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authorDavid Thompson <dthompson2@worcester.edu>2024-06-24 13:49:08 -0400
committerDavid Thompson <dthompson2@worcester.edu>2024-06-24 13:52:17 -0400
commitd283f7e661e14d6ae1881fe803e5b4f1ed0689ff (patch)
tree84d3811c6dcb7d7f02aecadad7b2dfacce83bd4f /2024-06-18-guix-social/reveal.js/plugin/notes/speaker-view.html
parent3d9dcd3099fb252fa35697148fbbd541eb9eecc9 (diff)
Add 2024 Guix social talk.HEADmaster
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+<!--
+ NOTE: You need to build the notes plugin after making changes to this file.
+-->
+<html lang="en">
+ <head>
+ <meta charset="utf-8">
+
+ <title>reveal.js - Speaker View</title>
+
+ <style>
+ body {
+ font-family: Helvetica;
+ font-size: 18px;
+ }
+
+ #current-slide,
+ #upcoming-slide,
+ #speaker-controls {
+ padding: 6px;
+ box-sizing: border-box;
+ -moz-box-sizing: border-box;
+ }
+
+ #current-slide iframe,
+ #upcoming-slide iframe {
+ width: 100%;
+ height: 100%;
+ border: 1px solid #ddd;
+ }
+
+ #current-slide .label,
+ #upcoming-slide .label {
+ position: absolute;
+ top: 10px;
+ left: 10px;
+ z-index: 2;
+ }
+
+ #connection-status {
+ position: absolute;
+ top: 0;
+ left: 0;
+ width: 100%;
+ height: 100%;
+ z-index: 20;
+ padding: 30% 20% 20% 20%;
+ font-size: 18px;
+ color: #222;
+ background: #fff;
+ text-align: center;
+ box-sizing: border-box;
+ line-height: 1.4;
+ }
+
+ .overlay-element {
+ height: 34px;
+ line-height: 34px;
+ padding: 0 10px;
+ text-shadow: none;
+ background: rgba( 220, 220, 220, 0.8 );
+ color: #222;
+ font-size: 14px;
+ }
+
+ .overlay-element.interactive:hover {
+ background: rgba( 220, 220, 220, 1 );
+ }
+
+ #current-slide {
+ position: absolute;
+ width: 60%;
+ height: 100%;
+ top: 0;
+ left: 0;
+ padding-right: 0;
+ }
+
+ #upcoming-slide {
+ position: absolute;
+ width: 40%;
+ height: 40%;
+ right: 0;
+ top: 0;
+ }
+
+ /* Speaker controls */
+ #speaker-controls {
+ position: absolute;
+ top: 40%;
+ right: 0;
+ width: 40%;
+ height: 60%;
+ overflow: auto;
+ font-size: 18px;
+ }
+
+ .speaker-controls-time.hidden,
+ .speaker-controls-notes.hidden {
+ display: none;
+ }
+
+ .speaker-controls-time .label,
+ .speaker-controls-pace .label,
+ .speaker-controls-notes .label {
+ text-transform: uppercase;
+ font-weight: normal;
+ font-size: 0.66em;
+ color: #666;
+ margin: 0;
+ }
+
+ .speaker-controls-time, .speaker-controls-pace {
+ border-bottom: 1px solid rgba( 200, 200, 200, 0.5 );
+ margin-bottom: 10px;
+ padding: 10px 16px;
+ padding-bottom: 20px;
+ cursor: pointer;
+ }
+
+ .speaker-controls-time .reset-button {
+ opacity: 0;
+ float: right;
+ color: #666;
+ text-decoration: none;
+ }
+ .speaker-controls-time:hover .reset-button {
+ opacity: 1;
+ }
+
+ .speaker-controls-time .timer,
+ .speaker-controls-time .clock {
+ width: 50%;
+ }
+
+ .speaker-controls-time .timer,
+ .speaker-controls-time .clock,
+ .speaker-controls-time .pacing .hours-value,
+ .speaker-controls-time .pacing .minutes-value,
+ .speaker-controls-time .pacing .seconds-value {
+ font-size: 1.9em;
+ }
+
+ .speaker-controls-time .timer {
+ float: left;
+ }
+
+ .speaker-controls-time .clock {
+ float: right;
+ text-align: right;
+ }
+
+ .speaker-controls-time span.mute {
+ opacity: 0.3;
+ }
+
+ .speaker-controls-time .pacing-title {
+ margin-top: 5px;
+ }
+
+ .speaker-controls-time .pacing.ahead {
+ color: blue;
+ }
+
+ .speaker-controls-time .pacing.on-track {
+ color: green;
+ }
+
+ .speaker-controls-time .pacing.behind {
+ color: red;
+ }
+
+ .speaker-controls-notes {
+ padding: 10px 16px;
+ }
+
+ .speaker-controls-notes .value {
+ margin-top: 5px;
+ line-height: 1.4;
+ font-size: 1.2em;
+ }
+
+ /* Layout selector */
+ #speaker-layout {
+ position: absolute;
+ top: 10px;
+ right: 10px;
+ color: #222;
+ z-index: 10;
+ }
+ #speaker-layout select {
+ position: absolute;
+ width: 100%;
+ height: 100%;
+ top: 0;
+ left: 0;
+ border: 0;
+ box-shadow: 0;
+ cursor: pointer;
+ opacity: 0;
+
+ font-size: 1em;
+ background-color: transparent;
+
+ -moz-appearance: none;
+ -webkit-appearance: none;
+ -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
+ }
+
+ #speaker-layout select:focus {
+ outline: none;
+ box-shadow: none;
+ }
+
+ .clear {
+ clear: both;
+ }
+
+ /* Speaker layout: Wide */
+ body[data-speaker-layout="wide"] #current-slide,
+ body[data-speaker-layout="wide"] #upcoming-slide {
+ width: 50%;
+ height: 45%;
+ padding: 6px;
+ }
+
+ body[data-speaker-layout="wide"] #current-slide {
+ top: 0;
+ left: 0;
+ }
+
+ body[data-speaker-layout="wide"] #upcoming-slide {
+ top: 0;
+ left: 50%;
+ }
+
+ body[data-speaker-layout="wide"] #speaker-controls {
+ top: 45%;
+ left: 0;
+ width: 100%;
+ height: 50%;
+ font-size: 1.25em;
+ }
+
+ /* Speaker layout: Tall */
+ body[data-speaker-layout="tall"] #current-slide,
+ body[data-speaker-layout="tall"] #upcoming-slide {
+ width: 45%;
+ height: 50%;
+ padding: 6px;
+ }
+
+ body[data-speaker-layout="tall"] #current-slide {
+ top: 0;
+ left: 0;
+ }
+
+ body[data-speaker-layout="tall"] #upcoming-slide {
+ top: 50%;
+ left: 0;
+ }
+
+ body[data-speaker-layout="tall"] #speaker-controls {
+ padding-top: 40px;
+ top: 0;
+ left: 45%;
+ width: 55%;
+ height: 100%;
+ font-size: 1.25em;
+ }
+
+ /* Speaker layout: Notes only */
+ body[data-speaker-layout="notes-only"] #current-slide,
+ body[data-speaker-layout="notes-only"] #upcoming-slide {
+ display: none;
+ }
+
+ body[data-speaker-layout="notes-only"] #speaker-controls {
+ padding-top: 40px;
+ top: 0;
+ left: 0;
+ width: 100%;
+ height: 100%;
+ font-size: 1.25em;
+ }
+
+ @media screen and (max-width: 1080px) {
+ body[data-speaker-layout="default"] #speaker-controls {
+ font-size: 16px;
+ }
+ }
+
+ @media screen and (max-width: 900px) {
+ body[data-speaker-layout="default"] #speaker-controls {
+ font-size: 14px;
+ }
+ }
+
+ @media screen and (max-width: 800px) {
+ body[data-speaker-layout="default"] #speaker-controls {
+ font-size: 12px;
+ }
+ }
+
+ </style>
+ </head>
+
+ <body>
+
+ <div id="connection-status">Loading speaker view...</div>
+
+ <div id="current-slide"></div>
+ <div id="upcoming-slide"><span class="overlay-element label">Upcoming</span></div>
+ <div id="speaker-controls">
+ <div class="speaker-controls-time">
+ <h4 class="label">Time <span class="reset-button">Click to Reset</span></h4>
+ <div class="clock">
+ <span class="clock-value">0:00 AM</span>
+ </div>
+ <div class="timer">
+ <span class="hours-value">00</span><span class="minutes-value">:00</span><span class="seconds-value">:00</span>
+ </div>
+ <div class="clear"></div>
+
+ <h4 class="label pacing-title" style="display: none">Pacing – Time to finish current slide</h4>
+ <div class="pacing" style="display: none">
+ <span class="hours-value">00</span><span class="minutes-value">:00</span><span class="seconds-value">:00</span>
+ </div>
+ </div>
+
+ <div class="speaker-controls-notes hidden">
+ <h4 class="label">Notes</h4>
+ <div class="value"></div>
+ </div>
+ </div>
+ <div id="speaker-layout" class="overlay-element interactive">
+ <span class="speaker-layout-label"></span>
+ <select class="speaker-layout-dropdown"></select>
+ </div>
+
+ <script>
+
+ (function() {
+
+ var notes,
+ notesValue,
+ currentState,
+ currentSlide,
+ upcomingSlide,
+ layoutLabel,
+ layoutDropdown,
+ pendingCalls = {},
+ lastRevealApiCallId = 0,
+ connected = false
+
+ var connectionStatus = document.querySelector( '#connection-status' );
+
+ var SPEAKER_LAYOUTS = {
+ 'default': 'Default',
+ 'wide': 'Wide',
+ 'tall': 'Tall',
+ 'notes-only': 'Notes only'
+ };
+
+ setupLayout();
+
+ let openerOrigin;
+
+ try {
+ openerOrigin = window.opener.location.origin;
+ }
+ catch ( error ) { console.warn( error ) }
+
+ // In order to prevent XSS, the speaker view will only run if its
+ // opener has the same origin as itself
+ if( window.location.origin !== openerOrigin ) {
+ connectionStatus.innerHTML = 'Cross origin error.<br>The speaker window can only be opened from the same origin.';
+ return;
+ }
+
+ var connectionTimeout = setTimeout( function() {
+ connectionStatus.innerHTML = 'Error connecting to main window.<br>Please try closing and reopening the speaker view.';
+ }, 5000 );
+
+ window.addEventListener( 'message', function( event ) {
+
+ // Validate the origin of all messages to avoid parsing messages
+ // that aren't meant for us. Ignore when running off file:// so
+ // that the speaker view continues to work without a web server.
+ if( window.location.origin !== event.origin && window.location.origin !== 'file://' ) {
+ return
+ }
+
+ clearTimeout( connectionTimeout );
+ connectionStatus.style.display = 'none';
+
+ var data = JSON.parse( event.data );
+
+ // The overview mode is only useful to the reveal.js instance
+ // where navigation occurs so we don't sync it
+ if( data.state ) delete data.state.overview;
+
+ // Messages sent by the notes plugin inside of the main window
+ if( data && data.namespace === 'reveal-notes' ) {
+ if( data.type === 'connect' ) {
+ handleConnectMessage( data );
+ }
+ else if( data.type === 'state' ) {
+ handleStateMessage( data );
+ }
+ else if( data.type === 'return' ) {
+ pendingCalls[data.callId](data.result);
+ delete pendingCalls[data.callId];
+ }
+ }
+ // Messages sent by the reveal.js inside of the current slide preview
+ else if( data && data.namespace === 'reveal' ) {
+ if( /ready/.test( data.eventName ) ) {
+ // Send a message back to notify that the handshake is complete
+ window.opener.postMessage( JSON.stringify({ namespace: 'reveal-notes', type: 'connected'} ), '*' );
+ }
+ else if( /slidechanged|fragmentshown|fragmenthidden|paused|resumed/.test( data.eventName ) && currentState !== JSON.stringify( data.state ) ) {
+
+ dispatchStateToMainWindow( data.state );
+
+ }
+ }
+
+ } );
+
+ /**
+ * Updates the presentation in the main window to match the state
+ * of the presentation in the notes window.
+ */
+ const dispatchStateToMainWindow = debounce(( state ) => {
+ window.opener.postMessage( JSON.stringify({ method: 'setState', args: [ state ]} ), '*' );
+ }, 500);
+
+ /**
+ * Asynchronously calls the Reveal.js API of the main frame.
+ */
+ function callRevealApi( methodName, methodArguments, callback ) {
+
+ var callId = ++lastRevealApiCallId;
+ pendingCalls[callId] = callback;
+ window.opener.postMessage( JSON.stringify( {
+ namespace: 'reveal-notes',
+ type: 'call',
+ callId: callId,
+ methodName: methodName,
+ arguments: methodArguments
+ } ), '*' );
+
+ }
+
+ /**
+ * Called when the main window is trying to establish a
+ * connection.
+ */
+ function handleConnectMessage( data ) {
+
+ if( connected === false ) {
+ connected = true;
+
+ setupIframes( data );
+ setupKeyboard();
+ setupNotes();
+ setupTimer();
+ setupHeartbeat();
+ }
+
+ }
+
+ /**
+ * Called when the main window sends an updated state.
+ */
+ function handleStateMessage( data ) {
+
+ // Store the most recently set state to avoid circular loops
+ // applying the same state
+ currentState = JSON.stringify( data.state );
+
+ // No need for updating the notes in case of fragment changes
+ if ( data.notes ) {
+ notes.classList.remove( 'hidden' );
+ notesValue.style.whiteSpace = data.whitespace;
+ if( data.markdown ) {
+ notesValue.innerHTML = marked( data.notes );
+ }
+ else {
+ notesValue.innerHTML = data.notes;
+ }
+ }
+ else {
+ notes.classList.add( 'hidden' );
+ }
+
+ // Update the note slides
+ currentSlide.contentWindow.postMessage( JSON.stringify({ method: 'setState', args: [ data.state ] }), '*' );
+ upcomingSlide.contentWindow.postMessage( JSON.stringify({ method: 'setState', args: [ data.state ] }), '*' );
+ upcomingSlide.contentWindow.postMessage( JSON.stringify({ method: 'next' }), '*' );
+
+ }
+
+ // Limit to max one state update per X ms
+ handleStateMessage = debounce( handleStateMessage, 200 );
+
+ /**
+ * Forward keyboard events to the current slide window.
+ * This enables keyboard events to work even if focus
+ * isn't set on the current slide iframe.
+ *
+ * Block F5 default handling, it reloads and disconnects
+ * the speaker notes window.
+ */
+ function setupKeyboard() {
+
+ document.addEventListener( 'keydown', function( event ) {
+ if( event.keyCode === 116 || ( event.metaKey && event.keyCode === 82 ) ) {
+ event.preventDefault();
+ return false;
+ }
+ currentSlide.contentWindow.postMessage( JSON.stringify({ method: 'triggerKey', args: [ event.keyCode ] }), '*' );
+ } );
+
+ }
+
+ /**
+ * Creates the preview iframes.
+ */
+ function setupIframes( data ) {
+
+ var params = [
+ 'receiver',
+ 'progress=false',
+ 'history=false',
+ 'transition=none',
+ 'autoSlide=0',
+ 'backgroundTransition=none'
+ ].join( '&' );
+
+ var urlSeparator = /\?/.test(data.url) ? '&' : '?';
+ var hash = '#/' + data.state.indexh + '/' + data.state.indexv;
+ var currentURL = data.url + urlSeparator + params + '&scrollActivationWidth=false&postMessageEvents=true' + hash;
+ var upcomingURL = data.url + urlSeparator + params + '&scrollActivationWidth=false&controls=false' + hash;
+
+ currentSlide = document.createElement( 'iframe' );
+ currentSlide.setAttribute( 'width', 1280 );
+ currentSlide.setAttribute( 'height', 1024 );
+ currentSlide.setAttribute( 'src', currentURL );
+ document.querySelector( '#current-slide' ).appendChild( currentSlide );
+
+ upcomingSlide = document.createElement( 'iframe' );
+ upcomingSlide.setAttribute( 'width', 640 );
+ upcomingSlide.setAttribute( 'height', 512 );
+ upcomingSlide.setAttribute( 'src', upcomingURL );
+ document.querySelector( '#upcoming-slide' ).appendChild( upcomingSlide );
+
+ }
+
+ /**
+ * Setup the notes UI.
+ */
+ function setupNotes() {
+
+ notes = document.querySelector( '.speaker-controls-notes' );
+ notesValue = document.querySelector( '.speaker-controls-notes .value' );
+
+ }
+
+ /**
+ * We send out a heartbeat at all times to ensure we can
+ * reconnect with the main presentation window after reloads.
+ */
+ function setupHeartbeat() {
+
+ setInterval( () => {
+ window.opener.postMessage( JSON.stringify({ namespace: 'reveal-notes', type: 'heartbeat'} ), '*' );
+ }, 1000 );
+
+ }
+
+ function getTimings( callback ) {
+
+ callRevealApi( 'getSlidesAttributes', [], function ( slideAttributes ) {
+ callRevealApi( 'getConfig', [], function ( config ) {
+ var totalTime = config.totalTime;
+ var minTimePerSlide = config.minimumTimePerSlide || 0;
+ var defaultTiming = config.defaultTiming;
+ if ((defaultTiming == null) && (totalTime == null)) {
+ callback(null);
+ return;
+ }
+ // Setting totalTime overrides defaultTiming
+ if (totalTime) {
+ defaultTiming = 0;
+ }
+ var timings = [];
+ for ( var i in slideAttributes ) {
+ var slide = slideAttributes[ i ];
+ var timing = defaultTiming;
+ if( slide.hasOwnProperty( 'data-timing' )) {
+ var t = slide[ 'data-timing' ];
+ timing = parseInt(t);
+ if( isNaN(timing) ) {
+ console.warn("Could not parse timing '" + t + "' of slide " + i + "; using default of " + defaultTiming);
+ timing = defaultTiming;
+ }
+ }
+ timings.push(timing);
+ }
+ if ( totalTime ) {
+ // After we've allocated time to individual slides, we summarize it and
+ // subtract it from the total time
+ var remainingTime = totalTime - timings.reduce( function(a, b) { return a + b; }, 0 );
+ // The remaining time is divided by the number of slides that have 0 seconds
+ // allocated at the moment, giving the average time-per-slide on the remaining slides
+ var remainingSlides = (timings.filter( function(x) { return x == 0 }) ).length
+ var timePerSlide = Math.round( remainingTime / remainingSlides, 0 )
+ // And now we replace every zero-value timing with that average
+ timings = timings.map( function(x) { return (x==0 ? timePerSlide : x) } );
+ }
+ var slidesUnderMinimum = timings.filter( function(x) { return (x < minTimePerSlide) } ).length
+ if ( slidesUnderMinimum ) {
+ message = "The pacing time for " + slidesUnderMinimum + " slide(s) is under the configured minimum of " + minTimePerSlide + " seconds. Check the data-timing attribute on individual slides, or consider increasing the totalTime or minimumTimePerSlide configuration options (or removing some slides).";
+ alert(message);
+ }
+ callback( timings );
+ } );
+ } );
+
+ }
+
+ /**
+ * Return the number of seconds allocated for presenting
+ * all slides up to and including this one.
+ */
+ function getTimeAllocated( timings, callback ) {
+
+ callRevealApi( 'getSlidePastCount', [], function ( currentSlide ) {
+ var allocated = 0;
+ for (var i in timings.slice(0, currentSlide + 1)) {
+ allocated += timings[i];
+ }
+ callback( allocated );
+ } );
+
+ }
+
+ /**
+ * Create the timer and clock and start updating them
+ * at an interval.
+ */
+ function setupTimer() {
+
+ var start = new Date(),
+ timeEl = document.querySelector( '.speaker-controls-time' ),
+ clockEl = timeEl.querySelector( '.clock-value' ),
+ hoursEl = timeEl.querySelector( '.hours-value' ),
+ minutesEl = timeEl.querySelector( '.minutes-value' ),
+ secondsEl = timeEl.querySelector( '.seconds-value' ),
+ pacingTitleEl = timeEl.querySelector( '.pacing-title' ),
+ pacingEl = timeEl.querySelector( '.pacing' ),
+ pacingHoursEl = pacingEl.querySelector( '.hours-value' ),
+ pacingMinutesEl = pacingEl.querySelector( '.minutes-value' ),
+ pacingSecondsEl = pacingEl.querySelector( '.seconds-value' );
+
+ var timings = null;
+ getTimings( function ( _timings ) {
+
+ timings = _timings;
+ if (_timings !== null) {
+ pacingTitleEl.style.removeProperty('display');
+ pacingEl.style.removeProperty('display');
+ }
+
+ // Update once directly
+ _updateTimer();
+
+ // Then update every second
+ setInterval( _updateTimer, 1000 );
+
+ } );
+
+
+ function _resetTimer() {
+
+ if (timings == null) {
+ start = new Date();
+ _updateTimer();
+ }
+ else {
+ // Reset timer to beginning of current slide
+ getTimeAllocated( timings, function ( slideEndTimingSeconds ) {
+ var slideEndTiming = slideEndTimingSeconds * 1000;
+ callRevealApi( 'getSlidePastCount', [], function ( currentSlide ) {
+ var currentSlideTiming = timings[currentSlide] * 1000;
+ var previousSlidesTiming = slideEndTiming - currentSlideTiming;
+ var now = new Date();
+ start = new Date(now.getTime() - previousSlidesTiming);
+ _updateTimer();
+ } );
+ } );
+ }
+
+ }
+
+ timeEl.addEventListener( 'click', function() {
+ _resetTimer();
+ return false;
+ } );
+
+ function _displayTime( hrEl, minEl, secEl, time) {
+
+ var sign = Math.sign(time) == -1 ? "-" : "";
+ time = Math.abs(Math.round(time / 1000));
+ var seconds = time % 60;
+ var minutes = Math.floor( time / 60 ) % 60 ;
+ var hours = Math.floor( time / ( 60 * 60 )) ;
+ hrEl.innerHTML = sign + zeroPadInteger( hours );
+ if (hours == 0) {
+ hrEl.classList.add( 'mute' );
+ }
+ else {
+ hrEl.classList.remove( 'mute' );
+ }
+ minEl.innerHTML = ':' + zeroPadInteger( minutes );
+ if (hours == 0 && minutes == 0) {
+ minEl.classList.add( 'mute' );
+ }
+ else {
+ minEl.classList.remove( 'mute' );
+ }
+ secEl.innerHTML = ':' + zeroPadInteger( seconds );
+ }
+
+ function _updateTimer() {
+
+ var diff, hours, minutes, seconds,
+ now = new Date();
+
+ diff = now.getTime() - start.getTime();
+
+ clockEl.innerHTML = now.toLocaleTimeString( 'en-US', { hour12: true, hour: '2-digit', minute:'2-digit' } );
+ _displayTime( hoursEl, minutesEl, secondsEl, diff );
+ if (timings !== null) {
+ _updatePacing(diff);
+ }
+
+ }
+
+ function _updatePacing(diff) {
+
+ getTimeAllocated( timings, function ( slideEndTimingSeconds ) {
+ var slideEndTiming = slideEndTimingSeconds * 1000;
+
+ callRevealApi( 'getSlidePastCount', [], function ( currentSlide ) {
+ var currentSlideTiming = timings[currentSlide] * 1000;
+ var timeLeftCurrentSlide = slideEndTiming - diff;
+ if (timeLeftCurrentSlide < 0) {
+ pacingEl.className = 'pacing behind';
+ }
+ else if (timeLeftCurrentSlide < currentSlideTiming) {
+ pacingEl.className = 'pacing on-track';
+ }
+ else {
+ pacingEl.className = 'pacing ahead';
+ }
+ _displayTime( pacingHoursEl, pacingMinutesEl, pacingSecondsEl, timeLeftCurrentSlide );
+ } );
+ } );
+ }
+
+ }
+
+ /**
+ * Sets up the speaker view layout and layout selector.
+ */
+ function setupLayout() {
+
+ layoutDropdown = document.querySelector( '.speaker-layout-dropdown' );
+ layoutLabel = document.querySelector( '.speaker-layout-label' );
+
+ // Render the list of available layouts
+ for( var id in SPEAKER_LAYOUTS ) {
+ var option = document.createElement( 'option' );
+ option.setAttribute( 'value', id );
+ option.textContent = SPEAKER_LAYOUTS[ id ];
+ layoutDropdown.appendChild( option );
+ }
+
+ // Monitor the dropdown for changes
+ layoutDropdown.addEventListener( 'change', function( event ) {
+
+ setLayout( layoutDropdown.value );
+
+ }, false );
+
+ // Restore any currently persisted layout
+ setLayout( getLayout() );
+
+ }
+
+ /**
+ * Sets a new speaker view layout. The layout is persisted
+ * in local storage.
+ */
+ function setLayout( value ) {
+
+ var title = SPEAKER_LAYOUTS[ value ];
+
+ layoutLabel.innerHTML = 'Layout' + ( title ? ( ': ' + title ) : '' );
+ layoutDropdown.value = value;
+
+ document.body.setAttribute( 'data-speaker-layout', value );
+
+ // Persist locally
+ if( supportsLocalStorage() ) {
+ window.localStorage.setItem( 'reveal-speaker-layout', value );
+ }
+
+ }
+
+ /**
+ * Returns the ID of the most recently set speaker layout
+ * or our default layout if none has been set.
+ */
+ function getLayout() {
+
+ if( supportsLocalStorage() ) {
+ var layout = window.localStorage.getItem( 'reveal-speaker-layout' );
+ if( layout ) {
+ return layout;
+ }
+ }
+
+ // Default to the first record in the layouts hash
+ for( var id in SPEAKER_LAYOUTS ) {
+ return id;
+ }
+
+ }
+
+ function supportsLocalStorage() {
+
+ try {
+ localStorage.setItem('test', 'test');
+ localStorage.removeItem('test');
+ return true;
+ }
+ catch( e ) {
+ return false;
+ }
+
+ }
+
+ function zeroPadInteger( num ) {
+
+ var str = '00' + parseInt( num );
+ return str.substring( str.length - 2 );
+
+ }
+
+ /**
+ * Limits the frequency at which a function can be called.
+ */
+ function debounce( fn, ms ) {
+
+ var lastTime = 0,
+ timeout;
+
+ return function() {
+
+ var args = arguments;
+ var context = this;
+
+ clearTimeout( timeout );
+
+ var timeSinceLastCall = Date.now() - lastTime;
+ if( timeSinceLastCall > ms ) {
+ fn.apply( context, args );
+ lastTime = Date.now();
+ }
+ else {
+ timeout = setTimeout( function() {
+ fn.apply( context, args );
+ lastTime = Date.now();
+ }, ms - timeSinceLastCall );
+ }
+
+ }
+
+ }
+
+ })();
+
+ </script>
+ </body>
+</html> \ No newline at end of file