reveal.js
Version:
The HTML Presentation Framework
389 lines (292 loc) • 10.2 kB
JavaScript
/**
* Handles the display of reveal.js' overlay elements used
* to preview iframes, images & videos.
*/
export default class Overlay {
constructor( Reveal ) {
this.Reveal = Reveal;
this.onSlidesClicked = this.onSlidesClicked.bind( this );
this.iframeTriggerSelector = null;
this.mediaTriggerSelector = '[data-preview-image], [data-preview-video]';
this.stateProps = ['previewIframe', 'previewImage', 'previewVideo', 'previewFit'];
this.state = {};
}
update() {
// Enable link previews globally
if( this.Reveal.getConfig().previewLinks ) {
this.iframeTriggerSelector = 'a[href]:not([data-preview-link=false]), [data-preview-link]:not(a):not([data-preview-link=false])';
}
// Enable link previews for individual elements
else {
this.iframeTriggerSelector = '[data-preview-link]:not([data-preview-link=false])';
}
const hasLinkPreviews = this.Reveal.getSlidesElement().querySelectorAll( this.iframeTriggerSelector ).length > 0;
const hasMediaPreviews = this.Reveal.getSlidesElement().querySelectorAll( this.mediaTriggerSelector ).length > 0;
// Only add the listener when there are previewable elements in the slides
if( hasLinkPreviews || hasMediaPreviews ) {
this.Reveal.getSlidesElement().addEventListener( 'click', this.onSlidesClicked, false );
}
else {
this.Reveal.getSlidesElement().removeEventListener( 'click', this.onSlidesClicked, false );
}
}
createOverlay( className ) {
this.dom = document.createElement( 'div' );
this.dom.classList.add( 'r-overlay' );
this.dom.classList.add( className );
this.viewport = document.createElement( 'div' );
this.viewport.classList.add( 'r-overlay-viewport' );
this.dom.appendChild( this.viewport );
this.Reveal.getRevealElement().appendChild( this.dom );
}
/**
* Opens a lightbox that previews the target URL.
*
* @param {string} url - url for lightbox iframe src
*/
previewIframe( url ) {
this.close();
this.state = { previewIframe: url };
this.createOverlay( 'r-overlay-preview' );
this.dom.dataset.state = 'loading';
this.viewport.innerHTML =
`<header class="r-overlay-header">
<a class="r-overlay-button r-overlay-external" href="${url}" target="_blank"><span class="icon"></span></a>
<button class="r-overlay-button r-overlay-close"><span class="icon"></span></button>
</header>
<div class="r-overlay-spinner"></div>
<div class="r-overlay-content">
<iframe src="${url}"></iframe>
<small class="r-overlay-content-inner">
<span class="r-overlay-error x-frame-error">Unable to load iframe. This is likely due to the site's policy (x-frame-options).</span>
</small>
</div>`;
this.dom.querySelector( 'iframe' ).addEventListener( 'load', event => {
this.dom.dataset.state = 'loaded';
}, false );
this.dom.querySelector( '.r-overlay-close' ).addEventListener( 'click', event => {
this.close();
event.preventDefault();
}, false );
this.dom.querySelector( '.r-overlay-external' ).addEventListener( 'click', event => {
this.close();
}, false );
this.Reveal.dispatchEvent({ type: 'previewiframe', data: { url } });
}
/**
* Opens a lightbox window that provides a larger view of the
* given image/video.
*
* @param {string} url - url to the image/video to preview
* @param {image|video} mediaType
* @param {string} [fitMode] - the fit mode to use for the preview
*/
previewMedia( url, mediaType, fitMode ) {
if( mediaType !== 'image' && mediaType !== 'video' ) {
console.warn( 'Please specify a valid media type to preview (image|video)' );
return;
}
this.close();
fitMode = fitMode || 'scale-down';
this.createOverlay( 'r-overlay-preview' );
this.dom.dataset.state = 'loading';
this.dom.dataset.previewFit = fitMode;
this.viewport.innerHTML =
`<header class="r-overlay-header">
<button class="r-overlay-button r-overlay-close">Esc <span class="icon"></span></button>
</header>
<div class="r-overlay-spinner"></div>
<div class="r-overlay-content"></div>`;
const contentElement = this.dom.querySelector( '.r-overlay-content' );
if( mediaType === 'image' ) {
this.state = { previewImage: url, previewFit: fitMode }
const img = document.createElement( 'img', {} );
img.src = url;
contentElement.appendChild( img );
img.addEventListener( 'load', () => {
this.dom.dataset.state = 'loaded';
}, false );
img.addEventListener( 'error', () => {
this.dom.dataset.state = 'error';
contentElement.innerHTML =
`<span class="r-overlay-error">Unable to load image.</span>`
}, false );
// Hide image overlays when clicking outside the overlay
this.dom.style.cursor = 'zoom-out';
this.dom.addEventListener( 'click', ( event ) => {
this.close();
}, false );
this.Reveal.dispatchEvent({ type: 'previewimage', data: { url } });
}
else if( mediaType === 'video' ) {
this.state = { previewVideo: url, previewFit: fitMode }
const video = document.createElement( 'video' );
video.autoplay = this.dom.dataset.previewAutoplay === 'false' ? false : true;
video.controls = this.dom.dataset.previewControls === 'false' ? false : true;
video.loop = this.dom.dataset.previewLoop === 'true' ? true : false;
video.muted = this.dom.dataset.previewMuted === 'true' ? true : false;
video.playsInline = true;
video.src = url;
contentElement.appendChild( video );
video.addEventListener( 'loadeddata', () => {
this.dom.dataset.state = 'loaded';
}, false );
video.addEventListener( 'error', () => {
this.dom.dataset.state = 'error';
contentElement.innerHTML =
`<span class="r-overlay-error">Unable to load video.</span>`;
}, false );
this.Reveal.dispatchEvent({ type: 'previewvideo', data: { url } });
}
else {
throw new Error( 'Please specify a valid media type to preview' );
}
this.dom.querySelector( '.r-overlay-close' ).addEventListener( 'click', ( event ) => {
this.close();
event.preventDefault();
}, false );
}
previewImage( url, fitMode ) {
this.previewMedia( url, 'image', fitMode );
}
previewVideo( url, fitMode ) {
this.previewMedia( url, 'video', fitMode );
}
/**
* Open or close help overlay window.
*
* @param {Boolean} [override] Flag which overrides the
* toggle logic and forcibly sets the desired state. True means
* help is open, false means it's closed.
*/
toggleHelp( override ) {
if( typeof override === 'boolean' ) {
override ? this.showHelp() : this.close();
}
else {
if( this.dom ) {
this.close();
}
else {
this.showHelp();
}
}
}
/**
* Opens an overlay window with help material.
*/
showHelp() {
if( this.Reveal.getConfig().help ) {
this.close();
this.createOverlay( 'r-overlay-help' );
let html = '<p class="title">Keyboard Shortcuts</p>';
let shortcuts = this.Reveal.keyboard.getShortcuts(),
bindings = this.Reveal.keyboard.getBindings();
html += '<table><th>KEY</th><th>ACTION</th>';
for( let key in shortcuts ) {
html += `<tr><td>${key}</td><td>${shortcuts[ key ]}</td></tr>`;
}
// Add custom key bindings that have associated descriptions
for( let binding in bindings ) {
if( bindings[binding].key && bindings[binding].description ) {
html += `<tr><td>${bindings[binding].key}</td><td>${bindings[binding].description}</td></tr>`;
}
}
html += '</table>';
this.viewport.innerHTML = `
<header class="r-overlay-header">
<button class="r-overlay-button r-overlay-close">Esc <span class="icon"></span></button>
</header>
<div class="r-overlay-content">
<div class="r-overlay-help-content">${html}</div>
</div>
`;
this.dom.querySelector( '.r-overlay-close' ).addEventListener( 'click', event => {
this.close();
event.preventDefault();
}, false );
this.Reveal.dispatchEvent({ type: 'showhelp' });
}
}
isOpen() {
return !!this.dom;
}
/**
* Closes any currently open overlay.
*/
close() {
if( this.dom ) {
this.dom.remove();
this.dom = null;
this.state = {};
this.Reveal.dispatchEvent({ type: 'closeoverlay' });
return true;
}
return false;
}
getState() {
return this.state;
}
setState( state ) {
// Ignore the incoming state if none of the preview related
// props have changed
if( this.stateProps.every( key => this.state[ key ] === state[ key ] ) ) {
return;
}
if( state.previewIframe ) {
this.previewIframe( state.previewIframe );
}
else if( state.previewImage ) {
this.previewImage( state.previewImage, state.previewFit );
}
else if( state.previewVideo ) {
this.previewVideo( state.previewVideo, state.previewFit );
}
else {
this.close();
}
}
onSlidesClicked( event ) {
const target = event.target;
const linkTarget = target.closest( this.iframeTriggerSelector );
const mediaTarget = target.closest( this.mediaTriggerSelector );
// Was an iframe lightbox trigger clicked?
if( linkTarget ) {
if( event.metaKey || event.shiftKey || event.altKey ) {
// Let the browser handle meta keys naturally so users can cmd+click
return;
}
let url = linkTarget.getAttribute( 'href' ) || linkTarget.getAttribute( 'data-preview-link' );
if( url ) {
this.previewIframe( url );
event.preventDefault();
}
}
// Was a media lightbox trigger clicked?
else if( mediaTarget ) {
if( mediaTarget.hasAttribute( 'data-preview-image' ) ) {
let url = mediaTarget.dataset.previewImage || mediaTarget.getAttribute( 'src' );
if( url ) {
this.previewImage( url, mediaTarget.dataset.previewFit );
event.preventDefault();
}
}
else if( mediaTarget.hasAttribute( 'data-preview-video' ) ) {
let url = mediaTarget.dataset.previewVideo || mediaTarget.getAttribute( 'src' );
if( !url ) {
let source = mediaTarget.querySelector( 'source' );
if( source ) {
url = source.getAttribute( 'src' );
}
}
if( url ) {
this.previewVideo( url, mediaTarget.dataset.previewFit );
event.preventDefault();
}
}
}
}
destroy() {
this.close();
}
}