js/reveal.js

   1 /*!
   2  * reveal.js
   3  * http://lab.hakim.se/reveal-js
   4  * MIT licensed
   5  *
   6  * Copyright (C) 2011-2013 Hakim El Hattab, http://hakim.se
   7  */
   8 var Reveal = (function(){
   9
  10         'use strict';
  11
  12         var SLIDES_SELECTOR = '.reveal .slides section',
  13                 HORIZONTAL_SLIDES_SELECTOR = '.reveal .slides>section',
  14                 VERTICAL_SLIDES_SELECTOR = '.reveal .slides>section.present>section',
  15                 HOME_SLIDE_SELECTOR = '.reveal .slides>section:first-child',
  16
  17                 // Configurations defaults, can be overridden at initialization time
  18                 config = {
  19
  20                         // The "normal" size of the presentation, aspect ratio will be preserved
  21                         // when the presentation is scaled to fit different resolutions
  22                         width: 960,
  23                         height: 700,
  24
  25                         // Factor of the display size that should remain empty around the content
  26                         margin: 0.1,
  27
  28                         // Bounds for smallest/largest possible scale to apply to content
  29                         minScale: 0.2,
  30                         maxScale: 1.0,
  31
  32                         // Display controls in the bottom right corner
  33                         controls: true,
  34
  35                         // Display a presentation progress bar
  36                         progress: true,
  37
  38                         // Push each slide change to the browser history
  39                         history: false,
  40
  41                         // Enable keyboard shortcuts for navigation
  42                         keyboard: true,
  43
  44                         // Enable the slide overview mode
  45                         overview: true,
  46
  47                         // Vertical centering of slides
  48                         center: true,
  49
  50                         // Enables touch navigation on devices with touch input
  51                         touch: true,
  52
  53                         // Loop the presentation
  54                         loop: false,
  55
  56                         // Change the presentation direction to be RTL
  57                         rtl: false,
  58
  59                         // Number of milliseconds between automatically proceeding to the
  60                         // next slide, disabled when set to 0, this value can be overwritten
  61                         // by using a data-autoslide attribute on your slides
  62                         autoSlide: 0,
  63
  64                         // Enable slide navigation via mouse wheel
  65                         mouseWheel: false,
  66
  67                         // Apply a 3D roll to links on hover
  68                         rollingLinks: true,
  69
  70                         // Theme (see /css/theme)
  71                         theme: null,
  72
  73                         // Transition style
  74                         transition: 'default', // default/cube/page/concave/zoom/linear/fade/none
  75
  76                         // Script dependencies to load
  77                         dependencies: []
  78                 },
  79
  80                 // Stores if the next slide should be shown automatically
  81                 // after n milliseconds
  82                 autoSlide = config.autoSlide,
  83
  84                 // The horizontal and verical index of the currently active slide
  85                 indexh = 0,
  86                 indexv = 0,
  87
  88                 // The previous and current slide HTML elements
  89                 previousSlide,
  90                 currentSlide,
  91
  92                 // Slides may hold a data-state attribute which we pick up and apply
  93                 // as a class to the body. This list contains the combined state of
  94                 // all current slides.
  95                 state = [],
  96
  97                 // The current scale of the presentation (see width/height config)
  98                 scale = 1,
  99
 100                 // Cached references to DOM elements
 101                 dom = {},
 102
 103                 // Detect support for CSS 3D transforms
 104                 supports3DTransforms =  'WebkitPerspective' in document.body.style ||
 105                                                                 'MozPerspective' in document.body.style ||
 106                                                                 'msPerspective' in document.body.style ||
 107                                                                 'OPerspective' in document.body.style ||
 108                                                                 'perspective' in document.body.style,
 109
 110                 // Detect support for CSS 2D transforms
 111                 supports2DTransforms =  'WebkitTransform' in document.body.style ||
 112                                                                 'MozTransform' in document.body.style ||
 113                                                                 'msTransform' in document.body.style ||
 114                                                                 'OTransform' in document.body.style ||
 115                                                                 'transform' in document.body.style,
 116
 117                 // Throttles mouse wheel navigation
 118                 mouseWheelTimeout = 0,
 119
 120                 // An interval used to automatically move on to the next slide
 121                 autoSlideTimeout = 0,
 122
 123                 // Delays updates to the URL due to a Chrome thumbnailer bug
 124                 writeURLTimeout = 0,
 125
 126                 // A delay used to activate the overview mode
 127                 activateOverviewTimeout = 0,
 128
 129                 // A delay used to deactivate the overview mode
 130                 deactivateOverviewTimeout = 0,
 131
 132                 // Holds information about the currently ongoing touch input
 133                 touch = {
 134                         startX: 0,
 135                         startY: 0,
 136                         startSpan: 0,
 137                         startCount: 0,
 138                         handled: false,
 139                         threshold: 80
 140                 };
 141
 142         /**
 143          * Starts up the presentation if the client is capable.
 144          */
 145         function initialize( options ) {
 146
 147                 if( !supports2DTransforms && !supports3DTransforms ) {
 148                         document.body.setAttribute( 'class', 'no-transforms' );
 149
 150                         // If the browser doesn't support core features we won't be
 151                         // using JavaScript to control the presentation
 152                         return;
 153                 }
 154
 155                 // Force a layout when the whole page, incl fonts, has loaded
 156                 window.addEventListener( 'load', layout, false );
 157
 158                 // Copy options over to our config object
 159                 extend( config, options );
 160
 161                 // Hide the address bar in mobile browsers
 162                 hideAddressBar();
 163
 164                 // Loads the dependencies and continues to #start() once done
 165                 load();
 166
 167         }
 168
 169         /**
 170          * Finds and stores references to DOM elements which are
 171          * required by the presentation. If a required element is
 172          * not found, it is created.
 173          */
 174         function setupDOM() {
 175
 176                 // Cache references to key DOM elements
 177                 dom.theme = document.querySelector( '#theme' );
 178                 dom.wrapper = document.querySelector( '.reveal' );
 179                 dom.slides = document.querySelector( '.reveal .slides' );
 180
 181                 // Progress bar
 182                 if( !dom.wrapper.querySelector( '.progress' ) && config.progress ) {
 183                         var progressElement = document.createElement( 'div' );
 184                         progressElement.classList.add( 'progress' );
 185                         progressElement.innerHTML = '<span></span>';
 186                         dom.wrapper.appendChild( progressElement );
 187                 }
 188
 189                 // Arrow controls
 190                 if( !dom.wrapper.querySelector( '.controls' ) && config.controls ) {
 191                         var controlsElement = document.createElement( 'aside' );
 192                         controlsElement.classList.add( 'controls' );
 193                         controlsElement.innerHTML = '<div class="navigate-left"></div>' +
 194                                                                                 '<div class="navigate-right"></div>' +
 195                                                                                 '<div class="navigate-up"></div>' +
 196                                                                                 '<div class="navigate-down"></div>';
 197                         dom.wrapper.appendChild( controlsElement );
 198                 }
 199
 200                 // Presentation background element
 201                 if( !dom.wrapper.querySelector( '.state-background' ) ) {
 202                         var backgroundElement = document.createElement( 'div' );
 203                         backgroundElement.classList.add( 'state-background' );
 204                         dom.wrapper.appendChild( backgroundElement );
 205                 }
 206
 207                 // Overlay graphic which is displayed during the paused mode
 208                 if( !dom.wrapper.querySelector( '.pause-overlay' ) ) {
 209                         var pausedElement = document.createElement( 'div' );
 210                         pausedElement.classList.add( 'pause-overlay' );
 211                         dom.wrapper.appendChild( pausedElement );
 212                 }
 213
 214                 // Cache references to elements
 215                 dom.progress = document.querySelector( '.reveal .progress' );
 216                 dom.progressbar = document.querySelector( '.reveal .progress span' );
 217
 218                 if ( config.controls ) {
 219                         dom.controls = document.querySelector( '.reveal .controls' );
 220
 221                         // There can be multiple instances of controls throughout the page
 222                         dom.controlsLeft = toArray( document.querySelectorAll( '.navigate-left' ) );
 223                         dom.controlsRight = toArray( document.querySelectorAll( '.navigate-right' ) );
 224                         dom.controlsUp = toArray( document.querySelectorAll( '.navigate-up' ) );
 225                         dom.controlsDown = toArray( document.querySelectorAll( '.navigate-down' ) );
 226                         dom.controlsPrev = toArray( document.querySelectorAll( '.navigate-prev' ) );
 227                         dom.controlsNext = toArray( document.querySelectorAll( '.navigate-next' ) );
 228                 }
 229
 230         }
 231
 232         /**
 233          * Hides the address bar if we're on a mobile device.
 234          */
 235         function hideAddressBar() {
 236
 237                 if( navigator.userAgent.match( /(iphone|ipod)/i ) ) {
 238                         // Events that should trigger the address bar to hide
 239                         window.addEventListener( 'load', removeAddressBar, false );
 240                         window.addEventListener( 'orientationchange', removeAddressBar, false );
 241                 }
 242
 243         }
 244
 245         /**
 246          * Loads the dependencies of reveal.js. Dependencies are
 247          * defined via the configuration option 'dependencies'
 248          * and will be loaded prior to starting/binding reveal.js.
 249          * Some dependencies may have an 'async' flag, if so they
 250          * will load after reveal.js has been started up.
 251          */
 252         function load() {
 253
 254                 var scripts = [],
 255                         scriptsAsync = [];
 256
 257                 for( var i = 0, len = config.dependencies.length; i < len; i++ ) {
 258                         var s = config.dependencies[i];
 259
 260                         // Load if there's no condition or the condition is truthy
 261                         if( !s.condition || s.condition() ) {
 262                                 if( s.async ) {
 263                                         scriptsAsync.push( s.src );
 264                                 }
 265                                 else {
 266                                         scripts.push( s.src );
 267                                 }
 268
 269                                 // Extension may contain callback functions
 270                                 if( typeof s.callback === 'function' ) {
 271                                         head.ready( s.src.match( /([\w\d_\-]*)\.?js$|[^\\\/]*$/i )[0], s.callback );
 272                                 }
 273                         }
 274                 }
 275
 276                 // Called once synchronous scritps finish loading
 277                 function proceed() {
 278                         if( scriptsAsync.length ) {
 279                                 // Load asynchronous scripts
 280                                 head.js.apply( null, scriptsAsync );
 281                         }
 282
 283                         start();
 284                 }
 285
 286                 if( scripts.length ) {
 287                         head.ready( proceed );
 288
 289                         // Load synchronous scripts
 290                         head.js.apply( null, scripts );
 291                 }
 292                 else {
 293                         proceed();
 294                 }
 295
 296         }
 297
 298         /**
 299          * Starts up reveal.js by binding input events and navigating
 300          * to the current URL deeplink if there is one.
 301          */
 302         function start() {
 303
 304                 // Make sure we've got all the DOM elements we need
 305                 setupDOM();
 306
 307                 // Subscribe to input
 308                 addEventListeners();
 309
 310                 // Updates the presentation to match the current configuration values
 311                 configure();
 312
 313                 // Force an initial layout, will thereafter be invoked as the window
 314                 // is resized
 315                 layout();
 316
 317                 // Read the initial hash
 318                 readURL();
 319
 320                 // Start auto-sliding if it's enabled
 321                 cueAutoSlide();
 322
 323                 // Notify listeners that the presentation is ready but use a 1ms
 324                 // timeout to ensure it's not fired synchronously after #initialize()
 325                 setTimeout( function() {
 326                         dispatchEvent( 'ready', {
 327                                 'indexh': indexh,
 328                                 'indexv': indexv,
 329                                 'currentSlide': currentSlide
 330                         } );
 331                 }, 1 );
 332
 333         }
 334
 335         /**
 336          * Applies the configuration settings from the config object.
 337          */
 338         function configure() {
 339
 340                 if( supports3DTransforms === false ) {
 341                         config.transition = 'linear';
 342                 }
 343
 344                 if( config.controls && dom.controls ) {
 345                         dom.controls.style.display = 'block';
 346                 }
 347
 348                 if( config.progress && dom.progress ) {
 349                         dom.progress.style.display = 'block';
 350                 }
 351
 352                 if( config.transition !== 'default' ) {
 353                         dom.wrapper.classList.add( config.transition );
 354                 }
 355
 356                 if( config.rtl ) {
 357                         dom.wrapper.classList.add( 'rtl' );
 358                 }
 359
 360                 if( config.center ) {
 361                         dom.wrapper.classList.add( 'center' );
 362                 }
 363
 364                 if( config.mouseWheel ) {
 365                         document.addEventListener( 'DOMMouseScroll', onDocumentMouseScroll, false ); // FF
 366                         document.addEventListener( 'mousewheel', onDocumentMouseScroll, false );
 367                 }
 368
 369                 // 3D links
 370                 if( config.rollingLinks ) {
 371                         linkify();
 372                 }
 373
 374                 // Load the theme in the config, if it's not already loaded
 375                 if( config.theme && dom.theme ) {
 376                         var themeURL = dom.theme.getAttribute( 'href' );
 377                         var themeFinder = /[^\/]*?(?=\.css)/;
 378                         var themeName = themeURL.match(themeFinder)[0];
 379
 380                         if(  config.theme !== themeName ) {
 381                                 themeURL = themeURL.replace(themeFinder, config.theme);
 382                                 dom.theme.setAttribute( 'href', themeURL );
 383                         }
 384                 }
 385
 386         }
 387
 388         /**
 389          * Binds all event listeners.
 390          */
 391         function addEventListeners() {
 392
 393                 window.addEventListener( 'hashchange', onWindowHashChange, false );
 394                 window.addEventListener( 'resize', onWindowResize, false );
 395
 396                 if( config.touch ) {
 397                         document.addEventListener( 'touchstart', onDocumentTouchStart, false );
 398                         document.addEventListener( 'touchmove', onDocumentTouchMove, false );
 399                         document.addEventListener( 'touchend', onDocumentTouchEnd, false );
 400                 }
 401
 402                 if( config.keyboard ) {
 403                         document.addEventListener( 'keydown', onDocumentKeyDown, false );
 404                 }
 405
 406                 if ( config.progress && dom.progress ) {
 407                         dom.progress.addEventListener( 'click', preventAndForward( onProgressClick ), false );
 408                 }
 409
 410                 if ( config.controls && dom.controls ) {
 411                         var actionEvent = 'ontouchstart' in window ? 'touchstart' : 'click';
 412                         dom.controlsLeft.forEach( function( el ) { el.addEventListener( actionEvent, preventAndForward( navigateLeft ), false ); } );
 413                         dom.controlsRight.forEach( function( el ) { el.addEventListener( actionEvent, preventAndForward( navigateRight ), false ); } );
 414                         dom.controlsUp.forEach( function( el ) { el.addEventListener( actionEvent, preventAndForward( navigateUp ), false ); } );
 415                         dom.controlsDown.forEach( function( el ) { el.addEventListener( actionEvent, preventAndForward( navigateDown ), false ); } );
 416                         dom.controlsPrev.forEach( function( el ) { el.addEventListener( actionEvent, preventAndForward( navigatePrev ), false ); } );
 417                         dom.controlsNext.forEach( function( el ) { el.addEventListener( actionEvent, preventAndForward( navigateNext ), false ); } );
 418                 }
 419
 420         }
 421
 422         /**
 423          * Unbinds all event listeners.
 424          */
 425         function removeEventListeners() {
 426
 427                 document.removeEventListener( 'keydown', onDocumentKeyDown, false );
 428                 window.removeEventListener( 'hashchange', onWindowHashChange, false );
 429                 window.removeEventListener( 'resize', onWindowResize, false );
 430
 431                 if( config.touch ) {
 432                         document.removeEventListener( 'touchstart', onDocumentTouchStart, false );
 433                         document.removeEventListener( 'touchmove', onDocumentTouchMove, false );
 434                         document.removeEventListener( 'touchend', onDocumentTouchEnd, false );
 435                 }
 436
 437                 if ( config.progress && dom.progress ) {
 438                         dom.progress.removeEventListener( 'click', preventAndForward( onProgressClick ), false );
 439                 }
 440
 441                 if ( config.controls && dom.controls ) {
 442                         var actionEvent = 'ontouchstart' in window ? 'touchstart' : 'click';
 443                         dom.controlsLeft.forEach( function( el ) { el.removeEventListener( actionEvent, preventAndForward( navigateLeft ), false ); } );
 444                         dom.controlsRight.forEach( function( el ) { el.removeEventListener( actionEvent, preventAndForward( navigateRight ), false ); } );
 445                         dom.controlsUp.forEach( function( el ) { el.removeEventListener( actionEvent, preventAndForward( navigateUp ), false ); } );
 446                         dom.controlsDown.forEach( function( el ) { el.removeEventListener( actionEvent, preventAndForward( navigateDown ), false ); } );
 447                         dom.controlsPrev.forEach( function( el ) { el.removeEventListener( actionEvent, preventAndForward( navigatePrev ), false ); } );
 448                         dom.controlsNext.forEach( function( el ) { el.removeEventListener( actionEvent, preventAndForward( navigateNext ), false ); } );
 449                 }
 450
 451         }
 452
 453         /**
 454          * Extend object a with the properties of object b.
 455          * If there's a conflict, object b takes precedence.
 456          */
 457         function extend( a, b ) {
 458
 459                 for( var i in b ) {
 460                         a[ i ] = b[ i ];
 461                 }
 462
 463         }
 464
 465         /**
 466          * Converts the target object to an array.
 467          */
 468         function toArray( o ) {
 469
 470                 return Array.prototype.slice.call( o );
 471
 472         }
 473
 474         /**
 475          * Measures the distance in pixels between point a
 476          * and point b.
 477          *
 478          * @param {Object} a point with x/y properties
 479          * @param {Object} b point with x/y properties
 480          */
 481         function distanceBetween( a, b ) {
 482
 483                 var dx = a.x - b.x,
 484                         dy = a.y - b.y;
 485
 486                 return Math.sqrt( dx*dx + dy*dy );
 487
 488         }
 489
 490         /**
 491          * Prevents an events defaults behavior calls the
 492          * specified delegate.
 493          *
 494          * @param {Function} delegate The method to call
 495          * after the wrapper has been executed
 496          */
 497         function preventAndForward( delegate ) {
 498
 499                 return function( event ) {
 500                         event.preventDefault();
 501                         delegate.call( null, event );
 502                 };
 503
 504         }
 505
 506         /**
 507          * Causes the address bar to hide on mobile devices,
 508          * more vertical space ftw.
 509          */
 510         function removeAddressBar() {
 511
 512                 if( window.orientation === 0 ) {
 513                         document.documentElement.style.overflow = 'scroll';
 514                         document.body.style.height = '120%';
 515                 }
 516                 else {
 517                         document.documentElement.style.overflow = '';
 518                         document.body.style.height = '100%';
 519                 }
 520
 521                 setTimeout( function() {
 522                         window.scrollTo( 0, 1 );
 523                 }, 10 );
 524
 525         }
 526
 527         /**
 528          * Dispatches an event of the specified type from the
 529          * reveal DOM element.
 530          */
 531         function dispatchEvent( type, properties ) {
 532
 533                 var event = document.createEvent( "HTMLEvents", 1, 2 );
 534                 event.initEvent( type, true, true );
 535                 extend( event, properties );
 536                 dom.wrapper.dispatchEvent( event );
 537
 538         }
 539
 540         /**
 541          * Wrap all links in 3D goodness.
 542          */
 543         function linkify() {
 544
 545                 if( supports3DTransforms && !( 'msPerspective' in document.body.style ) ) {
 546                         var nodes = document.querySelectorAll( SLIDES_SELECTOR + ' a:not(.image)' );
 547
 548                         for( var i = 0, len = nodes.length; i < len; i++ ) {
 549                                 var node = nodes[i];
 550
 551                                 if( node.textContent && !node.querySelector( '*' ) && ( !node.className || !node.classList.contains( node, 'roll' ) ) ) {
 552                                         var span = document.createElement('span');
 553                                         span.setAttribute('data-title', node.text);
 554                                         span.innerHTML = node.innerHTML;
 555
 556                                         node.classList.add( 'roll' );
 557                                         node.innerHTML = '';
 558                                         node.appendChild(span);
 559                                 }
 560                         }
 561                 }
 562
 563         }
 564
 565         /**
 566          * Applies JavaScript-controlled layout rules to the
 567          * presentation.
 568          */
 569         function layout() {
 570
 571                 // Available space to scale within
 572                 var availableWidth = dom.wrapper.offsetWidth,
 573                         availableHeight = dom.wrapper.offsetHeight;
 574
 575                 // Reduce availabe space by margin
 576                 availableWidth -= ( availableHeight * config.margin );
 577                 availableHeight -= ( availableHeight * config.margin );
 578
 579                 // Dimensions of the content
 580                 var slideWidth = config.width,
 581                         slideHeight = config.height;
 582
 583                 // Slide width may be a percentage of available width
 584                 if( typeof slideWidth === 'string' && /%$/.test( slideWidth ) ) {
 585                         slideWidth = parseInt( slideWidth, 10 ) / 100 * availableWidth;
 586                 }
 587
 588                 // Slide height may be a percentage of available height
 589                 if( typeof slideHeight === 'string' && /%$/.test( slideHeight ) ) {
 590                         slideHeight = parseInt( slideHeight, 10 ) / 100 * availableHeight;
 591                 }
 592
 593                 dom.slides.style.width = slideWidth + 'px';
 594                 dom.slides.style.height = slideHeight + 'px';
 595
 596                 // Determine scale of content to fit within available space
 597                 scale = Math.min( availableWidth / slideWidth, availableHeight / slideHeight );
 598
 599                 // Respect max/min scale settings
 600                 scale = Math.max( scale, config.minScale );
 601                 scale = Math.min( scale, config.maxScale );
 602
 603                 // Prefer applying scale via zoom since Chrome blurs scaled content
 604                 // with nested transforms
 605                 if( typeof dom.slides.style.zoom !== 'undefined' && !navigator.userAgent.match( /(iphone|ipod|android)/gi ) ) {
 606                         dom.slides.style.zoom = scale;
 607                 }
 608                 // Apply scale transform as a fallback
 609                 else {
 610                         var transform = 'translate(-50%, -50%) scale('+ scale +') translate(50%, 50%)';
 611
 612                         dom.slides.style.WebkitTransform = transform;
 613                         dom.slides.style.MozTransform = transform;
 614                         dom.slides.style.msTransform = transform;
 615                         dom.slides.style.OTransform = transform;
 616                         dom.slides.style.transform = transform;
 617                 }
 618
 619                 if( config.center ) {
 620
 621                         // Select all slides, vertical and horizontal
 622                         var slides = toArray( document.querySelectorAll( SLIDES_SELECTOR ) );
 623
 624                         // Determine the minimum top offset for slides
 625                         var minTop = -slideHeight / 2;
 626
 627                         for( var i = 0, len = slides.length; i < len; i++ ) {
 628                                 var slide = slides[ i ];
 629
 630                                 // Don't bother updating invisible slides
 631                                 if( slide.style.display === 'none' ) {
 632                                         continue;
 633                                 }
 634
 635                                 // Vertical stacks are not centered since their section
 636                                 // children will be
 637                                 if( slide.classList.contains( 'stack' ) ) {
 638                                         slide.style.top = 0;
 639                                 }
 640                                 else {
 641                                         slide.style.top = Math.max( - ( slide.offsetHeight / 2 ) - 20, minTop ) + 'px';
 642                                 }
 643                         }
 644
 645                 }
 646
 647         }
 648
 649         /**
 650          * Stores the vertical index of a stack so that the same
 651          * vertical slide can be selected when navigating to and
 652          * from the stack.
 653          *
 654          * @param {HTMLElement} stack The vertical stack element
 655          * @param {int} v Index to memorize
 656          */
 657         function setPreviousVerticalIndex( stack, v ) {
 658
 659                 if( stack ) {
 660                         stack.setAttribute( 'data-previous-indexv', v || 0 );
 661                 }
 662
 663         }
 664
 665         /**
 666          * Retrieves the vertical index which was stored using
 667          * #setPreviousVerticalIndex() or 0 if no previous index
 668          * exists.
 669          *
 670          * @param {HTMLElement} stack The vertical stack element
 671          */
 672         function getPreviousVerticalIndex( stack ) {
 673
 674                 if( stack && stack.classList.contains( 'stack' ) ) {
 675                         return parseInt( stack.getAttribute( 'data-previous-indexv' ) || 0, 10 );
 676                 }
 677
 678                 return 0;
 679
 680         }
 681
 682         /**
 683          * Displays the overview of slides (quick nav) by
 684          * scaling down and arranging all slide elements.
 685          *
 686          * Experimental feature, might be dropped if perf
 687          * can't be improved.
 688          */
 689         function activateOverview() {
 690
 691                 // Only proceed if enabled in config
 692                 if( config.overview ) {
 693
 694                         var wasActive = dom.wrapper.classList.contains( 'overview' );
 695
 696                         dom.wrapper.classList.add( 'overview' );
 697                         dom.wrapper.classList.remove( 'exit-overview' );
 698
 699                         clearTimeout( activateOverviewTimeout );
 700                         clearTimeout( deactivateOverviewTimeout );
 701
 702                         // Not the pretties solution, but need to let the overview
 703                         // class apply first so that slides are measured accurately
 704                         // before we can position them
 705                         activateOverviewTimeout = setTimeout( function(){
 706
 707                                 var horizontalSlides = document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR );
 708
 709                                 for( var i = 0, len1 = horizontalSlides.length; i < len1; i++ ) {
 710                                         var hslide = horizontalSlides[i],
 711                                                 htransform = 'translateZ(-2500px) translate(' + ( ( i - indexh ) * 105 ) + '%, 0%)';
 712
 713                                         hslide.setAttribute( 'data-index-h', i );
 714                                         hslide.style.display = 'block';
 715                                         hslide.style.WebkitTransform = htransform;
 716                                         hslide.style.MozTransform = htransform;
 717                                         hslide.style.msTransform = htransform;
 718                                         hslide.style.OTransform = htransform;
 719                                         hslide.style.transform = htransform;
 720
 721                                         if( hslide.classList.contains( 'stack' ) ) {
 722
 723                                                 var verticalSlides = hslide.querySelectorAll( 'section' );
 724
 725                                                 for( var j = 0, len2 = verticalSlides.length; j < len2; j++ ) {
 726                                                         var verticalIndex = i === indexh ? indexv : getPreviousVerticalIndex( hslide );
 727
 728                                                         var vslide = verticalSlides[j],
 729                                                                 vtransform = 'translate(0%, ' + ( ( j - verticalIndex ) * 105 ) + '%)';
 730
 731                                                         vslide.setAttribute( 'data-index-h', i );
 732                                                         vslide.setAttribute( 'data-index-v', j );
 733                                                         vslide.style.display = 'block';
 734                                                         vslide.style.WebkitTransform = vtransform;
 735                                                         vslide.style.MozTransform = vtransform;
 736                                                         vslide.style.msTransform = vtransform;
 737                                                         vslide.style.OTransform = vtransform;
 738                                                         vslide.style.transform = vtransform;
 739
 740                                                         // Navigate to this slide on click
 741                                                         vslide.addEventListener( 'click', onOverviewSlideClicked, true );
 742                                                 }
 743
 744                                         }
 745                                         else {
 746
 747                                                 // Navigate to this slide on click
 748                                                 hslide.addEventListener( 'click', onOverviewSlideClicked, true );
 749
 750                                         }
 751                                 }
 752
 753                                 layout();
 754
 755                                 if( !wasActive ) {
 756                                         // Notify observers of the overview showing
 757                                         dispatchEvent( 'overviewshown', {
 758                                                 'indexh': indexh,
 759                                                 'indexv': indexv,
 760                                                 'currentSlide': currentSlide
 761                                         } );
 762                                 }
 763
 764                         }, 10 );
 765
 766                 }
 767
 768         }
 769
 770         /**
 771          * Exits the slide overview and enters the currently
 772          * active slide.
 773          */
 774         function deactivateOverview() {
 775
 776                 // Only proceed if enabled in config
 777                 if( config.overview ) {
 778
 779                         clearTimeout( activateOverviewTimeout );
 780                         clearTimeout( deactivateOverviewTimeout );
 781
 782                         dom.wrapper.classList.remove( 'overview' );
 783
 784                         // Temporarily add a class so that transitions can do different things
 785                         // depending on whether they are exiting/entering overview, or just
 786                         // moving from slide to slide
 787                         dom.wrapper.classList.add( 'exit-overview' );
 788
 789                         deactivateOverviewTimeout = setTimeout( function () {
 790                                 dom.wrapper.classList.remove( 'exit-overview' );
 791                         }, 10);
 792
 793                         // Select all slides
 794                         var slides = toArray( document.querySelectorAll( SLIDES_SELECTOR ) );
 795
 796                         for( var i = 0, len = slides.length; i < len; i++ ) {
 797                                 var element = slides[i];
 798
 799                                 element.style.display = '';
 800
 801                                 // Resets all transforms to use the external styles
 802                                 element.style.WebkitTransform = '';
 803                                 element.style.MozTransform = '';
 804                                 element.style.msTransform = '';
 805                                 element.style.OTransform = '';
 806                                 element.style.transform = '';
 807
 808                                 element.removeEventListener( 'click', onOverviewSlideClicked, true );
 809                         }
 810
 811                         slide( indexh, indexv );
 812
 813                         // Notify observers of the overview hiding
 814                         dispatchEvent( 'overviewhidden', {
 815                                 'indexh': indexh,
 816                                 'indexv': indexv,
 817                                 'currentSlide': currentSlide
 818                         } );
 819
 820                 }
 821         }
 822
 823         /**
 824          * Toggles the slide overview mode on and off.
 825          *
 826          * @param {Boolean} override Optional flag which overrides the
 827          * toggle logic and forcibly sets the desired state. True means
 828          * overview is open, false means it's closed.
 829          */
 830         function toggleOverview( override ) {
 831
 832                 if( typeof override === 'boolean' ) {
 833                         override ? activateOverview() : deactivateOverview();
 834                 }
 835                 else {
 836                         isOverviewActive() ? deactivateOverview() : activateOverview();
 837                 }
 838
 839         }
 840
 841         /**
 842          * Checks if the overview is currently active.
 843          *
 844          * @return {Boolean} true if the overview is active,
 845          * false otherwise
 846          */
 847         function isOverviewActive() {
 848
 849                 return dom.wrapper.classList.contains( 'overview' );
 850
 851         }
 852
 853         /**
 854          * Handling the fullscreen functionality via the fullscreen API
 855          *
 856          * @see http://fullscreen.spec.whatwg.org/
 857          * @see https://developer.mozilla.org/en-US/docs/DOM/Using_fullscreen_mode
 858          */
 859         function enterFullscreen() {
 860
 861                 var element = document.body;
 862
 863                 // Check which implementation is available
 864                 var requestMethod = element.requestFullScreen ||
 865                                                         element.webkitRequestFullScreen ||
 866                                                         element.mozRequestFullScreen ||
 867                                                         element.msRequestFullScreen;
 868
 869                 if( requestMethod ) {
 870                         requestMethod.apply( element );
 871                 }
 872
 873         }
 874
 875         /**
 876          * Enters the paused mode which fades everything on screen to
 877          * black.
 878          */
 879         function pause() {
 880
 881                 dom.wrapper.classList.add( 'paused' );
 882
 883         }
 884
 885         /**
 886          * Exits from the paused mode.
 887          */
 888         function resume() {
 889
 890                 dom.wrapper.classList.remove( 'paused' );
 891
 892         }
 893
 894         /**
 895          * Toggles the paused mode on and off.
 896          */
 897         function togglePause() {
 898
 899                 if( isPaused() ) {
 900                         resume();
 901                 }
 902                 else {
 903                         pause();
 904                 }
 905
 906         }
 907
 908         /**
 909          * Checks if we are currently in the paused mode.
 910          */
 911         function isPaused() {
 912
 913                 return dom.wrapper.classList.contains( 'paused' );
 914
 915         }
 916
 917         /**
 918          * Steps from the current point in the presentation to the
 919          * slide which matches the specified horizontal and vertical
 920          * indices.
 921          *
 922          * @param {int} h Horizontal index of the target slide
 923          * @param {int} v Vertical index of the target slide
 924          * @param {int} f Optional index of a fragment within the
 925          * target slide to activate
 926          */
 927         function slide( h, v, f ) {
 928
 929                 // Remember where we were at before
 930                 previousSlide = currentSlide;
 931
 932                 // Query all horizontal slides in the deck
 933                 var horizontalSlides = document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR );
 934
 935                 // If no vertical index is specified and the upcoming slide is a
 936                 // stack, resume at its previous vertical index
 937                 if( v === undefined ) {
 938                         v = getPreviousVerticalIndex( horizontalSlides[ h ] );
 939                 }
 940
 941                 // If we were on a vertical stack, remember what vertical index
 942                 // it was on so we can resume at the same position when returning
 943                 if( previousSlide && previousSlide.parentNode && previousSlide.parentNode.classList.contains( 'stack' ) ) {
 944                         setPreviousVerticalIndex( previousSlide.parentNode, indexv );
 945                 }
 946
 947                 // Remember the state before this slide
 948                 var stateBefore = state.concat();
 949
 950                 // Reset the state array
 951                 state.length = 0;
 952
 953                 var indexhBefore = indexh,
 954                         indexvBefore = indexv;
 955
 956                 // Activate and transition to the new slide
 957                 indexh = updateSlides( HORIZONTAL_SLIDES_SELECTOR, h === undefined ? indexh : h );
 958                 indexv = updateSlides( VERTICAL_SLIDES_SELECTOR, v === undefined ? indexv : v );
 959
 960                 layout();
 961
 962                 // Apply the new state
 963                 stateLoop: for( var i = 0, len = state.length; i < len; i++ ) {
 964                         // Check if this state existed on the previous slide. If it
 965                         // did, we will avoid adding it repeatedly
 966                         for( var j = 0; j < stateBefore.length; j++ ) {
 967                                 if( stateBefore[j] === state[i] ) {
 968                                         stateBefore.splice( j, 1 );
 969                                         continue stateLoop;
 970                                 }
 971                         }
 972
 973                         document.documentElement.classList.add( state[i] );
 974
 975                         // Dispatch custom event matching the state's name
 976                         dispatchEvent( state[i] );
 977                 }
 978
 979                 // Clean up the remains of the previous state
 980                 while( stateBefore.length ) {
 981                         document.documentElement.classList.remove( stateBefore.pop() );
 982                 }
 983
 984                 // If the overview is active, re-activate it to update positions
 985                 if( isOverviewActive() ) {
 986                         activateOverview();
 987                 }
 988
 989                 // Update the URL hash after a delay since updating it mid-transition
 990                 // is likely to cause visual lag
 991                 writeURL( 1500 );
 992
 993                 // Find the current horizontal slide and any possible vertical slides
 994                 // within it
 995                 var currentHorizontalSlide = horizontalSlides[ indexh ],
 996                         currentVerticalSlides = currentHorizontalSlide.querySelectorAll( 'section' );
 997
 998                 // Store references to the previous and current slides
 999                 currentSlide = currentVerticalSlides[ indexv ] || currentHorizontalSlide;
1000
1001
1002                 // Show fragment, if specified
1003                 if( typeof f !== 'undefined' ) {
1004                         var fragments = currentSlide.querySelectorAll( '.fragment' );
1005
1006                         toArray( fragments ).forEach( function( fragment, indexf ) {
1007                                 if( indexf < f ) {
1008                                         fragment.classList.add( 'visible' );
1009                                 }
1010                                 else {
1011                                         fragment.classList.remove( 'visible' );
1012                                 }
1013                         } );
1014                 }
1015
1016                 // Dispatch an event if the slide changed
1017                 if( indexh !== indexhBefore || indexv !== indexvBefore ) {
1018                         dispatchEvent( 'slidechanged', {
1019                                 'indexh': indexh,
1020                                 'indexv': indexv,
1021                                 'previousSlide': previousSlide,
1022                                 'currentSlide': currentSlide
1023                         } );
1024                 }
1025                 else {
1026                         // Ensure that the previous slide is never the same as the current
1027                         previousSlide = null;
1028                 }
1029
1030                 // Solves an edge case where the previous slide maintains the
1031                 // 'present' class when navigating between adjacent vertical
1032                 // stacks
1033                 if( previousSlide ) {
1034                         previousSlide.classList.remove( 'present' );
1035
1036                         // Reset all slides upon navigate to home
1037                         // Issue: #285
1038                         if ( document.querySelector( HOME_SLIDE_SELECTOR ).classList.contains( 'present' ) ) {
1039                                 // Launch async task
1040                                 setTimeout( function () {
1041                                         var slides = toArray( document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR + '.stack') ), i;
1042                                         for( i in slides ) {
1043                                                 if( slides[i] ) {
1044                                                         // Reset stack
1045                                                         setPreviousVerticalIndex( slides[i], 0 );
1046                                                 }
1047                                         }
1048                                 }, 0 );
1049                         }
1050                 }
1051
1052                 updateControls();
1053                 updateProgress();
1054
1055         }
1056
1057         /**
1058          * Updates one dimension of slides by showing the slide
1059          * with the specified index.
1060          *
1061          * @param {String} selector A CSS selector that will fetch
1062          * the group of slides we are working with
1063          * @param {Number} index The index of the slide that should be
1064          * shown
1065          *
1066          * @return {Number} The index of the slide that is now shown,
1067          * might differ from the passed in index if it was out of
1068          * bounds.
1069          */
1070         function updateSlides( selector, index ) {
1071
1072                 // Select all slides and convert the NodeList result to
1073                 // an array
1074                 var slides = toArray( document.querySelectorAll( selector ) ),
1075                         slidesLength = slides.length;
1076
1077                 if( slidesLength ) {
1078
1079                         // Should the index loop?
1080                         if( config.loop ) {
1081                                 index %= slidesLength;
1082
1083                                 if( index < 0 ) {
1084                                         index = slidesLength + index;
1085                                 }
1086                         }
1087
1088                         // Enforce max and minimum index bounds
1089                         index = Math.max( Math.min( index, slidesLength - 1 ), 0 );
1090
1091                         for( var i = 0; i < slidesLength; i++ ) {
1092                                 var element = slides[i];
1093
1094                                 // Optimization; hide all slides that are three or more steps
1095                                 // away from the present slide
1096                                 if( isOverviewActive() === false ) {
1097                                         // The distance loops so that it measures 1 between the first
1098                                         // and last slides
1099                                         var distance = Math.abs( ( index - i ) % ( slidesLength - 3 ) ) || 0;
1100
1101                                         element.style.display = distance > 3 ? 'none' : 'block';
1102                                 }
1103
1104                                 slides[i].classList.remove( 'past' );
1105                                 slides[i].classList.remove( 'present' );
1106                                 slides[i].classList.remove( 'future' );
1107
1108                                 if( i < index ) {
1109                                         // Any element previous to index is given the 'past' class
1110                                         slides[i].classList.add( 'past' );
1111                                 }
1112                                 else if( i > index ) {
1113                                         // Any element subsequent to index is given the 'future' class
1114                                         slides[i].classList.add( 'future' );
1115                                 }
1116
1117                                 // If this element contains vertical slides
1118                                 if( element.querySelector( 'section' ) ) {
1119                                         slides[i].classList.add( 'stack' );
1120                                 }
1121                         }
1122
1123                         // Mark the current slide as present
1124                         slides[index].classList.add( 'present' );
1125
1126                         // If this slide has a state associated with it, add it
1127                         // onto the current state of the deck
1128                         var slideState = slides[index].getAttribute( 'data-state' );
1129                         if( slideState ) {
1130                                 state = state.concat( slideState.split( ' ' ) );
1131                         }
1132
1133                         // If this slide has a data-autoslide attribtue associated use this as
1134                         // autoSlide value otherwise use the global configured time
1135                         var slideAutoSlide = slides[index].getAttribute( 'data-autoslide' );
1136                         if( slideAutoSlide ) {
1137                                 autoSlide = parseInt( slideAutoSlide, 10 );
1138                         }
1139                         else {
1140                                 autoSlide = config.autoSlide;
1141                         }
1142
1143                 }
1144                 else {
1145                         // Since there are no slides we can't be anywhere beyond the
1146                         // zeroth index
1147                         index = 0;
1148                 }
1149
1150                 return index;
1151
1152         }
1153
1154         /**
1155          * Updates the progress bar to reflect the current slide.
1156          */
1157         function updateProgress() {
1158
1159                 // Update progress if enabled
1160                 if( config.progress && dom.progress ) {
1161
1162                         var horizontalSlides = toArray( document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) );
1163
1164                         // The number of past and total slides
1165                         var totalCount = document.querySelectorAll( SLIDES_SELECTOR + ':not(.stack)' ).length;
1166                         var pastCount = 0;
1167
1168                         // Step through all slides and count the past ones
1169                         mainLoop: for( var i = 0; i < horizontalSlides.length; i++ ) {
1170
1171                                 var horizontalSlide = horizontalSlides[i];
1172                                 var verticalSlides = toArray( horizontalSlide.querySelectorAll( 'section' ) );
1173
1174                                 for( var j = 0; j < verticalSlides.length; j++ ) {
1175
1176                                         // Stop as soon as we arrive at the present
1177                                         if( verticalSlides[j].classList.contains( 'present' ) ) {
1178                                                 break mainLoop;
1179                                         }
1180
1181                                         pastCount++;
1182
1183                                 }
1184
1185                                 // Stop as soon as we arrive at the present
1186                                 if( horizontalSlide.classList.contains( 'present' ) ) {
1187                                         break;
1188                                 }
1189
1190                                 // Don't count the wrapping section for vertical slides
1191                                 if( horizontalSlide.classList.contains( 'stack' ) === false ) {
1192                                         pastCount++;
1193                                 }
1194
1195                         }
1196
1197                         dom.progressbar.style.width = ( pastCount / ( totalCount - 1 ) ) * window.innerWidth + 'px';
1198
1199                 }
1200
1201         }
1202
1203         /**
1204          * Updates the state of all control/navigation arrows.
1205          */
1206         function updateControls() {
1207
1208                 if ( config.controls && dom.controls ) {
1209
1210                         var routes = availableRoutes();
1211
1212                         // Remove the 'enabled' class from all directions
1213                         dom.controlsLeft.concat( dom.controlsRight )
1214                                                         .concat( dom.controlsUp )
1215                                                         .concat( dom.controlsDown )
1216                                                         .concat( dom.controlsPrev )
1217                                                         .concat( dom.controlsNext ).forEach( function( node ) {
1218                                 node.classList.remove( 'enabled' );
1219                         } );
1220
1221                         // Add the 'enabled' class to the available routes
1222                         if( routes.left ) dom.controlsLeft.forEach( function( el ) { el.classList.add( 'enabled' );     } );
1223                         if( routes.right ) dom.controlsRight.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1224                         if( routes.up ) dom.controlsUp.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1225                         if( routes.down ) dom.controlsDown.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1226
1227                         // Prev/next buttons
1228                         if( routes.left || routes.up ) dom.controlsPrev.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1229                         if( routes.right || routes.down ) dom.controlsNext.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1230
1231                 }
1232
1233         }
1234
1235         /**
1236          * Determine what available routes there are for navigation.
1237          *
1238          * @return {Object} containing four booleans: left/right/up/down
1239          */
1240         function availableRoutes() {
1241
1242                 var horizontalSlides = document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ),
1243                         verticalSlides = document.querySelectorAll( VERTICAL_SLIDES_SELECTOR );
1244
1245                 return {
1246                         left: indexh > 0,
1247                         right: indexh < horizontalSlides.length - 1,
1248                         up: indexv > 0,
1249                         down: indexv < verticalSlides.length - 1
1250                 };
1251
1252         }
1253
1254         /**
1255          * Reads the current URL (hash) and navigates accordingly.
1256          */
1257         function readURL() {
1258
1259                 var hash = window.location.hash;
1260
1261                 // Attempt to parse the hash as either an index or name
1262                 var bits = hash.slice( 2 ).split( '/' ),
1263                         name = hash.replace( /#|\//gi, '' );
1264
1265                 // If the first bit is invalid and there is a name we can
1266                 // assume that this is a named link
1267                 if( isNaN( parseInt( bits[0], 10 ) ) && name.length ) {
1268                         // Find the slide with the specified name
1269                         var element = document.querySelector( '#' + name );
1270
1271                         if( element ) {
1272                                 // Find the position of the named slide and navigate to it
1273                                 var indices = Reveal.getIndices( element );
1274                                 slide( indices.h, indices.v );
1275                         }
1276                         // If the slide doesn't exist, navigate to the current slide
1277                         else {
1278                                 slide( indexh, indexv );
1279                         }
1280                 }
1281                 else {
1282                         // Read the index components of the hash
1283                         var h = parseInt( bits[0], 10 ) || 0,
1284                                 v = parseInt( bits[1], 10 ) || 0;
1285
1286                         slide( h, v );
1287                 }
1288
1289         }
1290
1291         /**
1292          * Updates the page URL (hash) to reflect the current
1293          * state.
1294          *
1295          * @param {Number} delay The time in ms to wait before
1296          * writing the hash
1297          */
1298         function writeURL( delay ) {
1299
1300                 if( config.history ) {
1301
1302                         // Make sure there's never more than one timeout running
1303                         clearTimeout( writeURLTimeout );
1304
1305                         // If a delay is specified, timeout this call
1306                         if( typeof delay === 'number' ) {
1307                                 writeURLTimeout = setTimeout( writeURL, delay );
1308                         }
1309                         else {
1310                                 var url = '/';
1311
1312                                 // If the current slide has an ID, use that as a named link
1313                                 if( currentSlide && typeof currentSlide.getAttribute( 'id' ) === 'string' ) {
1314                                         url = '/' + currentSlide.getAttribute( 'id' );
1315                                 }
1316                                 // Otherwise use the /h/v index
1317                                 else {
1318                                         if( indexh > 0 || indexv > 0 ) url += indexh;
1319                                         if( indexv > 0 ) url += '/' + indexv;
1320                                 }
1321
1322                                 window.location.hash = url;
1323                         }
1324                 }
1325
1326         }
1327
1328         /**
1329          * Retrieves the h/v location of the current, or specified,
1330          * slide.
1331          *
1332          * @param {HTMLElement} slide If specified, the returned
1333          * index will be for this slide rather than the currently
1334          * active one
1335          *
1336          * @return {Object} { h: <int>, v: <int> }
1337          */
1338         function getIndices( slide ) {
1339
1340                 // By default, return the current indices
1341                 var h = indexh,
1342                         v = indexv;
1343
1344                 // If a slide is specified, return the indices of that slide
1345                 if( slide ) {
1346                         var isVertical = !!slide.parentNode.nodeName.match( /section/gi );
1347                         var slideh = isVertical ? slide.parentNode : slide;
1348
1349                         // Select all horizontal slides
1350                         var horizontalSlides = toArray( document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) );
1351
1352                         // Now that we know which the horizontal slide is, get its index
1353                         h = Math.max( horizontalSlides.indexOf( slideh ), 0 );
1354
1355                         // If this is a vertical slide, grab the vertical index
1356                         if( isVertical ) {
1357                                 v = Math.max( toArray( slide.parentNode.querySelectorAll( 'section' ) ).indexOf( slide ), 0 );
1358                         }
1359                 }
1360
1361                 return { h: h, v: v };
1362
1363         }
1364
1365         /**
1366          * Navigate to the next slide fragment.
1367          *
1368          * @return {Boolean} true if there was a next fragment,
1369          * false otherwise
1370          */
1371         function nextFragment() {
1372
1373                 // Vertical slides:
1374                 if( document.querySelector( VERTICAL_SLIDES_SELECTOR + '.present' ) ) {
1375                         var verticalFragments = document.querySelectorAll( VERTICAL_SLIDES_SELECTOR + '.present .fragment:not(.visible)' );
1376                         if( verticalFragments.length ) {
1377                                 verticalFragments[0].classList.add( 'visible' );
1378
1379                                 // Notify subscribers of the change
1380                                 dispatchEvent( 'fragmentshown', { fragment: verticalFragments[0] } );
1381                                 return true;
1382                         }
1383                 }
1384                 // Horizontal slides:
1385                 else {
1386                         var horizontalFragments = document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR + '.present .fragment:not(.visible)' );
1387                         if( horizontalFragments.length ) {
1388                                 horizontalFragments[0].classList.add( 'visible' );
1389
1390                                 // Notify subscribers of the change
1391                                 dispatchEvent( 'fragmentshown', { fragment: horizontalFragments[0] } );
1392                                 return true;
1393                         }
1394                 }
1395
1396                 return false;
1397
1398         }
1399
1400         /**
1401          * Navigate to the previous slide fragment.
1402          *
1403          * @return {Boolean} true if there was a previous fragment,
1404          * false otherwise
1405          */
1406         function previousFragment() {
1407
1408                 // Vertical slides:
1409                 if( document.querySelector( VERTICAL_SLIDES_SELECTOR + '.present' ) ) {
1410                         var verticalFragments = document.querySelectorAll( VERTICAL_SLIDES_SELECTOR + '.present .fragment.visible' );
1411                         if( verticalFragments.length ) {
1412                                 verticalFragments[ verticalFragments.length - 1 ].classList.remove( 'visible' );
1413
1414                                 // Notify subscribers of the change
1415                                 dispatchEvent( 'fragmenthidden', { fragment: verticalFragments[ verticalFragments.length - 1 ] } );
1416                                 return true;
1417                         }
1418                 }
1419                 // Horizontal slides:
1420                 else {
1421                         var horizontalFragments = document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR + '.present .fragment.visible' );
1422                         if( horizontalFragments.length ) {
1423                                 horizontalFragments[ horizontalFragments.length - 1 ].classList.remove( 'visible' );
1424
1425                                 // Notify subscribers of the change
1426                                 dispatchEvent( 'fragmenthidden', { fragment: horizontalFragments[ horizontalFragments.length - 1 ] } );
1427                                 return true;
1428                         }
1429                 }
1430
1431                 return false;
1432
1433         }
1434
1435         /**
1436          * Cues a new automated slide if enabled in the config.
1437          */
1438         function cueAutoSlide() {
1439
1440                 clearTimeout( autoSlideTimeout );
1441
1442                 // Cue the next auto-slide if enabled
1443                 if( autoSlide ) {
1444                         autoSlideTimeout = setTimeout( navigateNext, autoSlide );
1445                 }
1446
1447         }
1448
1449         function navigateLeft() {
1450
1451                 // Prioritize hiding fragments
1452                 if( availableRoutes().left && isOverviewActive() || previousFragment() === false ) {
1453                         slide( indexh - 1 );
1454                 }
1455
1456         }
1457
1458         function navigateRight() {
1459
1460                 // Prioritize revealing fragments
1461                 if( availableRoutes().right && isOverviewActive() || nextFragment() === false ) {
1462                         slide( indexh + 1 );
1463                 }
1464
1465         }
1466
1467         function navigateUp() {
1468
1469                 // Prioritize hiding fragments
1470                 if( availableRoutes().up && isOverviewActive() || previousFragment() === false ) {
1471                         slide( indexh, indexv - 1 );
1472                 }
1473
1474         }
1475
1476         function navigateDown() {
1477
1478                 // Prioritize revealing fragments
1479                 if( availableRoutes().down && isOverviewActive() || nextFragment() === false ) {
1480                         slide( indexh, indexv + 1 );
1481                 }
1482
1483         }
1484
1485         /**
1486          * Navigates backwards, prioritized in the following order:
1487          * 1) Previous fragment
1488          * 2) Previous vertical slide
1489          * 3) Previous horizontal slide
1490          */
1491         function navigatePrev() {
1492
1493                 // Prioritize revealing fragments
1494                 if( previousFragment() === false ) {
1495                         if( availableRoutes().up ) {
1496                                 navigateUp();
1497                         }
1498                         else {
1499                                 // Fetch the previous horizontal slide, if there is one
1500                                 var previousSlide = document.querySelector( HORIZONTAL_SLIDES_SELECTOR + '.past:nth-child(' + indexh + ')' );
1501
1502                                 if( previousSlide ) {
1503                                         indexv = ( previousSlide.querySelectorAll( 'section' ).length + 1 ) || undefined;
1504                                         indexh --;
1505                                         slide();
1506                                 }
1507                         }
1508                 }
1509
1510         }
1511
1512         /**
1513          * Same as #navigatePrev() but navigates forwards.
1514          */
1515         function navigateNext() {
1516
1517                 // Prioritize revealing fragments
1518                 if( nextFragment() === false ) {
1519                         availableRoutes().down ? navigateDown() : navigateRight();
1520                 }
1521
1522                 // If auto-sliding is enabled we need to cue up
1523                 // another timeout
1524                 cueAutoSlide();
1525
1526         }
1527
1528
1529         // --------------------------------------------------------------------//
1530         // ----------------------------- EVENTS -------------------------------//
1531         // --------------------------------------------------------------------//
1532
1533
1534         /**
1535          * Handler for the document level 'keydown' event.
1536          *
1537          * @param {Object} event
1538          */
1539         function onDocumentKeyDown( event ) {
1540
1541                 // Check if there's a focused element that could be using
1542                 // the keyboard
1543                 var activeElement = document.activeElement;
1544                 var hasFocus = !!( document.activeElement && ( document.activeElement.type || document.activeElement.href || document.activeElement.contentEditable !== 'inherit' ) );
1545
1546                 // Disregard the event if there's a focused element or a
1547                 // keyboard modifier key is present
1548                 if( hasFocus || event.shiftKey || event.altKey || event.ctrlKey || event.metaKey ) return;
1549
1550                 var triggered = true;
1551
1552                 // while paused only allow "unpausing" keyboard events (b and .)
1553                 if( isPaused() && [66,190,191].indexOf( event.keyCode ) === -1 ) {
1554                         return false;
1555                 }
1556
1557                 switch( event.keyCode ) {
1558                         // p, page up
1559                         case 80: case 33: navigatePrev(); break;
1560                         // n, page down
1561                         case 78: case 34: navigateNext(); break;
1562                         // h, left
1563                         case 72: case 37: navigateLeft(); break;
1564                         // l, right
1565                         case 76: case 39: navigateRight(); break;
1566                         // k, up
1567                         case 75: case 38: navigateUp(); break;
1568                         // j, down
1569                         case 74: case 40: navigateDown(); break;
1570                         // home
1571                         case 36: slide( 0 ); break;
1572                         // end
1573                         case 35: slide( Number.MAX_VALUE ); break;
1574                         // space
1575                         case 32: isOverviewActive() ? deactivateOverview() : navigateNext(); break;
1576                         // return
1577                         case 13: isOverviewActive() ? deactivateOverview() : triggered = false; break;
1578                         // b, period, Logitech presenter tools "black screen" button
1579                         case 66: case 190: case 191: togglePause(); break;
1580                         // f
1581                         case 70: enterFullscreen(); break;
1582                         default:
1583                                 triggered = false;
1584                 }
1585
1586                 // If the input resulted in a triggered action we should prevent
1587                 // the browsers default behavior
1588                 if( triggered ) {
1589                         event.preventDefault();
1590                 }
1591                 else if ( event.keyCode === 27 && supports3DTransforms ) {
1592                         toggleOverview();
1593
1594                         event.preventDefault();
1595                 }
1596
1597                 // If auto-sliding is enabled we need to cue up
1598                 // another timeout
1599                 cueAutoSlide();
1600
1601         }
1602
1603         /**
1604          * Handler for the document level 'touchstart' event,
1605          * enables support for swipe and pinch gestures.
1606          */
1607         function onDocumentTouchStart( event ) {
1608
1609                 touch.startX = event.touches[0].clientX;
1610                 touch.startY = event.touches[0].clientY;
1611                 touch.startCount = event.touches.length;
1612
1613                 // If there's two touches we need to memorize the distance
1614                 // between those two points to detect pinching
1615                 if( event.touches.length === 2 && config.overview ) {
1616                         touch.startSpan = distanceBetween( {
1617                                 x: event.touches[1].clientX,
1618                                 y: event.touches[1].clientY
1619                         }, {
1620                                 x: touch.startX,
1621                                 y: touch.startY
1622                         } );
1623                 }
1624
1625         }
1626
1627         /**
1628          * Handler for the document level 'touchmove' event.
1629          */
1630         function onDocumentTouchMove( event ) {
1631
1632                 // Each touch should only trigger one action
1633                 if( !touch.handled ) {
1634                         var currentX = event.touches[0].clientX;
1635                         var currentY = event.touches[0].clientY;
1636
1637                         // If the touch started off with two points and still has
1638                         // two active touches; test for the pinch gesture
1639                         if( event.touches.length === 2 && touch.startCount === 2 && config.overview ) {
1640
1641                                 // The current distance in pixels between the two touch points
1642                                 var currentSpan = distanceBetween( {
1643                                         x: event.touches[1].clientX,
1644                                         y: event.touches[1].clientY
1645                                 }, {
1646                                         x: touch.startX,
1647                                         y: touch.startY
1648                                 } );
1649
1650                                 // If the span is larger than the desire amount we've got
1651                                 // ourselves a pinch
1652                                 if( Math.abs( touch.startSpan - currentSpan ) > touch.threshold ) {
1653                                         touch.handled = true;
1654
1655                                         if( currentSpan < touch.startSpan ) {
1656                                                 activateOverview();
1657                                         }
1658                                         else {
1659                                                 deactivateOverview();
1660                                         }
1661                                 }
1662
1663                                 event.preventDefault();
1664
1665                         }
1666                         // There was only one touch point, look for a swipe
1667                         else if( event.touches.length === 1 && touch.startCount !== 2 ) {
1668
1669                                 var deltaX = currentX - touch.startX,
1670                                         deltaY = currentY - touch.startY;
1671
1672                                 if( deltaX > touch.threshold && Math.abs( deltaX ) > Math.abs( deltaY ) ) {
1673                                         touch.handled = true;
1674                                         navigateLeft();
1675                                 }
1676                                 else if( deltaX < -touch.threshold && Math.abs( deltaX ) > Math.abs( deltaY ) ) {
1677                                         touch.handled = true;
1678                                         navigateRight();
1679                                 }
1680                                 else if( deltaY > touch.threshold ) {
1681                                         touch.handled = true;
1682                                         navigateUp();
1683                                 }
1684                                 else if( deltaY < -touch.threshold ) {
1685                                         touch.handled = true;
1686                                         navigateDown();
1687                                 }
1688
1689                                 event.preventDefault();
1690
1691                         }
1692                 }
1693                 // There's a bug with swiping on some Android devices unless
1694                 // the default action is always prevented
1695                 else if( navigator.userAgent.match( /android/gi ) ) {
1696                         event.preventDefault();
1697                 }
1698
1699         }
1700
1701         /**
1702          * Handler for the document level 'touchend' event.
1703          */
1704         function onDocumentTouchEnd( event ) {
1705
1706                 touch.handled = false;
1707
1708         }
1709
1710         /**
1711          * Handles mouse wheel scrolling, throttled to avoid skipping
1712          * multiple slides.
1713          */
1714         function onDocumentMouseScroll( event ) {
1715
1716                 clearTimeout( mouseWheelTimeout );
1717
1718                 mouseWheelTimeout = setTimeout( function() {
1719                         var delta = event.detail || -event.wheelDelta;
1720                         if( delta > 0 ) {
1721                                 navigateNext();
1722                         }
1723                         else {
1724                                 navigatePrev();
1725                         }
1726                 }, 100 );
1727
1728         }
1729
1730         /**
1731          * Clicking on the progress bar results in a navigation to the
1732          * closest approximate horizontal slide using this equation:
1733          *
1734          * ( clickX / presentationWidth ) * numberOfSlides
1735          */
1736         function onProgressClick( event ) {
1737
1738                 var slidesTotal = toArray( document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) ).length;
1739                 var slideIndex = Math.floor( ( event.clientX / dom.wrapper.offsetWidth ) * slidesTotal );
1740
1741                 slide( slideIndex );
1742
1743         }
1744
1745         /**
1746          * Handler for the window level 'hashchange' event.
1747          */
1748         function onWindowHashChange( event ) {
1749
1750                 readURL();
1751
1752         }
1753
1754         /**
1755          * Handler for the window level 'resize' event.
1756          */
1757         function onWindowResize( event ) {
1758
1759                 layout();
1760
1761         }
1762
1763         /**
1764          * Invoked when a slide is and we're in the overview.
1765          */
1766         function onOverviewSlideClicked( event ) {
1767
1768                 // TODO There's a bug here where the event listeners are not
1769                 // removed after deactivating the overview.
1770                 if( isOverviewActive() ) {
1771                         event.preventDefault();
1772
1773                         deactivateOverview();
1774
1775                         var element = event.target;
1776
1777                         while( element && !element.nodeName.match( /section/gi ) ) {
1778                                 element = element.parentNode;
1779                         }
1780
1781                         if( element.nodeName.match( /section/gi ) ) {
1782                                 var h = parseInt( element.getAttribute( 'data-index-h' ), 10 ),
1783                                         v = parseInt( element.getAttribute( 'data-index-v' ), 10 );
1784
1785                                 slide( h, v );
1786                         }
1787                 }
1788
1789         }
1790
1791
1792         // --------------------------------------------------------------------//
1793         // ------------------------------- API --------------------------------//
1794         // --------------------------------------------------------------------//
1795
1796
1797         return {
1798                 initialize: initialize,
1799
1800                 // Navigation methods
1801                 slide: slide,
1802                 left: navigateLeft,
1803                 right: navigateRight,
1804                 up: navigateUp,
1805                 down: navigateDown,
1806                 prev: navigatePrev,
1807                 next: navigateNext,
1808                 prevFragment: previousFragment,
1809                 nextFragment: nextFragment,
1810
1811                 // Deprecated aliases
1812                 navigateTo: slide,
1813                 navigateLeft: navigateLeft,
1814                 navigateRight: navigateRight,
1815                 navigateUp: navigateUp,
1816                 navigateDown: navigateDown,
1817                 navigatePrev: navigatePrev,
1818                 navigateNext: navigateNext,
1819
1820                 // Forces an update in slide layout
1821                 layout: layout,
1822
1823                 // Toggles the overview mode on/off
1824                 toggleOverview: toggleOverview,
1825
1826                 // Toggles the "black screen" mode on/off
1827                 togglePause: togglePause,
1828
1829                 // Adds or removes all internal event listeners (such as keyboard)
1830                 addEventListeners: addEventListeners,
1831                 removeEventListeners: removeEventListeners,
1832
1833                 // Returns the indices of the current, or specified, slide
1834                 getIndices: getIndices,
1835
1836                 // Returns the previous slide element, may be null
1837                 getPreviousSlide: function() {
1838                         return previousSlide;
1839                 },
1840
1841                 // Returns the current slide element
1842                 getCurrentSlide: function() {
1843                         return currentSlide;
1844                 },
1845
1846                 // Returns the current scale of the presentation content
1847                 getScale: function() {
1848                         return scale;
1849                 },
1850
1851                 // Helper method, retrieves query string as a key/value hash
1852                 getQueryHash: function() {
1853                         var query = {};
1854
1855                         location.search.replace( /[A-Z0-9]+?=(\w*)/gi, function(a) {
1856                                 query[ a.split( '=' ).shift() ] = a.split( '=' ).pop();
1857                         } );
1858
1859                         return query;
1860                 },
1861
1862                 // Forward event binding to the reveal DOM element
1863                 addEventListener: function( type, listener, useCapture ) {
1864                         if( 'addEventListener' in window ) {
1865                                 ( dom.wrapper || document.querySelector( '.reveal' ) ).addEventListener( type, listener, useCapture );
1866                         }
1867                 },
1868                 removeEventListener: function( type, listener, useCapture ) {
1869                         if( 'addEventListener' in window ) {
1870                                 ( dom.wrapper || document.querySelector( '.reveal' ) ).removeEventListener( type, listener, useCapture );
1871                         }
1872                 }
1873         };
1874
1875 })();