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1
/*!
2
 * reveal.js
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 * http://revealjs.com
4
 * MIT licensed
5
 *
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 * Copyright (C) 2017 Hakim El Hattab, http://hakim.se
7
 */
8
(function( root, factory ) {
9
	if( typeof define === 'function' && define.amd ) {
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		// AMD. Register as an anonymous module.
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		define( function() {
12
			root.Reveal = factory();
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			return root.Reveal;
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		} );
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	} else if( typeof exports === 'object' ) {
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		// Node. Does not work with strict CommonJS.
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		module.exports = factory();
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	} else {
19
		// Browser globals.
20
		root.Reveal = factory();
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	}
22
}( this, function() {
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24
	'use strict';
25

26
	var Reveal;
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28
	// The reveal.js version
29
	var VERSION = '3.6.0';
30

31
	var SLIDES_SELECTOR = '.slides section',
32
		HORIZONTAL_SLIDES_SELECTOR = '.slides>section',
33
		VERTICAL_SLIDES_SELECTOR = '.slides>section.present>section',
34
		HOME_SLIDE_SELECTOR = '.slides>section:first-of-type',
35
		UA = navigator.userAgent,
36

37
		// Configuration defaults, can be overridden at initialization time
38
		config = {
39

40
			// The "normal" size of the presentation, aspect ratio will be preserved
41
			// when the presentation is scaled to fit different resolutions
42
			width: 960,
43
			height: 700,
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45
			// Factor of the display size that should remain empty around the content
46
			margin: 0.04,
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48
			// Bounds for smallest/largest possible scale to apply to content
49
			minScale: 0.2,
50
			maxScale: 2.0,
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52
			// Display presentation control arrows
53
			controls: true,
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55
			// Help the user learn the controls by providing hints, for example by
56
			// bouncing the down arrow when they first encounter a vertical slide
57
			controlsTutorial: true,
58

59
			// Determines where controls appear, "edges" or "bottom-right"
60
			controlsLayout: 'bottom-right',
61

62
			// Visibility rule for backwards navigation arrows; "faded", "hidden"
63
			// or "visible"
64
			controlsBackArrows: 'faded',
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66
			// Display a presentation progress bar
67
			progress: true,
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69
			// Display the page number of the current slide
70
			slideNumber: false,
71

72
			// Determine which displays to show the slide number on
73
			showSlideNumber: 'all',
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75
			// Push each slide change to the browser history
76
			history: false,
77

78
			// Enable keyboard shortcuts for navigation
79
			keyboard: true,
80

81
			// Optional function that blocks keyboard events when retuning false
82
			keyboardCondition: null,
83

84
			// Enable the slide overview mode
85
			overview: true,
86

87
			// Vertical centering of slides
88
			center: true,
89

90
			// Enables touch navigation on devices with touch input
91
			touch: true,
92

93
			// Loop the presentation
94
			loop: false,
95

96
			// Change the presentation direction to be RTL
97
			rtl: false,
98

99
			// Randomizes the order of slides each time the presentation loads
100
			shuffle: false,
101

102
			// Turns fragments on and off globally
103
			fragments: true,
104

105
			// Flags if the presentation is running in an embedded mode,
106
			// i.e. contained within a limited portion of the screen
107
			embedded: false,
108

109
			// Flags if we should show a help overlay when the question-mark
110
			// key is pressed
111
			help: true,
112

113
			// Flags if it should be possible to pause the presentation (blackout)
114
			pause: true,
115

116
			// Flags if speaker notes should be visible to all viewers
117
			showNotes: false,
118

119
			// Global override for autolaying embedded media (video/audio/iframe)
120
			// - null:   Media will only autoplay if data-autoplay is present
121
			// - true:   All media will autoplay, regardless of individual setting
122
			// - false:  No media will autoplay, regardless of individual setting
123
			autoPlayMedia: null,
124

125
			// Controls automatic progression to the next slide
126
			// - 0:      Auto-sliding only happens if the data-autoslide HTML attribute
127
			//           is present on the current slide or fragment
128
			// - 1+:     All slides will progress automatically at the given interval
129
			// - false:  No auto-sliding, even if data-autoslide is present
130
			autoSlide: 0,
131

132
			// Stop auto-sliding after user input
133
			autoSlideStoppable: true,
134

135
			// Use this method for navigation when auto-sliding (defaults to navigateNext)
136
			autoSlideMethod: null,
137

138
			// Enable slide navigation via mouse wheel
139
			mouseWheel: false,
140

141
			// Apply a 3D roll to links on hover
142
			rollingLinks: false,
143

144
			// Hides the address bar on mobile devices
145
			hideAddressBar: true,
146

147
			// Opens links in an iframe preview overlay
148
			previewLinks: false,
149

150
			// Exposes the reveal.js API through window.postMessage
151
			postMessage: true,
152

153
			// Dispatches all reveal.js events to the parent window through postMessage
154
			postMessageEvents: false,
155

156
			// Focuses body when page changes visibility to ensure keyboard shortcuts work
157
			focusBodyOnPageVisibilityChange: true,
158

159
			// Transition style
160
			transition: 'slide', // none/fade/slide/convex/concave/zoom
161

162
			// Transition speed
163
			transitionSpeed: 'default', // default/fast/slow
164

165
			// Transition style for full page slide backgrounds
166
			backgroundTransition: 'fade', // none/fade/slide/convex/concave/zoom
167

168
			// Parallax background image
169
			parallaxBackgroundImage: '', // CSS syntax, e.g. "a.jpg"
170

171
			// Parallax background size
172
			parallaxBackgroundSize: '', // CSS syntax, e.g. "3000px 2000px"
173

174
			// Amount of pixels to move the parallax background per slide step
175
			parallaxBackgroundHorizontal: null,
176
			parallaxBackgroundVertical: null,
177

178
			// The maximum number of pages a single slide can expand onto when printing
179
			// to PDF, unlimited by default
180
			pdfMaxPagesPerSlide: Number.POSITIVE_INFINITY,
181

182
			// Offset used to reduce the height of content within exported PDF pages.
183
			// This exists to account for environment differences based on how you
184
			// print to PDF. CLI printing options, like phantomjs and wkpdf, can end
185
			// on precisely the total height of the document whereas in-browser
186
			// printing has to end one pixel before.
187
			pdfPageHeightOffset: -1,
188

189
			// Number of slides away from the current that are visible
190
			viewDistance: 3,
191

192
			// The display mode that will be used to show slides
193
			display: 'block',
194

195
			// Script dependencies to load
196
			dependencies: []
197

198
		},
199

200
		// Flags if Reveal.initialize() has been called
201
		initialized = false,
202

203
		// Flags if reveal.js is loaded (has dispatched the 'ready' event)
204
		loaded = false,
205

206
		// Flags if the overview mode is currently active
207
		overview = false,
208

209
		// Holds the dimensions of our overview slides, including margins
210
		overviewSlideWidth = null,
211
		overviewSlideHeight = null,
212

213
		// The horizontal and vertical index of the currently active slide
214
		indexh,
215
		indexv,
216

217
		// The previous and current slide HTML elements
218
		previousSlide,
219
		currentSlide,
220

221
		previousBackground,
222

223
		// Remember which directions that the user has navigated towards
224
		hasNavigatedRight = false,
225
		hasNavigatedDown = false,
226

227
		// Slides may hold a data-state attribute which we pick up and apply
228
		// as a class to the body. This list contains the combined state of
229
		// all current slides.
230
		state = [],
231

232
		// The current scale of the presentation (see width/height config)
233
		scale = 1,
234

235
		// CSS transform that is currently applied to the slides container,
236
		// split into two groups
237
		slidesTransform = { layout: '', overview: '' },
238

239
		// Cached references to DOM elements
240
		dom = {},
241

242
		// Features supported by the browser, see #checkCapabilities()
243
		features = {},
244

245
		// Client is a mobile device, see #checkCapabilities()
246
		isMobileDevice,
247

248
		// Client is a desktop Chrome, see #checkCapabilities()
249
		isChrome,
250

251
		// Throttles mouse wheel navigation
252
		lastMouseWheelStep = 0,
253

254
		// Delays updates to the URL due to a Chrome thumbnailer bug
255
		writeURLTimeout = 0,
256

257
		// Flags if the interaction event listeners are bound
258
		eventsAreBound = false,
259

260
		// The current auto-slide duration
261
		autoSlide = 0,
262

263
		// Auto slide properties
264
		autoSlidePlayer,
265
		autoSlideTimeout = 0,
266
		autoSlideStartTime = -1,
267
		autoSlidePaused = false,
268

269
		// Holds information about the currently ongoing touch input
270
		touch = {
271
			startX: 0,
272
			startY: 0,
273
			startSpan: 0,
274
			startCount: 0,
275
			captured: false,
276
			threshold: 40
277
		},
278

279
		// Holds information about the keyboard shortcuts
280
		keyboardShortcuts = {
281
			'N  ,  SPACE':			'Next slide',
282
			'P':					'Previous slide',
283
			'←  ,  H':		'Navigate left',
284
			'→  ,  L':		'Navigate right',
285
			'↑  ,  K':		'Navigate up',
286
			'↓  ,  J':		'Navigate down',
287
			'Home':					'First slide',
288
			'End':					'Last slide',
289
			'B  ,  .':				'Pause',
290
			'F':					'Fullscreen',
291
			'ESC, O':				'Slide overview'
292
		};
293

294
	/**
295
	 * Starts up the presentation if the client is capable.
296
	 */
297
	function initialize( options ) {
298

299
		// Make sure we only initialize once
300
		if( initialized === true ) return;
301

302
		initialized = true;
303

304
		checkCapabilities();
305

306
		if( !features.transforms2d && !features.transforms3d ) {
307
			document.body.setAttribute( 'class', 'no-transforms' );
308

309
			// Since JS won't be running any further, we load all lazy
310
			// loading elements upfront
311
			var images = toArray( document.getElementsByTagName( 'img' ) ),
312
				iframes = toArray( document.getElementsByTagName( 'iframe' ) );
313

314
			var lazyLoadable = images.concat( iframes );
315

316
			for( var i = 0, len = lazyLoadable.length; i < len; i++ ) {
317
				var element = lazyLoadable[i];
318
				if( element.getAttribute( 'data-src' ) ) {
319
					element.setAttribute( 'src', element.getAttribute( 'data-src' ) );
320
					element.removeAttribute( 'data-src' );
321
				}
322
			}
323

324
			// If the browser doesn't support core features we won't be
325
			// using JavaScript to control the presentation
326
			return;
327
		}
328

329
		// Cache references to key DOM elements
330
		dom.wrapper = document.querySelector( '.reveal' );
331
		dom.slides = document.querySelector( '.reveal .slides' );
332

333
		// Force a layout when the whole page, incl fonts, has loaded
334
		window.addEventListener( 'load', layout, false );
335

336
		var query = Reveal.getQueryHash();
337

338
		// Do not accept new dependencies via query config to avoid
339
		// the potential of malicious script injection
340
		if( typeof query['dependencies'] !== 'undefined' ) delete query['dependencies'];
341

342
		// Copy options over to our config object
343
		extend( config, options );
344
		extend( config, query );
345

346
		// Hide the address bar in mobile browsers
347
		hideAddressBar();
348

349
		// Loads the dependencies and continues to #start() once done
350
		load();
351

352
	}
353

354
	/**
355
	 * Inspect the client to see what it's capable of, this
356
	 * should only happens once per runtime.
357
	 */
358
	function checkCapabilities() {
359

360
		isMobileDevice = /(iphone|ipod|ipad|android)/gi.test( UA );
361
		isChrome = /chrome/i.test( UA ) && !/edge/i.test( UA );
362

363
		var testElement = document.createElement( 'div' );
364

365
		features.transforms3d = 'WebkitPerspective' in testElement.style ||
366
								'MozPerspective' in testElement.style ||
367
								'msPerspective' in testElement.style ||
368
								'OPerspective' in testElement.style ||
369
								'perspective' in testElement.style;
370

371
		features.transforms2d = 'WebkitTransform' in testElement.style ||
372
								'MozTransform' in testElement.style ||
373
								'msTransform' in testElement.style ||
374
								'OTransform' in testElement.style ||
375
								'transform' in testElement.style;
376

377
		features.requestAnimationFrameMethod = window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame;
378
		features.requestAnimationFrame = typeof features.requestAnimationFrameMethod === 'function';
379

380
		features.canvas = !!document.createElement( 'canvas' ).getContext;
381

382
		// Transitions in the overview are disabled in desktop and
383
		// Safari due to lag
384
		features.overviewTransitions = !/Version\/[\d\.]+.*Safari/.test( UA );
385

386
		// Flags if we should use zoom instead of transform to scale
387
		// up slides. Zoom produces crisper results but has a lot of
388
		// xbrowser quirks so we only use it in whitelsited browsers.
389
		features.zoom = 'zoom' in testElement.style && !isMobileDevice &&
390
						( isChrome || /Version\/[\d\.]+.*Safari/.test( UA ) );
391

392
	}
393

394
    /**
395
     * Loads the dependencies of reveal.js. Dependencies are
396
     * defined via the configuration option 'dependencies'
397
     * and will be loaded prior to starting/binding reveal.js.
398
     * Some dependencies may have an 'async' flag, if so they
399
     * will load after reveal.js has been started up.
400
     */
401
	function load() {
402

403
		var scripts = [],
404
			scriptsAsync = [],
405
			scriptsToPreload = 0;
406

407
		// Called once synchronous scripts finish loading
408
		function proceed() {
409
			if( scriptsAsync.length ) {
410
				// Load asynchronous scripts
411
				head.js.apply( null, scriptsAsync );
412
			}
413

414
			start();
415
		}
416

417
		function loadScript( s ) {
418
			head.ready( s.src.match( /([\w\d_\-]*)\.?js$|[^\\\/]*$/i )[0], function() {
419
				// Extension may contain callback functions
420
				if( typeof s.callback === 'function' ) {
421
					s.callback.apply( this );
422
				}
423

424
				if( --scriptsToPreload === 0 ) {
425
					proceed();
426
				}
427
			});
428
		}
429

430
		for( var i = 0, len = config.dependencies.length; i < len; i++ ) {
431
			var s = config.dependencies[i];
432

433
			// Load if there's no condition or the condition is truthy
434
			if( !s.condition || s.condition() ) {
435
				if( s.async ) {
436
					scriptsAsync.push( s.src );
437
				}
438
				else {
439
					scripts.push( s.src );
440
				}
441

442
				loadScript( s );
443
			}
444
		}
445

446
		if( scripts.length ) {
447
			scriptsToPreload = scripts.length;
448

449
			// Load synchronous scripts
450
			head.js.apply( null, scripts );
451
		}
452
		else {
453
			proceed();
454
		}
455

456
	}
457

458
	/**
459
	 * Starts up reveal.js by binding input events and navigating
460
	 * to the current URL deeplink if there is one.
461
	 */
462
	function start() {
463

464
		loaded = true;
465

466
		// Make sure we've got all the DOM elements we need
467
		setupDOM();
468

469
		// Listen to messages posted to this window
470
		setupPostMessage();
471

472
		// Prevent the slides from being scrolled out of view
473
		setupScrollPrevention();
474

475
		// Resets all vertical slides so that only the first is visible
476
		resetVerticalSlides();
477

478
		// Updates the presentation to match the current configuration values
479
		configure();
480

481
		// Read the initial hash
482
		readURL();
483

484
		// Update all backgrounds
485
		updateBackground( true );
486

487
		// Notify listeners that the presentation is ready but use a 1ms
488
		// timeout to ensure it's not fired synchronously after #initialize()
489
		setTimeout( function() {
490
			// Enable transitions now that we're loaded
491
			dom.slides.classList.remove( 'no-transition' );
492

493
			dom.wrapper.classList.add( 'ready' );
494

495
			dispatchEvent( 'ready', {
496
				'indexh': indexh,
497
				'indexv': indexv,
498
				'currentSlide': currentSlide
499
			} );
500
		}, 1 );
501

502
		// Special setup and config is required when printing to PDF
503
		if( isPrintingPDF() ) {
504
			removeEventListeners();
505

506
			// The document needs to have loaded for the PDF layout
507
			// measurements to be accurate
508
			if( document.readyState === 'complete' ) {
509
				setupPDF();
510
			}
511
			else {
512
				window.addEventListener( 'load', setupPDF );
513
			}
514
		}
515

516
	}
517

518
	/**
519
	 * Finds and stores references to DOM elements which are
520
	 * required by the presentation. If a required element is
521
	 * not found, it is created.
522
	 */
523
	function setupDOM() {
524

525
		// Prevent transitions while we're loading
526
		dom.slides.classList.add( 'no-transition' );
527

528
		if( isMobileDevice ) {
529
			dom.wrapper.classList.add( 'no-hover' );
530
		}
531
		else {
532
			dom.wrapper.classList.remove( 'no-hover' );
533
		}
534

535
		if( /iphone/gi.test( UA ) ) {
536
			dom.wrapper.classList.add( 'ua-iphone' );
537
		}
538
		else {
539
			dom.wrapper.classList.remove( 'ua-iphone' );
540
		}
541

542
		// Background element
543
		dom.background = createSingletonNode( dom.wrapper, 'div', 'backgrounds', null );
544

545
		// Progress bar
546
		dom.progress = createSingletonNode( dom.wrapper, 'div', 'progress', '<span></span>' );
547
		dom.progressbar = dom.progress.querySelector( 'span' );
548

549
		// Arrow controls
550
		dom.controls = createSingletonNode( dom.wrapper, 'aside', 'controls',
551
			'<button class="navigate-left" aria-label="previous slide"><div class="controls-arrow"></div></button>' +
552
			'<button class="navigate-right" aria-label="next slide"><div class="controls-arrow"></div></button>' +
553
			'<button class="navigate-up" aria-label="above slide"><div class="controls-arrow"></div></button>' +
554
			'<button class="navigate-down" aria-label="below slide"><div class="controls-arrow"></div></button>' );
555

556
		// Slide number
557
		dom.slideNumber = createSingletonNode( dom.wrapper, 'div', 'slide-number', '' );
558

559
		// Element containing notes that are visible to the audience
560
		dom.speakerNotes = createSingletonNode( dom.wrapper, 'div', 'speaker-notes', null );
561
		dom.speakerNotes.setAttribute( 'data-prevent-swipe', '' );
562
		dom.speakerNotes.setAttribute( 'tabindex', '0' );
563

564
		// Overlay graphic which is displayed during the paused mode
565
		createSingletonNode( dom.wrapper, 'div', 'pause-overlay', null );
566

567
		dom.wrapper.setAttribute( 'role', 'application' );
568

569
		// There can be multiple instances of controls throughout the page
570
		dom.controlsLeft = toArray( document.querySelectorAll( '.navigate-left' ) );
571
		dom.controlsRight = toArray( document.querySelectorAll( '.navigate-right' ) );
572
		dom.controlsUp = toArray( document.querySelectorAll( '.navigate-up' ) );
573
		dom.controlsDown = toArray( document.querySelectorAll( '.navigate-down' ) );
574
		dom.controlsPrev = toArray( document.querySelectorAll( '.navigate-prev' ) );
575
		dom.controlsNext = toArray( document.querySelectorAll( '.navigate-next' ) );
576

577
		// The right and down arrows in the standard reveal.js controls
578
		dom.controlsRightArrow = dom.controls.querySelector( '.navigate-right' );
579
		dom.controlsDownArrow = dom.controls.querySelector( '.navigate-down' );
580

581
		dom.statusDiv = createStatusDiv();
582
	}
583

584
	/**
585
	 * Creates a hidden div with role aria-live to announce the
586
	 * current slide content. Hide the div off-screen to make it
587
	 * available only to Assistive Technologies.
588
	 *
589
	 * @return {HTMLElement}
590
	 */
591
	function createStatusDiv() {
592

593
		var statusDiv = document.getElementById( 'aria-status-div' );
594
		if( !statusDiv ) {
595
			statusDiv = document.createElement( 'div' );
596
			statusDiv.style.position = 'absolute';
597
			statusDiv.style.height = '1px';
598
			statusDiv.style.width = '1px';
599
			statusDiv.style.overflow = 'hidden';
600
			statusDiv.style.clip = 'rect( 1px, 1px, 1px, 1px )';
601
			statusDiv.setAttribute( 'id', 'aria-status-div' );
602
			statusDiv.setAttribute( 'aria-live', 'polite' );
603
			statusDiv.setAttribute( 'aria-atomic','true' );
604
			dom.wrapper.appendChild( statusDiv );
605
		}
606
		return statusDiv;
607

608
	}
609

610
	/**
611
	 * Converts the given HTML element into a string of text
612
	 * that can be announced to a screen reader. Hidden
613
	 * elements are excluded.
614
	 */
615
	function getStatusText( node ) {
616

617
		var text = '';
618

619
		// Text node
620
		if( node.nodeType === 3 ) {
621
			text += node.textContent;
622
		}
623
		// Element node
624
		else if( node.nodeType === 1 ) {
625

626
			var isAriaHidden = node.getAttribute( 'aria-hidden' );
627
			var isDisplayHidden = window.getComputedStyle( node )['display'] === 'none';
628
			if( isAriaHidden !== 'true' && !isDisplayHidden ) {
629

630
				toArray( node.childNodes ).forEach( function( child ) {
631
					text += getStatusText( child );
632
				} );
633

634
			}
635

636
		}
637

638
		return text;
639

640
	}
641

642
	/**
643
	 * Configures the presentation for printing to a static
644
	 * PDF.
645
	 */
646
	function setupPDF() {
647

648
		var slideSize = getComputedSlideSize( window.innerWidth, window.innerHeight );
649

650
		// Dimensions of the PDF pages
651
		var pageWidth = Math.floor( slideSize.width * ( 1 + config.margin ) ),
652
			pageHeight = Math.floor( slideSize.height * ( 1 + config.margin ) );
653

654
		// Dimensions of slides within the pages
655
		var slideWidth = slideSize.width,
656
			slideHeight = slideSize.height;
657

658
		// Let the browser know what page size we want to print
659
		injectStyleSheet( '@page{size:'+ pageWidth +'px '+ pageHeight +'px; margin: 0px;}' );
660

661
		// Limit the size of certain elements to the dimensions of the slide
662
		injectStyleSheet( '.reveal section>img, .reveal section>video, .reveal section>iframe{max-width: '+ slideWidth +'px; max-height:'+ slideHeight +'px}' );
663

664
		document.body.classList.add( 'print-pdf' );
665
		document.body.style.width = pageWidth + 'px';
666
		document.body.style.height = pageHeight + 'px';
667

668
		// Make sure stretch elements fit on slide
669
		layoutSlideContents( slideWidth, slideHeight );
670

671
		// Add each slide's index as attributes on itself, we need these
672
		// indices to generate slide numbers below
673
		toArray( dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) ).forEach( function( hslide, h ) {
674
			hslide.setAttribute( 'data-index-h', h );
675

676
			if( hslide.classList.contains( 'stack' ) ) {
677
				toArray( hslide.querySelectorAll( 'section' ) ).forEach( function( vslide, v ) {
678
					vslide.setAttribute( 'data-index-h', h );
679
					vslide.setAttribute( 'data-index-v', v );
680
				} );
681
			}
682
		} );
683

684
		// Slide and slide background layout
685
		toArray( dom.wrapper.querySelectorAll( SLIDES_SELECTOR ) ).forEach( function( slide ) {
686

687
			// Vertical stacks are not centred since their section
688
			// children will be
689
			if( slide.classList.contains( 'stack' ) === false ) {
690
				// Center the slide inside of the page, giving the slide some margin
691
				var left = ( pageWidth - slideWidth ) / 2,
692
					top = ( pageHeight - slideHeight ) / 2;
693

694
				var contentHeight = slide.scrollHeight;
695
				var numberOfPages = Math.max( Math.ceil( contentHeight / pageHeight ), 1 );
696

697
				// Adhere to configured pages per slide limit
698
				numberOfPages = Math.min( numberOfPages, config.pdfMaxPagesPerSlide );
699

700
				// Center slides vertically
701
				if( numberOfPages === 1 && config.center || slide.classList.contains( 'center' ) ) {
702
					top = Math.max( ( pageHeight - contentHeight ) / 2, 0 );
703
				}
704

705
				// Wrap the slide in a page element and hide its overflow
706
				// so that no page ever flows onto another
707
				var page = document.createElement( 'div' );
708
				page.className = 'pdf-page';
709
				page.style.height = ( ( pageHeight + config.pdfPageHeightOffset ) * numberOfPages ) + 'px';
710
				slide.parentNode.insertBefore( page, slide );
711
				page.appendChild( slide );
712

713
				// Position the slide inside of the page
714
				slide.style.left = left + 'px';
715
				slide.style.top = top + 'px';
716
				slide.style.width = slideWidth + 'px';
717

718
				if( slide.slideBackgroundElement ) {
719
					page.insertBefore( slide.slideBackgroundElement, slide );
720
				}
721

722
				// Inject notes if `showNotes` is enabled
723
				if( config.showNotes ) {
724

725
					// Are there notes for this slide?
726
					var notes = getSlideNotes( slide );
727
					if( notes ) {
728

729
						var notesSpacing = 8;
730
						var notesLayout = typeof config.showNotes === 'string' ? config.showNotes : 'inline';
731
						var notesElement = document.createElement( 'div' );
732
						notesElement.classList.add( 'speaker-notes' );
733
						notesElement.classList.add( 'speaker-notes-pdf' );
734
						notesElement.setAttribute( 'data-layout', notesLayout );
735
						notesElement.innerHTML = notes;
736

737
						if( notesLayout === 'separate-page' ) {
738
							page.parentNode.insertBefore( notesElement, page.nextSibling );
739
						}
740
						else {
741
							notesElement.style.left = notesSpacing + 'px';
742
							notesElement.style.bottom = notesSpacing + 'px';
743
							notesElement.style.width = ( pageWidth - notesSpacing*2 ) + 'px';
744
							page.appendChild( notesElement );
745
						}
746

747
					}
748

749
				}
750

751
				// Inject slide numbers if `slideNumbers` are enabled
752
				if( config.slideNumber && /all|print/i.test( config.showSlideNumber ) ) {
753
					var slideNumberH = parseInt( slide.getAttribute( 'data-index-h' ), 10 ) + 1,
754
						slideNumberV = parseInt( slide.getAttribute( 'data-index-v' ), 10 ) + 1;
755

756
					var numberElement = document.createElement( 'div' );
757
					numberElement.classList.add( 'slide-number' );
758
					numberElement.classList.add( 'slide-number-pdf' );
759
					numberElement.innerHTML = formatSlideNumber( slideNumberH, '.', slideNumberV );
760
					page.appendChild( numberElement );
761
				}
762
			}
763

764
		} );
765

766
		// Show all fragments
767
		toArray( dom.wrapper.querySelectorAll( SLIDES_SELECTOR + ' .fragment' ) ).forEach( function( fragment ) {
768
			fragment.classList.add( 'visible' );
769
		} );
770

771
		// Notify subscribers that the PDF layout is good to go
772
		dispatchEvent( 'pdf-ready' );
773

774
	}
775

776
	/**
777
	 * This is an unfortunate necessity. Some actions – such as
778
	 * an input field being focused in an iframe or using the
779
	 * keyboard to expand text selection beyond the bounds of
780
	 * a slide – can trigger our content to be pushed out of view.
781
	 * This scrolling can not be prevented by hiding overflow in
782
	 * CSS (we already do) so we have to resort to repeatedly
783
	 * checking if the slides have been offset :(
784
	 */
785
	function setupScrollPrevention() {
786

787
		setInterval( function() {
788
			if( dom.wrapper.scrollTop !== 0 || dom.wrapper.scrollLeft !== 0 ) {
789
				dom.wrapper.scrollTop = 0;
790
				dom.wrapper.scrollLeft = 0;
791
			}
792
		}, 1000 );
793

794
	}
795

796
	/**
797
	 * Creates an HTML element and returns a reference to it.
798
	 * If the element already exists the existing instance will
799
	 * be returned.
800
	 *
801
	 * @param {HTMLElement} container
802
	 * @param {string} tagname
803
	 * @param {string} classname
804
	 * @param {string} innerHTML
805
	 *
806
	 * @return {HTMLElement}
807
	 */
808
	function createSingletonNode( container, tagname, classname, innerHTML ) {
809

810
		// Find all nodes matching the description
811
		var nodes = container.querySelectorAll( '.' + classname );
812

813
		// Check all matches to find one which is a direct child of
814
		// the specified container
815
		for( var i = 0; i < nodes.length; i++ ) {
816
			var testNode = nodes[i];
817
			if( testNode.parentNode === container ) {
818
				return testNode;
819
			}
820
		}
821

822
		// If no node was found, create it now
823
		var node = document.createElement( tagname );
824
		node.className = classname;
825
		if( typeof innerHTML === 'string' ) {
826
			node.innerHTML = innerHTML;
827
		}
828
		container.appendChild( node );
829

830
		return node;
831

832
	}
833

834
	/**
835
	 * Creates the slide background elements and appends them
836
	 * to the background container. One element is created per
837
	 * slide no matter if the given slide has visible background.
838
	 */
839
	function createBackgrounds() {
840

841
		var printMode = isPrintingPDF();
842

843
		// Clear prior backgrounds
844
		dom.background.innerHTML = '';
845
		dom.background.classList.add( 'no-transition' );
846

847
		// Iterate over all horizontal slides
848
		toArray( dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) ).forEach( function( slideh ) {
849

850
			var backgroundStack = createBackground( slideh, dom.background );
851

852
			// Iterate over all vertical slides
853
			toArray( slideh.querySelectorAll( 'section' ) ).forEach( function( slidev ) {
854

855
				createBackground( slidev, backgroundStack );
856

857
				backgroundStack.classList.add( 'stack' );
858

859
			} );
860

861
		} );
862

863
		// Add parallax background if specified
864
		if( config.parallaxBackgroundImage ) {
865

866
			dom.background.style.backgroundImage = 'url("' + config.parallaxBackgroundImage + '")';
867
			dom.background.style.backgroundSize = config.parallaxBackgroundSize;
868

869
			// Make sure the below properties are set on the element - these properties are
870
			// needed for proper transitions to be set on the element via CSS. To remove
871
			// annoying background slide-in effect when the presentation starts, apply
872
			// these properties after short time delay
873
			setTimeout( function() {
874
				dom.wrapper.classList.add( 'has-parallax-background' );
875
			}, 1 );
876

877
		}
878
		else {
879

880
			dom.background.style.backgroundImage = '';
881
			dom.wrapper.classList.remove( 'has-parallax-background' );
882

883
		}
884

885
	}
886

887
	/**
888
	 * Creates a background for the given slide.
889
	 *
890
	 * @param {HTMLElement} slide
891
	 * @param {HTMLElement} container The element that the background
892
	 * should be appended to
893
	 * @return {HTMLElement} New background div
894
	 */
895
	function createBackground( slide, container ) {
896

897
		var data = {
898
			background: slide.getAttribute( 'data-background' ),
899
			backgroundSize: slide.getAttribute( 'data-background-size' ),
900
			backgroundImage: slide.getAttribute( 'data-background-image' ),
901
			backgroundVideo: slide.getAttribute( 'data-background-video' ),
902
			backgroundIframe: slide.getAttribute( 'data-background-iframe' ),
903
			backgroundColor: slide.getAttribute( 'data-background-color' ),
904
			backgroundRepeat: slide.getAttribute( 'data-background-repeat' ),
905
			backgroundPosition: slide.getAttribute( 'data-background-position' ),
906
			backgroundTransition: slide.getAttribute( 'data-background-transition' )
907
		};
908

909
		var element = document.createElement( 'div' );
910

911
		// Carry over custom classes from the slide to the background
912
		element.className = 'slide-background ' + slide.className.replace( /present|past|future/, '' );
913

914
		if( data.background ) {
915
			// Auto-wrap image urls in url(...)
916
			if( /^(http|file|\/\/)/gi.test( data.background ) || /\.(svg|png|jpg|jpeg|gif|bmp)([?#]|$)/gi.test( data.background ) ) {
917
				slide.setAttribute( 'data-background-image', data.background );
918
			}
919
			else {
920
				element.style.background = data.background;
921
			}
922
		}
923

924
		// Create a hash for this combination of background settings.
925
		// This is used to determine when two slide backgrounds are
926
		// the same.
927
		if( data.background || data.backgroundColor || data.backgroundImage || data.backgroundVideo || data.backgroundIframe ) {
928
			element.setAttribute( 'data-background-hash', data.background +
929
															data.backgroundSize +
930
															data.backgroundImage +
931
															data.backgroundVideo +
932
															data.backgroundIframe +
933
															data.backgroundColor +
934
															data.backgroundRepeat +
935
															data.backgroundPosition +
936
															data.backgroundTransition );
937
		}
938

939
		// Additional and optional background properties
940
		if( data.backgroundSize ) element.style.backgroundSize = data.backgroundSize;
941
		if( data.backgroundSize ) element.setAttribute( 'data-background-size', data.backgroundSize );
942
		if( data.backgroundColor ) element.style.backgroundColor = data.backgroundColor;
943
		if( data.backgroundRepeat ) element.style.backgroundRepeat = data.backgroundRepeat;
944
		if( data.backgroundPosition ) element.style.backgroundPosition = data.backgroundPosition;
945
		if( data.backgroundTransition ) element.setAttribute( 'data-background-transition', data.backgroundTransition );
946

947
		container.appendChild( element );
948

949
		// If backgrounds are being recreated, clear old classes
950
		slide.classList.remove( 'has-dark-background' );
951
		slide.classList.remove( 'has-light-background' );
952

953
		slide.slideBackgroundElement = element;
954

955
		// If this slide has a background color, add a class that
956
		// signals if it is light or dark. If the slide has no background
957
		// color, no class will be set
958
		var computedBackgroundStyle = window.getComputedStyle( element );
959
		if( computedBackgroundStyle && computedBackgroundStyle.backgroundColor ) {
960
			var rgb = colorToRgb( computedBackgroundStyle.backgroundColor );
961

962
			// Ignore fully transparent backgrounds. Some browsers return
963
			// rgba(0,0,0,0) when reading the computed background color of
964
			// an element with no background
965
			if( rgb && rgb.a !== 0 ) {
966
				if( colorBrightness( computedBackgroundStyle.backgroundColor ) < 128 ) {
967
					slide.classList.add( 'has-dark-background' );
968
				}
969
				else {
970
					slide.classList.add( 'has-light-background' );
971
				}
972
			}
973
		}
974

975
		return element;
976

977
	}
978

979
	/**
980
	 * Registers a listener to postMessage events, this makes it
981
	 * possible to call all reveal.js API methods from another
982
	 * window. For example:
983
	 *
984
	 * revealWindow.postMessage( JSON.stringify({
985
	 *   method: 'slide',
986
	 *   args: [ 2 ]
987
	 * }), '*' );
988
	 */
989
	function setupPostMessage() {
990

991
		if( config.postMessage ) {
992
			window.addEventListener( 'message', function ( event ) {
993
				var data = event.data;
994

995
				// Make sure we're dealing with JSON
996
				if( typeof data === 'string' && data.charAt( 0 ) === '{' && data.charAt( data.length - 1 ) === '}' ) {
997
					data = JSON.parse( data );
998

999
					// Check if the requested method can be found
1000
					if( data.method && typeof Reveal[data.method] === 'function' ) {
1001
						Reveal[data.method].apply( Reveal, data.args );
1002
					}
1003
				}
1004
			}, false );
1005
		}
1006

1007
	}
1008

1009
	/**
1010
	 * Applies the configuration settings from the config
1011
	 * object. May be called multiple times.
1012
	 *
1013
	 * @param {object} options
1014
	 */
1015
	function configure( options ) {
1016

1017
		var oldTransition = config.transition;
1018

1019
		// New config options may be passed when this method
1020
		// is invoked through the API after initialization
1021
		if( typeof options === 'object' ) extend( config, options );
1022

1023
		// Abort if reveal.js hasn't finished loading, config
1024
		// changes will be applied automatically once loading
1025
		// finishes
1026
		if( loaded === false ) return;
1027

1028
		var numberOfSlides = dom.wrapper.querySelectorAll( SLIDES_SELECTOR ).length;
1029

1030
		// Remove the previously configured transition class
1031
		dom.wrapper.classList.remove( oldTransition );
1032

1033
		// Force linear transition based on browser capabilities
1034
		if( features.transforms3d === false ) config.transition = 'linear';
1035

1036
		dom.wrapper.classList.add( config.transition );
1037

1038
		dom.wrapper.setAttribute( 'data-transition-speed', config.transitionSpeed );
1039
		dom.wrapper.setAttribute( 'data-background-transition', config.backgroundTransition );
1040

1041
		dom.controls.style.display = config.controls ? 'block' : 'none';
1042
		dom.progress.style.display = config.progress ? 'block' : 'none';
1043

1044
		dom.controls.setAttribute( 'data-controls-layout', config.controlsLayout );
1045
		dom.controls.setAttribute( 'data-controls-back-arrows', config.controlsBackArrows );
1046

1047
		if( config.shuffle ) {
1048
			shuffle();
1049
		}
1050

1051
		if( config.rtl ) {
1052
			dom.wrapper.classList.add( 'rtl' );
1053
		}
1054
		else {
1055
			dom.wrapper.classList.remove( 'rtl' );
1056
		}
1057

1058
		if( config.center ) {
1059
			dom.wrapper.classList.add( 'center' );
1060
		}
1061
		else {
1062
			dom.wrapper.classList.remove( 'center' );
1063
		}
1064

1065
		// Exit the paused mode if it was configured off
1066
		if( config.pause === false ) {
1067
			resume();
1068
		}
1069

1070
		if( config.showNotes ) {
1071
			dom.speakerNotes.setAttribute( 'data-layout', typeof config.showNotes === 'string' ? config.showNotes : 'inline' );
1072
		}
1073

1074
		if( config.mouseWheel ) {
1075
			document.addEventListener( 'DOMMouseScroll', onDocumentMouseScroll, false ); // FF
1076
			document.addEventListener( 'mousewheel', onDocumentMouseScroll, false );
1077
		}
1078
		else {
1079
			document.removeEventListener( 'DOMMouseScroll', onDocumentMouseScroll, false ); // FF
1080
			document.removeEventListener( 'mousewheel', onDocumentMouseScroll, false );
1081
		}
1082

1083
		// Rolling 3D links
1084
		if( config.rollingLinks ) {
1085
			enableRollingLinks();
1086
		}
1087
		else {
1088
			disableRollingLinks();
1089
		}
1090

1091
		// Iframe link previews
1092
		if( config.previewLinks ) {
1093
			enablePreviewLinks();
1094
			disablePreviewLinks( '[data-preview-link=false]' );
1095
		}
1096
		else {
1097
			disablePreviewLinks();
1098
			enablePreviewLinks( '[data-preview-link]:not([data-preview-link=false])' );
1099
		}
1100

1101
		// Remove existing auto-slide controls
1102
		if( autoSlidePlayer ) {
1103
			autoSlidePlayer.destroy();
1104
			autoSlidePlayer = null;
1105
		}
1106

1107
		// Generate auto-slide controls if needed
1108
		if( numberOfSlides > 1 && config.autoSlide && config.autoSlideStoppable && features.canvas && features.requestAnimationFrame ) {
1109
			autoSlidePlayer = new Playback( dom.wrapper, function() {
1110
				return Math.min( Math.max( ( Date.now() - autoSlideStartTime ) / autoSlide, 0 ), 1 );
1111
			} );
1112

1113
			autoSlidePlayer.on( 'click', onAutoSlidePlayerClick );
1114
			autoSlidePaused = false;
1115
		}
1116

1117
		// When fragments are turned off they should be visible
1118
		if( config.fragments === false ) {
1119
			toArray( dom.slides.querySelectorAll( '.fragment' ) ).forEach( function( element ) {
1120
				element.classList.add( 'visible' );
1121
				element.classList.remove( 'current-fragment' );
1122
			} );
1123
		}
1124

1125
		// Slide numbers
1126
		var slideNumberDisplay = 'none';
1127
		if( config.slideNumber && !isPrintingPDF() ) {
1128
			if( config.showSlideNumber === 'all' ) {
1129
				slideNumberDisplay = 'block';
1130
			}
1131
			else if( config.showSlideNumber === 'speaker' && isSpeakerNotes() ) {
1132
				slideNumberDisplay = 'block';
1133
			}
1134
		}
1135

1136
		dom.slideNumber.style.display = slideNumberDisplay;
1137

1138
		sync();
1139

1140
	}
1141

1142
	/**
1143
	 * Binds all event listeners.
1144
	 */
1145
	function addEventListeners() {
1146

1147
		eventsAreBound = true;
1148

1149
		window.addEventListener( 'hashchange', onWindowHashChange, false );
1150
		window.addEventListener( 'resize', onWindowResize, false );
1151

1152
		if( config.touch ) {
1153
			dom.wrapper.addEventListener( 'touchstart', onTouchStart, false );
1154
			dom.wrapper.addEventListener( 'touchmove', onTouchMove, false );
1155
			dom.wrapper.addEventListener( 'touchend', onTouchEnd, false );
1156

1157
			// Support pointer-style touch interaction as well
1158
			if( window.navigator.pointerEnabled ) {
1159
				// IE 11 uses un-prefixed version of pointer events
1160
				dom.wrapper.addEventListener( 'pointerdown', onPointerDown, false );
1161
				dom.wrapper.addEventListener( 'pointermove', onPointerMove, false );
1162
				dom.wrapper.addEventListener( 'pointerup', onPointerUp, false );
1163
			}
1164
			else if( window.navigator.msPointerEnabled ) {
1165
				// IE 10 uses prefixed version of pointer events
1166
				dom.wrapper.addEventListener( 'MSPointerDown', onPointerDown, false );
1167
				dom.wrapper.addEventListener( 'MSPointerMove', onPointerMove, false );
1168
				dom.wrapper.addEventListener( 'MSPointerUp', onPointerUp, false );
1169
			}
1170
		}
1171

1172
		if( config.keyboard ) {
1173
			document.addEventListener( 'keydown', onDocumentKeyDown, false );
1174
			document.addEventListener( 'keypress', onDocumentKeyPress, false );
1175
		}
1176

1177
		if( config.progress && dom.progress ) {
1178
			dom.progress.addEventListener( 'click', onProgressClicked, false );
1179
		}
1180

1181
		if( config.focusBodyOnPageVisibilityChange ) {
1182
			var visibilityChange;
1183

1184
			if( 'hidden' in document ) {
1185
				visibilityChange = 'visibilitychange';
1186
			}
1187
			else if( 'msHidden' in document ) {
1188
				visibilityChange = 'msvisibilitychange';
1189
			}
1190
			else if( 'webkitHidden' in document ) {
1191
				visibilityChange = 'webkitvisibilitychange';
1192
			}
1193

1194
			if( visibilityChange ) {
1195
				document.addEventListener( visibilityChange, onPageVisibilityChange, false );
1196
			}
1197
		}
1198

1199
		// Listen to both touch and click events, in case the device
1200
		// supports both
1201
		var pointerEvents = [ 'touchstart', 'click' ];
1202

1203
		// Only support touch for Android, fixes double navigations in
1204
		// stock browser
1205
		if( UA.match( /android/gi ) ) {
1206
			pointerEvents = [ 'touchstart' ];
1207
		}
1208

1209
		pointerEvents.forEach( function( eventName ) {
1210
			dom.controlsLeft.forEach( function( el ) { el.addEventListener( eventName, onNavigateLeftClicked, false ); } );
1211
			dom.controlsRight.forEach( function( el ) { el.addEventListener( eventName, onNavigateRightClicked, false ); } );
1212
			dom.controlsUp.forEach( function( el ) { el.addEventListener( eventName, onNavigateUpClicked, false ); } );
1213
			dom.controlsDown.forEach( function( el ) { el.addEventListener( eventName, onNavigateDownClicked, false ); } );
1214
			dom.controlsPrev.forEach( function( el ) { el.addEventListener( eventName, onNavigatePrevClicked, false ); } );
1215
			dom.controlsNext.forEach( function( el ) { el.addEventListener( eventName, onNavigateNextClicked, false ); } );
1216
		} );
1217

1218
	}
1219

1220
	/**
1221
	 * Unbinds all event listeners.
1222
	 */
1223
	function removeEventListeners() {
1224

1225
		eventsAreBound = false;
1226

1227
		document.removeEventListener( 'keydown', onDocumentKeyDown, false );
1228
		document.removeEventListener( 'keypress', onDocumentKeyPress, false );
1229
		window.removeEventListener( 'hashchange', onWindowHashChange, false );
1230
		window.removeEventListener( 'resize', onWindowResize, false );
1231

1232
		dom.wrapper.removeEventListener( 'touchstart', onTouchStart, false );
1233
		dom.wrapper.removeEventListener( 'touchmove', onTouchMove, false );
1234
		dom.wrapper.removeEventListener( 'touchend', onTouchEnd, false );
1235

1236
		// IE11
1237
		if( window.navigator.pointerEnabled ) {
1238
			dom.wrapper.removeEventListener( 'pointerdown', onPointerDown, false );
1239
			dom.wrapper.removeEventListener( 'pointermove', onPointerMove, false );
1240
			dom.wrapper.removeEventListener( 'pointerup', onPointerUp, false );
1241
		}
1242
		// IE10
1243
		else if( window.navigator.msPointerEnabled ) {
1244
			dom.wrapper.removeEventListener( 'MSPointerDown', onPointerDown, false );
1245
			dom.wrapper.removeEventListener( 'MSPointerMove', onPointerMove, false );
1246
			dom.wrapper.removeEventListener( 'MSPointerUp', onPointerUp, false );
1247
		}
1248

1249
		if ( config.progress && dom.progress ) {
1250
			dom.progress.removeEventListener( 'click', onProgressClicked, false );
1251
		}
1252

1253
		[ 'touchstart', 'click' ].forEach( function( eventName ) {
1254
			dom.controlsLeft.forEach( function( el ) { el.removeEventListener( eventName, onNavigateLeftClicked, false ); } );
1255
			dom.controlsRight.forEach( function( el ) { el.removeEventListener( eventName, onNavigateRightClicked, false ); } );
1256
			dom.controlsUp.forEach( function( el ) { el.removeEventListener( eventName, onNavigateUpClicked, false ); } );
1257
			dom.controlsDown.forEach( function( el ) { el.removeEventListener( eventName, onNavigateDownClicked, false ); } );
1258
			dom.controlsPrev.forEach( function( el ) { el.removeEventListener( eventName, onNavigatePrevClicked, false ); } );
1259
			dom.controlsNext.forEach( function( el ) { el.removeEventListener( eventName, onNavigateNextClicked, false ); } );
1260
		} );
1261

1262
	}
1263

1264
	/**
1265
	 * Extend object a with the properties of object b.
1266
	 * If there's a conflict, object b takes precedence.
1267
	 *
1268
	 * @param {object} a
1269
	 * @param {object} b
1270
	 */
1271
	function extend( a, b ) {
1272

1273
		for( var i in b ) {
1274
			a[ i ] = b[ i ];
1275
		}
1276

1277
		return a;
1278

1279
	}
1280

1281
	/**
1282
	 * Converts the target object to an array.
1283
	 *
1284
	 * @param {object} o
1285
	 * @return {object[]}
1286
	 */
1287
	function toArray( o ) {
1288

1289
		return Array.prototype.slice.call( o );
1290

1291
	}
1292

1293
	/**
1294
	 * Utility for deserializing a value.
1295
	 *
1296
	 * @param {*} value
1297
	 * @return {*}
1298
	 */
1299
	function deserialize( value ) {
1300

1301
		if( typeof value === 'string' ) {
1302
			if( value === 'null' ) return null;
1303
			else if( value === 'true' ) return true;
1304
			else if( value === 'false' ) return false;
1305
			else if( value.match( /^-?[\d\.]+$/ ) ) return parseFloat( value );
1306
		}
1307

1308
		return value;
1309

1310
	}
1311

1312
	/**
1313
	 * Measures the distance in pixels between point a
1314
	 * and point b.
1315
	 *
1316
	 * @param {object} a point with x/y properties
1317
	 * @param {object} b point with x/y properties
1318
	 *
1319
	 * @return {number}
1320
	 */
1321
	function distanceBetween( a, b ) {
1322

1323
		var dx = a.x - b.x,
1324
			dy = a.y - b.y;
1325

1326
		return Math.sqrt( dx*dx + dy*dy );
1327

1328
	}
1329

1330
	/**
1331
	 * Applies a CSS transform to the target element.
1332
	 *
1333
	 * @param {HTMLElement} element
1334
	 * @param {string} transform
1335
	 */
1336
	function transformElement( element, transform ) {
1337

1338
		element.style.WebkitTransform = transform;
1339
		element.style.MozTransform = transform;
1340
		element.style.msTransform = transform;
1341
		element.style.transform = transform;
1342

1343
	}
1344

1345
	/**
1346
	 * Applies CSS transforms to the slides container. The container
1347
	 * is transformed from two separate sources: layout and the overview
1348
	 * mode.
1349
	 *
1350
	 * @param {object} transforms
1351
	 */
1352
	function transformSlides( transforms ) {
1353

1354
		// Pick up new transforms from arguments
1355
		if( typeof transforms.layout === 'string' ) slidesTransform.layout = transforms.layout;
1356
		if( typeof transforms.overview === 'string' ) slidesTransform.overview = transforms.overview;
1357

1358
		// Apply the transforms to the slides container
1359
		if( slidesTransform.layout ) {
1360
			transformElement( dom.slides, slidesTransform.layout + ' ' + slidesTransform.overview );
1361
		}
1362
		else {
1363
			transformElement( dom.slides, slidesTransform.overview );
1364
		}
1365

1366
	}
1367

1368
	/**
1369
	 * Injects the given CSS styles into the DOM.
1370
	 *
1371
	 * @param {string} value
1372
	 */
1373
	function injectStyleSheet( value ) {
1374

1375
		var tag = document.createElement( 'style' );
1376
		tag.type = 'text/css';
1377
		if( tag.styleSheet ) {
1378
			tag.styleSheet.cssText = value;
1379
		}
1380
		else {
1381
			tag.appendChild( document.createTextNode( value ) );
1382
		}
1383
		document.getElementsByTagName( 'head' )[0].appendChild( tag );
1384

1385
	}
1386

1387
	/**
1388
	 * Find the closest parent that matches the given
1389
	 * selector.
1390
	 *
1391
	 * @param {HTMLElement} target The child element
1392
	 * @param {String} selector The CSS selector to match
1393
	 * the parents against
1394
	 *
1395
	 * @return {HTMLElement} The matched parent or null
1396
	 * if no matching parent was found
1397
	 */
1398
	function closestParent( target, selector ) {
1399

1400
		var parent = target.parentNode;
1401

1402
		while( parent ) {
1403

1404
			// There's some overhead doing this each time, we don't
1405
			// want to rewrite the element prototype but should still
1406
			// be enough to feature detect once at startup...
1407
			var matchesMethod = parent.matches || parent.matchesSelector || parent.msMatchesSelector;
1408

1409
			// If we find a match, we're all set
1410
			if( matchesMethod && matchesMethod.call( parent, selector ) ) {
1411
				return parent;
1412
			}
1413

1414
			// Keep searching
1415
			parent = parent.parentNode;
1416

1417
		}
1418

1419
		return null;
1420

1421
	}
1422

1423
	/**
1424
	 * Converts various color input formats to an {r:0,g:0,b:0} object.
1425
	 *
1426
	 * @param {string} color The string representation of a color
1427
	 * @example
1428
	 * colorToRgb('#000');
1429
	 * @example
1430
	 * colorToRgb('#000000');
1431
	 * @example
1432
	 * colorToRgb('rgb(0,0,0)');
1433
	 * @example
1434
	 * colorToRgb('rgba(0,0,0)');
1435
	 *
1436
	 * @return {{r: number, g: number, b: number, [a]: number}|null}
1437
	 */
1438
	function colorToRgb( color ) {
1439

1440
		var hex3 = color.match( /^#([0-9a-f]{3})$/i );
1441
		if( hex3 && hex3[1] ) {
1442
			hex3 = hex3[1];
1443
			return {
1444
				r: parseInt( hex3.charAt( 0 ), 16 ) * 0x11,
1445
				g: parseInt( hex3.charAt( 1 ), 16 ) * 0x11,
1446
				b: parseInt( hex3.charAt( 2 ), 16 ) * 0x11
1447
			};
1448
		}
1449

1450
		var hex6 = color.match( /^#([0-9a-f]{6})$/i );
1451
		if( hex6 && hex6[1] ) {
1452
			hex6 = hex6[1];
1453
			return {
1454
				r: parseInt( hex6.substr( 0, 2 ), 16 ),
1455
				g: parseInt( hex6.substr( 2, 2 ), 16 ),
1456
				b: parseInt( hex6.substr( 4, 2 ), 16 )
1457
			};
1458
		}
1459

1460
		var rgb = color.match( /^rgb\s*\(\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*\)$/i );
1461
		if( rgb ) {
1462
			return {
1463
				r: parseInt( rgb[1], 10 ),
1464
				g: parseInt( rgb[2], 10 ),
1465
				b: parseInt( rgb[3], 10 )
1466
			};
1467
		}
1468

1469
		var rgba = color.match( /^rgba\s*\(\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*\,\s*([\d]+|[\d]*.[\d]+)\s*\)$/i );
1470
		if( rgba ) {
1471
			return {
1472
				r: parseInt( rgba[1], 10 ),
1473
				g: parseInt( rgba[2], 10 ),
1474
				b: parseInt( rgba[3], 10 ),
1475
				a: parseFloat( rgba[4] )
1476
			};
1477
		}
1478

1479
		return null;
1480

1481
	}
1482

1483
	/**
1484
	 * Calculates brightness on a scale of 0-255.
1485
	 *
1486
	 * @param {string} color See colorToRgb for supported formats.
1487
	 * @see {@link colorToRgb}
1488
	 */
1489
	function colorBrightness( color ) {
1490

1491
		if( typeof color === 'string' ) color = colorToRgb( color );
1492

1493
		if( color ) {
1494
			return ( color.r * 299 + color.g * 587 + color.b * 114 ) / 1000;
1495
		}
1496

1497
		return null;
1498

1499
	}
1500

1501
	/**
1502
	 * Returns the remaining height within the parent of the
1503
	 * target element.
1504
	 *
1505
	 * remaining height = [ configured parent height ] - [ current parent height ]
1506
	 *
1507
	 * @param {HTMLElement} element
1508
	 * @param {number} [height]
1509
	 */
1510
	function getRemainingHeight( element, height ) {
1511

1512
		height = height || 0;
1513

1514
		if( element ) {
1515
			var newHeight, oldHeight = element.style.height;
1516

1517
			// Change the .stretch element height to 0 in order find the height of all
1518
			// the other elements
1519
			element.style.height = '0px';
1520
			newHeight = height - element.parentNode.offsetHeight;
1521

1522
			// Restore the old height, just in case
1523
			element.style.height = oldHeight + 'px';
1524

1525
			return newHeight;
1526
		}
1527

1528
		return height;
1529

1530
	}
1531

1532
	/**
1533
	 * Checks if this instance is being used to print a PDF.
1534
	 */
1535
	function isPrintingPDF() {
1536

1537
		return ( /print-pdf/gi ).test( window.location.search );
1538

1539
	}
1540

1541
	/**
1542
	 * Hides the address bar if we're on a mobile device.
1543
	 */
1544
	function hideAddressBar() {
1545

1546
		if( config.hideAddressBar && isMobileDevice ) {
1547
			// Events that should trigger the address bar to hide
1548
			window.addEventListener( 'load', removeAddressBar, false );
1549
			window.addEventListener( 'orientationchange', removeAddressBar, false );
1550
		}
1551

1552
	}
1553

1554
	/**
1555
	 * Causes the address bar to hide on mobile devices,
1556
	 * more vertical space ftw.
1557
	 */
1558
	function removeAddressBar() {
1559

1560
		setTimeout( function() {
1561
			window.scrollTo( 0, 1 );
1562
		}, 10 );
1563

1564
	}
1565

1566
	/**
1567
	 * Dispatches an event of the specified type from the
1568
	 * reveal DOM element.
1569
	 */
1570
	function dispatchEvent( type, args ) {
1571

1572
		var event = document.createEvent( 'HTMLEvents', 1, 2 );
1573
		event.initEvent( type, true, true );
1574
		extend( event, args );
1575
		dom.wrapper.dispatchEvent( event );
1576

1577
		// If we're in an iframe, post each reveal.js event to the
1578
		// parent window. Used by the notes plugin
1579
		if( config.postMessageEvents && window.parent !== window.self ) {
1580
			window.parent.postMessage( JSON.stringify({ namespace: 'reveal', eventName: type, state: getState() }), '*' );
1581
		}
1582

1583
	}
1584

1585
	/**
1586
	 * Wrap all links in 3D goodness.
1587
	 */
1588
	function enableRollingLinks() {
1589

1590
		if( features.transforms3d && !( 'msPerspective' in document.body.style ) ) {
1591
			var anchors = dom.wrapper.querySelectorAll( SLIDES_SELECTOR + ' a' );
1592

1593
			for( var i = 0, len = anchors.length; i < len; i++ ) {
1594
				var anchor = anchors[i];
1595

1596
				if( anchor.textContent && !anchor.querySelector( '*' ) && ( !anchor.className || !anchor.classList.contains( anchor, 'roll' ) ) ) {
1597
					var span = document.createElement('span');
1598
					span.setAttribute('data-title', anchor.text);
1599
					span.innerHTML = anchor.innerHTML;
1600

1601
					anchor.classList.add( 'roll' );
1602
					anchor.innerHTML = '';
1603
					anchor.appendChild(span);
1604
				}
1605
			}
1606
		}
1607

1608
	}
1609

1610
	/**
1611
	 * Unwrap all 3D links.
1612
	 */
1613
	function disableRollingLinks() {
1614

1615
		var anchors = dom.wrapper.querySelectorAll( SLIDES_SELECTOR + ' a.roll' );
1616

1617
		for( var i = 0, len = anchors.length; i < len; i++ ) {
1618
			var anchor = anchors[i];
1619
			var span = anchor.querySelector( 'span' );
1620

1621
			if( span ) {
1622
				anchor.classList.remove( 'roll' );
1623
				anchor.innerHTML = span.innerHTML;
1624
			}
1625
		}
1626

1627
	}
1628

1629
	/**
1630
	 * Bind preview frame links.
1631
	 *
1632
	 * @param {string} [selector=a] - selector for anchors
1633
	 */
1634
	function enablePreviewLinks( selector ) {
1635

1636
		var anchors = toArray( document.querySelectorAll( selector ? selector : 'a' ) );
1637

1638
		anchors.forEach( function( element ) {
1639
			if( /^(http|www)/gi.test( element.getAttribute( 'href' ) ) ) {
1640
				element.addEventListener( 'click', onPreviewLinkClicked, false );
1641
			}
1642
		} );
1643

1644
	}
1645

1646
	/**
1647
	 * Unbind preview frame links.
1648
	 */
1649
	function disablePreviewLinks( selector ) {
1650

1651
		var anchors = toArray( document.querySelectorAll( selector ? selector : 'a' ) );
1652

1653
		anchors.forEach( function( element ) {
1654
			if( /^(http|www)/gi.test( element.getAttribute( 'href' ) ) ) {
1655
				element.removeEventListener( 'click', onPreviewLinkClicked, false );
1656
			}
1657
		} );
1658

1659
	}
1660

1661
	/**
1662
	 * Opens a preview window for the target URL.
1663
	 *
1664
	 * @param {string} url - url for preview iframe src
1665
	 */
1666
	function showPreview( url ) {
1667

1668
		closeOverlay();
1669

1670
		dom.overlay = document.createElement( 'div' );
1671
		dom.overlay.classList.add( 'overlay' );
1672
		dom.overlay.classList.add( 'overlay-preview' );
1673
		dom.wrapper.appendChild( dom.overlay );
1674

1675
		dom.overlay.innerHTML = [
1676
			'<header>',
1677
				'<a class="close" href="#"><span class="icon"></span></a>',
1678
				'<a class="external" href="'+ url +'" target="_blank"><span class="icon"></span></a>',
1679
			'</header>',
1680
			'<div class="spinner"></div>',
1681
			'<div class="viewport">',
1682
				'<iframe src="'+ url +'"></iframe>',
1683
				'<small class="viewport-inner">',
1684
					'<span class="x-frame-error">Unable to load iframe. This is likely due to the site\'s policy (x-frame-options).</span>',
1685
				'</small>',
1686
			'</div>'
1687
		].join('');
1688

1689
		dom.overlay.querySelector( 'iframe' ).addEventListener( 'load', function( event ) {
1690
			dom.overlay.classList.add( 'loaded' );
1691
		}, false );
1692

1693
		dom.overlay.querySelector( '.close' ).addEventListener( 'click', function( event ) {
1694
			closeOverlay();
1695
			event.preventDefault();
1696
		}, false );
1697

1698
		dom.overlay.querySelector( '.external' ).addEventListener( 'click', function( event ) {
1699
			closeOverlay();
1700
		}, false );
1701

1702
		setTimeout( function() {
1703
			dom.overlay.classList.add( 'visible' );
1704
		}, 1 );
1705

1706
	}
1707

1708
	/**
1709
	 * Open or close help overlay window.
1710
	 *
1711
	 * @param {Boolean} [override] Flag which overrides the
1712
	 * toggle logic and forcibly sets the desired state. True means
1713
	 * help is open, false means it's closed.
1714
	 */
1715
	function toggleHelp( override ){
1716

1717
		if( typeof override === 'boolean' ) {
1718
			override ? showHelp() : closeOverlay();
1719
		}
1720
		else {
1721
			if( dom.overlay ) {
1722
				closeOverlay();
1723
			}
1724
			else {
1725
				showHelp();
1726
			}
1727
		}
1728
	}
1729

1730
	/**
1731
	 * Opens an overlay window with help material.
1732
	 */
1733
	function showHelp() {
1734

1735
		if( config.help ) {
1736

1737
			closeOverlay();
1738

1739
			dom.overlay = document.createElement( 'div' );
1740
			dom.overlay.classList.add( 'overlay' );
1741
			dom.overlay.classList.add( 'overlay-help' );
1742
			dom.wrapper.appendChild( dom.overlay );
1743

1744
			var html = '<p class="title">Keyboard Shortcuts</p><br/>';
1745

1746
			html += '<table><th>KEY</th><th>ACTION</th>';
1747
			for( var key in keyboardShortcuts ) {
1748
				html += '<tr><td>' + key + '</td><td>' + keyboardShortcuts[ key ] + '</td></tr>';
1749
			}
1750

1751
			html += '</table>';
1752

1753
			dom.overlay.innerHTML = [
1754
				'<header>',
1755
					'<a class="close" href="#"><span class="icon"></span></a>',
1756
				'</header>',
1757
				'<div class="viewport">',
1758
					'<div class="viewport-inner">'+ html +'</div>',
1759
				'</div>'
1760
			].join('');
1761

1762
			dom.overlay.querySelector( '.close' ).addEventListener( 'click', function( event ) {
1763
				closeOverlay();
1764
				event.preventDefault();
1765
			}, false );
1766

1767
			setTimeout( function() {
1768
				dom.overlay.classList.add( 'visible' );
1769
			}, 1 );
1770

1771
		}
1772

1773
	}
1774

1775
	/**
1776
	 * Closes any currently open overlay.
1777
	 */
1778
	function closeOverlay() {
1779

1780
		if( dom.overlay ) {
1781
			dom.overlay.parentNode.removeChild( dom.overlay );
1782
			dom.overlay = null;
1783
		}
1784

1785
	}
1786

1787
	/**
1788
	 * Applies JavaScript-controlled layout rules to the
1789
	 * presentation.
1790
	 */
1791
	function layout() {
1792

1793
		if( dom.wrapper && !isPrintingPDF() ) {
1794

1795
			var size = getComputedSlideSize();
1796

1797
			// Layout the contents of the slides
1798
			layoutSlideContents( config.width, config.height );
1799

1800
			dom.slides.style.width = size.width + 'px';
1801
			dom.slides.style.height = size.height + 'px';
1802

1803
			// Determine scale of content to fit within available space
1804
			scale = Math.min( size.presentationWidth / size.width, size.presentationHeight / size.height );
1805

1806
			// Respect max/min scale settings
1807
			scale = Math.max( scale, config.minScale );
1808
			scale = Math.min( scale, config.maxScale );
1809

1810
			// Don't apply any scaling styles if scale is 1
1811
			if( scale === 1 ) {
1812
				dom.slides.style.zoom = '';
1813
				dom.slides.style.left = '';
1814
				dom.slides.style.top = '';
1815
				dom.slides.style.bottom = '';
1816
				dom.slides.style.right = '';
1817
				transformSlides( { layout: '' } );
1818
			}
1819
			else {
1820
				// Prefer zoom for scaling up so that content remains crisp.
1821
				// Don't use zoom to scale down since that can lead to shifts
1822
				// in text layout/line breaks.
1823
				if( scale > 1 && features.zoom ) {
1824
					dom.slides.style.zoom = scale;
1825
					dom.slides.style.left = '';
1826
					dom.slides.style.top = '';
1827
					dom.slides.style.bottom = '';
1828
					dom.slides.style.right = '';
1829
					transformSlides( { layout: '' } );
1830
				}
1831
				// Apply scale transform as a fallback
1832
				else {
1833
					dom.slides.style.zoom = '';
1834
					dom.slides.style.left = '50%';
1835
					dom.slides.style.top = '50%';
1836
					dom.slides.style.bottom = 'auto';
1837
					dom.slides.style.right = 'auto';
1838
					transformSlides( { layout: 'translate(-50%, -50%) scale('+ scale +')' } );
1839
				}
1840
			}
1841

1842
			// Select all slides, vertical and horizontal
1843
			var slides = toArray( dom.wrapper.querySelectorAll( SLIDES_SELECTOR ) );
1844

1845
			for( var i = 0, len = slides.length; i < len; i++ ) {
1846
				var slide = slides[ i ];
1847

1848
				// Don't bother updating invisible slides
1849
				if( slide.style.display === 'none' ) {
1850
					continue;
1851
				}
1852

1853
				if( config.center || slide.classList.contains( 'center' ) ) {
1854
					// Vertical stacks are not centred since their section
1855
					// children will be
1856
					if( slide.classList.contains( 'stack' ) ) {
1857
						slide.style.top = 0;
1858
					}
1859
					else {
1860
						slide.style.top = Math.max( ( size.height - slide.scrollHeight ) / 2, 0 ) + 'px';
1861
					}
1862
				}
1863
				else {
1864
					slide.style.top = '';
1865
				}
1866

1867
			}
1868

1869
			updateProgress();
1870
			updateParallax();
1871

1872
			if( isOverview() ) {
1873
				updateOverview();
1874
			}
1875

1876
		}
1877

1878
	}
1879

1880
	/**
1881
	 * Applies layout logic to the contents of all slides in
1882
	 * the presentation.
1883
	 *
1884
	 * @param {string|number} width
1885
	 * @param {string|number} height
1886
	 */
1887
	function layoutSlideContents( width, height ) {
1888

1889
		// Handle sizing of elements with the 'stretch' class
1890
		toArray( dom.slides.querySelectorAll( 'section > .stretch' ) ).forEach( function( element ) {
1891

1892
			// Determine how much vertical space we can use
1893
			var remainingHeight = getRemainingHeight( element, height );
1894

1895
			// Consider the aspect ratio of media elements
1896
			if( /(img|video)/gi.test( element.nodeName ) ) {
1897
				var nw = element.naturalWidth || element.videoWidth,
1898
					nh = element.naturalHeight || element.videoHeight;
1899

1900
				var es = Math.min( width / nw, remainingHeight / nh );
1901

1902
				element.style.width = ( nw * es ) + 'px';
1903
				element.style.height = ( nh * es ) + 'px';
1904

1905
			}
1906
			else {
1907
				element.style.width = width + 'px';
1908
				element.style.height = remainingHeight + 'px';
1909
			}
1910

1911
		} );
1912

1913
	}
1914

1915
	/**
1916
	 * Calculates the computed pixel size of our slides. These
1917
	 * values are based on the width and height configuration
1918
	 * options.
1919
	 *
1920
	 * @param {number} [presentationWidth=dom.wrapper.offsetWidth]
1921
	 * @param {number} [presentationHeight=dom.wrapper.offsetHeight]
1922
	 */
1923
	function getComputedSlideSize( presentationWidth, presentationHeight ) {
1924

1925
		var size = {
1926
			// Slide size
1927
			width: config.width,
1928
			height: config.height,
1929

1930
			// Presentation size
1931
			presentationWidth: presentationWidth || dom.wrapper.offsetWidth,
1932
			presentationHeight: presentationHeight || dom.wrapper.offsetHeight
1933
		};
1934

1935
		// Reduce available space by margin
1936
		size.presentationWidth -= ( size.presentationWidth * config.margin );
1937
		size.presentationHeight -= ( size.presentationHeight * config.margin );
1938

1939
		// Slide width may be a percentage of available width
1940
		if( typeof size.width === 'string' && /%$/.test( size.width ) ) {
1941
			size.width = parseInt( size.width, 10 ) / 100 * size.presentationWidth;
1942
		}
1943

1944
		// Slide height may be a percentage of available height
1945
		if( typeof size.height === 'string' && /%$/.test( size.height ) ) {
1946
			size.height = parseInt( size.height, 10 ) / 100 * size.presentationHeight;
1947
		}
1948

1949
		return size;
1950

1951
	}
1952

1953
	/**
1954
	 * Stores the vertical index of a stack so that the same
1955
	 * vertical slide can be selected when navigating to and
1956
	 * from the stack.
1957
	 *
1958
	 * @param {HTMLElement} stack The vertical stack element
1959
	 * @param {string|number} [v=0] Index to memorize
1960
	 */
1961
	function setPreviousVerticalIndex( stack, v ) {
1962

1963
		if( typeof stack === 'object' && typeof stack.setAttribute === 'function' ) {
1964
			stack.setAttribute( 'data-previous-indexv', v || 0 );
1965
		}
1966

1967
	}
1968

1969
	/**
1970
	 * Retrieves the vertical index which was stored using
1971
	 * #setPreviousVerticalIndex() or 0 if no previous index
1972
	 * exists.
1973
	 *
1974
	 * @param {HTMLElement} stack The vertical stack element
1975
	 */
1976
	function getPreviousVerticalIndex( stack ) {
1977

1978
		if( typeof stack === 'object' && typeof stack.setAttribute === 'function' && stack.classList.contains( 'stack' ) ) {
1979
			// Prefer manually defined start-indexv
1980
			var attributeName = stack.hasAttribute( 'data-start-indexv' ) ? 'data-start-indexv' : 'data-previous-indexv';
1981

1982
			return parseInt( stack.getAttribute( attributeName ) || 0, 10 );
1983
		}
1984

1985
		return 0;
1986

1987
	}
1988

1989
	/**
1990
	 * Displays the overview of slides (quick nav) by scaling
1991
	 * down and arranging all slide elements.
1992
	 */
1993
	function activateOverview() {
1994

1995
		// Only proceed if enabled in config
1996
		if( config.overview && !isOverview() ) {
1997

1998
			overview = true;
1999

2000
			dom.wrapper.classList.add( 'overview' );
2001
			dom.wrapper.classList.remove( 'overview-deactivating' );
2002

2003
			if( features.overviewTransitions ) {
2004
				setTimeout( function() {
2005
					dom.wrapper.classList.add( 'overview-animated' );
2006
				}, 1 );
2007
			}
2008

2009
			// Don't auto-slide while in overview mode
2010
			cancelAutoSlide();
2011

2012
			// Move the backgrounds element into the slide container to
2013
			// that the same scaling is applied
2014
			dom.slides.appendChild( dom.background );
2015

2016
			// Clicking on an overview slide navigates to it
2017
			toArray( dom.wrapper.querySelectorAll( SLIDES_SELECTOR ) ).forEach( function( slide ) {
2018
				if( !slide.classList.contains( 'stack' ) ) {
2019
					slide.addEventListener( 'click', onOverviewSlideClicked, true );
2020
				}
2021
			} );
2022

2023
			// Calculate slide sizes
2024
			var margin = 70;
2025
			var slideSize = getComputedSlideSize();
2026
			overviewSlideWidth = slideSize.width + margin;
2027
			overviewSlideHeight = slideSize.height + margin;
2028

2029
			// Reverse in RTL mode
2030
			if( config.rtl ) {
2031
				overviewSlideWidth = -overviewSlideWidth;
2032
			}
2033

2034
			updateSlidesVisibility();
2035
			layoutOverview();
2036
			updateOverview();
2037

2038
			layout();
2039

2040
			// Notify observers of the overview showing
2041
			dispatchEvent( 'overviewshown', {
2042
				'indexh': indexh,
2043
				'indexv': indexv,
2044
				'currentSlide': currentSlide
2045
			} );
2046

2047
		}
2048

2049
	}
2050

2051
	/**
2052
	 * Uses CSS transforms to position all slides in a grid for
2053
	 * display inside of the overview mode.
2054
	 */
2055
	function layoutOverview() {
2056

2057
		// Layout slides
2058
		toArray( dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) ).forEach( function( hslide, h ) {
2059
			hslide.setAttribute( 'data-index-h', h );
2060
			transformElement( hslide, 'translate3d(' + ( h * overviewSlideWidth ) + 'px, 0, 0)' );
2061

2062
			if( hslide.classList.contains( 'stack' ) ) {
2063

2064
				toArray( hslide.querySelectorAll( 'section' ) ).forEach( function( vslide, v ) {
2065
					vslide.setAttribute( 'data-index-h', h );
2066
					vslide.setAttribute( 'data-index-v', v );
2067

2068
					transformElement( vslide, 'translate3d(0, ' + ( v * overviewSlideHeight ) + 'px, 0)' );
2069
				} );
2070

2071
			}
2072
		} );
2073

2074
		// Layout slide backgrounds
2075
		toArray( dom.background.childNodes ).forEach( function( hbackground, h ) {
2076
			transformElement( hbackground, 'translate3d(' + ( h * overviewSlideWidth ) + 'px, 0, 0)' );
2077

2078
			toArray( hbackground.querySelectorAll( '.slide-background' ) ).forEach( function( vbackground, v ) {
2079
				transformElement( vbackground, 'translate3d(0, ' + ( v * overviewSlideHeight ) + 'px, 0)' );
2080
			} );
2081
		} );
2082

2083
	}
2084

2085
	/**
2086
	 * Moves the overview viewport to the current slides.
2087
	 * Called each time the current slide changes.
2088
	 */
2089
	function updateOverview() {
2090

2091
		var vmin = Math.min( window.innerWidth, window.innerHeight );
2092
		var scale = Math.max( vmin / 5, 150 ) / vmin;
2093

2094
		transformSlides( {
2095
			overview: [
2096
				'scale('+ scale +')',
2097
				'translateX('+ ( -indexh * overviewSlideWidth ) +'px)',
2098
				'translateY('+ ( -indexv * overviewSlideHeight ) +'px)'
2099
			].join( ' ' )
2100
		} );
2101

2102
	}
2103

2104
	/**
2105
	 * Exits the slide overview and enters the currently
2106
	 * active slide.
2107
	 */
2108
	function deactivateOverview() {
2109

2110
		// Only proceed if enabled in config
2111
		if( config.overview ) {
2112

2113
			overview = false;
2114

2115
			dom.wrapper.classList.remove( 'overview' );
2116
			dom.wrapper.classList.remove( 'overview-animated' );
2117

2118
			// Temporarily add a class so that transitions can do different things
2119
			// depending on whether they are exiting/entering overview, or just
2120
			// moving from slide to slide
2121
			dom.wrapper.classList.add( 'overview-deactivating' );
2122

2123
			setTimeout( function () {
2124
				dom.wrapper.classList.remove( 'overview-deactivating' );
2125
			}, 1 );
2126

2127
			// Move the background element back out
2128
			dom.wrapper.appendChild( dom.background );
2129

2130
			// Clean up changes made to slides
2131
			toArray( dom.wrapper.querySelectorAll( SLIDES_SELECTOR ) ).forEach( function( slide ) {
2132
				transformElement( slide, '' );
2133

2134
				slide.removeEventListener( 'click', onOverviewSlideClicked, true );
2135
			} );
2136

2137
			// Clean up changes made to backgrounds
2138
			toArray( dom.background.querySelectorAll( '.slide-background' ) ).forEach( function( background ) {
2139
				transformElement( background, '' );
2140
			} );
2141

2142
			transformSlides( { overview: '' } );
2143

2144
			slide( indexh, indexv );
2145

2146
			layout();
2147

2148
			cueAutoSlide();
2149

2150
			// Notify observers of the overview hiding
2151
			dispatchEvent( 'overviewhidden', {
2152
				'indexh': indexh,
2153
				'indexv': indexv,
2154
				'currentSlide': currentSlide
2155
			} );
2156

2157
		}
2158
	}
2159

2160
	/**
2161
	 * Toggles the slide overview mode on and off.
2162
	 *
2163
	 * @param {Boolean} [override] Flag which overrides the
2164
	 * toggle logic and forcibly sets the desired state. True means
2165
	 * overview is open, false means it's closed.
2166
	 */
2167
	function toggleOverview( override ) {
2168

2169
		if( typeof override === 'boolean' ) {
2170
			override ? activateOverview() : deactivateOverview();
2171
		}
2172
		else {
2173
			isOverview() ? deactivateOverview() : activateOverview();
2174
		}
2175

2176
	}
2177

2178
	/**
2179
	 * Checks if the overview is currently active.
2180
	 *
2181
	 * @return {Boolean} true if the overview is active,
2182
	 * false otherwise
2183
	 */
2184
	function isOverview() {
2185

2186
		return overview;
2187

2188
	}
2189

2190
	/**
2191
	 * Checks if the current or specified slide is vertical
2192
	 * (nested within another slide).
2193
	 *
2194
	 * @param {HTMLElement} [slide=currentSlide] The slide to check
2195
	 * orientation of
2196
	 * @return {Boolean}
2197
	 */
2198
	function isVerticalSlide( slide ) {
2199

2200
		// Prefer slide argument, otherwise use current slide
2201
		slide = slide ? slide : currentSlide;
2202

2203
		return slide && slide.parentNode && !!slide.parentNode.nodeName.match( /section/i );
2204

2205
	}
2206

2207
	/**
2208
	 * Handling the fullscreen functionality via the fullscreen API
2209
	 *
2210
	 * @see http://fullscreen.spec.whatwg.org/
2211
	 * @see https://developer.mozilla.org/en-US/docs/DOM/Using_fullscreen_mode
2212
	 */
2213
	function enterFullscreen() {
2214

2215
		var element = document.documentElement;
2216

2217
		// Check which implementation is available
2218
		var requestMethod = element.requestFullscreen ||
2219
							element.webkitRequestFullscreen ||
2220
							element.webkitRequestFullScreen ||
2221
							element.mozRequestFullScreen ||
2222
							element.msRequestFullscreen;
2223

2224
		if( requestMethod ) {
2225
			requestMethod.apply( element );
2226
		}
2227

2228
	}
2229

2230
	/**
2231
	 * Enters the paused mode which fades everything on screen to
2232
	 * black.
2233
	 */
2234
	function pause() {
2235

2236
		if( config.pause ) {
2237
			var wasPaused = dom.wrapper.classList.contains( 'paused' );
2238

2239
			cancelAutoSlide();
2240
			dom.wrapper.classList.add( 'paused' );
2241

2242
			if( wasPaused === false ) {
2243
				dispatchEvent( 'paused' );
2244
			}
2245
		}
2246

2247
	}
2248

2249
	/**
2250
	 * Exits from the paused mode.
2251
	 */
2252
	function resume() {
2253

2254
		var wasPaused = dom.wrapper.classList.contains( 'paused' );
2255
		dom.wrapper.classList.remove( 'paused' );
2256

2257
		cueAutoSlide();
2258

2259
		if( wasPaused ) {
2260
			dispatchEvent( 'resumed' );
2261
		}
2262

2263
	}
2264

2265
	/**
2266
	 * Toggles the paused mode on and off.
2267
	 */
2268
	function togglePause( override ) {
2269

2270
		if( typeof override === 'boolean' ) {
2271
			override ? pause() : resume();
2272
		}
2273
		else {
2274
			isPaused() ? resume() : pause();
2275
		}
2276

2277
	}
2278

2279
	/**
2280
	 * Checks if we are currently in the paused mode.
2281
	 *
2282
	 * @return {Boolean}
2283
	 */
2284
	function isPaused() {
2285

2286
		return dom.wrapper.classList.contains( 'paused' );
2287

2288
	}
2289

2290
	/**
2291
	 * Toggles the auto slide mode on and off.
2292
	 *
2293
	 * @param {Boolean} [override] Flag which sets the desired state.
2294
	 * True means autoplay starts, false means it stops.
2295
	 */
2296

2297
	function toggleAutoSlide( override ) {
2298

2299
		if( typeof override === 'boolean' ) {
2300
			override ? resumeAutoSlide() : pauseAutoSlide();
2301
		}
2302

2303
		else {
2304
			autoSlidePaused ? resumeAutoSlide() : pauseAutoSlide();
2305
		}
2306

2307
	}
2308

2309
	/**
2310
	 * Checks if the auto slide mode is currently on.
2311
	 *
2312
	 * @return {Boolean}
2313
	 */
2314
	function isAutoSliding() {
2315

2316
		return !!( autoSlide && !autoSlidePaused );
2317

2318
	}
2319

2320
	/**
2321
	 * Steps from the current point in the presentation to the
2322
	 * slide which matches the specified horizontal and vertical
2323
	 * indices.
2324
	 *
2325
	 * @param {number} [h=indexh] Horizontal index of the target slide
2326
	 * @param {number} [v=indexv] Vertical index of the target slide
2327
	 * @param {number} [f] Index of a fragment within the
2328
	 * target slide to activate
2329
	 * @param {number} [o] Origin for use in multimaster environments
2330
	 */
2331
	function slide( h, v, f, o ) {
2332

2333
		// Remember where we were at before
2334
		previousSlide = currentSlide;
2335

2336
		// Query all horizontal slides in the deck
2337
		var horizontalSlides = dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR );
2338

2339
		// Abort if there are no slides
2340
		if( horizontalSlides.length === 0 ) return;
2341

2342
		// If no vertical index is specified and the upcoming slide is a
2343
		// stack, resume at its previous vertical index
2344
		if( v === undefined && !isOverview() ) {
2345
			v = getPreviousVerticalIndex( horizontalSlides[ h ] );
2346
		}
2347

2348
		// If we were on a vertical stack, remember what vertical index
2349
		// it was on so we can resume at the same position when returning
2350
		if( previousSlide && previousSlide.parentNode && previousSlide.parentNode.classList.contains( 'stack' ) ) {
2351
			setPreviousVerticalIndex( previousSlide.parentNode, indexv );
2352
		}
2353

2354
		// Remember the state before this slide
2355
		var stateBefore = state.concat();
2356

2357
		// Reset the state array
2358
		state.length = 0;
2359

2360
		var indexhBefore = indexh || 0,
2361
			indexvBefore = indexv || 0;
2362

2363
		// Activate and transition to the new slide
2364
		indexh = updateSlides( HORIZONTAL_SLIDES_SELECTOR, h === undefined ? indexh : h );
2365
		indexv = updateSlides( VERTICAL_SLIDES_SELECTOR, v === undefined ? indexv : v );
2366

2367
		// Update the visibility of slides now that the indices have changed
2368
		updateSlidesVisibility();
2369

2370
		layout();
2371

2372
		// Apply the new state
2373
		stateLoop: for( var i = 0, len = state.length; i < len; i++ ) {
2374
			// Check if this state existed on the previous slide. If it
2375
			// did, we will avoid adding it repeatedly
2376
			for( var j = 0; j < stateBefore.length; j++ ) {
2377
				if( stateBefore[j] === state[i] ) {
2378
					stateBefore.splice( j, 1 );
2379
					continue stateLoop;
2380
				}
2381
			}
2382

2383
			document.documentElement.classList.add( state[i] );
2384

2385
			// Dispatch custom event matching the state's name
2386
			dispatchEvent( state[i] );
2387
		}
2388

2389
		// Clean up the remains of the previous state
2390
		while( stateBefore.length ) {
2391
			document.documentElement.classList.remove( stateBefore.pop() );
2392
		}
2393

2394
		// Update the overview if it's currently active
2395
		if( isOverview() ) {
2396
			updateOverview();
2397
		}
2398

2399
		// Find the current horizontal slide and any possible vertical slides
2400
		// within it
2401
		var currentHorizontalSlide = horizontalSlides[ indexh ],
2402
			currentVerticalSlides = currentHorizontalSlide.querySelectorAll( 'section' );
2403

2404
		// Store references to the previous and current slides
2405
		currentSlide = currentVerticalSlides[ indexv ] || currentHorizontalSlide;
2406

2407
		// Show fragment, if specified
2408
		if( typeof f !== 'undefined' ) {
2409
			navigateFragment( f );
2410
		}
2411

2412
		// Dispatch an event if the slide changed
2413
		var slideChanged = ( indexh !== indexhBefore || indexv !== indexvBefore );
2414
		if( slideChanged ) {
2415
			dispatchEvent( 'slidechanged', {
2416
				'indexh': indexh,
2417
				'indexv': indexv,
2418
				'previousSlide': previousSlide,
2419
				'currentSlide': currentSlide,
2420
				'origin': o
2421
			} );
2422
		}
2423
		else {
2424
			// Ensure that the previous slide is never the same as the current
2425
			previousSlide = null;
2426
		}
2427

2428
		// Solves an edge case where the previous slide maintains the
2429
		// 'present' class when navigating between adjacent vertical
2430
		// stacks
2431
		if( previousSlide ) {
2432
			previousSlide.classList.remove( 'present' );
2433
			previousSlide.setAttribute( 'aria-hidden', 'true' );
2434

2435
			// Reset all slides upon navigate to home
2436
			// Issue: #285
2437
			if ( dom.wrapper.querySelector( HOME_SLIDE_SELECTOR ).classList.contains( 'present' ) ) {
2438
				// Launch async task
2439
				setTimeout( function () {
2440
					var slides = toArray( dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR + '.stack') ), i;
2441
					for( i in slides ) {
2442
						if( slides[i] ) {
2443
							// Reset stack
2444
							setPreviousVerticalIndex( slides[i], 0 );
2445
						}
2446
					}
2447
				}, 0 );
2448
			}
2449
		}
2450

2451
		// Handle embedded content
2452
		if( slideChanged || !previousSlide ) {
2453
			stopEmbeddedContent( previousSlide );
2454
			startEmbeddedContent( currentSlide );
2455
		}
2456

2457
		// Announce the current slide contents, for screen readers
2458
		dom.statusDiv.textContent = getStatusText( currentSlide );
2459

2460
		updateControls();
2461
		updateProgress();
2462
		updateBackground();
2463
		updateParallax();
2464
		updateSlideNumber();
2465
		updateNotes();
2466

2467
		// Update the URL hash
2468
		writeURL();
2469

2470
		cueAutoSlide();
2471

2472
	}
2473

2474
	/**
2475
	 * Syncs the presentation with the current DOM. Useful
2476
	 * when new slides or control elements are added or when
2477
	 * the configuration has changed.
2478
	 */
2479
	function sync() {
2480

2481
		// Subscribe to input
2482
		removeEventListeners();
2483
		addEventListeners();
2484

2485
		// Force a layout to make sure the current config is accounted for
2486
		layout();
2487

2488
		// Reflect the current autoSlide value
2489
		autoSlide = config.autoSlide;
2490

2491
		// Start auto-sliding if it's enabled
2492
		cueAutoSlide();
2493

2494
		// Re-create the slide backgrounds
2495
		createBackgrounds();
2496

2497
		// Write the current hash to the URL
2498
		writeURL();
2499

2500
		sortAllFragments();
2501

2502
		updateControls();
2503
		updateProgress();
2504
		updateSlideNumber();
2505
		updateSlidesVisibility();
2506
		updateBackground( true );
2507
		updateNotesVisibility();
2508
		updateNotes();
2509

2510
		formatEmbeddedContent();
2511

2512
		// Start or stop embedded content depending on global config
2513
		if( config.autoPlayMedia === false ) {
2514
			stopEmbeddedContent( currentSlide, { unloadIframes: false } );
2515
		}
2516
		else {
2517
			startEmbeddedContent( currentSlide );
2518
		}
2519

2520
		if( isOverview() ) {
2521
			layoutOverview();
2522
		}
2523

2524
	}
2525

2526
	/**
2527
	 * Resets all vertical slides so that only the first
2528
	 * is visible.
2529
	 */
2530
	function resetVerticalSlides() {
2531

2532
		var horizontalSlides = toArray( dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) );
2533
		horizontalSlides.forEach( function( horizontalSlide ) {
2534

2535
			var verticalSlides = toArray( horizontalSlide.querySelectorAll( 'section' ) );
2536
			verticalSlides.forEach( function( verticalSlide, y ) {
2537

2538
				if( y > 0 ) {
2539
					verticalSlide.classList.remove( 'present' );
2540
					verticalSlide.classList.remove( 'past' );
2541
					verticalSlide.classList.add( 'future' );
2542
					verticalSlide.setAttribute( 'aria-hidden', 'true' );
2543
				}
2544

2545
			} );
2546

2547
		} );
2548

2549
	}
2550

2551
	/**
2552
	 * Sorts and formats all of fragments in the
2553
	 * presentation.
2554
	 */
2555
	function sortAllFragments() {
2556

2557
		var horizontalSlides = toArray( dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) );
2558
		horizontalSlides.forEach( function( horizontalSlide ) {
2559

2560
			var verticalSlides = toArray( horizontalSlide.querySelectorAll( 'section' ) );
2561
			verticalSlides.forEach( function( verticalSlide, y ) {
2562

2563
				sortFragments( verticalSlide.querySelectorAll( '.fragment' ) );
2564

2565
			} );
2566

2567
			if( verticalSlides.length === 0 ) sortFragments( horizontalSlide.querySelectorAll( '.fragment' ) );
2568

2569
		} );
2570

2571
	}
2572

2573
	/**
2574
	 * Randomly shuffles all slides in the deck.
2575
	 */
2576
	function shuffle() {
2577

2578
		var slides = toArray( dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) );
2579

2580
		slides.forEach( function( slide ) {
2581

2582
			// Insert this slide next to another random slide. This may
2583
			// cause the slide to insert before itself but that's fine.
2584
			dom.slides.insertBefore( slide, slides[ Math.floor( Math.random() * slides.length ) ] );
2585

2586
		} );
2587

2588
	}
2589

2590
	/**
2591
	 * Updates one dimension of slides by showing the slide
2592
	 * with the specified index.
2593
	 *
2594
	 * @param {string} selector A CSS selector that will fetch
2595
	 * the group of slides we are working with
2596
	 * @param {number} index The index of the slide that should be
2597
	 * shown
2598
	 *
2599
	 * @return {number} The index of the slide that is now shown,
2600
	 * might differ from the passed in index if it was out of
2601
	 * bounds.
2602
	 */
2603
	function updateSlides( selector, index ) {
2604

2605
		// Select all slides and convert the NodeList result to
2606
		// an array
2607
		var slides = toArray( dom.wrapper.querySelectorAll( selector ) ),
2608
			slidesLength = slides.length;
2609

2610
		var printMode = isPrintingPDF();
2611

2612
		if( slidesLength ) {
2613

2614
			// Should the index loop?
2615
			if( config.loop ) {
2616
				index %= slidesLength;
2617

2618
				if( index < 0 ) {
2619
					index = slidesLength + index;
2620
				}
2621
			}
2622

2623
			// Enforce max and minimum index bounds
2624
			index = Math.max( Math.min( index, slidesLength - 1 ), 0 );
2625

2626
			for( var i = 0; i < slidesLength; i++ ) {
2627
				var element = slides[i];
2628

2629
				var reverse = config.rtl && !isVerticalSlide( element );
2630

2631
				element.classList.remove( 'past' );
2632
				element.classList.remove( 'present' );
2633
				element.classList.remove( 'future' );
2634

2635
				// http://www.w3.org/html/wg/drafts/html/master/editing.html#the-hidden-attribute
2636
				element.setAttribute( 'hidden', '' );
2637
				element.setAttribute( 'aria-hidden', 'true' );
2638

2639
				// If this element contains vertical slides
2640
				if( element.querySelector( 'section' ) ) {
2641
					element.classList.add( 'stack' );
2642
				}
2643

2644
				// If we're printing static slides, all slides are "present"
2645
				if( printMode ) {
2646
					element.classList.add( 'present' );
2647
					continue;
2648
				}
2649

2650
				if( i < index ) {
2651
					// Any element previous to index is given the 'past' class
2652
					element.classList.add( reverse ? 'future' : 'past' );
2653

2654
					if( config.fragments ) {
2655
						var pastFragments = toArray( element.querySelectorAll( '.fragment' ) );
2656

2657
						// Show all fragments on prior slides
2658
						while( pastFragments.length ) {
2659
							var pastFragment = pastFragments.pop();
2660
							pastFragment.classList.add( 'visible' );
2661
							pastFragment.classList.remove( 'current-fragment' );
2662
						}
2663
					}
2664
				}
2665
				else if( i > index ) {
2666
					// Any element subsequent to index is given the 'future' class
2667
					element.classList.add( reverse ? 'past' : 'future' );
2668

2669
					if( config.fragments ) {
2670
						var futureFragments = toArray( element.querySelectorAll( '.fragment.visible' ) );
2671

2672
						// No fragments in future slides should be visible ahead of time
2673
						while( futureFragments.length ) {
2674
							var futureFragment = futureFragments.pop();
2675
							futureFragment.classList.remove( 'visible' );
2676
							futureFragment.classList.remove( 'current-fragment' );
2677
						}
2678
					}
2679
				}
2680
			}
2681

2682
			// Mark the current slide as present
2683
			slides[index].classList.add( 'present' );
2684
			slides[index].removeAttribute( 'hidden' );
2685
			slides[index].removeAttribute( 'aria-hidden' );
2686

2687
			// If this slide has a state associated with it, add it
2688
			// onto the current state of the deck
2689
			var slideState = slides[index].getAttribute( 'data-state' );
2690
			if( slideState ) {
2691
				state = state.concat( slideState.split( ' ' ) );
2692
			}
2693

2694
		}
2695
		else {
2696
			// Since there are no slides we can't be anywhere beyond the
2697
			// zeroth index
2698
			index = 0;
2699
		}
2700

2701
		return index;
2702

2703
	}
2704

2705
	/**
2706
	 * Optimization method; hide all slides that are far away
2707
	 * from the present slide.
2708
	 */
2709
	function updateSlidesVisibility() {
2710

2711
		// Select all slides and convert the NodeList result to
2712
		// an array
2713
		var horizontalSlides = toArray( dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) ),
2714
			horizontalSlidesLength = horizontalSlides.length,
2715
			distanceX,
2716
			distanceY;
2717

2718
		if( horizontalSlidesLength && typeof indexh !== 'undefined' ) {
2719

2720
			// The number of steps away from the present slide that will
2721
			// be visible
2722
			var viewDistance = isOverview() ? 10 : config.viewDistance;
2723

2724
			// Limit view distance on weaker devices
2725
			if( isMobileDevice ) {
2726
				viewDistance = isOverview() ? 6 : 2;
2727
			}
2728

2729
			// All slides need to be visible when exporting to PDF
2730
			if( isPrintingPDF() ) {
2731
				viewDistance = Number.MAX_VALUE;
2732
			}
2733

2734
			for( var x = 0; x < horizontalSlidesLength; x++ ) {
2735
				var horizontalSlide = horizontalSlides[x];
2736

2737
				var verticalSlides = toArray( horizontalSlide.querySelectorAll( 'section' ) ),
2738
					verticalSlidesLength = verticalSlides.length;
2739

2740
				// Determine how far away this slide is from the present
2741
				distanceX = Math.abs( ( indexh || 0 ) - x ) || 0;
2742

2743
				// If the presentation is looped, distance should measure
2744
				// 1 between the first and last slides
2745
				if( config.loop ) {
2746
					distanceX = Math.abs( ( ( indexh || 0 ) - x ) % ( horizontalSlidesLength - viewDistance ) ) || 0;
2747
				}
2748

2749
				// Show the horizontal slide if it's within the view distance
2750
				if( distanceX < viewDistance ) {
2751
					loadSlide( horizontalSlide );
2752
				}
2753
				else {
2754
					unloadSlide( horizontalSlide );
2755
				}
2756

2757
				if( verticalSlidesLength ) {
2758

2759
					var oy = getPreviousVerticalIndex( horizontalSlide );
2760

2761
					for( var y = 0; y < verticalSlidesLength; y++ ) {
2762
						var verticalSlide = verticalSlides[y];
2763

2764
						distanceY = x === ( indexh || 0 ) ? Math.abs( ( indexv || 0 ) - y ) : Math.abs( y - oy );
2765

2766
						if( distanceX + distanceY < viewDistance ) {
2767
							loadSlide( verticalSlide );
2768
						}
2769
						else {
2770
							unloadSlide( verticalSlide );
2771
						}
2772
					}
2773

2774
				}
2775
			}
2776

2777
			// Flag if there are ANY vertical slides, anywhere in the deck
2778
			if( dom.wrapper.querySelectorAll( '.slides>section>section' ).length ) {
2779
				dom.wrapper.classList.add( 'has-vertical-slides' );
2780
			}
2781
			else {
2782
				dom.wrapper.classList.remove( 'has-vertical-slides' );
2783
			}
2784

2785
			// Flag if there are ANY horizontal slides, anywhere in the deck
2786
			if( dom.wrapper.querySelectorAll( '.slides>section' ).length > 1 ) {
2787
				dom.wrapper.classList.add( 'has-horizontal-slides' );
2788
			}
2789
			else {
2790
				dom.wrapper.classList.remove( 'has-horizontal-slides' );
2791
			}
2792

2793
		}
2794

2795
	}
2796

2797
	/**
2798
	 * Pick up notes from the current slide and display them
2799
	 * to the viewer.
2800
	 *
2801
	 * @see {@link config.showNotes}
2802
	 */
2803
	function updateNotes() {
2804

2805
		if( config.showNotes && dom.speakerNotes && currentSlide && !isPrintingPDF() ) {
2806

2807
			dom.speakerNotes.innerHTML = getSlideNotes() || '<span class="notes-placeholder">No notes on this slide.</span>';
2808

2809
		}
2810

2811
	}
2812

2813
	/**
2814
	 * Updates the visibility of the speaker notes sidebar that
2815
	 * is used to share annotated slides. The notes sidebar is
2816
	 * only visible if showNotes is true and there are notes on
2817
	 * one or more slides in the deck.
2818
	 */
2819
	function updateNotesVisibility() {
2820

2821
		if( config.showNotes && hasNotes() ) {
2822
			dom.wrapper.classList.add( 'show-notes' );
2823
		}
2824
		else {
2825
			dom.wrapper.classList.remove( 'show-notes' );
2826
		}
2827

2828
	}
2829

2830
	/**
2831
	 * Checks if there are speaker notes for ANY slide in the
2832
	 * presentation.
2833
	 */
2834
	function hasNotes() {
2835

2836
		return dom.slides.querySelectorAll( '[data-notes], aside.notes' ).length > 0;
2837

2838
	}
2839

2840
	/**
2841
	 * Updates the progress bar to reflect the current slide.
2842
	 */
2843
	function updateProgress() {
2844

2845
		// Update progress if enabled
2846
		if( config.progress && dom.progressbar ) {
2847

2848
			dom.progressbar.style.width = getProgress() * dom.wrapper.offsetWidth + 'px';
2849

2850
		}
2851

2852
	}
2853

2854
	/**
2855
	 * Updates the slide number div to reflect the current slide.
2856
	 *
2857
	 * The following slide number formats are available:
2858
	 *  "h.v":	horizontal . vertical slide number (default)
2859
	 *  "h/v":	horizontal / vertical slide number
2860
	 *    "c":	flattened slide number
2861
	 *  "c/t":	flattened slide number / total slides
2862
	 */
2863
	function updateSlideNumber() {
2864

2865
		// Update slide number if enabled
2866
		if( config.slideNumber && dom.slideNumber ) {
2867

2868
			var value = [];
2869
			var format = 'h.v';
2870

2871
			// Check if a custom number format is available
2872
			if( typeof config.slideNumber === 'string' ) {
2873
				format = config.slideNumber;
2874
			}
2875

2876
			switch( format ) {
2877
				case 'c':
2878
					value.push( getSlidePastCount() + 1 );
2879
					break;
2880
				case 'c/t':
2881
					value.push( getSlidePastCount() + 1, '/', getTotalSlides() );
2882
					break;
2883
				case 'h/v':
2884
					value.push( indexh + 1 );
2885
					if( isVerticalSlide() ) value.push( '/', indexv + 1 );
2886
					break;
2887
				default:
2888
					value.push( indexh + 1 );
2889
					if( isVerticalSlide() ) value.push( '.', indexv + 1 );
2890
			}
2891

2892
			dom.slideNumber.innerHTML = formatSlideNumber( value[0], value[1], value[2] );
2893
		}
2894

2895
	}
2896

2897
	/**
2898
	 * Applies HTML formatting to a slide number before it's
2899
	 * written to the DOM.
2900
	 *
2901
	 * @param {number} a Current slide
2902
	 * @param {string} delimiter Character to separate slide numbers
2903
	 * @param {(number|*)} b Total slides
2904
	 * @return {string} HTML string fragment
2905
	 */
2906
	function formatSlideNumber( a, delimiter, b ) {
2907

2908
		if( typeof b === 'number' && !isNaN( b ) ) {
2909
			return  '<span class="slide-number-a">'+ a +'</span>' +
2910
					'<span class="slide-number-delimiter">'+ delimiter +'</span>' +
2911
					'<span class="slide-number-b">'+ b +'</span>';
2912
		}
2913
		else {
2914
			return '<span class="slide-number-a">'+ a +'</span>';
2915
		}
2916

2917
	}
2918

2919
	/**
2920
	 * Updates the state of all control/navigation arrows.
2921
	 */
2922
	function updateControls() {
2923

2924
		var routes = availableRoutes();
2925
		var fragments = availableFragments();
2926

2927
		// Remove the 'enabled' class from all directions
2928
		dom.controlsLeft.concat( dom.controlsRight )
2929
						.concat( dom.controlsUp )
2930
						.concat( dom.controlsDown )
2931
						.concat( dom.controlsPrev )
2932
						.concat( dom.controlsNext ).forEach( function( node ) {
2933
			node.classList.remove( 'enabled' );
2934
			node.classList.remove( 'fragmented' );
2935

2936
			// Set 'disabled' attribute on all directions
2937
			node.setAttribute( 'disabled', 'disabled' );
2938
		} );
2939

2940
		// Add the 'enabled' class to the available routes; remove 'disabled' attribute to enable buttons
2941
		if( routes.left ) dom.controlsLeft.forEach( function( el ) { el.classList.add( 'enabled' ); el.removeAttribute( 'disabled' ); } );
2942
		if( routes.right ) dom.controlsRight.forEach( function( el ) { el.classList.add( 'enabled' ); el.removeAttribute( 'disabled' ); } );
2943
		if( routes.up ) dom.controlsUp.forEach( function( el ) { el.classList.add( 'enabled' ); el.removeAttribute( 'disabled' ); } );
2944
		if( routes.down ) dom.controlsDown.forEach( function( el ) { el.classList.add( 'enabled' ); el.removeAttribute( 'disabled' ); } );
2945

2946
		// Prev/next buttons
2947
		if( routes.left || routes.up ) dom.controlsPrev.forEach( function( el ) { el.classList.add( 'enabled' ); el.removeAttribute( 'disabled' ); } );
2948
		if( routes.right || routes.down ) dom.controlsNext.forEach( function( el ) { el.classList.add( 'enabled' ); el.removeAttribute( 'disabled' ); } );
2949

2950
		// Highlight fragment directions
2951
		if( currentSlide ) {
2952

2953
			// Always apply fragment decorator to prev/next buttons
2954
			if( fragments.prev ) dom.controlsPrev.forEach( function( el ) { el.classList.add( 'fragmented', 'enabled' ); el.removeAttribute( 'disabled' ); } );
2955
			if( fragments.next ) dom.controlsNext.forEach( function( el ) { el.classList.add( 'fragmented', 'enabled' ); el.removeAttribute( 'disabled' ); } );
2956

2957
			// Apply fragment decorators to directional buttons based on
2958
			// what slide axis they are in
2959
			if( isVerticalSlide( currentSlide ) ) {
2960
				if( fragments.prev ) dom.controlsUp.forEach( function( el ) { el.classList.add( 'fragmented', 'enabled' ); el.removeAttribute( 'disabled' ); } );
2961
				if( fragments.next ) dom.controlsDown.forEach( function( el ) { el.classList.add( 'fragmented', 'enabled' ); el.removeAttribute( 'disabled' ); } );
2962
			}
2963
			else {
2964
				if( fragments.prev ) dom.controlsLeft.forEach( function( el ) { el.classList.add( 'fragmented', 'enabled' ); el.removeAttribute( 'disabled' ); } );
2965
				if( fragments.next ) dom.controlsRight.forEach( function( el ) { el.classList.add( 'fragmented', 'enabled' ); el.removeAttribute( 'disabled' ); } );
2966
			}
2967

2968
		}
2969

2970
		if( config.controlsTutorial ) {
2971

2972
			// Highlight control arrows with an animation to ensure
2973
			// that the viewer knows how to navigate
2974
			if( !hasNavigatedDown && routes.down ) {
2975
				dom.controlsDownArrow.classList.add( 'highlight' );
2976
			}
2977
			else {
2978
				dom.controlsDownArrow.classList.remove( 'highlight' );
2979

2980
				if( !hasNavigatedRight && routes.right && indexv === 0 ) {
2981
					dom.controlsRightArrow.classList.add( 'highlight' );
2982
				}
2983
				else {
2984
					dom.controlsRightArrow.classList.remove( 'highlight' );
2985
				}
2986
			}
2987

2988
		}
2989

2990
	}
2991

2992
	/**
2993
	 * Updates the background elements to reflect the current
2994
	 * slide.
2995
	 *
2996
	 * @param {boolean} includeAll If true, the backgrounds of
2997
	 * all vertical slides (not just the present) will be updated.
2998
	 */
2999
	function updateBackground( includeAll ) {
3000

3001
		var currentBackground = null;
3002

3003
		// Reverse past/future classes when in RTL mode
3004
		var horizontalPast = config.rtl ? 'future' : 'past',
3005
			horizontalFuture = config.rtl ? 'past' : 'future';
3006

3007
		// Update the classes of all backgrounds to match the
3008
		// states of their slides (past/present/future)
3009
		toArray( dom.background.childNodes ).forEach( function( backgroundh, h ) {
3010

3011
			backgroundh.classList.remove( 'past' );
3012
			backgroundh.classList.remove( 'present' );
3013
			backgroundh.classList.remove( 'future' );
3014

3015
			if( h < indexh ) {
3016
				backgroundh.classList.add( horizontalPast );
3017
			}
3018
			else if ( h > indexh ) {
3019
				backgroundh.classList.add( horizontalFuture );
3020
			}
3021
			else {
3022
				backgroundh.classList.add( 'present' );
3023

3024
				// Store a reference to the current background element
3025
				currentBackground = backgroundh;
3026
			}
3027

3028
			if( includeAll || h === indexh ) {
3029
				toArray( backgroundh.querySelectorAll( '.slide-background' ) ).forEach( function( backgroundv, v ) {
3030

3031
					backgroundv.classList.remove( 'past' );
3032
					backgroundv.classList.remove( 'present' );
3033
					backgroundv.classList.remove( 'future' );
3034

3035
					if( v < indexv ) {
3036
						backgroundv.classList.add( 'past' );
3037
					}
3038
					else if ( v > indexv ) {
3039
						backgroundv.classList.add( 'future' );
3040
					}
3041
					else {
3042
						backgroundv.classList.add( 'present' );
3043

3044
						// Only if this is the present horizontal and vertical slide
3045
						if( h === indexh ) currentBackground = backgroundv;
3046
					}
3047

3048
				} );
3049
			}
3050

3051
		} );
3052

3053
		// Stop content inside of previous backgrounds
3054
		if( previousBackground ) {
3055

3056
			stopEmbeddedContent( previousBackground );
3057

3058
		}
3059

3060
		// Start content in the current background
3061
		if( currentBackground ) {
3062

3063
			startEmbeddedContent( currentBackground );
3064

3065
			var backgroundImageURL = currentBackground.style.backgroundImage || '';
3066

3067
			// Restart GIFs (doesn't work in Firefox)
3068
			if( /\.gif/i.test( backgroundImageURL ) ) {
3069
				currentBackground.style.backgroundImage = '';
3070
				window.getComputedStyle( currentBackground ).opacity;
3071
				currentBackground.style.backgroundImage = backgroundImageURL;
3072
			}
3073

3074
			// Don't transition between identical backgrounds. This
3075
			// prevents unwanted flicker.
3076
			var previousBackgroundHash = previousBackground ? previousBackground.getAttribute( 'data-background-hash' ) : null;
3077
			var currentBackgroundHash = currentBackground.getAttribute( 'data-background-hash' );
3078
			if( currentBackgroundHash && currentBackgroundHash === previousBackgroundHash && currentBackground !== previousBackground ) {
3079
				dom.background.classList.add( 'no-transition' );
3080
			}
3081

3082
			previousBackground = currentBackground;
3083

3084
		}
3085

3086
		// If there's a background brightness flag for this slide,
3087
		// bubble it to the .reveal container
3088
		if( currentSlide ) {
3089
			[ 'has-light-background', 'has-dark-background' ].forEach( function( classToBubble ) {
3090
				if( currentSlide.classList.contains( classToBubble ) ) {
3091
					dom.wrapper.classList.add( classToBubble );
3092
				}
3093
				else {
3094
					dom.wrapper.classList.remove( classToBubble );
3095
				}
3096
			} );
3097
		}
3098

3099
		// Allow the first background to apply without transition
3100
		setTimeout( function() {
3101
			dom.background.classList.remove( 'no-transition' );
3102
		}, 1 );
3103

3104
	}
3105

3106
	/**
3107
	 * Updates the position of the parallax background based
3108
	 * on the current slide index.
3109
	 */
3110
	function updateParallax() {
3111

3112
		if( config.parallaxBackgroundImage ) {
3113

3114
			var horizontalSlides = dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ),
3115
				verticalSlides = dom.wrapper.querySelectorAll( VERTICAL_SLIDES_SELECTOR );
3116

3117
			var backgroundSize = dom.background.style.backgroundSize.split( ' ' ),
3118
				backgroundWidth, backgroundHeight;
3119

3120
			if( backgroundSize.length === 1 ) {
3121
				backgroundWidth = backgroundHeight = parseInt( backgroundSize[0], 10 );
3122
			}
3123
			else {
3124
				backgroundWidth = parseInt( backgroundSize[0], 10 );
3125
				backgroundHeight = parseInt( backgroundSize[1], 10 );
3126
			}
3127

3128
			var slideWidth = dom.background.offsetWidth,
3129
				horizontalSlideCount = horizontalSlides.length,
3130
				horizontalOffsetMultiplier,
3131
				horizontalOffset;
3132

3133
			if( typeof config.parallaxBackgroundHorizontal === 'number' ) {
3134
				horizontalOffsetMultiplier = config.parallaxBackgroundHorizontal;
3135
			}
3136
			else {
3137
				horizontalOffsetMultiplier = horizontalSlideCount > 1 ? ( backgroundWidth - slideWidth ) / ( horizontalSlideCount-1 ) : 0;
3138
			}
3139

3140
			horizontalOffset = horizontalOffsetMultiplier * indexh * -1;
3141

3142
			var slideHeight = dom.background.offsetHeight,
3143
				verticalSlideCount = verticalSlides.length,
3144
				verticalOffsetMultiplier,
3145
				verticalOffset;
3146

3147
			if( typeof config.parallaxBackgroundVertical === 'number' ) {
3148
				verticalOffsetMultiplier = config.parallaxBackgroundVertical;
3149
			}
3150
			else {
3151
				verticalOffsetMultiplier = ( backgroundHeight - slideHeight ) / ( verticalSlideCount-1 );
3152
			}
3153

3154
			verticalOffset = verticalSlideCount > 0 ?  verticalOffsetMultiplier * indexv : 0;
3155

3156
			dom.background.style.backgroundPosition = horizontalOffset + 'px ' + -verticalOffset + 'px';
3157

3158
		}
3159

3160
	}
3161

3162
	/**
3163
	 * Called when the given slide is within the configured view
3164
	 * distance. Shows the slide element and loads any content
3165
	 * that is set to load lazily (data-src).
3166
	 *
3167
	 * @param {HTMLElement} slide Slide to show
3168
	 */
3169
	function loadSlide( slide, options ) {
3170

3171
		options = options || {};
3172

3173
		// Show the slide element
3174
		slide.style.display = config.display;
3175

3176
		// Media elements with data-src attributes
3177
		toArray( slide.querySelectorAll( 'img[data-src], video[data-src], audio[data-src]' ) ).forEach( function( element ) {
3178
			element.setAttribute( 'src', element.getAttribute( 'data-src' ) );
3179
			element.setAttribute( 'data-lazy-loaded', '' );
3180
			element.removeAttribute( 'data-src' );
3181
		} );
3182

3183
		// Media elements with <source> children
3184
		toArray( slide.querySelectorAll( 'video, audio' ) ).forEach( function( media ) {
3185
			var sources = 0;
3186

3187
			toArray( media.querySelectorAll( 'source[data-src]' ) ).forEach( function( source ) {
3188
				source.setAttribute( 'src', source.getAttribute( 'data-src' ) );
3189
				source.removeAttribute( 'data-src' );
3190
				source.setAttribute( 'data-lazy-loaded', '' );
3191
				sources += 1;
3192
			} );
3193

3194
			// If we rewrote sources for this video/audio element, we need
3195
			// to manually tell it to load from its new origin
3196
			if( sources > 0 ) {
3197
				media.load();
3198
			}
3199
		} );
3200

3201

3202
		// Show the corresponding background element
3203
		var indices = getIndices( slide );
3204
		var background = getSlideBackground( indices.h, indices.v );
3205
		if( background ) {
3206
			background.style.display = 'block';
3207

3208
			// If the background contains media, load it
3209
			if( background.hasAttribute( 'data-loaded' ) === false ) {
3210
				background.setAttribute( 'data-loaded', 'true' );
3211

3212
				var backgroundImage = slide.getAttribute( 'data-background-image' ),
3213
					backgroundVideo = slide.getAttribute( 'data-background-video' ),
3214
					backgroundVideoLoop = slide.hasAttribute( 'data-background-video-loop' ),
3215
					backgroundVideoMuted = slide.hasAttribute( 'data-background-video-muted' ),
3216
					backgroundIframe = slide.getAttribute( 'data-background-iframe' );
3217

3218
				// Images
3219
				if( backgroundImage ) {
3220
					background.style.backgroundImage = 'url('+ backgroundImage +')';
3221
				}
3222
				// Videos
3223
				else if ( backgroundVideo && !isSpeakerNotes() ) {
3224
					var video = document.createElement( 'video' );
3225

3226
					if( backgroundVideoLoop ) {
3227
						video.setAttribute( 'loop', '' );
3228
					}
3229

3230
					if( backgroundVideoMuted ) {
3231
						video.muted = true;
3232
					}
3233

3234
					// Inline video playback works (at least in Mobile Safari) as
3235
					// long as the video is muted and the `playsinline` attribute is
3236
					// present
3237
					if( isMobileDevice ) {
3238
						video.muted = true;
3239
						video.autoplay = true;
3240
						video.setAttribute( 'playsinline', '' );
3241
					}
3242

3243
					// Support comma separated lists of video sources
3244
					backgroundVideo.split( ',' ).forEach( function( source ) {
3245
						video.innerHTML += '<source src="'+ source +'">';
3246
					} );
3247

3248
					background.appendChild( video );
3249
				}
3250
				// Iframes
3251
				else if( backgroundIframe && options.excludeIframes !== true ) {
3252
					var iframe = document.createElement( 'iframe' );
3253
					iframe.setAttribute( 'allowfullscreen', '' );
3254
					iframe.setAttribute( 'mozallowfullscreen', '' );
3255
					iframe.setAttribute( 'webkitallowfullscreen', '' );
3256

3257
					// Only load autoplaying content when the slide is shown to
3258
					// avoid having it play in the background
3259
					if( /autoplay=(1|true|yes)/gi.test( backgroundIframe ) ) {
3260
						iframe.setAttribute( 'data-src', backgroundIframe );
3261
					}
3262
					else {
3263
						iframe.setAttribute( 'src', backgroundIframe );
3264
					}
3265

3266
					iframe.style.width  = '100%';
3267
					iframe.style.height = '100%';
3268
					iframe.style.maxHeight = '100%';
3269
					iframe.style.maxWidth = '100%';
3270

3271
					background.appendChild( iframe );
3272
				}
3273
			}
3274

3275
		}
3276

3277
	}
3278

3279
	/**
3280
	 * Unloads and hides the given slide. This is called when the
3281
	 * slide is moved outside of the configured view distance.
3282
	 *
3283
	 * @param {HTMLElement} slide
3284
	 */
3285
	function unloadSlide( slide ) {
3286

3287
		// Hide the slide element
3288
		slide.style.display = 'none';
3289

3290
		// Hide the corresponding background element
3291
		var indices = getIndices( slide );
3292
		var background = getSlideBackground( indices.h, indices.v );
3293
		if( background ) {
3294
			background.style.display = 'none';
3295
		}
3296

3297
		// Reset lazy-loaded media elements with src attributes
3298
		toArray( slide.querySelectorAll( 'video[data-lazy-loaded][src], audio[data-lazy-loaded][src]' ) ).forEach( function( element ) {
3299
			element.setAttribute( 'data-src', element.getAttribute( 'src' ) );
3300
			element.removeAttribute( 'src' );
3301
		} );
3302

3303
		// Reset lazy-loaded media elements with <source> children
3304
		toArray( slide.querySelectorAll( 'video[data-lazy-loaded] source[src], audio source[src]' ) ).forEach( function( source ) {
3305
			source.setAttribute( 'data-src', source.getAttribute( 'src' ) );
3306
			source.removeAttribute( 'src' );
3307
		} );
3308

3309
	}
3310

3311
	/**
3312
	 * Determine what available routes there are for navigation.
3313
	 *
3314
	 * @return {{left: boolean, right: boolean, up: boolean, down: boolean}}
3315
	 */
3316
	function availableRoutes() {
3317

3318
		var horizontalSlides = dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ),
3319
			verticalSlides = dom.wrapper.querySelectorAll( VERTICAL_SLIDES_SELECTOR );
3320

3321
		var routes = {
3322
			left: indexh > 0 || config.loop,
3323
			right: indexh < horizontalSlides.length - 1 || config.loop,
3324
			up: indexv > 0,
3325
			down: indexv < verticalSlides.length - 1
3326
		};
3327

3328
		// reverse horizontal controls for rtl
3329
		if( config.rtl ) {
3330
			var left = routes.left;
3331
			routes.left = routes.right;
3332
			routes.right = left;
3333
		}
3334

3335
		return routes;
3336

3337
	}
3338

3339
	/**
3340
	 * Returns an object describing the available fragment
3341
	 * directions.
3342
	 *
3343
	 * @return {{prev: boolean, next: boolean}}
3344
	 */
3345
	function availableFragments() {
3346

3347
		if( currentSlide && config.fragments ) {
3348
			var fragments = currentSlide.querySelectorAll( '.fragment' );
3349
			var hiddenFragments = currentSlide.querySelectorAll( '.fragment:not(.visible)' );
3350

3351
			return {
3352
				prev: fragments.length - hiddenFragments.length > 0,
3353
				next: !!hiddenFragments.length
3354
			};
3355
		}
3356
		else {
3357
			return { prev: false, next: false };
3358
		}
3359

3360
	}
3361

3362
	/**
3363
	 * Enforces origin-specific format rules for embedded media.
3364
	 */
3365
	function formatEmbeddedContent() {
3366

3367
		var _appendParamToIframeSource = function( sourceAttribute, sourceURL, param ) {
3368
			toArray( dom.slides.querySelectorAll( 'iframe['+ sourceAttribute +'*="'+ sourceURL +'"]' ) ).forEach( function( el ) {
3369
				var src = el.getAttribute( sourceAttribute );
3370
				if( src && src.indexOf( param ) === -1 ) {
3371
					el.setAttribute( sourceAttribute, src + ( !/\?/.test( src ) ? '?' : '&' ) + param );
3372
				}
3373
			});
3374
		};
3375

3376
		// YouTube frames must include "?enablejsapi=1"
3377
		_appendParamToIframeSource( 'src', 'youtube.com/embed/', 'enablejsapi=1' );
3378
		_appendParamToIframeSource( 'data-src', 'youtube.com/embed/', 'enablejsapi=1' );
3379

3380
		// Vimeo frames must include "?api=1"
3381
		_appendParamToIframeSource( 'src', 'player.vimeo.com/', 'api=1' );
3382
		_appendParamToIframeSource( 'data-src', 'player.vimeo.com/', 'api=1' );
3383

3384
		// Always show media controls on mobile devices
3385
		if( isMobileDevice ) {
3386
			toArray( dom.slides.querySelectorAll( 'video, audio' ) ).forEach( function( el ) {
3387
				el.controls = true;
3388
			} );
3389
		}
3390

3391
	}
3392

3393
	/**
3394
	 * Start playback of any embedded content inside of
3395
	 * the given element.
3396
	 *
3397
	 * @param {HTMLElement} element
3398
	 */
3399
	function startEmbeddedContent( element ) {
3400

3401
		if( element && !isSpeakerNotes() ) {
3402

3403
			// Restart GIFs
3404
			toArray( element.querySelectorAll( 'img[src$=".gif"]' ) ).forEach( function( el ) {
3405
				// Setting the same unchanged source like this was confirmed
3406
				// to work in Chrome, FF & Safari
3407
				el.setAttribute( 'src', el.getAttribute( 'src' ) );
3408
			} );
3409

3410
			// HTML5 media elements
3411
			toArray( element.querySelectorAll( 'video, audio' ) ).forEach( function( el ) {
3412
				if( closestParent( el, '.fragment' ) && !closestParent( el, '.fragment.visible' ) ) {
3413
					return;
3414
				}
3415

3416
				// Prefer an explicit global autoplay setting
3417
				var autoplay = config.autoPlayMedia;
3418

3419
				// If no global setting is available, fall back on the element's
3420
				// own autoplay setting
3421
				if( typeof autoplay !== 'boolean' ) {
3422
					autoplay = el.hasAttribute( 'data-autoplay' ) || !!closestParent( el, '.slide-background' );
3423
				}
3424

3425
				if( autoplay && typeof el.play === 'function' ) {
3426

3427
					if( el.readyState > 1 ) {
3428
						startEmbeddedMedia( { target: el } );
3429
					}
3430
					else {
3431
						el.removeEventListener( 'loadeddata', startEmbeddedMedia ); // remove first to avoid dupes
3432
						el.addEventListener( 'loadeddata', startEmbeddedMedia );
3433
					}
3434

3435
				}
3436
			} );
3437

3438
			// Normal iframes
3439
			toArray( element.querySelectorAll( 'iframe[src]' ) ).forEach( function( el ) {
3440
				if( closestParent( el, '.fragment' ) && !closestParent( el, '.fragment.visible' ) ) {
3441
					return;
3442
				}
3443

3444
				startEmbeddedIframe( { target: el } );
3445
			} );
3446

3447
			// Lazy loading iframes
3448
			toArray( element.querySelectorAll( 'iframe[data-src]' ) ).forEach( function( el ) {
3449
				if( closestParent( el, '.fragment' ) && !closestParent( el, '.fragment.visible' ) ) {
3450
					return;
3451
				}
3452

3453
				if( el.getAttribute( 'src' ) !== el.getAttribute( 'data-src' ) ) {
3454
					el.removeEventListener( 'load', startEmbeddedIframe ); // remove first to avoid dupes
3455
					el.addEventListener( 'load', startEmbeddedIframe );
3456
					el.setAttribute( 'src', el.getAttribute( 'data-src' ) );
3457
				}
3458
			} );
3459

3460
		}
3461

3462
	}
3463

3464
	/**
3465
	 * Starts playing an embedded video/audio element after
3466
	 * it has finished loading.
3467
	 *
3468
	 * @param {object} event
3469
	 */
3470
	function startEmbeddedMedia( event ) {
3471

3472
		var isAttachedToDOM = !!closestParent( event.target, 'html' ),
3473
			isVisible  		= !!closestParent( event.target, '.present' );
3474

3475
		if( isAttachedToDOM && isVisible ) {
3476
			event.target.currentTime = 0;
3477
			event.target.play();
3478
		}
3479

3480
		event.target.removeEventListener( 'loadeddata', startEmbeddedMedia );
3481

3482
	}
3483

3484
	/**
3485
	 * "Starts" the content of an embedded iframe using the
3486
	 * postMessage API.
3487
	 *
3488
	 * @param {object} event
3489
	 */
3490
	function startEmbeddedIframe( event ) {
3491

3492
		var iframe = event.target;
3493

3494
		if( iframe && iframe.contentWindow ) {
3495

3496
			var isAttachedToDOM = !!closestParent( event.target, 'html' ),
3497
				isVisible  		= !!closestParent( event.target, '.present' );
3498

3499
			if( isAttachedToDOM && isVisible ) {
3500

3501
				// Prefer an explicit global autoplay setting
3502
				var autoplay = config.autoPlayMedia;
3503

3504
				// If no global setting is available, fall back on the element's
3505
				// own autoplay setting
3506
				if( typeof autoplay !== 'boolean' ) {
3507
					autoplay = iframe.hasAttribute( 'data-autoplay' ) || !!closestParent( iframe, '.slide-background' );
3508
				}
3509

3510
				// YouTube postMessage API
3511
				if( /youtube\.com\/embed\//.test( iframe.getAttribute( 'src' ) ) && autoplay ) {
3512
					iframe.contentWindow.postMessage( '{"event":"command","func":"playVideo","args":""}', '*' );
3513
				}
3514
				// Vimeo postMessage API
3515
				else if( /player\.vimeo\.com\//.test( iframe.getAttribute( 'src' ) ) && autoplay ) {
3516
					iframe.contentWindow.postMessage( '{"method":"play"}', '*' );
3517
				}
3518
				// Generic postMessage API
3519
				else {
3520
					iframe.contentWindow.postMessage( 'slide:start', '*' );
3521
				}
3522

3523
			}
3524

3525
		}
3526

3527
	}
3528

3529
	/**
3530
	 * Stop playback of any embedded content inside of
3531
	 * the targeted slide.
3532
	 *
3533
	 * @param {HTMLElement} element
3534
	 */
3535
	function stopEmbeddedContent( element, options ) {
3536

3537
		options = extend( {
3538
			// Defaults
3539
			unloadIframes: true
3540
		}, options || {} );
3541

3542
		if( element && element.parentNode ) {
3543
			// HTML5 media elements
3544
			toArray( element.querySelectorAll( 'video, audio' ) ).forEach( function( el ) {
3545
				if( !el.hasAttribute( 'data-ignore' ) && typeof el.pause === 'function' ) {
3546
					el.setAttribute('data-paused-by-reveal', '');
3547
					el.pause();
3548
				}
3549
			} );
3550

3551
			// Generic postMessage API for non-lazy loaded iframes
3552
			toArray( element.querySelectorAll( 'iframe' ) ).forEach( function( el ) {
3553
				if( el.contentWindow ) el.contentWindow.postMessage( 'slide:stop', '*' );
3554
				el.removeEventListener( 'load', startEmbeddedIframe );
3555
			});
3556

3557
			// YouTube postMessage API
3558
			toArray( element.querySelectorAll( 'iframe[src*="youtube.com/embed/"]' ) ).forEach( function( el ) {
3559
				if( !el.hasAttribute( 'data-ignore' ) && el.contentWindow && typeof el.contentWindow.postMessage === 'function' ) {
3560
					el.contentWindow.postMessage( '{"event":"command","func":"pauseVideo","args":""}', '*' );
3561
				}
3562
			});
3563

3564
			// Vimeo postMessage API
3565
			toArray( element.querySelectorAll( 'iframe[src*="player.vimeo.com/"]' ) ).forEach( function( el ) {
3566
				if( !el.hasAttribute( 'data-ignore' ) && el.contentWindow && typeof el.contentWindow.postMessage === 'function' ) {
3567
					el.contentWindow.postMessage( '{"method":"pause"}', '*' );
3568
				}
3569
			});
3570

3571
			if( options.unloadIframes === true ) {
3572
				// Unload lazy-loaded iframes
3573
				toArray( element.querySelectorAll( 'iframe[data-src]' ) ).forEach( function( el ) {
3574
					// Only removing the src doesn't actually unload the frame
3575
					// in all browsers (Firefox) so we set it to blank first
3576
					el.setAttribute( 'src', 'about:blank' );
3577
					el.removeAttribute( 'src' );
3578
				} );
3579
			}
3580
		}
3581

3582
	}
3583

3584
	/**
3585
	 * Returns the number of past slides. This can be used as a global
3586
	 * flattened index for slides.
3587
	 *
3588
	 * @return {number} Past slide count
3589
	 */
3590
	function getSlidePastCount() {
3591

3592
		var horizontalSlides = toArray( dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) );
3593

3594
		// The number of past slides
3595
		var pastCount = 0;
3596

3597
		// Step through all slides and count the past ones
3598
		mainLoop: for( var i = 0; i < horizontalSlides.length; i++ ) {
3599

3600
			var horizontalSlide = horizontalSlides[i];
3601
			var verticalSlides = toArray( horizontalSlide.querySelectorAll( 'section' ) );
3602

3603
			for( var j = 0; j < verticalSlides.length; j++ ) {
3604

3605
				// Stop as soon as we arrive at the present
3606
				if( verticalSlides[j].classList.contains( 'present' ) ) {
3607
					break mainLoop;
3608
				}
3609

3610
				pastCount++;
3611

3612
			}
3613

3614
			// Stop as soon as we arrive at the present
3615
			if( horizontalSlide.classList.contains( 'present' ) ) {
3616
				break;
3617
			}
3618

3619
			// Don't count the wrapping section for vertical slides
3620
			if( horizontalSlide.classList.contains( 'stack' ) === false ) {
3621
				pastCount++;
3622
			}
3623

3624
		}
3625

3626
		return pastCount;
3627

3628
	}
3629

3630
	/**
3631
	 * Returns a value ranging from 0-1 that represents
3632
	 * how far into the presentation we have navigated.
3633
	 *
3634
	 * @return {number}
3635
	 */
3636
	function getProgress() {
3637

3638
		// The number of past and total slides
3639
		var totalCount = getTotalSlides();
3640
		var pastCount = getSlidePastCount();
3641

3642
		if( currentSlide ) {
3643

3644
			var allFragments = currentSlide.querySelectorAll( '.fragment' );
3645

3646
			// If there are fragments in the current slide those should be
3647
			// accounted for in the progress.
3648
			if( allFragments.length > 0 ) {
3649
				var visibleFragments = currentSlide.querySelectorAll( '.fragment.visible' );
3650

3651
				// This value represents how big a portion of the slide progress
3652
				// that is made up by its fragments (0-1)
3653
				var fragmentWeight = 0.9;
3654

3655
				// Add fragment progress to the past slide count
3656
				pastCount += ( visibleFragments.length / allFragments.length ) * fragmentWeight;
3657
			}
3658

3659
		}
3660

3661
		return pastCount / ( totalCount - 1 );
3662

3663
	}
3664

3665
	/**
3666
	 * Checks if this presentation is running inside of the
3667
	 * speaker notes window.
3668
	 *
3669
	 * @return {boolean}
3670
	 */
3671
	function isSpeakerNotes() {
3672

3673
		return !!window.location.search.match( /receiver/gi );
3674

3675
	}
3676

3677
	/**
3678
	 * Reads the current URL (hash) and navigates accordingly.
3679
	 */
3680
	function readURL() {
3681

3682
		var hash = window.location.hash;
3683

3684
		// Attempt to parse the hash as either an index or name
3685
		var bits = hash.slice( 2 ).split( '/' ),
3686
			name = hash.replace( /#|\//gi, '' );
3687

3688
		// If the first bit is invalid and there is a name we can
3689
		// assume that this is a named link
3690
		if( isNaN( parseInt( bits[0], 10 ) ) && name.length ) {
3691
			var element;
3692

3693
			// Ensure the named link is a valid HTML ID attribute
3694
			if( /^[a-zA-Z][\w:.-]*$/.test( name ) ) {
3695
				// Find the slide with the specified ID
3696
				element = document.getElementById( name );
3697
			}
3698

3699
			if( element ) {
3700
				// Find the position of the named slide and navigate to it
3701
				var indices = Reveal.getIndices( element );
3702
				slide( indices.h, indices.v );
3703
			}
3704
			// If the slide doesn't exist, navigate to the current slide
3705
			else {
3706
				slide( indexh || 0, indexv || 0 );
3707
			}
3708
		}
3709
		else {
3710
			// Read the index components of the hash
3711
			var h = parseInt( bits[0], 10 ) || 0,
3712
				v = parseInt( bits[1], 10 ) || 0;
3713

3714
			if( h !== indexh || v !== indexv ) {
3715
				slide( h, v );
3716
			}
3717
		}
3718

3719
	}
3720

3721
	/**
3722
	 * Updates the page URL (hash) to reflect the current
3723
	 * state.
3724
	 *
3725
	 * @param {number} delay The time in ms to wait before
3726
	 * writing the hash
3727
	 */
3728
	function writeURL( delay ) {
3729

3730
		if( config.history ) {
3731

3732
			// Make sure there's never more than one timeout running
3733
			clearTimeout( writeURLTimeout );
3734

3735
			// If a delay is specified, timeout this call
3736
			if( typeof delay === 'number' ) {
3737
				writeURLTimeout = setTimeout( writeURL, delay );
3738
			}
3739
			else if( currentSlide ) {
3740
				var url = '/';
3741

3742
				// Attempt to create a named link based on the slide's ID
3743
				var id = currentSlide.getAttribute( 'id' );
3744
				if( id ) {
3745
					id = id.replace( /[^a-zA-Z0-9\-\_\:\.]/g, '' );
3746
				}
3747

3748
				// If the current slide has an ID, use that as a named link
3749
				if( typeof id === 'string' && id.length ) {
3750
					url = '/' + id;
3751
				}
3752
				// Otherwise use the /h/v index
3753
				else {
3754
					if( indexh > 0 || indexv > 0 ) url += indexh;
3755
					if( indexv > 0 ) url += '/' + indexv;
3756
				}
3757

3758
				window.location.hash = url;
3759
			}
3760
		}
3761

3762
	}
3763
	/**
3764
	 * Retrieves the h/v location and fragment of the current,
3765
	 * or specified, slide.
3766
	 *
3767
	 * @param {HTMLElement} [slide] If specified, the returned
3768
	 * index will be for this slide rather than the currently
3769
	 * active one
3770
	 *
3771
	 * @return {{h: number, v: number, f: number}}
3772
	 */
3773
	function getIndices( slide ) {
3774

3775
		// By default, return the current indices
3776
		var h = indexh,
3777
			v = indexv,
3778
			f;
3779

3780
		// If a slide is specified, return the indices of that slide
3781
		if( slide ) {
3782
			var isVertical = isVerticalSlide( slide );
3783
			var slideh = isVertical ? slide.parentNode : slide;
3784

3785
			// Select all horizontal slides
3786
			var horizontalSlides = toArray( dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) );
3787

3788
			// Now that we know which the horizontal slide is, get its index
3789
			h = Math.max( horizontalSlides.indexOf( slideh ), 0 );
3790

3791
			// Assume we're not vertical
3792
			v = undefined;
3793

3794
			// If this is a vertical slide, grab the vertical index
3795
			if( isVertical ) {
3796
				v = Math.max( toArray( slide.parentNode.querySelectorAll( 'section' ) ).indexOf( slide ), 0 );
3797
			}
3798
		}
3799

3800
		if( !slide && currentSlide ) {
3801
			var hasFragments = currentSlide.querySelectorAll( '.fragment' ).length > 0;
3802
			if( hasFragments ) {
3803
				var currentFragment = currentSlide.querySelector( '.current-fragment' );
3804
				if( currentFragment && currentFragment.hasAttribute( 'data-fragment-index' ) ) {
3805
					f = parseInt( currentFragment.getAttribute( 'data-fragment-index' ), 10 );
3806
				}
3807
				else {
3808
					f = currentSlide.querySelectorAll( '.fragment.visible' ).length - 1;
3809
				}
3810
			}
3811
		}
3812

3813
		return { h: h, v: v, f: f };
3814

3815
	}
3816

3817
	/**
3818
	 * Retrieves all slides in this presentation.
3819
	 */
3820
	function getSlides() {
3821

3822
		return toArray( dom.wrapper.querySelectorAll( SLIDES_SELECTOR + ':not(.stack)' ));
3823

3824
	}
3825

3826
	/**
3827
	 * Retrieves the total number of slides in this presentation.
3828
	 *
3829
	 * @return {number}
3830
	 */
3831
	function getTotalSlides() {
3832

3833
		return getSlides().length;
3834

3835
	}
3836

3837
	/**
3838
	 * Returns the slide element matching the specified index.
3839
	 *
3840
	 * @return {HTMLElement}
3841
	 */
3842
	function getSlide( x, y ) {
3843

3844
		var horizontalSlide = dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR )[ x ];
3845
		var verticalSlides = horizontalSlide && horizontalSlide.querySelectorAll( 'section' );
3846

3847
		if( verticalSlides && verticalSlides.length && typeof y === 'number' ) {
3848
			return verticalSlides ? verticalSlides[ y ] : undefined;
3849
		}
3850

3851
		return horizontalSlide;
3852

3853
	}
3854

3855
	/**
3856
	 * Returns the background element for the given slide.
3857
	 * All slides, even the ones with no background properties
3858
	 * defined, have a background element so as long as the
3859
	 * index is valid an element will be returned.
3860
	 *
3861
	 * @param {number} x Horizontal background index
3862
	 * @param {number} y Vertical background index
3863
	 * @return {(HTMLElement[]|*)}
3864
	 */
3865
	function getSlideBackground( x, y ) {
3866

3867
		var slide = getSlide( x, y );
3868
		if( slide ) {
3869
			return slide.slideBackgroundElement;
3870
		}
3871

3872
		return undefined;
3873

3874
	}
3875

3876
	/**
3877
	 * Retrieves the speaker notes from a slide. Notes can be
3878
	 * defined in two ways:
3879
	 * 1. As a data-notes attribute on the slide <section>
3880
	 * 2. As an <aside class="notes"> inside of the slide
3881
	 *
3882
	 * @param {HTMLElement} [slide=currentSlide]
3883
	 * @return {(string|null)}
3884
	 */
3885
	function getSlideNotes( slide ) {
3886

3887
		// Default to the current slide
3888
		slide = slide || currentSlide;
3889

3890
		// Notes can be specified via the data-notes attribute...
3891
		if( slide.hasAttribute( 'data-notes' ) ) {
3892
			return slide.getAttribute( 'data-notes' );
3893
		}
3894

3895
		// ... or using an <aside class="notes"> element
3896
		var notesElement = slide.querySelector( 'aside.notes' );
3897
		if( notesElement ) {
3898
			return notesElement.innerHTML;
3899
		}
3900

3901
		return null;
3902

3903
	}
3904

3905
	/**
3906
	 * Retrieves the current state of the presentation as
3907
	 * an object. This state can then be restored at any
3908
	 * time.
3909
	 *
3910
	 * @return {{indexh: number, indexv: number, indexf: number, paused: boolean, overview: boolean}}
3911
	 */
3912
	function getState() {
3913

3914
		var indices = getIndices();
3915

3916
		return {
3917
			indexh: indices.h,
3918
			indexv: indices.v,
3919
			indexf: indices.f,
3920
			paused: isPaused(),
3921
			overview: isOverview()
3922
		};
3923

3924
	}
3925

3926
	/**
3927
	 * Restores the presentation to the given state.
3928
	 *
3929
	 * @param {object} state As generated by getState()
3930
	 * @see {@link getState} generates the parameter `state`
3931
	 */
3932
	function setState( state ) {
3933

3934
		if( typeof state === 'object' ) {
3935
			slide( deserialize( state.indexh ), deserialize( state.indexv ), deserialize( state.indexf ) );
3936

3937
			var pausedFlag = deserialize( state.paused ),
3938
				overviewFlag = deserialize( state.overview );
3939

3940
			if( typeof pausedFlag === 'boolean' && pausedFlag !== isPaused() ) {
3941
				togglePause( pausedFlag );
3942
			}
3943

3944
			if( typeof overviewFlag === 'boolean' && overviewFlag !== isOverview() ) {
3945
				toggleOverview( overviewFlag );
3946
			}
3947
		}
3948

3949
	}
3950

3951
	/**
3952
	 * Return a sorted fragments list, ordered by an increasing
3953
	 * "data-fragment-index" attribute.
3954
	 *
3955
	 * Fragments will be revealed in the order that they are returned by
3956
	 * this function, so you can use the index attributes to control the
3957
	 * order of fragment appearance.
3958
	 *
3959
	 * To maintain a sensible default fragment order, fragments are presumed
3960
	 * to be passed in document order. This function adds a "fragment-index"
3961
	 * attribute to each node if such an attribute is not already present,
3962
	 * and sets that attribute to an integer value which is the position of
3963
	 * the fragment within the fragments list.
3964
	 *
3965
	 * @param {object[]|*} fragments
3966
	 * @return {object[]} sorted Sorted array of fragments
3967
	 */
3968
	function sortFragments( fragments ) {
3969

3970
		fragments = toArray( fragments );
3971

3972
		var ordered = [],
3973
			unordered = [],
3974
			sorted = [];
3975

3976
		// Group ordered and unordered elements
3977
		fragments.forEach( function( fragment, i ) {
3978
			if( fragment.hasAttribute( 'data-fragment-index' ) ) {
3979
				var index = parseInt( fragment.getAttribute( 'data-fragment-index' ), 10 );
3980

3981
				if( !ordered[index] ) {
3982
					ordered[index] = [];
3983
				}
3984

3985
				ordered[index].push( fragment );
3986
			}
3987
			else {
3988
				unordered.push( [ fragment ] );
3989
			}
3990
		} );
3991

3992
		// Append fragments without explicit indices in their
3993
		// DOM order
3994
		ordered = ordered.concat( unordered );
3995

3996
		// Manually count the index up per group to ensure there
3997
		// are no gaps
3998
		var index = 0;
3999

4000
		// Push all fragments in their sorted order to an array,
4001
		// this flattens the groups
4002
		ordered.forEach( function( group ) {
4003
			group.forEach( function( fragment ) {
4004
				sorted.push( fragment );
4005
				fragment.setAttribute( 'data-fragment-index', index );
4006
			} );
4007

4008
			index ++;
4009
		} );
4010

4011
		return sorted;
4012

4013
	}
4014

4015
	/**
4016
	 * Navigate to the specified slide fragment.
4017
	 *
4018
	 * @param {?number} index The index of the fragment that
4019
	 * should be shown, -1 means all are invisible
4020
	 * @param {number} offset Integer offset to apply to the
4021
	 * fragment index
4022
	 *
4023
	 * @return {boolean} true if a change was made in any
4024
	 * fragments visibility as part of this call
4025
	 */
4026
	function navigateFragment( index, offset ) {
4027

4028
		if( currentSlide && config.fragments ) {
4029

4030
			var fragments = sortFragments( currentSlide.querySelectorAll( '.fragment' ) );
4031
			if( fragments.length ) {
4032

4033
				// If no index is specified, find the current
4034
				if( typeof index !== 'number' ) {
4035
					var lastVisibleFragment = sortFragments( currentSlide.querySelectorAll( '.fragment.visible' ) ).pop();
4036

4037
					if( lastVisibleFragment ) {
4038
						index = parseInt( lastVisibleFragment.getAttribute( 'data-fragment-index' ) || 0, 10 );
4039
					}
4040
					else {
4041
						index = -1;
4042
					}
4043
				}
4044

4045
				// If an offset is specified, apply it to the index
4046
				if( typeof offset === 'number' ) {
4047
					index += offset;
4048
				}
4049

4050
				var fragmentsShown = [],
4051
					fragmentsHidden = [];
4052

4053
				toArray( fragments ).forEach( function( element, i ) {
4054

4055
					if( element.hasAttribute( 'data-fragment-index' ) ) {
4056
						i = parseInt( element.getAttribute( 'data-fragment-index' ), 10 );
4057
					}
4058

4059
					// Visible fragments
4060
					if( i <= index ) {
4061
						if( !element.classList.contains( 'visible' ) ) fragmentsShown.push( element );
4062
						element.classList.add( 'visible' );
4063
						element.classList.remove( 'current-fragment' );
4064

4065
						// Announce the fragments one by one to the Screen Reader
4066
						dom.statusDiv.textContent = getStatusText( element );
4067

4068
						if( i === index ) {
4069
							element.classList.add( 'current-fragment' );
4070
							startEmbeddedContent( element );
4071
						}
4072
					}
4073
					// Hidden fragments
4074
					else {
4075
						if( element.classList.contains( 'visible' ) ) fragmentsHidden.push( element );
4076
						element.classList.remove( 'visible' );
4077
						element.classList.remove( 'current-fragment' );
4078
					}
4079

4080
				} );
4081

4082
				if( fragmentsHidden.length ) {
4083
					dispatchEvent( 'fragmenthidden', { fragment: fragmentsHidden[0], fragments: fragmentsHidden } );
4084
				}
4085

4086
				if( fragmentsShown.length ) {
4087
					dispatchEvent( 'fragmentshown', { fragment: fragmentsShown[0], fragments: fragmentsShown } );
4088
				}
4089

4090
				updateControls();
4091
				updateProgress();
4092

4093
				return !!( fragmentsShown.length || fragmentsHidden.length );
4094

4095
			}
4096

4097
		}
4098

4099
		return false;
4100

4101
	}
4102

4103
	/**
4104
	 * Navigate to the next slide fragment.
4105
	 *
4106
	 * @return {boolean} true if there was a next fragment,
4107
	 * false otherwise
4108
	 */
4109
	function nextFragment() {
4110

4111
		return navigateFragment( null, 1 );
4112

4113
	}
4114

4115
	/**
4116
	 * Navigate to the previous slide fragment.
4117
	 *
4118
	 * @return {boolean} true if there was a previous fragment,
4119
	 * false otherwise
4120
	 */
4121
	function previousFragment() {
4122

4123
		return navigateFragment( null, -1 );
4124

4125
	}
4126

4127
	/**
4128
	 * Cues a new automated slide if enabled in the config.
4129
	 */
4130
	function cueAutoSlide() {
4131

4132
		cancelAutoSlide();
4133

4134
		if( currentSlide && config.autoSlide !== false ) {
4135

4136
			var fragment = currentSlide.querySelector( '.current-fragment' );
4137

4138
			// When the slide first appears there is no "current" fragment so
4139
			// we look for a data-autoslide timing on the first fragment
4140
			if( !fragment ) fragment = currentSlide.querySelector( '.fragment' );
4141

4142
			var fragmentAutoSlide = fragment ? fragment.getAttribute( 'data-autoslide' ) : null;
4143
			var parentAutoSlide = currentSlide.parentNode ? currentSlide.parentNode.getAttribute( 'data-autoslide' ) : null;
4144
			var slideAutoSlide = currentSlide.getAttribute( 'data-autoslide' );
4145

4146
			// Pick value in the following priority order:
4147
			// 1. Current fragment's data-autoslide
4148
			// 2. Current slide's data-autoslide
4149
			// 3. Parent slide's data-autoslide
4150
			// 4. Global autoSlide setting
4151
			if( fragmentAutoSlide ) {
4152
				autoSlide = parseInt( fragmentAutoSlide, 10 );
4153
			}
4154
			else if( slideAutoSlide ) {
4155
				autoSlide = parseInt( slideAutoSlide, 10 );
4156
			}
4157
			else if( parentAutoSlide ) {
4158
				autoSlide = parseInt( parentAutoSlide, 10 );
4159
			}
4160
			else {
4161
				autoSlide = config.autoSlide;
4162
			}
4163

4164
			// If there are media elements with data-autoplay,
4165
			// automatically set the autoSlide duration to the
4166
			// length of that media. Not applicable if the slide
4167
			// is divided up into fragments.
4168
			// playbackRate is accounted for in the duration.
4169
			if( currentSlide.querySelectorAll( '.fragment' ).length === 0 ) {
4170
				toArray( currentSlide.querySelectorAll( 'video, audio' ) ).forEach( function( el ) {
4171
					if( el.hasAttribute( 'data-autoplay' ) ) {
4172
						if( autoSlide && (el.duration * 1000 / el.playbackRate ) > autoSlide ) {
4173
							autoSlide = ( el.duration * 1000 / el.playbackRate ) + 1000;
4174
						}
4175
					}
4176
				} );
4177
			}
4178

4179
			// Cue the next auto-slide if:
4180
			// - There is an autoSlide value
4181
			// - Auto-sliding isn't paused by the user
4182
			// - The presentation isn't paused
4183
			// - The overview isn't active
4184
			// - The presentation isn't over
4185
			if( autoSlide && !autoSlidePaused && !isPaused() && !isOverview() && ( !Reveal.isLastSlide() || availableFragments().next || config.loop === true ) ) {
4186
				autoSlideTimeout = setTimeout( function() {
4187
					typeof config.autoSlideMethod === 'function' ? config.autoSlideMethod() : navigateNext();
4188
					cueAutoSlide();
4189
				}, autoSlide );
4190
				autoSlideStartTime = Date.now();
4191
			}
4192

4193
			if( autoSlidePlayer ) {
4194
				autoSlidePlayer.setPlaying( autoSlideTimeout !== -1 );
4195
			}
4196

4197
		}
4198

4199
	}
4200

4201
	/**
4202
	 * Cancels any ongoing request to auto-slide.
4203
	 */
4204
	function cancelAutoSlide() {
4205

4206
		clearTimeout( autoSlideTimeout );
4207
		autoSlideTimeout = -1;
4208

4209
	}
4210

4211
	function pauseAutoSlide() {
4212

4213
		if( autoSlide && !autoSlidePaused ) {
4214
			autoSlidePaused = true;
4215
			dispatchEvent( 'autoslidepaused' );
4216
			clearTimeout( autoSlideTimeout );
4217

4218
			if( autoSlidePlayer ) {
4219
				autoSlidePlayer.setPlaying( false );
4220
			}
4221
		}
4222

4223
	}
4224

4225
	function resumeAutoSlide() {
4226

4227
		if( autoSlide && autoSlidePaused ) {
4228
			autoSlidePaused = false;
4229
			dispatchEvent( 'autoslideresumed' );
4230
			cueAutoSlide();
4231
		}
4232

4233
	}
4234

4235
	function navigateLeft() {
4236

4237
		// Reverse for RTL
4238
		if( config.rtl ) {
4239
			if( ( isOverview() || nextFragment() === false ) && availableRoutes().left ) {
4240
				slide( indexh + 1 );
4241
			}
4242
		}
4243
		// Normal navigation
4244
		else if( ( isOverview() || previousFragment() === false ) && availableRoutes().left ) {
4245
			slide( indexh - 1 );
4246
		}
4247

4248
	}
4249

4250
	function navigateRight() {
4251

4252
		hasNavigatedRight = true;
4253

4254
		// Reverse for RTL
4255
		if( config.rtl ) {
4256
			if( ( isOverview() || previousFragment() === false ) && availableRoutes().right ) {
4257
				slide( indexh - 1 );
4258
			}
4259
		}
4260
		// Normal navigation
4261
		else if( ( isOverview() || nextFragment() === false ) && availableRoutes().right ) {
4262
			slide( indexh + 1 );
4263
		}
4264

4265
	}
4266

4267
	function navigateUp() {
4268

4269
		// Prioritize hiding fragments
4270
		if( ( isOverview() || previousFragment() === false ) && availableRoutes().up ) {
4271
			slide( indexh, indexv - 1 );
4272
		}
4273

4274
	}
4275

4276
	function navigateDown() {
4277

4278
		hasNavigatedDown = true;
4279

4280
		// Prioritize revealing fragments
4281
		if( ( isOverview() || nextFragment() === false ) && availableRoutes().down ) {
4282
			slide( indexh, indexv + 1 );
4283
		}
4284

4285
	}
4286

4287
	/**
4288
	 * Navigates backwards, prioritized in the following order:
4289
	 * 1) Previous fragment
4290
	 * 2) Previous vertical slide
4291
	 * 3) Previous horizontal slide
4292
	 */
4293
	function navigatePrev() {
4294

4295
		// Prioritize revealing fragments
4296
		if( previousFragment() === false ) {
4297
			if( availableRoutes().up ) {
4298
				navigateUp();
4299
			}
4300
			else {
4301
				// Fetch the previous horizontal slide, if there is one
4302
				var previousSlide;
4303

4304
				if( config.rtl ) {
4305
					previousSlide = toArray( dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR + '.future' ) ).pop();
4306
				}
4307
				else {
4308
					previousSlide = toArray( dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR + '.past' ) ).pop();
4309
				}
4310

4311
				if( previousSlide ) {
4312
					var v = ( previousSlide.querySelectorAll( 'section' ).length - 1 ) || undefined;
4313
					var h = indexh - 1;
4314
					slide( h, v );
4315
				}
4316
			}
4317
		}
4318

4319
	}
4320

4321
	/**
4322
	 * The reverse of #navigatePrev().
4323
	 */
4324
	function navigateNext() {
4325

4326
		hasNavigatedRight = true;
4327
		hasNavigatedDown = true;
4328

4329
		// Prioritize revealing fragments
4330
		if( nextFragment() === false ) {
4331
			if( availableRoutes().down ) {
4332
				navigateDown();
4333
			}
4334
			else if( config.rtl ) {
4335
				navigateLeft();
4336
			}
4337
			else {
4338
				navigateRight();
4339
			}
4340
		}
4341

4342
	}
4343

4344
	/**
4345
	 * Checks if the target element prevents the triggering of
4346
	 * swipe navigation.
4347
	 */
4348
	function isSwipePrevented( target ) {
4349

4350
		while( target && typeof target.hasAttribute === 'function' ) {
4351
			if( target.hasAttribute( 'data-prevent-swipe' ) ) return true;
4352
			target = target.parentNode;
4353
		}
4354

4355
		return false;
4356

4357
	}
4358

4359

4360
	// --------------------------------------------------------------------//
4361
	// ----------------------------- EVENTS -------------------------------//
4362
	// --------------------------------------------------------------------//
4363

4364
	/**
4365
	 * Called by all event handlers that are based on user
4366
	 * input.
4367
	 *
4368
	 * @param {object} [event]
4369
	 */
4370
	function onUserInput( event ) {
4371

4372
		if( config.autoSlideStoppable ) {
4373
			pauseAutoSlide();
4374
		}
4375

4376
	}
4377

4378
	/**
4379
	 * Handler for the document level 'keypress' event.
4380
	 *
4381
	 * @param {object} event
4382
	 */
4383
	function onDocumentKeyPress( event ) {
4384

4385
		// Check if the pressed key is question mark
4386
		if( event.shiftKey && event.charCode === 63 ) {
4387
			toggleHelp();
4388
		}
4389

4390
	}
4391

4392
	/**
4393
	 * Handler for the document level 'keydown' event.
4394
	 *
4395
	 * @param {object} event
4396
	 */
4397
	function onDocumentKeyDown( event ) {
4398

4399
		// If there's a condition specified and it returns false,
4400
		// ignore this event
4401
		if( typeof config.keyboardCondition === 'function' && config.keyboardCondition() === false ) {
4402
			return true;
4403
		}
4404

4405
		// Remember if auto-sliding was paused so we can toggle it
4406
		var autoSlideWasPaused = autoSlidePaused;
4407

4408
		onUserInput( event );
4409

4410
		// Check if there's a focused element that could be using
4411
		// the keyboard
4412
		var activeElementIsCE = document.activeElement && document.activeElement.contentEditable !== 'inherit';
4413
		var activeElementIsInput = document.activeElement && document.activeElement.tagName && /input|textarea/i.test( document.activeElement.tagName );
4414
		var activeElementIsNotes = document.activeElement && document.activeElement.className && /speaker-notes/i.test( document.activeElement.className);
4415

4416
		// Disregard the event if there's a focused element or a
4417
		// keyboard modifier key is present
4418
		if( activeElementIsCE || activeElementIsInput || activeElementIsNotes || (event.shiftKey && event.keyCode !== 32) || event.altKey || event.ctrlKey || event.metaKey ) return;
4419

4420
		// While paused only allow resume keyboard events; 'b', 'v', '.'
4421
		var resumeKeyCodes = [66,86,190,191];
4422
		var key;
4423

4424
		// Custom key bindings for togglePause should be able to resume
4425
		if( typeof config.keyboard === 'object' ) {
4426
			for( key in config.keyboard ) {
4427
				if( config.keyboard[key] === 'togglePause' ) {
4428
					resumeKeyCodes.push( parseInt( key, 10 ) );
4429
				}
4430
			}
4431
		}
4432

4433
		if( isPaused() && resumeKeyCodes.indexOf( event.keyCode ) === -1 ) {
4434
			return false;
4435
		}
4436

4437
		var triggered = false;
4438

4439
		// 1. User defined key bindings
4440
		if( typeof config.keyboard === 'object' ) {
4441

4442
			for( key in config.keyboard ) {
4443

4444
				// Check if this binding matches the pressed key
4445
				if( parseInt( key, 10 ) === event.keyCode ) {
4446

4447
					var value = config.keyboard[ key ];
4448

4449
					// Callback function
4450
					if( typeof value === 'function' ) {
4451
						value.apply( null, [ event ] );
4452
					}
4453
					// String shortcuts to reveal.js API
4454
					else if( typeof value === 'string' && typeof Reveal[ value ] === 'function' ) {
4455
						Reveal[ value ].call();
4456
					}
4457

4458
					triggered = true;
4459

4460
				}
4461

4462
			}
4463

4464
		}
4465

4466
		// 2. System defined key bindings
4467
		if( triggered === false ) {
4468

4469
			// Assume true and try to prove false
4470
			triggered = true;
4471

4472
			switch( event.keyCode ) {
4473
				// p, page up
4474
				case 80: case 33: navigatePrev(); break;
4475
				// n, page down
4476
				case 78: case 34: navigateNext(); break;
4477
				// h, left
4478
				case 72: case 37: navigateLeft(); break;
4479
				// l, right
4480
				case 76: case 39: navigateRight(); break;
4481
				// k, up
4482
				case 75: case 38: navigateUp(); break;
4483
				// j, down
4484
				case 74: case 40: navigateDown(); break;
4485
				// home
4486
				case 36: slide( 0 ); break;
4487
				// end
4488
				case 35: slide( Number.MAX_VALUE ); break;
4489
				// space
4490
				case 32: isOverview() ? deactivateOverview() : event.shiftKey ? navigatePrev() : navigateNext(); break;
4491
				// return
4492
				case 13: isOverview() ? deactivateOverview() : triggered = false; break;
4493
				// two-spot, semicolon, b, v, period, Logitech presenter tools "black screen" button
4494
				case 58: case 59: case 66: case 86: case 190: case 191: togglePause(); break;
4495
				// f
4496
				case 70: enterFullscreen(); break;
4497
				// a
4498
				case 65: if ( config.autoSlideStoppable ) toggleAutoSlide( autoSlideWasPaused ); break;
4499
				default:
4500
					triggered = false;
4501
			}
4502

4503
		}
4504

4505
		// If the input resulted in a triggered action we should prevent
4506
		// the browsers default behavior
4507
		if( triggered ) {
4508
			event.preventDefault && event.preventDefault();
4509
		}
4510
		// ESC or O key
4511
		else if ( ( event.keyCode === 27 || event.keyCode === 79 ) && features.transforms3d ) {
4512
			if( dom.overlay ) {
4513
				closeOverlay();
4514
			}
4515
			else {
4516
				toggleOverview();
4517
			}
4518

4519
			event.preventDefault && event.preventDefault();
4520
		}
4521

4522
		// If auto-sliding is enabled we need to cue up
4523
		// another timeout
4524
		cueAutoSlide();
4525

4526
	}
4527

4528
	/**
4529
	 * Handler for the 'touchstart' event, enables support for
4530
	 * swipe and pinch gestures.
4531
	 *
4532
	 * @param {object} event
4533
	 */
4534
	function onTouchStart( event ) {
4535

4536
		if( isSwipePrevented( event.target ) ) return true;
4537

4538
		touch.startX = event.touches[0].clientX;
4539
		touch.startY = event.touches[0].clientY;
4540
		touch.startCount = event.touches.length;
4541

4542
		// If there's two touches we need to memorize the distance
4543
		// between those two points to detect pinching
4544
		if( event.touches.length === 2 && config.overview ) {
4545
			touch.startSpan = distanceBetween( {
4546
				x: event.touches[1].clientX,
4547
				y: event.touches[1].clientY
4548
			}, {
4549
				x: touch.startX,
4550
				y: touch.startY
4551
			} );
4552
		}
4553

4554
	}
4555

4556
	/**
4557
	 * Handler for the 'touchmove' event.
4558
	 *
4559
	 * @param {object} event
4560
	 */
4561
	function onTouchMove( event ) {
4562

4563
		if( isSwipePrevented( event.target ) ) return true;
4564

4565
		// Each touch should only trigger one action
4566
		if( !touch.captured ) {
4567
			onUserInput( event );
4568

4569
			var currentX = event.touches[0].clientX;
4570
			var currentY = event.touches[0].clientY;
4571

4572
			// If the touch started with two points and still has
4573
			// two active touches; test for the pinch gesture
4574
			if( event.touches.length === 2 && touch.startCount === 2 && config.overview ) {
4575

4576
				// The current distance in pixels between the two touch points
4577
				var currentSpan = distanceBetween( {
4578
					x: event.touches[1].clientX,
4579
					y: event.touches[1].clientY
4580
				}, {
4581
					x: touch.startX,
4582
					y: touch.startY
4583
				} );
4584

4585
				// If the span is larger than the desire amount we've got
4586
				// ourselves a pinch
4587
				if( Math.abs( touch.startSpan - currentSpan ) > touch.threshold ) {
4588
					touch.captured = true;
4589

4590
					if( currentSpan < touch.startSpan ) {
4591
						activateOverview();
4592
					}
4593
					else {
4594
						deactivateOverview();
4595
					}
4596
				}
4597

4598
				event.preventDefault();
4599

4600
			}
4601
			// There was only one touch point, look for a swipe
4602
			else if( event.touches.length === 1 && touch.startCount !== 2 ) {
4603

4604
				var deltaX = currentX - touch.startX,
4605
					deltaY = currentY - touch.startY;
4606

4607
				if( deltaX > touch.threshold && Math.abs( deltaX ) > Math.abs( deltaY ) ) {
4608
					touch.captured = true;
4609
					navigateLeft();
4610
				}
4611
				else if( deltaX < -touch.threshold && Math.abs( deltaX ) > Math.abs( deltaY ) ) {
4612
					touch.captured = true;
4613
					navigateRight();
4614
				}
4615
				else if( deltaY > touch.threshold ) {
4616
					touch.captured = true;
4617
					navigateUp();
4618
				}
4619
				else if( deltaY < -touch.threshold ) {
4620
					touch.captured = true;
4621
					navigateDown();
4622
				}
4623

4624
				// If we're embedded, only block touch events if they have
4625
				// triggered an action
4626
				if( config.embedded ) {
4627
					if( touch.captured || isVerticalSlide( currentSlide ) ) {
4628
						event.preventDefault();
4629
					}
4630
				}
4631
				// Not embedded? Block them all to avoid needless tossing
4632
				// around of the viewport in iOS
4633
				else {
4634
					event.preventDefault();
4635
				}
4636

4637
			}
4638
		}
4639
		// There's a bug with swiping on some Android devices unless
4640
		// the default action is always prevented
4641
		else if( UA.match( /android/gi ) ) {
4642
			event.preventDefault();
4643
		}
4644

4645
	}
4646

4647
	/**
4648
	 * Handler for the 'touchend' event.
4649
	 *
4650
	 * @param {object} event
4651
	 */
4652
	function onTouchEnd( event ) {
4653

4654
		touch.captured = false;
4655

4656
	}
4657

4658
	/**
4659
	 * Convert pointer down to touch start.
4660
	 *
4661
	 * @param {object} event
4662
	 */
4663
	function onPointerDown( event ) {
4664

4665
		if( event.pointerType === event.MSPOINTER_TYPE_TOUCH || event.pointerType === "touch" ) {
4666
			event.touches = [{ clientX: event.clientX, clientY: event.clientY }];
4667
			onTouchStart( event );
4668
		}
4669

4670
	}
4671

4672
	/**
4673
	 * Convert pointer move to touch move.
4674
	 *
4675
	 * @param {object} event
4676
	 */
4677
	function onPointerMove( event ) {
4678

4679
		if( event.pointerType === event.MSPOINTER_TYPE_TOUCH || event.pointerType === "touch" )  {
4680
			event.touches = [{ clientX: event.clientX, clientY: event.clientY }];
4681
			onTouchMove( event );
4682
		}
4683

4684
	}
4685

4686
	/**
4687
	 * Convert pointer up to touch end.
4688
	 *
4689
	 * @param {object} event
4690
	 */
4691
	function onPointerUp( event ) {
4692

4693
		if( event.pointerType === event.MSPOINTER_TYPE_TOUCH || event.pointerType === "touch" )  {
4694
			event.touches = [{ clientX: event.clientX, clientY: event.clientY }];
4695
			onTouchEnd( event );
4696
		}
4697

4698
	}
4699

4700
	/**
4701
	 * Handles mouse wheel scrolling, throttled to avoid skipping
4702
	 * multiple slides.
4703
	 *
4704
	 * @param {object} event
4705
	 */
4706
	function onDocumentMouseScroll( event ) {
4707

4708
		if( Date.now() - lastMouseWheelStep > 600 ) {
4709

4710
			lastMouseWheelStep = Date.now();
4711

4712
			var delta = event.detail || -event.wheelDelta;
4713
			if( delta > 0 ) {
4714
				navigateNext();
4715
			}
4716
			else if( delta < 0 ) {
4717
				navigatePrev();
4718
			}
4719

4720
		}
4721

4722
	}
4723

4724
	/**
4725
	 * Clicking on the progress bar results in a navigation to the
4726
	 * closest approximate horizontal slide using this equation:
4727
	 *
4728
	 * ( clickX / presentationWidth ) * numberOfSlides
4729
	 *
4730
	 * @param {object} event
4731
	 */
4732
	function onProgressClicked( event ) {
4733

4734
		onUserInput( event );
4735

4736
		event.preventDefault();
4737

4738
		var slidesTotal = toArray( dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) ).length;
4739
		var slideIndex = Math.floor( ( event.clientX / dom.wrapper.offsetWidth ) * slidesTotal );
4740

4741
		if( config.rtl ) {
4742
			slideIndex = slidesTotal - slideIndex;
4743
		}
4744

4745
		slide( slideIndex );
4746

4747
	}
4748

4749
	/**
4750
	 * Event handler for navigation control buttons.
4751
	 */
4752
	function onNavigateLeftClicked( event ) { event.preventDefault(); onUserInput(); navigateLeft(); }
4753
	function onNavigateRightClicked( event ) { event.preventDefault(); onUserInput(); navigateRight(); }
4754
	function onNavigateUpClicked( event ) { event.preventDefault(); onUserInput(); navigateUp(); }
4755
	function onNavigateDownClicked( event ) { event.preventDefault(); onUserInput(); navigateDown(); }
4756
	function onNavigatePrevClicked( event ) { event.preventDefault(); onUserInput(); navigatePrev(); }
4757
	function onNavigateNextClicked( event ) { event.preventDefault(); onUserInput(); navigateNext(); }
4758

4759
	/**
4760
	 * Handler for the window level 'hashchange' event.
4761
	 *
4762
	 * @param {object} [event]
4763
	 */
4764
	function onWindowHashChange( event ) {
4765

4766
		readURL();
4767

4768
	}
4769

4770
	/**
4771
	 * Handler for the window level 'resize' event.
4772
	 *
4773
	 * @param {object} [event]
4774
	 */
4775
	function onWindowResize( event ) {
4776

4777
		layout();
4778

4779
	}
4780

4781
	/**
4782
	 * Handle for the window level 'visibilitychange' event.
4783
	 *
4784
	 * @param {object} [event]
4785
	 */
4786
	function onPageVisibilityChange( event ) {
4787

4788
		var isHidden =  document.webkitHidden ||
4789
						document.msHidden ||
4790
						document.hidden;
4791

4792
		// If, after clicking a link or similar and we're coming back,
4793
		// focus the document.body to ensure we can use keyboard shortcuts
4794
		if( isHidden === false && document.activeElement !== document.body ) {
4795
			// Not all elements support .blur() - SVGs among them.
4796
			if( typeof document.activeElement.blur === 'function' ) {
4797
				document.activeElement.blur();
4798
			}
4799
			document.body.focus();
4800
		}
4801

4802
	}
4803

4804
	/**
4805
	 * Invoked when a slide is and we're in the overview.
4806
	 *
4807
	 * @param {object} event
4808
	 */
4809
	function onOverviewSlideClicked( event ) {
4810

4811
		// TODO There's a bug here where the event listeners are not
4812
		// removed after deactivating the overview.
4813
		if( eventsAreBound && isOverview() ) {
4814
			event.preventDefault();
4815

4816
			var element = event.target;
4817

4818
			while( element && !element.nodeName.match( /section/gi ) ) {
4819
				element = element.parentNode;
4820
			}
4821

4822
			if( element && !element.classList.contains( 'disabled' ) ) {
4823

4824
				deactivateOverview();
4825

4826
				if( element.nodeName.match( /section/gi ) ) {
4827
					var h = parseInt( element.getAttribute( 'data-index-h' ), 10 ),
4828
						v = parseInt( element.getAttribute( 'data-index-v' ), 10 );
4829

4830
					slide( h, v );
4831
				}
4832

4833
			}
4834
		}
4835

4836
	}
4837

4838
	/**
4839
	 * Handles clicks on links that are set to preview in the
4840
	 * iframe overlay.
4841
	 *
4842
	 * @param {object} event
4843
	 */
4844
	function onPreviewLinkClicked( event ) {
4845

4846
		if( event.currentTarget && event.currentTarget.hasAttribute( 'href' ) ) {
4847
			var url = event.currentTarget.getAttribute( 'href' );
4848
			if( url ) {
4849
				showPreview( url );
4850
				event.preventDefault();
4851
			}
4852
		}
4853

4854
	}
4855

4856
	/**
4857
	 * Handles click on the auto-sliding controls element.
4858
	 *
4859
	 * @param {object} [event]
4860
	 */
4861
	function onAutoSlidePlayerClick( event ) {
4862

4863
		// Replay
4864
		if( Reveal.isLastSlide() && config.loop === false ) {
4865
			slide( 0, 0 );
4866
			resumeAutoSlide();
4867
		}
4868
		// Resume
4869
		else if( autoSlidePaused ) {
4870
			resumeAutoSlide();
4871
		}
4872
		// Pause
4873
		else {
4874
			pauseAutoSlide();
4875
		}
4876

4877
	}
4878

4879

4880
	// --------------------------------------------------------------------//
4881
	// ------------------------ PLAYBACK COMPONENT ------------------------//
4882
	// --------------------------------------------------------------------//
4883

4884

4885
	/**
4886
	 * Constructor for the playback component, which displays
4887
	 * play/pause/progress controls.
4888
	 *
4889
	 * @param {HTMLElement} container The component will append
4890
	 * itself to this
4891
	 * @param {function} progressCheck A method which will be
4892
	 * called frequently to get the current progress on a range
4893
	 * of 0-1
4894
	 */
4895
	function Playback( container, progressCheck ) {
4896

4897
		// Cosmetics
4898
		this.diameter = 100;
4899
		this.diameter2 = this.diameter/2;
4900
		this.thickness = 6;
4901

4902
		// Flags if we are currently playing
4903
		this.playing = false;
4904

4905
		// Current progress on a 0-1 range
4906
		this.progress = 0;
4907

4908
		// Used to loop the animation smoothly
4909
		this.progressOffset = 1;
4910

4911
		this.container = container;
4912
		this.progressCheck = progressCheck;
4913

4914
		this.canvas = document.createElement( 'canvas' );
4915
		this.canvas.className = 'playback';
4916
		this.canvas.width = this.diameter;
4917
		this.canvas.height = this.diameter;
4918
		this.canvas.style.width = this.diameter2 + 'px';
4919
		this.canvas.style.height = this.diameter2 + 'px';
4920
		this.context = this.canvas.getContext( '2d' );
4921

4922
		this.container.appendChild( this.canvas );
4923

4924
		this.render();
4925

4926
	}
4927

4928
	/**
4929
	 * @param value
4930
	 */
4931
	Playback.prototype.setPlaying = function( value ) {
4932

4933
		var wasPlaying = this.playing;
4934

4935
		this.playing = value;
4936

4937
		// Start repainting if we weren't already
4938
		if( !wasPlaying && this.playing ) {
4939
			this.animate();
4940
		}
4941
		else {
4942
			this.render();
4943
		}
4944

4945
	};
4946

4947
	Playback.prototype.animate = function() {
4948

4949
		var progressBefore = this.progress;
4950

4951
		this.progress = this.progressCheck();
4952

4953
		// When we loop, offset the progress so that it eases
4954
		// smoothly rather than immediately resetting
4955
		if( progressBefore > 0.8 && this.progress < 0.2 ) {
4956
			this.progressOffset = this.progress;
4957
		}
4958

4959
		this.render();
4960

4961
		if( this.playing ) {
4962
			features.requestAnimationFrameMethod.call( window, this.animate.bind( this ) );
4963
		}
4964

4965
	};
4966

4967
	/**
4968
	 * Renders the current progress and playback state.
4969
	 */
4970
	Playback.prototype.render = function() {
4971

4972
		var progress = this.playing ? this.progress : 0,
4973
			radius = ( this.diameter2 ) - this.thickness,
4974
			x = this.diameter2,
4975
			y = this.diameter2,
4976
			iconSize = 28;
4977

4978
		// Ease towards 1
4979
		this.progressOffset += ( 1 - this.progressOffset ) * 0.1;
4980

4981
		var endAngle = ( - Math.PI / 2 ) + ( progress * ( Math.PI * 2 ) );
4982
		var startAngle = ( - Math.PI / 2 ) + ( this.progressOffset * ( Math.PI * 2 ) );
4983

4984
		this.context.save();
4985
		this.context.clearRect( 0, 0, this.diameter, this.diameter );
4986

4987
		// Solid background color
4988
		this.context.beginPath();
4989
		this.context.arc( x, y, radius + 4, 0, Math.PI * 2, false );
4990
		this.context.fillStyle = 'rgba( 0, 0, 0, 0.4 )';
4991
		this.context.fill();
4992

4993
		// Draw progress track
4994
		this.context.beginPath();
4995
		this.context.arc( x, y, radius, 0, Math.PI * 2, false );
4996
		this.context.lineWidth = this.thickness;
4997
		this.context.strokeStyle = 'rgba( 255, 255, 255, 0.2 )';
4998
		this.context.stroke();
4999

5000
		if( this.playing ) {
5001
			// Draw progress on top of track
5002
			this.context.beginPath();
5003
			this.context.arc( x, y, radius, startAngle, endAngle, false );
5004
			this.context.lineWidth = this.thickness;
5005
			this.context.strokeStyle = '#fff';
5006
			this.context.stroke();
5007
		}
5008

5009
		this.context.translate( x - ( iconSize / 2 ), y - ( iconSize / 2 ) );
5010

5011
		// Draw play/pause icons
5012
		if( this.playing ) {
5013
			this.context.fillStyle = '#fff';
5014
			this.context.fillRect( 0, 0, iconSize / 2 - 4, iconSize );
5015
			this.context.fillRect( iconSize / 2 + 4, 0, iconSize / 2 - 4, iconSize );
5016
		}
5017
		else {
5018
			this.context.beginPath();
5019
			this.context.translate( 4, 0 );
5020
			this.context.moveTo( 0, 0 );
5021
			this.context.lineTo( iconSize - 4, iconSize / 2 );
5022
			this.context.lineTo( 0, iconSize );
5023
			this.context.fillStyle = '#fff';
5024
			this.context.fill();
5025
		}
5026

5027
		this.context.restore();
5028

5029
	};
5030

5031
	Playback.prototype.on = function( type, listener ) {
5032
		this.canvas.addEventListener( type, listener, false );
5033
	};
5034

5035
	Playback.prototype.off = function( type, listener ) {
5036
		this.canvas.removeEventListener( type, listener, false );
5037
	};
5038

5039
	Playback.prototype.destroy = function() {
5040

5041
		this.playing = false;
5042

5043
		if( this.canvas.parentNode ) {
5044
			this.container.removeChild( this.canvas );
5045
		}
5046

5047
	};
5048

5049

5050
	// --------------------------------------------------------------------//
5051
	// ------------------------------- API --------------------------------//
5052
	// --------------------------------------------------------------------//
5053

5054

5055
	Reveal = {
5056
		VERSION: VERSION,
5057

5058
		initialize: initialize,
5059
		configure: configure,
5060
		sync: sync,
5061

5062
		// Navigation methods
5063
		slide: slide,
5064
		left: navigateLeft,
5065
		right: navigateRight,
5066
		up: navigateUp,
5067
		down: navigateDown,
5068
		prev: navigatePrev,
5069
		next: navigateNext,
5070

5071
		// Fragment methods
5072
		navigateFragment: navigateFragment,
5073
		prevFragment: previousFragment,
5074
		nextFragment: nextFragment,
5075

5076
		// Deprecated aliases
5077
		navigateTo: slide,
5078
		navigateLeft: navigateLeft,
5079
		navigateRight: navigateRight,
5080
		navigateUp: navigateUp,
5081
		navigateDown: navigateDown,
5082
		navigatePrev: navigatePrev,
5083
		navigateNext: navigateNext,
5084

5085
		// Forces an update in slide layout
5086
		layout: layout,
5087

5088
		// Randomizes the order of slides
5089
		shuffle: shuffle,
5090

5091
		// Returns an object with the available routes as booleans (left/right/top/bottom)
5092
		availableRoutes: availableRoutes,
5093

5094
		// Returns an object with the available fragments as booleans (prev/next)
5095
		availableFragments: availableFragments,
5096

5097
		// Toggles a help overlay with keyboard shortcuts
5098
		toggleHelp: toggleHelp,
5099

5100
		// Toggles the overview mode on/off
5101
		toggleOverview: toggleOverview,
5102

5103
		// Toggles the "black screen" mode on/off
5104
		togglePause: togglePause,
5105

5106
		// Toggles the auto slide mode on/off
5107
		toggleAutoSlide: toggleAutoSlide,
5108

5109
		// State checks
5110
		isOverview: isOverview,
5111
		isPaused: isPaused,
5112
		isAutoSliding: isAutoSliding,
5113
		isSpeakerNotes: isSpeakerNotes,
5114

5115
		// Slide preloading
5116
		loadSlide: loadSlide,
5117
		unloadSlide: unloadSlide,
5118

5119
		// Adds or removes all internal event listeners (such as keyboard)
5120
		addEventListeners: addEventListeners,
5121
		removeEventListeners: removeEventListeners,
5122

5123
		// Facility for persisting and restoring the presentation state
5124
		getState: getState,
5125
		setState: setState,
5126

5127
		// Presentation progress
5128
		getSlidePastCount: getSlidePastCount,
5129

5130
		// Presentation progress on range of 0-1
5131
		getProgress: getProgress,
5132

5133
		// Returns the indices of the current, or specified, slide
5134
		getIndices: getIndices,
5135

5136
		// Returns an Array of all slides
5137
		getSlides: getSlides,
5138

5139
		// Returns the total number of slides
5140
		getTotalSlides: getTotalSlides,
5141

5142
		// Returns the slide element at the specified index
5143
		getSlide: getSlide,
5144

5145
		// Returns the slide background element at the specified index
5146
		getSlideBackground: getSlideBackground,
5147

5148
		// Returns the speaker notes string for a slide, or null
5149
		getSlideNotes: getSlideNotes,
5150

5151
		// Returns the previous slide element, may be null
5152
		getPreviousSlide: function() {
5153
			return previousSlide;
5154
		},
5155

5156
		// Returns the current slide element
5157
		getCurrentSlide: function() {
5158
			return currentSlide;
5159
		},
5160

5161
		// Returns the current scale of the presentation content
5162
		getScale: function() {
5163
			return scale;
5164
		},
5165

5166
		// Returns the current configuration object
5167
		getConfig: function() {
5168
			return config;
5169
		},
5170

5171
		// Helper method, retrieves query string as a key/value hash
5172
		getQueryHash: function() {
5173
			var query = {};
5174

5175
			location.search.replace( /[A-Z0-9]+?=([\w\.%-]*)/gi, function(a) {
5176
				query[ a.split( '=' ).shift() ] = a.split( '=' ).pop();
5177
			} );
5178

5179
			// Basic deserialization
5180
			for( var i in query ) {
5181
				var value = query[ i ];
5182

5183
				query[ i ] = deserialize( unescape( value ) );
5184
			}
5185

5186
			return query;
5187
		},
5188

5189
		// Returns true if we're currently on the first slide
5190
		isFirstSlide: function() {
5191
			return ( indexh === 0 && indexv === 0 );
5192
		},
5193

5194
		// Returns true if we're currently on the last slide
5195
		isLastSlide: function() {
5196
			if( currentSlide ) {
5197
				// Does this slide has next a sibling?
5198
				if( currentSlide.nextElementSibling ) return false;
5199

5200
				// If it's vertical, does its parent have a next sibling?
5201
				if( isVerticalSlide( currentSlide ) && currentSlide.parentNode.nextElementSibling ) return false;
5202

5203
				return true;
5204
			}
5205

5206
			return false;
5207
		},
5208

5209
		// Checks if reveal.js has been loaded and is ready for use
5210
		isReady: function() {
5211
			return loaded;
5212
		},
5213

5214
		// Forward event binding to the reveal DOM element
5215
		addEventListener: function( type, listener, useCapture ) {
5216
			if( 'addEventListener' in window ) {
5217
				( dom.wrapper || document.querySelector( '.reveal' ) ).addEventListener( type, listener, useCapture );
5218
			}
5219
		},
5220
		removeEventListener: function( type, listener, useCapture ) {
5221
			if( 'addEventListener' in window ) {
5222
				( dom.wrapper || document.querySelector( '.reveal' ) ).removeEventListener( type, listener, useCapture );
5223
			}
5224
		},
5225

5226
		// Programatically triggers a keyboard event
5227
		triggerKey: function( keyCode ) {
5228
			onDocumentKeyDown( { keyCode: keyCode } );
5229
		},
5230

5231
		// Registers a new shortcut to include in the help overlay
5232
		registerKeyboardShortcut: function( key, value ) {
5233
			keyboardShortcuts[key] = value;
5234
		}
5235
	};
5236

5237
	return Reveal;
5238

5239
}));
5240

5241