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: 1.4,
  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                 // Cached references to DOM elements
  98                 dom = {},
  99
 100                 // Detect support for CSS 3D transforms
 101                 supports3DTransforms =  'WebkitPerspective' in document.body.style ||
 102                                                                 'MozPerspective' in document.body.style ||
 103                                                                 'msPerspective' in document.body.style ||
 104                                                                 'OPerspective' in document.body.style ||
 105                                                                 'perspective' in document.body.style,
 106
 107                 // Detect support for CSS 2D transforms
 108                 supports2DTransforms =  'WebkitTransform' in document.body.style ||
 109                                                                 'MozTransform' in document.body.style ||
 110                                                                 'msTransform' in document.body.style ||
 111                                                                 'OTransform' in document.body.style ||
 112                                                                 'transform' in document.body.style,
 113
 114                 // Throttles mouse wheel navigation
 115                 mouseWheelTimeout = 0,
 116
 117                 // An interval used to automatically move on to the next slide
 118                 autoSlideTimeout = 0,
 119
 120                 // Delays updates to the URL due to a Chrome thumbnailer bug
 121                 writeURLTimeout = 0,
 122
 123                 // A delay used to activate the overview mode
 124                 activateOverviewTimeout = 0,
 125
 126                 // A delay used to deactivate the overview mode
 127                 deactivateOverviewTimeout = 0,
 128
 129                 // Holds information about the currently ongoing touch input
 130                 touch = {
 131                         startX: 0,
 132                         startY: 0,
 133                         startSpan: 0,
 134                         startCount: 0,
 135                         handled: false,
 136                         threshold: 80
 137                 };
 138
 139         /**
 140          * Starts up the presentation if the client is capable.
 141          */
 142         function initialize( options ) {
 143
 144                 if( ( !supports2DTransforms && !supports3DTransforms ) ) {
 145                         document.body.setAttribute( 'class', 'no-transforms' );
 146
 147                         // If the browser doesn't support core features we won't be
 148                         // using JavaScript to control the presentation
 149                         return;
 150                 }
 151
 152                 // Force a layout when the whole page, incl fonts, has loaded
 153                 window.addEventListener( 'load', layout, false );
 154
 155                 // Copy options over to our config object
 156                 extend( config, options );
 157
 158                 // Hide the address bar in mobile browsers
 159                 hideAddressBar();
 160
 161                 // Loads the dependencies and continues to #start() once done
 162                 load();
 163
 164         }
 165
 166         /**
 167          * Finds and stores references to DOM elements which are
 168          * required by the presentation. If a required element is
 169          * not found, it is created.
 170          */
 171         function setupDOM() {
 172
 173                 // Cache references to key DOM elements
 174                 dom.theme = document.querySelector( '#theme' );
 175                 dom.wrapper = document.querySelector( '.reveal' );
 176                 dom.slides = document.querySelector( '.reveal .slides' );
 177
 178                 // Progress bar
 179                 if( !dom.wrapper.querySelector( '.progress' ) && config.progress ) {
 180                         var progressElement = document.createElement( 'div' );
 181                         progressElement.classList.add( 'progress' );
 182                         progressElement.innerHTML = '<span></span>';
 183                         dom.wrapper.appendChild( progressElement );
 184                 }
 185
 186                 // Arrow controls
 187                 if( !dom.wrapper.querySelector( '.controls' ) && config.controls ) {
 188                         var controlsElement = document.createElement( 'aside' );
 189                         controlsElement.classList.add( 'controls' );
 190                         controlsElement.innerHTML = '<div class="navigate-left"></div>' +
 191                                                                                 '<div class="navigate-right"></div>' +
 192                                                                                 '<div class="navigate-up"></div>' +
 193                                                                                 '<div class="navigate-down"></div>';
 194                         dom.wrapper.appendChild( controlsElement );
 195                 }
 196
 197                 // Presentation background element
 198                 if( !dom.wrapper.querySelector( '.state-background' ) ) {
 199                         var backgroundElement = document.createElement( 'div' );
 200                         backgroundElement.classList.add( 'state-background' );
 201                         dom.wrapper.appendChild( backgroundElement );
 202                 }
 203
 204                 // Overlay graphic which is displayed during the paused mode
 205                 if( !dom.wrapper.querySelector( '.pause-overlay' ) ) {
 206                         var pausedElement = document.createElement( 'div' );
 207                         pausedElement.classList.add( 'pause-overlay' );
 208                         dom.wrapper.appendChild( pausedElement );
 209                 }
 210
 211                 // Cache references to elements
 212                 dom.progress = document.querySelector( '.reveal .progress' );
 213                 dom.progressbar = document.querySelector( '.reveal .progress span' );
 214
 215                 if ( config.controls ) {
 216                         dom.controls = document.querySelector( '.reveal .controls' );
 217
 218                         // There can be multiple instances of controls throughout the page
 219                         dom.controlsLeft = toArray( document.querySelectorAll( '.navigate-left' ) );
 220                         dom.controlsRight = toArray( document.querySelectorAll( '.navigate-right' ) );
 221                         dom.controlsUp = toArray( document.querySelectorAll( '.navigate-up' ) );
 222                         dom.controlsDown = toArray( document.querySelectorAll( '.navigate-down' ) );
 223                         dom.controlsPrev = toArray( document.querySelectorAll( '.navigate-prev' ) );
 224                         dom.controlsNext = toArray( document.querySelectorAll( '.navigate-next' ) );
 225                 }
 226
 227         }
 228
 229         /**
 230          * Hides the address bar if we're on a mobile device.
 231          */
 232         function hideAddressBar() {
 233
 234                 if( navigator.userAgent.match( /(iphone|ipod)/i ) ) {
 235                         // Events that should trigger the address bar to hide
 236                         window.addEventListener( 'load', removeAddressBar, false );
 237                         window.addEventListener( 'orientationchange', removeAddressBar, false );
 238                 }
 239
 240         }
 241
 242         /**
 243          * Loads the dependencies of reveal.js. Dependencies are
 244          * defined via the configuration option 'dependencies'
 245          * and will be loaded prior to starting/binding reveal.js.
 246          * Some dependencies may have an 'async' flag, if so they
 247          * will load after reveal.js has been started up.
 248          */
 249         function load() {
 250
 251                 var scripts = [],
 252                         scriptsAsync = [];
 253
 254                 for( var i = 0, len = config.dependencies.length; i < len; i++ ) {
 255                         var s = config.dependencies[i];
 256
 257                         // Load if there's no condition or the condition is truthy
 258                         if( !s.condition || s.condition() ) {
 259                                 if( s.async ) {
 260                                         scriptsAsync.push( s.src );
 261                                 }
 262                                 else {
 263                                         scripts.push( s.src );
 264                                 }
 265
 266                                 // Extension may contain callback functions
 267                                 if( typeof s.callback === 'function' ) {
 268                                         head.ready( s.src.match( /([\w\d_\-]*)\.?js$|[^\\\/]*$/i )[0], s.callback );
 269                                 }
 270                         }
 271                 }
 272
 273                 // Called once synchronous scritps finish loading
 274                 function proceed() {
 275                         if( scriptsAsync.length ) {
 276                                 // Load asynchronous scripts
 277                                 head.js.apply( null, scriptsAsync );
 278                         }
 279
 280                         start();
 281                 }
 282
 283                 if( scripts.length ) {
 284                         head.ready( proceed );
 285
 286                         // Load synchronous scripts
 287                         head.js.apply( null, scripts );
 288                 }
 289                 else {
 290                         proceed();
 291                 }
 292
 293         }
 294
 295         /**
 296          * Starts up reveal.js by binding input events and navigating
 297          * to the current URL deeplink if there is one.
 298          */
 299         function start() {
 300
 301                 // Make sure we've got all the DOM elements we need
 302                 setupDOM();
 303
 304                 // Subscribe to input
 305                 addEventListeners();
 306
 307                 // Updates the presentation to match the current configuration values
 308                 configure();
 309
 310                 // Force an initial layout, will thereafter be invoked as the window
 311                 // is resized
 312                 layout();
 313
 314                 // Read the initial hash
 315                 readURL();
 316
 317                 // Start auto-sliding if it's enabled
 318                 cueAutoSlide();
 319
 320                 // Notify listeners that the presentation is ready but use a 1ms
 321                 // timeout to ensure it's not fired synchronously after #initialize()
 322                 setTimeout( function() {
 323                         dispatchEvent( 'ready', {
 324                                 'indexh': indexh,
 325                                 'indexv': indexv,
 326                                 'currentSlide': currentSlide
 327                         } );
 328                 }, 1 );
 329
 330         }
 331
 332         /**
 333          * Applies the configuration settings from the config object.
 334          */
 335         function configure() {
 336
 337                 if( supports3DTransforms === false ) {
 338                         config.transition = 'linear';
 339                 }
 340
 341                 if( config.controls && dom.controls ) {
 342                         dom.controls.style.display = 'block';
 343                 }
 344
 345                 if( config.progress && dom.progress ) {
 346                         dom.progress.style.display = 'block';
 347                 }
 348
 349                 if( config.transition !== 'default' ) {
 350                         dom.wrapper.classList.add( config.transition );
 351                 }
 352
 353                 if( config.rtl ) {
 354                         dom.wrapper.classList.add( 'rtl' );
 355                 }
 356
 357                 if( config.center ) {
 358                         dom.wrapper.classList.add( 'center' );
 359                 }
 360
 361                 if( config.mouseWheel ) {
 362                         document.addEventListener( 'DOMMouseScroll', onDocumentMouseScroll, false ); // FF
 363                         document.addEventListener( 'mousewheel', onDocumentMouseScroll, false );
 364                 }
 365
 366                 // 3D links
 367                 if( config.rollingLinks ) {
 368                         linkify();
 369                 }
 370
 371                 // Load the theme in the config, if it's not already loaded
 372                 if( config.theme && dom.theme ) {
 373                         var themeURL = dom.theme.getAttribute( 'href' );
 374                         var themeFinder = /[^\/]*?(?=\.css)/;
 375                         var themeName = themeURL.match(themeFinder)[0];
 376
 377                         if(  config.theme !== themeName ) {
 378                                 themeURL = themeURL.replace(themeFinder, config.theme);
 379                                 dom.theme.setAttribute( 'href', themeURL );
 380                         }
 381                 }
 382
 383         }
 384
 385         /**
 386          * Binds all event listeners.
 387          */
 388         function addEventListeners() {
 389
 390                 window.addEventListener( 'hashchange', onWindowHashChange, false );
 391                 window.addEventListener( 'resize', onWindowResize, false );
 392
 393                 if( config.touch ) {
 394                         document.addEventListener( 'touchstart', onDocumentTouchStart, false );
 395                         document.addEventListener( 'touchmove', onDocumentTouchMove, false );
 396                         document.addEventListener( 'touchend', onDocumentTouchEnd, false );
 397                 }
 398
 399                 if( config.keyboard ) {
 400                         document.addEventListener( 'keydown', onDocumentKeyDown, false );
 401                 }
 402
 403                 if ( config.progress && dom.progress ) {
 404                         dom.progress.addEventListener( 'click', preventAndForward( onProgressClick ), false );
 405                 }
 406
 407                 if ( config.controls && dom.controls ) {
 408                         var actionEvent = 'ontouchstart' in window ? 'touchstart' : 'click';
 409                         dom.controlsLeft.forEach( function( el ) { el.addEventListener( actionEvent, preventAndForward( navigateLeft ), false ); } );
 410                         dom.controlsRight.forEach( function( el ) { el.addEventListener( actionEvent, preventAndForward( navigateRight ), false ); } );
 411                         dom.controlsUp.forEach( function( el ) { el.addEventListener( actionEvent, preventAndForward( navigateUp ), false ); } );
 412                         dom.controlsDown.forEach( function( el ) { el.addEventListener( actionEvent, preventAndForward( navigateDown ), false ); } );
 413                         dom.controlsPrev.forEach( function( el ) { el.addEventListener( actionEvent, preventAndForward( navigatePrev ), false ); } );
 414                         dom.controlsNext.forEach( function( el ) { el.addEventListener( actionEvent, preventAndForward( navigateNext ), false ); } );
 415                 }
 416
 417         }
 418
 419         /**
 420          * Unbinds all event listeners.
 421          */
 422         function removeEventListeners() {
 423
 424                 document.removeEventListener( 'keydown', onDocumentKeyDown, false );
 425                 window.removeEventListener( 'hashchange', onWindowHashChange, false );
 426                 window.removeEventListener( 'resize', onWindowResize, false );
 427
 428                 if( config.touch ) {
 429                         document.removeEventListener( 'touchstart', onDocumentTouchStart, false );
 430                         document.removeEventListener( 'touchmove', onDocumentTouchMove, false );
 431                         document.removeEventListener( 'touchend', onDocumentTouchEnd, false );
 432                 }
 433
 434                 if ( config.progress && dom.progress ) {
 435                         dom.progress.removeEventListener( 'click', preventAndForward( onProgressClick ), false );
 436                 }
 437
 438                 if ( config.controls && dom.controls ) {
 439                         var actionEvent = 'ontouchstart' in window ? 'touchstart' : 'click';
 440                         dom.controlsLeft.forEach( function( el ) { el.removeEventListener( actionEvent, preventAndForward( navigateLeft ), false ); } );
 441                         dom.controlsRight.forEach( function( el ) { el.removeEventListener( actionEvent, preventAndForward( navigateRight ), false ); } );
 442                         dom.controlsUp.forEach( function( el ) { el.removeEventListener( actionEvent, preventAndForward( navigateUp ), false ); } );
 443                         dom.controlsDown.forEach( function( el ) { el.removeEventListener( actionEvent, preventAndForward( navigateDown ), false ); } );
 444                         dom.controlsPrev.forEach( function( el ) { el.removeEventListener( actionEvent, preventAndForward( navigatePrev ), false ); } );
 445                         dom.controlsNext.forEach( function( el ) { el.removeEventListener( actionEvent, preventAndForward( navigateNext ), false ); } );
 446                 }
 447
 448         }
 449
 450         /**
 451          * Extend object a with the properties of object b.
 452          * If there's a conflict, object b takes precedence.
 453          */
 454         function extend( a, b ) {
 455
 456                 for( var i in b ) {
 457                         a[ i ] = b[ i ];
 458                 }
 459
 460         }
 461
 462         /**
 463          * Converts the target object to an array.
 464          */
 465         function toArray( o ) {
 466
 467                 return Array.prototype.slice.call( o );
 468
 469         }
 470
 471         /**
 472          * Measures the distance in pixels between point a
 473          * and point b.
 474          *
 475          * @param {Object} a point with x/y properties
 476          * @param {Object} b point with x/y properties
 477          */
 478         function distanceBetween( a, b ) {
 479
 480                 var dx = a.x - b.x,
 481                         dy = a.y - b.y;
 482
 483                 return Math.sqrt( dx*dx + dy*dy );
 484
 485         }
 486
 487         /**
 488          * Prevents an events defaults behavior calls the
 489          * specified delegate.
 490          *
 491          * @param {Function} delegate The method to call
 492          * after the wrapper has been executed
 493          */
 494         function preventAndForward( delegate ) {
 495
 496                 return function( event ) {
 497                         event.preventDefault();
 498                         delegate.call( null, event );
 499                 };
 500
 501         }
 502
 503         /**
 504          * Causes the address bar to hide on mobile devices,
 505          * more vertical space ftw.
 506          */
 507         function removeAddressBar() {
 508
 509                 if( window.orientation === 0 ) {
 510                         document.documentElement.style.overflow = 'scroll';
 511                         document.body.style.height = '120%';
 512                 }
 513                 else {
 514                         document.documentElement.style.overflow = '';
 515                         document.body.style.height = '100%';
 516                 }
 517
 518                 setTimeout( function() {
 519                         window.scrollTo( 0, 1 );
 520                 }, 10 );
 521
 522         }
 523
 524         /**
 525          * Dispatches an event of the specified type from the
 526          * reveal DOM element.
 527          */
 528         function dispatchEvent( type, properties ) {
 529
 530                 var event = document.createEvent( "HTMLEvents", 1, 2 );
 531                 event.initEvent( type, true, true );
 532                 extend( event, properties );
 533                 dom.wrapper.dispatchEvent( event );
 534
 535         }
 536
 537         /**
 538          * Wrap all links in 3D goodness.
 539          */
 540         function linkify() {
 541
 542                 if( supports3DTransforms && !( 'msPerspective' in document.body.style ) ) {
 543                         var nodes = document.querySelectorAll( SLIDES_SELECTOR + ' a:not(.image)' );
 544
 545                         for( var i = 0, len = nodes.length; i < len; i++ ) {
 546                                 var node = nodes[i];
 547
 548                                 if( node.textContent && !node.querySelector( '*' ) && ( !node.className || !node.classList.contains( node, 'roll' ) ) ) {
 549                                         var span = document.createElement('span');
 550                                         span.setAttribute('data-title', node.text);
 551                                         span.innerHTML = node.innerHTML;
 552
 553                                         node.classList.add( 'roll' );
 554                                         node.innerHTML = '';
 555                                         node.appendChild(span);
 556                                 }
 557                         }
 558                 }
 559
 560         }
 561
 562         /**
 563          * Applies JavaScript-controlled layout rules to the
 564          * presentation.
 565          */
 566         function layout() {
 567
 568                 // Available space to scale within
 569                 var availableWidth = dom.wrapper.offsetWidth,
 570                         availableHeight = dom.wrapper.offsetHeight;
 571
 572                 // Reduce availabe space by margin
 573                 availableWidth -= ( availableHeight * config.margin );
 574                 availableHeight -= ( availableHeight * config.margin );
 575
 576                 // Dimensions of the content
 577                 var slideWidth = config.width,
 578                         slideHeight = config.height;
 579
 580                 // Slide width may be a percentage of available width
 581                 if( typeof slideWidth === 'string' && /%$/.test( slideWidth ) ) {
 582                         slideWidth = parseInt( slideWidth, 10 ) / 100 * availableWidth;
 583                 }
 584
 585                 // Slide height may be a percentage of available height
 586                 if( typeof slideHeight === 'string' && /%$/.test( slideHeight ) ) {
 587                         slideHeight = parseInt( slideHeight, 10 ) / 100 * availableHeight;
 588                 }
 589
 590                 dom.slides.style.width = slideWidth + 'px';
 591                 dom.slides.style.height = slideHeight + 'px';
 592
 593                 // Determine scale of content to fit within available space
 594                 var scale = Math.min( availableWidth / slideWidth, availableHeight / slideHeight );
 595
 596                 // Respect max/min scale settings
 597                 scale = Math.max( scale, config.minScale );
 598                 scale = Math.min( scale, config.maxScale );
 599
 600                 // Prefer applying scale via zoom since Chrome blurs scaled content
 601                 // with nested transforms
 602                 if( typeof dom.slides.style.zoom !== 'undefined' && !navigator.userAgent.match( /(iphone|ipod|android)/gi ) ) {
 603                         dom.slides.style.zoom = scale;
 604                 }
 605                 // Apply scale transform as a fallback
 606                 else {
 607                         var transform = 'translate(-50%, -50%) scale('+ scale +') translate(50%, 50%)';
 608
 609                         dom.slides.style.WebkitTransform = transform;
 610                         dom.slides.style.MozTransform = transform;
 611                         dom.slides.style.msTransform = transform;
 612                         dom.slides.style.OTransform = transform;
 613                         dom.slides.style.transform = transform;
 614                 }
 615
 616                 if( config.center ) {
 617
 618                         // Select all slides, vertical and horizontal
 619                         var slides = toArray( document.querySelectorAll( SLIDES_SELECTOR ) );
 620
 621                         // Determine the minimum top offset for slides
 622                         var minTop = -slideHeight / 2;
 623
 624                         for( var i = 0, len = slides.length; i < len; i++ ) {
 625                                 var slide = slides[ i ];
 626
 627                                 // Don't bother updating invisible slides
 628                                 if( slide.style.display === 'none' ) {
 629                                         continue;
 630                                 }
 631
 632                                 // Vertical stacks are not centered since their section
 633                                 // children will be
 634                                 if( slide.classList.contains( 'stack' ) ) {
 635                                         slide.style.top = 0;
 636                                 }
 637                                 else {
 638                                         slide.style.top = Math.max( - ( slide.offsetHeight / 2 ) - 20, minTop ) + 'px';
 639                                 }
 640                         }
 641
 642                 }
 643
 644         }
 645
 646         /**
 647          * Stores the vertical index of a stack so that the same
 648          * vertical slide can be selected when navigating to and
 649          * from the stack.
 650          *
 651          * @param {HTMLElement} stack The vertical stack element
 652          * @param {int} v Index to memorize
 653          */
 654         function setPreviousVerticalIndex( stack, v ) {
 655
 656                 if( stack ) {
 657                         stack.setAttribute( 'data-previous-indexv', v || 0 );
 658                 }
 659
 660         }
 661
 662         /**
 663          * Retrieves the vertical index which was stored using
 664          * #setPreviousVerticalIndex() or 0 if no previous index
 665          * exists.
 666          *
 667          * @param {HTMLElement} stack The vertical stack element
 668          */
 669         function getPreviousVerticalIndex( stack ) {
 670
 671                 if( stack && stack.classList.contains( 'stack' ) ) {
 672                         return parseInt( stack.getAttribute( 'data-previous-indexv' ) || 0, 10 );
 673                 }
 674
 675                 return 0;
 676
 677         }
 678
 679         /**
 680          * Displays the overview of slides (quick nav) by
 681          * scaling down and arranging all slide elements.
 682          *
 683          * Experimental feature, might be dropped if perf
 684          * can't be improved.
 685          */
 686         function activateOverview() {
 687
 688                 // Only proceed if enabled in config
 689                 if( config.overview ) {
 690
 691                         var wasActive = dom.wrapper.classList.contains( 'overview' );
 692
 693                         dom.wrapper.classList.add( 'overview' );
 694                         dom.wrapper.classList.remove( 'exit-overview' );
 695
 696                         clearTimeout( activateOverviewTimeout );
 697                         clearTimeout( deactivateOverviewTimeout );
 698
 699                         // Not the pretties solution, but need to let the overview
 700                         // class apply first so that slides are measured accurately
 701                         // before we can position them
 702                         activateOverviewTimeout = setTimeout( function(){
 703
 704                                 var horizontalSlides = document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR );
 705
 706                                 for( var i = 0, len1 = horizontalSlides.length; i < len1; i++ ) {
 707                                         var hslide = horizontalSlides[i],
 708                                                 htransform = 'translateZ(-2500px) translate(' + ( ( i - indexh ) * 105 ) + '%, 0%)';
 709
 710                                         hslide.setAttribute( 'data-index-h', i );
 711                                         hslide.style.display = 'block';
 712                                         hslide.style.WebkitTransform = htransform;
 713                                         hslide.style.MozTransform = htransform;
 714                                         hslide.style.msTransform = htransform;
 715                                         hslide.style.OTransform = htransform;
 716                                         hslide.style.transform = htransform;
 717
 718                                         if( hslide.classList.contains( 'stack' ) ) {
 719
 720                                                 var verticalSlides = hslide.querySelectorAll( 'section' );
 721
 722                                                 for( var j = 0, len2 = verticalSlides.length; j < len2; j++ ) {
 723                                                         var verticalIndex = i === indexh ? indexv : getPreviousVerticalIndex( hslide );
 724
 725                                                         var vslide = verticalSlides[j],
 726                                                                 vtransform = 'translate(0%, ' + ( ( j - verticalIndex ) * 105 ) + '%)';
 727
 728                                                         vslide.setAttribute( 'data-index-h', i );
 729                                                         vslide.setAttribute( 'data-index-v', j );
 730                                                         vslide.style.display = 'block';
 731                                                         vslide.style.WebkitTransform = vtransform;
 732                                                         vslide.style.MozTransform = vtransform;
 733                                                         vslide.style.msTransform = vtransform;
 734                                                         vslide.style.OTransform = vtransform;
 735                                                         vslide.style.transform = vtransform;
 736
 737                                                         // Navigate to this slide on click
 738                                                         vslide.addEventListener( 'click', onOverviewSlideClicked, true );
 739                                                 }
 740
 741                                         }
 742                                         else {
 743
 744                                                 // Navigate to this slide on click
 745                                                 hslide.addEventListener( 'click', onOverviewSlideClicked, true );
 746
 747                                         }
 748                                 }
 749
 750                                 layout();
 751
 752                                 if( !wasActive ) {
 753                                         // Notify observers of the overview showing
 754                                         dispatchEvent( 'overviewshown', {
 755                                                 'indexh': indexh,
 756                                                 'indexv': indexv,
 757                                                 'currentSlide': currentSlide
 758                                         } );
 759                                 }
 760
 761                         }, 10 );
 762
 763                 }
 764
 765         }
 766
 767         /**
 768          * Exits the slide overview and enters the currently
 769          * active slide.
 770          */
 771         function deactivateOverview() {
 772
 773                 // Only proceed if enabled in config
 774                 if( config.overview ) {
 775
 776                         clearTimeout( activateOverviewTimeout );
 777                         clearTimeout( deactivateOverviewTimeout );
 778
 779                         dom.wrapper.classList.remove( 'overview' );
 780
 781                         // Temporarily add a class so that transitions can do different things
 782                         // depending on whether they are exiting/entering overview, or just
 783                         // moving from slide to slide
 784                         dom.wrapper.classList.add( 'exit-overview' );
 785
 786                         deactivateOverviewTimeout = setTimeout( function () {
 787                                 dom.wrapper.classList.remove( 'exit-overview' );
 788                         }, 10);
 789
 790                         // Select all slides
 791                         var slides = toArray( document.querySelectorAll( SLIDES_SELECTOR ) );
 792
 793                         for( var i = 0, len = slides.length; i < len; i++ ) {
 794                                 var element = slides[i];
 795
 796                                 element.style.display = '';
 797
 798                                 // Resets all transforms to use the external styles
 799                                 element.style.WebkitTransform = '';
 800                                 element.style.MozTransform = '';
 801                                 element.style.msTransform = '';
 802                                 element.style.OTransform = '';
 803                                 element.style.transform = '';
 804
 805                                 element.removeEventListener( 'click', onOverviewSlideClicked, true );
 806                         }
 807
 808                         slide( indexh, indexv );
 809
 810                         // Notify observers of the overview hiding
 811                         dispatchEvent( 'overviewhidden', {
 812                                 'indexh': indexh,
 813                                 'indexv': indexv,
 814                                 'currentSlide': currentSlide
 815                         } );
 816
 817                 }
 818         }
 819
 820         /**
 821          * Toggles the slide overview mode on and off.
 822          *
 823          * @param {Boolean} override Optional flag which overrides the
 824          * toggle logic and forcibly sets the desired state. True means
 825          * overview is open, false means it's closed.
 826          */
 827         function toggleOverview( override ) {
 828
 829                 if( typeof override === 'boolean' ) {
 830                         override ? activateOverview() : deactivateOverview();
 831                 }
 832                 else {
 833                         isOverviewActive() ? deactivateOverview() : activateOverview();
 834                 }
 835
 836         }
 837
 838         /**
 839          * Checks if the overview is currently active.
 840          *
 841          * @return {Boolean} true if the overview is active,
 842          * false otherwise
 843          */
 844         function isOverviewActive() {
 845
 846                 return dom.wrapper.classList.contains( 'overview' );
 847
 848         }
 849
 850         /**
 851          * Handling the fullscreen functionality via the fullscreen API
 852          *
 853          * @see http://fullscreen.spec.whatwg.org/
 854          * @see https://developer.mozilla.org/en-US/docs/DOM/Using_fullscreen_mode
 855          */
 856         function enterFullscreen() {
 857
 858                 var element = document.body;
 859
 860                 // Check which implementation is available
 861                 var requestMethod = element.requestFullScreen ||
 862                                                         element.webkitRequestFullScreen ||
 863                                                         element.mozRequestFullScreen ||
 864                                                         element.msRequestFullScreen;
 865
 866                 if( requestMethod ) {
 867                         requestMethod.apply( element );
 868                 }
 869
 870         }
 871
 872         /**
 873          * Enters the paused mode which fades everything on screen to
 874          * black.
 875          */
 876         function pause() {
 877
 878                 dom.wrapper.classList.add( 'paused' );
 879
 880         }
 881
 882         /**
 883          * Exits from the paused mode.
 884          */
 885         function resume() {
 886
 887                 dom.wrapper.classList.remove( 'paused' );
 888
 889         }
 890
 891         /**
 892          * Toggles the paused mode on and off.
 893          */
 894         function togglePause() {
 895
 896                 if( isPaused() ) {
 897                         resume();
 898                 }
 899                 else {
 900                         pause();
 901                 }
 902
 903         }
 904
 905         /**
 906          * Checks if we are currently in the paused mode.
 907          */
 908         function isPaused() {
 909
 910                 return dom.wrapper.classList.contains( 'paused' );
 911
 912         }
 913
 914         /**
 915          * Steps from the current point in the presentation to the
 916          * slide which matches the specified horizontal and vertical
 917          * indices.
 918          *
 919          * @param {int} h Horizontal index of the target slide
 920          * @param {int} v Vertical index of the target slide
 921          * @param {int} f Optional index of a fragment within the
 922          * target slide to activate
 923          */
 924         function slide( h, v, f ) {
 925
 926                 // Remember where we were at before
 927                 previousSlide = currentSlide;
 928
 929                 // Query all horizontal slides in the deck
 930                 var horizontalSlides = document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR );
 931
 932                 // If no vertical index is specified and the upcoming slide is a
 933                 // stack, resume at its previous vertical index
 934                 if( v === undefined ) {
 935                         v = getPreviousVerticalIndex( horizontalSlides[ h ] );
 936                 }
 937
 938                 // If we were on a vertical stack, remember what vertical index
 939                 // it was on so we can resume at the same position when returning
 940                 if( previousSlide && previousSlide.parentNode && previousSlide.parentNode.classList.contains( 'stack' ) ) {
 941                         setPreviousVerticalIndex( previousSlide.parentNode, indexv );
 942                 }
 943
 944                 // Remember the state before this slide
 945                 var stateBefore = state.concat();
 946
 947                 // Reset the state array
 948                 state.length = 0;
 949
 950                 var indexhBefore = indexh,
 951                         indexvBefore = indexv;
 952
 953                 // Activate and transition to the new slide
 954                 indexh = updateSlides( HORIZONTAL_SLIDES_SELECTOR, h === undefined ? indexh : h );
 955                 indexv = updateSlides( VERTICAL_SLIDES_SELECTOR, v === undefined ? indexv : v );
 956
 957                 layout();
 958
 959                 // Apply the new state
 960                 stateLoop: for( var i = 0, len = state.length; i < len; i++ ) {
 961                         // Check if this state existed on the previous slide. If it
 962                         // did, we will avoid adding it repeatedly
 963                         for( var j = 0; j < stateBefore.length; j++ ) {
 964                                 if( stateBefore[j] === state[i] ) {
 965                                         stateBefore.splice( j, 1 );
 966                                         continue stateLoop;
 967                                 }
 968                         }
 969
 970                         document.documentElement.classList.add( state[i] );
 971
 972                         // Dispatch custom event matching the state's name
 973                         dispatchEvent( state[i] );
 974                 }
 975
 976                 // Clean up the remains of the previous state
 977                 while( stateBefore.length ) {
 978                         document.documentElement.classList.remove( stateBefore.pop() );
 979                 }
 980
 981                 // If the overview is active, re-activate it to update positions
 982                 if( isOverviewActive() ) {
 983                         activateOverview();
 984                 }
 985
 986                 // Update the URL hash after a delay since updating it mid-transition
 987                 // is likely to cause visual lag
 988                 writeURL( 1500 );
 989
 990                 // Find the current horizontal slide and any possible vertical slides
 991                 // within it
 992                 var currentHorizontalSlide = horizontalSlides[ indexh ],
 993                         currentVerticalSlides = currentHorizontalSlide.querySelectorAll( 'section' );
 994
 995                 // Store references to the previous and current slides
 996                 currentSlide = currentVerticalSlides[ indexv ] || currentHorizontalSlide;
 997
 998
 999                 // Show fragment, if specified
1000                 if( typeof f !== 'undefined' ) {
1001                         var fragments = currentSlide.querySelectorAll( '.fragment' );
1002
1003                         toArray( fragments ).forEach( function( fragment, indexf ) {
1004                                 if( indexf < f ) {
1005                                         fragment.classList.add( 'visible' );
1006                                 }
1007                                 else {
1008                                         fragment.classList.remove( 'visible' );
1009                                 }
1010                         } );
1011                 }
1012
1013                 // Dispatch an event if the slide changed
1014                 if( indexh !== indexhBefore || indexv !== indexvBefore ) {
1015                         dispatchEvent( 'slidechanged', {
1016                                 'indexh': indexh,
1017                                 'indexv': indexv,
1018                                 'previousSlide': previousSlide,
1019                                 'currentSlide': currentSlide
1020                         } );
1021                 }
1022                 else {
1023                         // Ensure that the previous slide is never the same as the current
1024                         previousSlide = null;
1025                 }
1026
1027                 // Solves an edge case where the previous slide maintains the
1028                 // 'present' class when navigating between adjacent vertical
1029                 // stacks
1030                 if( previousSlide ) {
1031                         previousSlide.classList.remove( 'present' );
1032
1033                         // Reset all slides upon navigate to home
1034                         // Issue: #285
1035                         if ( document.querySelector( HOME_SLIDE_SELECTOR ).classList.contains( 'present' ) ) {
1036                                 // Launch async task
1037                                 setTimeout( function () {
1038                                         var slides = toArray( document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR + '.stack') ), i;
1039                                         for( i in slides ) {
1040                                                 if( slides[i] ) {
1041                                                         // Reset stack
1042                                                         setPreviousVerticalIndex( slides[i], 0 );
1043                                                 }
1044                                         }
1045                                 }, 0 );
1046                         }
1047                 }
1048
1049                 updateControls();
1050                 updateProgress();
1051
1052         }
1053
1054         /**
1055          * Updates one dimension of slides by showing the slide
1056          * with the specified index.
1057          *
1058          * @param {String} selector A CSS selector that will fetch
1059          * the group of slides we are working with
1060          * @param {Number} index The index of the slide that should be
1061          * shown
1062          *
1063          * @return {Number} The index of the slide that is now shown,
1064          * might differ from the passed in index if it was out of
1065          * bounds.
1066          */
1067         function updateSlides( selector, index ) {
1068
1069                 // Select all slides and convert the NodeList result to
1070                 // an array
1071                 var slides = toArray( document.querySelectorAll( selector ) ),
1072                         slidesLength = slides.length;
1073
1074                 if( slidesLength ) {
1075
1076                         // Should the index loop?
1077                         if( config.loop ) {
1078                                 index %= slidesLength;
1079
1080                                 if( index < 0 ) {
1081                                         index = slidesLength + index;
1082                                 }
1083                         }
1084
1085                         // Enforce max and minimum index bounds
1086                         index = Math.max( Math.min( index, slidesLength - 1 ), 0 );
1087
1088                         for( var i = 0; i < slidesLength; i++ ) {
1089                                 var element = slides[i];
1090
1091                                 // Optimization; hide all slides that are three or more steps
1092                                 // away from the present slide
1093                                 if( isOverviewActive() === false ) {
1094                                         // The distance loops so that it measures 1 between the first
1095                                         // and last slides
1096                                         var distance = Math.abs( ( index - i ) % ( slidesLength - 3 ) ) || 0;
1097
1098                                         element.style.display = distance > 3 ? 'none' : 'block';
1099                                 }
1100
1101                                 slides[i].classList.remove( 'past' );
1102                                 slides[i].classList.remove( 'present' );
1103                                 slides[i].classList.remove( 'future' );
1104
1105                                 if( i < index ) {
1106                                         // Any element previous to index is given the 'past' class
1107                                         slides[i].classList.add( 'past' );
1108                                 }
1109                                 else if( i > index ) {
1110                                         // Any element subsequent to index is given the 'future' class
1111                                         slides[i].classList.add( 'future' );
1112                                 }
1113
1114                                 // If this element contains vertical slides
1115                                 if( element.querySelector( 'section' ) ) {
1116                                         slides[i].classList.add( 'stack' );
1117                                 }
1118                         }
1119
1120                         // Mark the current slide as present
1121                         slides[index].classList.add( 'present' );
1122
1123                         // If this slide has a state associated with it, add it
1124                         // onto the current state of the deck
1125                         var slideState = slides[index].getAttribute( 'data-state' );
1126                         if( slideState ) {
1127                                 state = state.concat( slideState.split( ' ' ) );
1128                         }
1129
1130                         // If this slide has a data-autoslide attribtue associated use this as
1131                         // autoSlide value otherwise use the global configured time
1132                         var slideAutoSlide = slides[index].getAttribute( 'data-autoslide' );
1133                         if( slideAutoSlide ) {
1134                                 autoSlide = parseInt( slideAutoSlide, 10 );
1135                         }
1136                         else {
1137                                 autoSlide = config.autoSlide;
1138                         }
1139
1140                 }
1141                 else {
1142                         // Since there are no slides we can't be anywhere beyond the
1143                         // zeroth index
1144                         index = 0;
1145                 }
1146
1147                 return index;
1148
1149         }
1150
1151         /**
1152          * Updates the progress bar to reflect the current slide.
1153          */
1154         function updateProgress() {
1155
1156                 // Update progress if enabled
1157                 if( config.progress && dom.progress ) {
1158
1159                         var horizontalSlides = toArray( document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) );
1160
1161                         // The number of past and total slides
1162                         var totalCount = document.querySelectorAll( SLIDES_SELECTOR + ':not(.stack)' ).length;
1163                         var pastCount = 0;
1164
1165                         // Step through all slides and count the past ones
1166                         mainLoop: for( var i = 0; i < horizontalSlides.length; i++ ) {
1167
1168                                 var horizontalSlide = horizontalSlides[i];
1169                                 var verticalSlides = toArray( horizontalSlide.querySelectorAll( 'section' ) );
1170
1171                                 for( var j = 0; j < verticalSlides.length; j++ ) {
1172
1173                                         // Stop as soon as we arrive at the present
1174                                         if( verticalSlides[j].classList.contains( 'present' ) ) {
1175                                                 break mainLoop;
1176                                         }
1177
1178                                         pastCount++;
1179
1180                                 }
1181
1182                                 // Stop as soon as we arrive at the present
1183                                 if( horizontalSlide.classList.contains( 'present' ) ) {
1184                                         break;
1185                                 }
1186
1187                                 // Don't count the wrapping section for vertical slides
1188                                 if( horizontalSlide.classList.contains( 'stack' ) === false ) {
1189                                         pastCount++;
1190                                 }
1191
1192                         }
1193
1194                         dom.progressbar.style.width = ( pastCount / ( totalCount - 1 ) ) * window.innerWidth + 'px';
1195
1196                 }
1197
1198         }
1199
1200         /**
1201          * Updates the state of all control/navigation arrows.
1202          */
1203         function updateControls() {
1204
1205                 if ( config.controls && dom.controls ) {
1206
1207                         var routes = availableRoutes();
1208
1209                         // Remove the 'enabled' class from all directions
1210                         dom.controlsLeft.concat( dom.controlsRight )
1211                                                         .concat( dom.controlsUp )
1212                                                         .concat( dom.controlsDown )
1213                                                         .concat( dom.controlsPrev )
1214                                                         .concat( dom.controlsNext ).forEach( function( node ) {
1215                                 node.classList.remove( 'enabled' );
1216                         } );
1217
1218                         // Add the 'enabled' class to the available routes
1219                         if( routes.left ) dom.controlsLeft.forEach( function( el ) { el.classList.add( 'enabled' );     } );
1220                         if( routes.right ) dom.controlsRight.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1221                         if( routes.up ) dom.controlsUp.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1222                         if( routes.down ) dom.controlsDown.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1223
1224                         // Prev/next buttons
1225                         if( routes.left || routes.up ) dom.controlsPrev.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1226                         if( routes.right || routes.down ) dom.controlsNext.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1227
1228                 }
1229
1230         }
1231
1232         /**
1233          * Determine what available routes there are for navigation.
1234          *
1235          * @return {Object} containing four booleans: left/right/up/down
1236          */
1237         function availableRoutes() {
1238
1239                 var horizontalSlides = document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ),
1240                         verticalSlides = document.querySelectorAll( VERTICAL_SLIDES_SELECTOR );
1241
1242                 return {
1243                         left: indexh > 0,
1244                         right: indexh < horizontalSlides.length - 1,
1245                         up: indexv > 0,
1246                         down: indexv < verticalSlides.length - 1
1247                 };
1248
1249         }
1250
1251         /**
1252          * Reads the current URL (hash) and navigates accordingly.
1253          */
1254         function readURL() {
1255
1256                 var hash = window.location.hash;
1257
1258                 // Attempt to parse the hash as either an index or name
1259                 var bits = hash.slice( 2 ).split( '/' ),
1260                         name = hash.replace( /#|\//gi, '' );
1261
1262                 // If the first bit is invalid and there is a name we can
1263                 // assume that this is a named link
1264                 if( isNaN( parseInt( bits[0], 10 ) ) && name.length ) {
1265                         // Find the slide with the specified name
1266                         var element = document.querySelector( '#' + name );
1267
1268                         if( element ) {
1269                                 // Find the position of the named slide and navigate to it
1270                                 var indices = Reveal.getIndices( element );
1271                                 slide( indices.h, indices.v );
1272                         }
1273                         // If the slide doesn't exist, navigate to the current slide
1274                         else {
1275                                 slide( indexh, indexv );
1276                         }
1277                 }
1278                 else {
1279                         // Read the index components of the hash
1280                         var h = parseInt( bits[0], 10 ) || 0,
1281                                 v = parseInt( bits[1], 10 ) || 0;
1282
1283                         slide( h, v );
1284                 }
1285
1286         }
1287
1288         /**
1289          * Updates the page URL (hash) to reflect the current
1290          * state.
1291          *
1292          * @param {Number} delay The time in ms to wait before
1293          * writing the hash
1294          */
1295         function writeURL( delay ) {
1296
1297                 if( config.history ) {
1298
1299                         // Make sure there's never more than one timeout running
1300                         clearTimeout( writeURLTimeout );
1301
1302                         // If a delay is specified, timeout this call
1303                         if( typeof delay === 'number' ) {
1304                                 writeURLTimeout = setTimeout( writeURL, delay );
1305                         }
1306                         else {
1307                                 var url = '/';
1308
1309                                 // If the current slide has an ID, use that as a named link
1310                                 if( currentSlide && typeof currentSlide.getAttribute( 'id' ) === 'string' ) {
1311                                         url = '/' + currentSlide.getAttribute( 'id' );
1312                                 }
1313                                 // Otherwise use the /h/v index
1314                                 else {
1315                                         if( indexh > 0 || indexv > 0 ) url += indexh;
1316                                         if( indexv > 0 ) url += '/' + indexv;
1317                                 }
1318
1319                                 window.location.hash = url;
1320                         }
1321                 }
1322
1323         }
1324
1325         /**
1326          * Retrieves the h/v location of the current, or specified,
1327          * slide.
1328          *
1329          * @param {HTMLElement} slide If specified, the returned
1330          * index will be for this slide rather than the currently
1331          * active one
1332          *
1333          * @return {Object} { h: <int>, v: <int> }
1334          */
1335         function getIndices( slide ) {
1336
1337                 // By default, return the current indices
1338                 var h = indexh,
1339                         v = indexv;
1340
1341                 // If a slide is specified, return the indices of that slide
1342                 if( slide ) {
1343                         var isVertical = !!slide.parentNode.nodeName.match( /section/gi );
1344                         var slideh = isVertical ? slide.parentNode : slide;
1345
1346                         // Select all horizontal slides
1347                         var horizontalSlides = toArray( document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) );
1348
1349                         // Now that we know which the horizontal slide is, get its index
1350                         h = Math.max( horizontalSlides.indexOf( slideh ), 0 );
1351
1352                         // If this is a vertical slide, grab the vertical index
1353                         if( isVertical ) {
1354                                 v = Math.max( toArray( slide.parentNode.querySelectorAll( 'section' ) ).indexOf( slide ), 0 );
1355                         }
1356                 }
1357
1358                 return { h: h, v: v };
1359
1360         }
1361
1362         /**
1363          * Navigate to the next slide fragment.
1364          *
1365          * @return {Boolean} true if there was a next fragment,
1366          * false otherwise
1367          */
1368         function nextFragment() {
1369
1370                 // Vertical slides:
1371                 if( document.querySelector( VERTICAL_SLIDES_SELECTOR + '.present' ) ) {
1372                         var verticalFragments = document.querySelectorAll( VERTICAL_SLIDES_SELECTOR + '.present .fragment:not(.visible)' );
1373                         if( verticalFragments.length ) {
1374                                 verticalFragments[0].classList.add( 'visible' );
1375
1376                                 // Notify subscribers of the change
1377                                 dispatchEvent( 'fragmentshown', { fragment: verticalFragments[0] } );
1378                                 return true;
1379                         }
1380                 }
1381                 // Horizontal slides:
1382                 else {
1383                         var horizontalFragments = document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR + '.present .fragment:not(.visible)' );
1384                         if( horizontalFragments.length ) {
1385                                 horizontalFragments[0].classList.add( 'visible' );
1386
1387                                 // Notify subscribers of the change
1388                                 dispatchEvent( 'fragmentshown', { fragment: horizontalFragments[0] } );
1389                                 return true;
1390                         }
1391                 }
1392
1393                 return false;
1394
1395         }
1396
1397         /**
1398          * Navigate to the previous slide fragment.
1399          *
1400          * @return {Boolean} true if there was a previous fragment,
1401          * false otherwise
1402          */
1403         function previousFragment() {
1404
1405                 // Vertical slides:
1406                 if( document.querySelector( VERTICAL_SLIDES_SELECTOR + '.present' ) ) {
1407                         var verticalFragments = document.querySelectorAll( VERTICAL_SLIDES_SELECTOR + '.present .fragment.visible' );
1408                         if( verticalFragments.length ) {
1409                                 verticalFragments[ verticalFragments.length - 1 ].classList.remove( 'visible' );
1410
1411                                 // Notify subscribers of the change
1412                                 dispatchEvent( 'fragmenthidden', { fragment: verticalFragments[ verticalFragments.length - 1 ] } );
1413                                 return true;
1414                         }
1415                 }
1416                 // Horizontal slides:
1417                 else {
1418                         var horizontalFragments = document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR + '.present .fragment.visible' );
1419                         if( horizontalFragments.length ) {
1420                                 horizontalFragments[ horizontalFragments.length - 1 ].classList.remove( 'visible' );
1421
1422                                 // Notify subscribers of the change
1423                                 dispatchEvent( 'fragmenthidden', { fragment: horizontalFragments[ horizontalFragments.length - 1 ] } );
1424                                 return true;
1425                         }
1426                 }
1427
1428                 return false;
1429
1430         }
1431
1432         /**
1433          * Cues a new automated slide if enabled in the config.
1434          */
1435         function cueAutoSlide() {
1436
1437                 clearTimeout( autoSlideTimeout );
1438
1439                 // Cue the next auto-slide if enabled
1440                 if( autoSlide ) {
1441                         autoSlideTimeout = setTimeout( navigateNext, autoSlide );
1442                 }
1443
1444         }
1445
1446         function navigateLeft() {
1447
1448                 // Prioritize hiding fragments
1449                 if( availableRoutes().left && isOverviewActive() || previousFragment() === false ) {
1450                         slide( indexh - 1 );
1451                 }
1452
1453         }
1454
1455         function navigateRight() {
1456
1457                 // Prioritize revealing fragments
1458                 if( availableRoutes().right && isOverviewActive() || nextFragment() === false ) {
1459                         slide( indexh + 1 );
1460                 }
1461
1462         }
1463
1464         function navigateUp() {
1465
1466                 // Prioritize hiding fragments
1467                 if( availableRoutes().up && isOverviewActive() || previousFragment() === false ) {
1468                         slide( indexh, indexv - 1 );
1469                 }
1470
1471         }
1472
1473         function navigateDown() {
1474
1475                 // Prioritize revealing fragments
1476                 if( availableRoutes().down && isOverviewActive() || nextFragment() === false ) {
1477                         slide( indexh, indexv + 1 );
1478                 }
1479
1480         }
1481
1482         /**
1483          * Navigates backwards, prioritized in the following order:
1484          * 1) Previous fragment
1485          * 2) Previous vertical slide
1486          * 3) Previous horizontal slide
1487          */
1488         function navigatePrev() {
1489
1490                 // Prioritize revealing fragments
1491                 if( previousFragment() === false ) {
1492                         if( availableRoutes().up ) {
1493                                 navigateUp();
1494                         }
1495                         else {
1496                                 // Fetch the previous horizontal slide, if there is one
1497                                 var previousSlide = document.querySelector( HORIZONTAL_SLIDES_SELECTOR + '.past:nth-child(' + indexh + ')' );
1498
1499                                 if( previousSlide ) {
1500                                         indexv = ( previousSlide.querySelectorAll( 'section' ).length + 1 ) || undefined;
1501                                         indexh --;
1502                                         slide();
1503                                 }
1504                         }
1505                 }
1506
1507         }
1508
1509         /**
1510          * Same as #navigatePrev() but navigates forwards.
1511          */
1512         function navigateNext() {
1513
1514                 // Prioritize revealing fragments
1515                 if( nextFragment() === false ) {
1516                         availableRoutes().down ? navigateDown() : navigateRight();
1517                 }
1518
1519                 // If auto-sliding is enabled we need to cue up
1520                 // another timeout
1521                 cueAutoSlide();
1522
1523         }
1524
1525
1526         // --------------------------------------------------------------------//
1527         // ----------------------------- EVENTS -------------------------------//
1528         // --------------------------------------------------------------------//
1529
1530
1531         /**
1532          * Handler for the document level 'keydown' event.
1533          *
1534          * @param {Object} event
1535          */
1536         function onDocumentKeyDown( event ) {
1537
1538                 // Check if there's a focused element that could be using
1539                 // the keyboard
1540                 var activeElement = document.activeElement;
1541                 var hasFocus = !!( document.activeElement && ( document.activeElement.type || document.activeElement.href || document.activeElement.contentEditable !== 'inherit' ) );
1542
1543                 // Disregard the event if there's a focused element or a
1544                 // keyboard modifier key is present
1545                 if ( hasFocus || event.shiftKey || event.altKey || event.ctrlKey || event.metaKey ) return;
1546
1547                 var triggered = true;
1548
1549                 switch( event.keyCode ) {
1550                         // p, page up
1551                         case 80: case 33: navigatePrev(); break;
1552                         // n, page down
1553                         case 78: case 34: navigateNext(); break;
1554                         // h, left
1555                         case 72: case 37: navigateLeft(); break;
1556                         // l, right
1557                         case 76: case 39: navigateRight(); break;
1558                         // k, up
1559                         case 75: case 38: navigateUp(); break;
1560                         // j, down
1561                         case 74: case 40: navigateDown(); break;
1562                         // home
1563                         case 36: slide( 0 ); break;
1564                         // end
1565                         case 35: slide( Number.MAX_VALUE ); break;
1566                         // space
1567                         case 32: isOverviewActive() ? deactivateOverview() : navigateNext(); break;
1568                         // return
1569                         case 13: isOverviewActive() ? deactivateOverview() : triggered = false; break;
1570                         // b, period, Logitech presenter tools "black screen" button
1571                         case 66: case 190: case 191: togglePause(); break;
1572                         // f
1573                         case 70: enterFullscreen(); break;
1574                         default:
1575                                 triggered = false;
1576                 }
1577
1578                 // If the input resulted in a triggered action we should prevent
1579                 // the browsers default behavior
1580                 if( triggered ) {
1581                         event.preventDefault();
1582                 }
1583                 else if ( event.keyCode === 27 && supports3DTransforms ) {
1584                         toggleOverview();
1585
1586                         event.preventDefault();
1587                 }
1588
1589                 // If auto-sliding is enabled we need to cue up
1590                 // another timeout
1591                 cueAutoSlide();
1592
1593         }
1594
1595         /**
1596          * Handler for the document level 'touchstart' event,
1597          * enables support for swipe and pinch gestures.
1598          */
1599         function onDocumentTouchStart( event ) {
1600
1601                 touch.startX = event.touches[0].clientX;
1602                 touch.startY = event.touches[0].clientY;
1603                 touch.startCount = event.touches.length;
1604
1605                 // If there's two touches we need to memorize the distance
1606                 // between those two points to detect pinching
1607                 if( event.touches.length === 2 && config.overview ) {
1608                         touch.startSpan = distanceBetween( {
1609                                 x: event.touches[1].clientX,
1610                                 y: event.touches[1].clientY
1611                         }, {
1612                                 x: touch.startX,
1613                                 y: touch.startY
1614                         } );
1615                 }
1616
1617         }
1618
1619         /**
1620          * Handler for the document level 'touchmove' event.
1621          */
1622         function onDocumentTouchMove( event ) {
1623
1624                 // Each touch should only trigger one action
1625                 if( !touch.handled ) {
1626                         var currentX = event.touches[0].clientX;
1627                         var currentY = event.touches[0].clientY;
1628
1629                         // If the touch started off with two points and still has
1630                         // two active touches; test for the pinch gesture
1631                         if( event.touches.length === 2 && touch.startCount === 2 && config.overview ) {
1632
1633                                 // The current distance in pixels between the two touch points
1634                                 var currentSpan = distanceBetween( {
1635                                         x: event.touches[1].clientX,
1636                                         y: event.touches[1].clientY
1637                                 }, {
1638                                         x: touch.startX,
1639                                         y: touch.startY
1640                                 } );
1641
1642                                 // If the span is larger than the desire amount we've got
1643                                 // ourselves a pinch
1644                                 if( Math.abs( touch.startSpan - currentSpan ) > touch.threshold ) {
1645                                         touch.handled = true;
1646
1647                                         if( currentSpan < touch.startSpan ) {
1648                                                 activateOverview();
1649                                         }
1650                                         else {
1651                                                 deactivateOverview();
1652                                         }
1653                                 }
1654
1655                                 event.preventDefault();
1656
1657                         }
1658                         // There was only one touch point, look for a swipe
1659                         else if( event.touches.length === 1 && touch.startCount !== 2 ) {
1660
1661                                 var deltaX = currentX - touch.startX,
1662                                         deltaY = currentY - touch.startY;
1663
1664                                 if( deltaX > touch.threshold && Math.abs( deltaX ) > Math.abs( deltaY ) ) {
1665                                         touch.handled = true;
1666                                         navigateLeft();
1667                                 }
1668                                 else if( deltaX < -touch.threshold && Math.abs( deltaX ) > Math.abs( deltaY ) ) {
1669                                         touch.handled = true;
1670                                         navigateRight();
1671                                 }
1672                                 else if( deltaY > touch.threshold ) {
1673                                         touch.handled = true;
1674                                         navigateUp();
1675                                 }
1676                                 else if( deltaY < -touch.threshold ) {
1677                                         touch.handled = true;
1678                                         navigateDown();
1679                                 }
1680
1681                                 event.preventDefault();
1682
1683                         }
1684                 }
1685                 // There's a bug with swiping on some Android devices unless
1686                 // the default action is always prevented
1687                 else if( navigator.userAgent.match( /android/gi ) ) {
1688                         event.preventDefault();
1689                 }
1690
1691         }
1692
1693         /**
1694          * Handler for the document level 'touchend' event.
1695          */
1696         function onDocumentTouchEnd( event ) {
1697
1698                 touch.handled = false;
1699
1700         }
1701
1702         /**
1703          * Handles mouse wheel scrolling, throttled to avoid skipping
1704          * multiple slides.
1705          */
1706         function onDocumentMouseScroll( event ) {
1707
1708                 clearTimeout( mouseWheelTimeout );
1709
1710                 mouseWheelTimeout = setTimeout( function() {
1711                         var delta = event.detail || -event.wheelDelta;
1712                         if( delta > 0 ) {
1713                                 navigateNext();
1714                         }
1715                         else {
1716                                 navigatePrev();
1717                         }
1718                 }, 100 );
1719
1720         }
1721
1722         /**
1723          * Clicking on the progress bar results in a navigation to the
1724          * closest approximate horizontal slide using this equation:
1725          *
1726          * ( clickX / presentationWidth ) * numberOfSlides
1727          */
1728         function onProgressClick( event ) {
1729
1730                 var slidesTotal = toArray( document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) ).length;
1731                 var slideIndex = Math.floor( ( event.clientX / dom.wrapper.offsetWidth ) * slidesTotal );
1732
1733                 slide( slideIndex );
1734
1735         }
1736
1737         /**
1738          * Handler for the window level 'hashchange' event.
1739          */
1740         function onWindowHashChange( event ) {
1741
1742                 readURL();
1743
1744         }
1745
1746         /**
1747          * Handler for the window level 'resize' event.
1748          */
1749         function onWindowResize( event ) {
1750
1751                 layout();
1752
1753         }
1754
1755         /**
1756          * Invoked when a slide is and we're in the overview.
1757          */
1758         function onOverviewSlideClicked( event ) {
1759
1760                 // TODO There's a bug here where the event listeners are not
1761                 // removed after deactivating the overview.
1762                 if( isOverviewActive() ) {
1763                         event.preventDefault();
1764
1765                         deactivateOverview();
1766
1767                         var element = event.target;
1768
1769                         while( element && !element.nodeName.match( /section/gi ) ) {
1770                                 element = element.parentNode;
1771                         }
1772
1773                         if( element.nodeName.match( /section/gi ) ) {
1774                                 var h = parseInt( element.getAttribute( 'data-index-h' ), 10 ),
1775                                         v = parseInt( element.getAttribute( 'data-index-v' ), 10 );
1776
1777                                 slide( h, v );
1778                         }
1779                 }
1780
1781         }
1782
1783
1784         // --------------------------------------------------------------------//
1785         // ------------------------------- API --------------------------------//
1786         // --------------------------------------------------------------------//
1787
1788
1789         return {
1790                 initialize: initialize,
1791
1792                 // Navigation methods
1793                 slide: slide,
1794                 left: navigateLeft,
1795                 right: navigateRight,
1796                 up: navigateUp,
1797                 down: navigateDown,
1798                 prev: navigatePrev,
1799                 next: navigateNext,
1800                 prevFragment: previousFragment,
1801                 nextFragment: nextFragment,
1802
1803                 // Deprecated aliases
1804                 navigateTo: slide,
1805                 navigateLeft: navigateLeft,
1806                 navigateRight: navigateRight,
1807                 navigateUp: navigateUp,
1808                 navigateDown: navigateDown,
1809                 navigatePrev: navigatePrev,
1810                 navigateNext: navigateNext,
1811
1812                 // Forces an update in slide layout
1813                 layout: layout,
1814
1815                 // Toggles the overview mode on/off
1816                 toggleOverview: toggleOverview,
1817
1818                 // Toggles the "black screen" mode on/off
1819                 togglePause: togglePause,
1820
1821                 // Adds or removes all internal event listeners (such as keyboard)
1822                 addEventListeners: addEventListeners,
1823                 removeEventListeners: removeEventListeners,
1824
1825                 // Returns the indices of the current, or specified, slide
1826                 getIndices: getIndices,
1827
1828                 // Returns the previous slide element, may be null
1829                 getPreviousSlide: function() {
1830                         return previousSlide;
1831                 },
1832
1833                 // Returns the current slide element
1834                 getCurrentSlide: function() {
1835                         return currentSlide;
1836                 },
1837
1838                 // Helper method, retrieves query string as a key/value hash
1839                 getQueryHash: function() {
1840                         var query = {};
1841
1842                         location.search.replace( /[A-Z0-9]+?=(\w*)/gi, function(a) {
1843                                 query[ a.split( '=' ).shift() ] = a.split( '=' ).pop();
1844                         } );
1845
1846                         return query;
1847                 },
1848
1849                 // Forward event binding to the reveal DOM element
1850                 addEventListener: function( type, listener, useCapture ) {
1851                         if( 'addEventListener' in window ) {
1852                                 ( dom.wrapper || document.querySelector( '.reveal' ) ).addEventListener( type, listener, useCapture );
1853                         }
1854                 },
1855                 removeEventListener: function( type, listener, useCapture ) {
1856                         if( 'addEventListener' in window ) {
1857                                 ( dom.wrapper || document.querySelector( '.reveal' ) ).removeEventListener( type, listener, useCapture );
1858                         }
1859                 }
1860         };
1861
1862 })();