> children
queryAll( slide, 'video, audio' ).forEach( media => {
let sources = 0;
queryAll( media, 'source[data-src]' ).forEach( source => {
source.setAttribute( 'src', source.getAttribute( 'data-src' ) );
source.removeAttribute( 'data-src' );
source.setAttribute( 'data-lazy-loaded', '' );
sources += 1;
} );
// Enable inline video playback in mobile Safari
if( isMobile && media.tagName === 'VIDEO' ) {
media.setAttribute( 'playsinline', '' );
}
// 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 ) {
// base64
if( /^data:/.test( backgroundImage.trim() ) ) {
backgroundContent.style.backgroundImage = `url(${backgroundImage.trim()})`;
}
// URL(s)
else {
backgroundContent.style.backgroundImage = backgroundImage.split( ',' ).map( background => {
// Decode URL(s) that are already encoded first
let decoded = decodeURI(background.trim());
return `url(${encodeRFC3986URI(decoded)})`;
}).join( ',' );
}
}
// Videos
else if ( backgroundVideo && !this.Reveal.isSpeakerNotes() ) {
let video = document.createElement( 'video' );
if( backgroundVideoLoop ) {
video.setAttribute( 'loop', '' );
}
if( backgroundVideoMuted ) {
video.muted = true;
}
// Enable inline playback in mobile Safari
//
// Mute is required for video to play when using
// swipe gestures to navigate since they don't
// count as direct user actions :'(
if( isMobile ) {
video.muted = true;
video.setAttribute( 'playsinline', '' );
}
// Support comma separated lists of video sources
backgroundVideo.split( ',' ).forEach( source => {
const sourceElement = document.createElement( 'source' );
sourceElement.setAttribute( 'src', source );
let type = getMimeTypeFromFile( source );
if( type ) {
sourceElement.setAttribute( 'type', type );
}
video.appendChild( sourceElement );
} );
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 );
}
}
}
}
this.layout( slide );
}
/**
* Applies JS-dependent layout helpers for the scope.
*/
layout( scopeElement ) {
// Autosize text with the r-fit-text class based on the
// size of its container. This needs to happen after the
// slide is visible in order to measure the text.
Array.from( scopeElement.querySelectorAll( '.r-fit-text' ) ).forEach( element => {
fitty( element, {
minSize: 24,
maxSize: this.Reveal.getConfig().height * 0.8,
observeMutations: false,
observeWindow: false
} );
} );
}
/**
* 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
queryAll( background, 'iframe[src]' ).forEach( element => {
element.removeAttribute( 'src' );
} );
}
// Reset lazy-loaded media elements with src attributes
queryAll( slide, '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 <source> children
queryAll( slide, '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 ) => {
queryAll( this.Reveal.getSlidesElement(), '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
queryAll( element, '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
queryAll( element, 'video, audio' ).forEach( el => {
if( closest( el, '.fragment' ) && !closest( 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' ) || !!closest( 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
queryAll( element, 'iframe[src]' ).forEach( el => {
if( closest( el, '.fragment' ) && !closest( el, '.fragment.visible' ) ) {
return;
}
this.startEmbeddedIframe( { target: el } );
} );
// Lazy loading iframes
queryAll( element, 'iframe[data-src]' ).forEach( el => {
if( closest( el, '.fragment' ) && !closest( 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 = !!closest( event.target, 'html' ),
isVisible = !!closest( event.target, '.present' );
if( isAttachedToDOM && isVisible ) {
// Don't restart if media is already playing
if( event.target.paused || event.target.ended ) {
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 = !!closest( event.target, 'html' ),
isVisible = !!closest( 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' ) || !!closest( 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
queryAll( element, '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
queryAll( element, 'iframe' ).forEach( el => {
if( el.contentWindow ) el.contentWindow.postMessage( 'slide:stop', '*' );
el.removeEventListener( 'load', this.startEmbeddedIframe );
});
// YouTube postMessage API
queryAll( element, '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
queryAll( element, '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
queryAll( element, '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' );
} );
}
}
}
}