js/reveal.js

   1 /*!
   2  * reveal.js
   3  * http://lab.hakim.se/reveal-js
   4  * MIT licensed
   5  *
   6  * Copyright (C) 2011-2012 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                         // Display controls in the bottom right corner
  20                         controls: true,
  21
  22                         // Display a presentation progress bar
  23                         progress: true,
  24
  25                         // Push each slide change to the browser history
  26                         history: false,
  27
  28                         // Enable keyboard shortcuts for navigation
  29                         keyboard: true,
  30
  31                         // Enable the slide overview mode
  32                         overview: true,
  33
  34                         // Vertical centering of slides
  35                         center: true,
  36
  37                         // Loop the presentation
  38                         loop: false,
  39
  40                         // Change the presentation direction to be RTL
  41                         rtl: false,
  42
  43                         // Number of milliseconds between automatically proceeding to the
  44                         // next slide, disabled when set to 0, this value can be overwritten
  45                         // by using a data-autoslide attribute on your slides
  46                         autoSlide: 0,
  47
  48                         // Enable slide navigation via mouse wheel
  49                         mouseWheel: false,
  50
  51                         // Apply a 3D roll to links on hover
  52                         rollingLinks: true,
  53
  54                         // Transition style (see /css/theme)
  55                         theme: null,
  56
  57                         // Transition style
  58                         transition: 'default', // default/cube/page/concave/zoom/linear/none
  59
  60                         // Script dependencies to load
  61                         dependencies: []
  62                 },
  63
  64                 // Stores if the next slide should be shown automatically
  65                 // after n milliseconds
  66                 autoSlide = config.autoSlide,
  67
  68                 // The horizontal and verical index of the currently active slide
  69                 indexh = 0,
  70                 indexv = 0,
  71
  72                 // The previous and current slide HTML elements
  73                 previousSlide,
  74                 currentSlide,
  75
  76                 // Slides may hold a data-state attribute which we pick up and apply
  77                 // as a class to the body. This list contains the combined state of
  78                 // all current slides.
  79                 state = [],
  80
  81                 // Cached references to DOM elements
  82                 dom = {},
  83
  84                 // Detect support for CSS 3D transforms
  85                 supports3DTransforms =  'WebkitPerspective' in document.body.style ||
  86                                                                 'MozPerspective' in document.body.style ||
  87                                                                 'msPerspective' in document.body.style ||
  88                                                                 'OPerspective' in document.body.style ||
  89                                                                 'perspective' in document.body.style,
  90
  91                 supports2DTransforms =  'WebkitTransform' in document.body.style ||
  92                                                                 'MozTransform' in document.body.style ||
  93                                                                 'msTransform' in document.body.style ||
  94                                                                 'OTransform' in document.body.style ||
  95                                                                 'transform' in document.body.style,
  96
  97                 // Throttles mouse wheel navigation
  98                 mouseWheelTimeout = 0,
  99
 100                 // An interval used to automatically move on to the next slide
 101                 autoSlideTimeout = 0,
 102
 103                 // Delays updates to the URL due to a Chrome thumbnailer bug
 104                 writeURLTimeout = 0,
 105
 106                 // A delay used to ativate the overview mode
 107                 activateOverviewTimeout = 0,
 108
 109                 // Holds information about the currently ongoing touch input
 110                 touch = {
 111                         startX: 0,
 112                         startY: 0,
 113                         startSpan: 0,
 114                         startCount: 0,
 115                         handled: false,
 116                         threshold: 80
 117                 };
 118
 119         /**
 120          * Starts up the presentation if the client is capable.
 121          */
 122         function initialize( options ) {
 123                 if( ( !supports2DTransforms && !supports3DTransforms ) ) {
 124                         document.body.setAttribute( 'class', 'no-transforms' );
 125
 126                         // If the browser doesn't support core features we won't be
 127                         // using JavaScript to control the presentation
 128                         return;
 129                 }
 130
 131                 // Force a layout when the whole page, incl fonts, has loaded
 132                 window.addEventListener( 'load', layout, false );
 133
 134                 // Copy options over to our config object
 135                 extend( config, options );
 136
 137                 // Hide the address bar in mobile browsers
 138                 hideAddressBar();
 139
 140                 // Loads the dependencies and continues to #start() once done
 141                 load();
 142
 143         }
 144
 145         /**
 146          * Finds and stores references to DOM elements which are
 147          * required by the presentation. If a required element is
 148          * not found, it is created.
 149          */
 150         function setupDOM() {
 151                 // Cache references to key DOM elements
 152                 dom.theme = document.querySelector( '#theme' );
 153                 dom.wrapper = document.querySelector( '.reveal' );
 154                 dom.slides = document.querySelector( '.reveal .slides' );
 155
 156                 // Progress bar
 157                 if( !dom.wrapper.querySelector( '.progress' ) && config.progress ) {
 158                         var progressElement = document.createElement( 'div' );
 159                         progressElement.classList.add( 'progress' );
 160                         progressElement.innerHTML = '<span></span>';
 161                         dom.wrapper.appendChild( progressElement );
 162                 }
 163
 164                 // Arrow controls
 165                 if( !dom.wrapper.querySelector( '.controls' ) && config.controls ) {
 166                         var controlsElement = document.createElement( 'aside' );
 167                         controlsElement.classList.add( 'controls' );
 168                         controlsElement.innerHTML = '<div class="navigate-left"></div>' +
 169                                                                                 '<div class="navigate-right"></div>' +
 170                                                                                 '<div class="navigate-up"></div>' +
 171                                                                                 '<div class="navigate-down"></div>';
 172                         dom.wrapper.appendChild( controlsElement );
 173                 }
 174
 175                 // Presentation background element
 176                 if( !dom.wrapper.querySelector( '.state-background' ) ) {
 177                         var backgroundElement = document.createElement( 'div' );
 178                         backgroundElement.classList.add( 'state-background' );
 179                         dom.wrapper.appendChild( backgroundElement );
 180                 }
 181
 182                 // Overlay graphic which is displayed during the paused mode
 183                 if( !dom.wrapper.querySelector( '.pause-overlay' ) ) {
 184                         var pausedElement = document.createElement( 'div' );
 185                         pausedElement.classList.add( 'pause-overlay' );
 186                         dom.wrapper.appendChild( pausedElement );
 187                 }
 188
 189                 // Cache references to elements
 190                 dom.progress = document.querySelector( '.reveal .progress' );
 191                 dom.progressbar = document.querySelector( '.reveal .progress span' );
 192
 193                 if ( config.controls ) {
 194                         dom.controls = document.querySelector( '.reveal .controls' );
 195
 196                         // There can be multiple instances of controls throughout the page
 197                         dom.controlsLeft = toArray( document.querySelectorAll( '.navigate-left' ) );
 198                         dom.controlsRight = toArray( document.querySelectorAll( '.navigate-right' ) );
 199                         dom.controlsUp = toArray( document.querySelectorAll( '.navigate-up' ) );
 200                         dom.controlsDown = toArray( document.querySelectorAll( '.navigate-down' ) );
 201                         dom.controlsPrev = toArray( document.querySelectorAll( '.navigate-prev' ) );
 202                         dom.controlsNext = toArray( document.querySelectorAll( '.navigate-next' ) );
 203                 }
 204         }
 205
 206         /**
 207          * Hides the address bar if we're on a mobile device.
 208          */
 209         function hideAddressBar() {
 210                 if( navigator.userAgent.match( /(iphone|ipod)/i ) ) {
 211                         // Give the page some scrollable overflow
 212                         document.documentElement.style.overflow = 'scroll';
 213                         document.body.style.height = '120%';
 214
 215                         // Events that should trigger the address bar to hide
 216                         window.addEventListener( 'load', removeAddressBar, false );
 217                         window.addEventListener( 'orientationchange', removeAddressBar, false );
 218                 }
 219         }
 220
 221         /**
 222          * Loads the dependencies of reveal.js. Dependencies are
 223          * defined via the configuration option 'dependencies'
 224          * and will be loaded prior to starting/binding reveal.js.
 225          * Some dependencies may have an 'async' flag, if so they
 226          * will load after reveal.js has been started up.
 227          */
 228         function load() {
 229                 var scripts = [],
 230                         scriptsAsync = [];
 231
 232                 for( var i = 0, len = config.dependencies.length; i < len; i++ ) {
 233                         var s = config.dependencies[i];
 234
 235                         // Load if there's no condition or the condition is truthy
 236                         if( !s.condition || s.condition() ) {
 237                                 if( s.async ) {
 238                                         scriptsAsync.push( s.src );
 239                                 }
 240                                 else {
 241                                         scripts.push( s.src );
 242                                 }
 243
 244                                 // Extension may contain callback functions
 245                                 if( typeof s.callback === 'function' ) {
 246                                         head.ready( s.src.match( /([\w\d_\-]*)\.?js$|[^\\\/]*$/i )[0], s.callback );
 247                                 }
 248                         }
 249                 }
 250
 251                 // Called once synchronous scritps finish loading
 252                 function proceed() {
 253                         if( scriptsAsync.length ) {
 254                                 // Load asynchronous scripts
 255                                 head.js.apply( null, scriptsAsync );
 256                         }
 257
 258                         start();
 259                 }
 260
 261                 if( scripts.length ) {
 262                         head.ready( proceed );
 263
 264                         // Load synchronous scripts
 265                         head.js.apply( null, scripts );
 266                 }
 267                 else {
 268                         proceed();
 269                 }
 270         }
 271
 272         /**
 273          * Starts up reveal.js by binding input events and navigating
 274          * to the current URL deeplink if there is one.
 275          */
 276         function start() {
 277                 // Make sure we've got all the DOM elements we need
 278                 setupDOM();
 279
 280                 // Subscribe to input
 281                 addEventListeners();
 282
 283                 // Updates the presentation to match the current configuration values
 284                 configure();
 285
 286                 // Force an initial layout, will thereafter be invoked as the window
 287                 // is resized
 288                 layout();
 289
 290                 // Read the initial hash
 291                 readURL();
 292
 293                 // Start auto-sliding if it's enabled
 294                 cueAutoSlide();
 295
 296                 // Notify listeners that the presentation is ready but use a 1ms
 297                 // timeout to ensure it's not fired synchronously after #initialize()
 298                 setTimeout( function() {
 299                         dispatchEvent( 'ready', {
 300                                 'indexh': indexh,
 301                                 'indexv': indexv,
 302                                 'currentSlide': currentSlide
 303                         } );
 304                 }, 1 );
 305         }
 306
 307         /**
 308          * Applies the configuration settings from the config object.
 309          */
 310         function configure() {
 311                 if( supports3DTransforms === false ) {
 312                         config.transition = 'linear';
 313                 }
 314
 315                 if( config.controls && dom.controls ) {
 316                         dom.controls.style.display = 'block';
 317                 }
 318
 319                 if( config.progress && dom.progress ) {
 320                         dom.progress.style.display = 'block';
 321                 }
 322
 323                 if( config.transition !== 'default' ) {
 324                         dom.wrapper.classList.add( config.transition );
 325                 }
 326
 327                 if( config.rtl ) {
 328                         dom.wrapper.classList.add( 'rtl' );
 329                 }
 330
 331                 if( config.center ) {
 332                         dom.wrapper.classList.add( 'center' );
 333                 }
 334
 335                 if( config.mouseWheel ) {
 336                         document.addEventListener( 'DOMMouseScroll', onDocumentMouseScroll, false ); // FF
 337                         document.addEventListener( 'mousewheel', onDocumentMouseScroll, false );
 338                 }
 339
 340                 // 3D links
 341                 if( config.rollingLinks ) {
 342                         linkify();
 343                 }
 344
 345                 // Load the theme in the config, if it's not already loaded
 346                 if( config.theme && dom.theme ) {
 347                         var themeURL = dom.theme.getAttribute( 'href' );
 348                         var themeFinder = /[^\/]*?(?=\.css)/;
 349                         var themeName = themeURL.match(themeFinder)[0];
 350
 351                         if(  config.theme !== themeName ) {
 352                                 themeURL = themeURL.replace(themeFinder, config.theme);
 353                                 dom.theme.setAttribute( 'href', themeURL );
 354                         }
 355                 }
 356         }
 357
 358         /**
 359          * Binds all event listeners.
 360          */
 361         function addEventListeners() {
 362                 document.addEventListener( 'touchstart', onDocumentTouchStart, false );
 363                 document.addEventListener( 'touchmove', onDocumentTouchMove, false );
 364                 document.addEventListener( 'touchend', onDocumentTouchEnd, false );
 365                 window.addEventListener( 'hashchange', onWindowHashChange, false );
 366                 window.addEventListener( 'resize', onWindowResize, false );
 367
 368                 if( config.keyboard ) {
 369                         document.addEventListener( 'keydown', onDocumentKeyDown, false );
 370                 }
 371
 372                 if ( config.progress && dom.progress ) {
 373                         dom.progress.addEventListener( 'click', preventAndForward( onProgressClick ), false );
 374                 }
 375
 376                 if ( config.controls && dom.controls ) {
 377                         var actionEvent = 'ontouchstart' in window ? 'touchstart' : 'click';
 378                         dom.controlsLeft.forEach( function( el ) { el.addEventListener( actionEvent, preventAndForward( navigateLeft ), false ); } );
 379                         dom.controlsRight.forEach( function( el ) { el.addEventListener( actionEvent, preventAndForward( navigateRight ), false ); } );
 380                         dom.controlsUp.forEach( function( el ) { el.addEventListener( actionEvent, preventAndForward( navigateUp ), false ); } );
 381                         dom.controlsDown.forEach( function( el ) { el.addEventListener( actionEvent, preventAndForward( navigateDown ), false ); } );
 382                         dom.controlsPrev.forEach( function( el ) { el.addEventListener( actionEvent, preventAndForward( navigatePrev ), false ); } );
 383                         dom.controlsNext.forEach( function( el ) { el.addEventListener( actionEvent, preventAndForward( navigateNext ), false ); } );
 384                 }
 385         }
 386
 387         /**
 388          * Unbinds all event listeners.
 389          */
 390         function removeEventListeners() {
 391                 document.removeEventListener( 'keydown', onDocumentKeyDown, false );
 392                 document.removeEventListener( 'touchstart', onDocumentTouchStart, false );
 393                 document.removeEventListener( 'touchmove', onDocumentTouchMove, false );
 394                 document.removeEventListener( 'touchend', onDocumentTouchEnd, false );
 395                 window.removeEventListener( 'hashchange', onWindowHashChange, false );
 396                 window.removeEventListener( 'resize', onWindowResize, false );
 397
 398                 if ( config.progress && dom.progress ) {
 399                         dom.progress.removeEventListener( 'click', preventAndForward( onProgressClick ), false );
 400                 }
 401
 402                 if ( config.controls && dom.controls ) {
 403                         var actionEvent = 'ontouchstart' in window ? 'touchstart' : 'click';
 404                         dom.controlsLeft.forEach( function( el ) { el.removeEventListener( actionEvent, preventAndForward( navigateLeft ), false ); } );
 405                         dom.controlsRight.forEach( function( el ) { el.removeEventListener( actionEvent, preventAndForward( navigateRight ), false ); } );
 406                         dom.controlsUp.forEach( function( el ) { el.removeEventListener( actionEvent, preventAndForward( navigateUp ), false ); } );
 407                         dom.controlsDown.forEach( function( el ) { el.removeEventListener( actionEvent, preventAndForward( navigateDown ), false ); } );
 408                         dom.controlsPrev.forEach( function( el ) { el.removeEventListener( actionEvent, preventAndForward( navigatePrev ), false ); } );
 409                         dom.controlsNext.forEach( function( el ) { el.removeEventListener( actionEvent, preventAndForward( navigateNext ), false ); } );
 410                 }
 411         }
 412
 413         /**
 414          * Extend object a with the properties of object b.
 415          * If there's a conflict, object b takes precedence.
 416          */
 417         function extend( a, b ) {
 418                 for( var i in b ) {
 419                         a[ i ] = b[ i ];
 420                 }
 421         }
 422
 423         /**
 424          * Converts the target object to an array.
 425          */
 426         function toArray( o ) {
 427                 return Array.prototype.slice.call( o );
 428         }
 429
 430         function each( targets, method, args ) {
 431                 targets.forEach( function( el ) {
 432                         el[method].apply( el, args );
 433                 } );
 434         }
 435
 436         /**
 437          * Measures the distance in pixels between point a
 438          * and point b.
 439          *
 440          * @param {Object} a point with x/y properties
 441          * @param {Object} b point with x/y properties
 442          */
 443         function distanceBetween( a, b ) {
 444                 var dx = a.x - b.x,
 445                         dy = a.y - b.y;
 446
 447                 return Math.sqrt( dx*dx + dy*dy );
 448         }
 449
 450         /**
 451          * Prevents an events defaults behavior calls the
 452          * specified delegate.
 453          *
 454          * @param {Function} delegate The method to call
 455          * after the wrapper has been executed
 456          */
 457         function preventAndForward( delegate ) {
 458                 return function( event ) {
 459                         event.preventDefault();
 460                         delegate.call( null, event );
 461                 };
 462         }
 463
 464         /**
 465          * Causes the address bar to hide on mobile devices,
 466          * more vertical space ftw.
 467          */
 468         function removeAddressBar() {
 469                 setTimeout( function() {
 470                         window.scrollTo( 0, 1 );
 471                 }, 0 );
 472         }
 473
 474         /**
 475          * Dispatches an event of the specified type from the
 476          * reveal DOM element.
 477          */
 478         function dispatchEvent( type, properties ) {
 479                 var event = document.createEvent( "HTMLEvents", 1, 2 );
 480                 event.initEvent( type, true, true );
 481                 extend( event, properties );
 482                 dom.wrapper.dispatchEvent( event );
 483         }
 484
 485         /**
 486          * Wrap all links in 3D goodness.
 487          */
 488         function linkify() {
 489                 if( supports3DTransforms && !( 'msPerspective' in document.body.style ) ) {
 490                         var nodes = document.querySelectorAll( SLIDES_SELECTOR + ' a:not(.image)' );
 491
 492                         for( var i = 0, len = nodes.length; i < len; i++ ) {
 493                                 var node = nodes[i];
 494
 495                                 if( node.textContent && !node.querySelector( 'img' ) && ( !node.className || !node.classList.contains( node, 'roll' ) ) ) {
 496                     var span = document.createElement('span');
 497                     span.setAttribute('data-title', node.text);
 498                     span.innerHTML = node.innerHTML;
 499
 500                                         node.classList.add( 'roll' );
 501                     node.innerHTML = '';
 502                     node.appendChild(span);
 503                                 }
 504                         }
 505                 }
 506         }
 507
 508         /**
 509          * Applies JavaScript-controlled layout rules to the
 510          * presentation.
 511          */
 512         function layout() {
 513
 514                 if( config.center ) {
 515
 516                         // Select all slides, vertical and horizontal
 517                         var slides = toArray( document.querySelectorAll( SLIDES_SELECTOR ) );
 518
 519                         // Determine the minimum top offset for slides
 520                         var minTop = -dom.wrapper.offsetHeight / 2;
 521
 522                         for( var i = 0, len = slides.length; i < len; i++ ) {
 523                                 var slide = slides[ i ];
 524
 525                                 // Don't bother update invisible slides
 526                                 if( slide.style.display === 'none' ) {
 527                                         continue;
 528                                 }
 529
 530                                 // Vertical stacks are not centered since their section
 531                                 // children will be
 532                                 if( slide.classList.contains( 'stack' ) ) {
 533                                         slide.style.top = 0;
 534                                 }
 535                                 else {
 536                                         slide.style.top = Math.max( - ( slide.offsetHeight / 2 ) - 20, minTop ) + 'px';
 537                                 }
 538                         }
 539
 540                 }
 541
 542         }
 543
 544         /**
 545          * Stores the vertical index of a stack so that the same
 546          * vertical slide can be selected when navigating to and
 547          * from the stack.
 548          *
 549          * @param {HTMLElement} stack The vertical stack element
 550          * @param {int} v Index to memorize
 551          */
 552         function setPreviousVerticalIndex( stack, v ) {
 553                 if( stack ) {
 554                         stack.setAttribute( 'data-previous-indexv', v || 0 );
 555                 }
 556         }
 557
 558         /**
 559          * Retrieves the vertical index which was stored using
 560          * #setPreviousVerticalIndex() or 0 if no previous index
 561          * exists.
 562          *
 563          * @param {HTMLElement} stack The vertical stack element
 564          */
 565         function getPreviousVerticalIndex( stack ) {
 566                 if( stack && stack.classList.contains( 'stack' ) ) {
 567                         return parseInt( stack.getAttribute( 'data-previous-indexv' ) || 0, 10 );
 568                 }
 569
 570                 return 0;
 571         }
 572
 573         /**
 574          * Displays the overview of slides (quick nav) by
 575          * scaling down and arranging all slide elements.
 576          *
 577          * Experimental feature, might be dropped if perf
 578          * can't be improved.
 579          */
 580         function activateOverview() {
 581
 582                 // Only proceed if enabled in config
 583                 if( config.overview ) {
 584
 585                         dom.wrapper.classList.add( 'overview' );
 586
 587                         clearTimeout( activateOverviewTimeout );
 588
 589                         // Not the pretties solution, but need to let the overview
 590                         // class apply first so that slides are measured accurately
 591                         // before we can positon them
 592                         activateOverviewTimeout = setTimeout( function(){
 593
 594                                 var horizontalSlides = document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR );
 595
 596                                 for( var i = 0, len1 = horizontalSlides.length; i < len1; i++ ) {
 597                                         var hslide = horizontalSlides[i],
 598                                                 htransform = 'translateZ(-2500px) translate(' + ( ( i - indexh ) * 105 ) + '%, 0%)';
 599
 600                                         hslide.setAttribute( 'data-index-h', i );
 601                                         hslide.style.display = 'block';
 602                                         hslide.style.WebkitTransform = htransform;
 603                                         hslide.style.MozTransform = htransform;
 604                                         hslide.style.msTransform = htransform;
 605                                         hslide.style.OTransform = htransform;
 606                                         hslide.style.transform = htransform;
 607
 608                                         if( hslide.classList.contains( 'stack' ) ) {
 609
 610                                                 var verticalSlides = hslide.querySelectorAll( 'section' );
 611
 612                                                 for( var j = 0, len2 = verticalSlides.length; j < len2; j++ ) {
 613                                                         var verticalIndex = i === indexh ? indexv : getPreviousVerticalIndex( hslide );
 614
 615                                                         var vslide = verticalSlides[j],
 616                                                                 vtransform = 'translate(0%, ' + ( ( j - verticalIndex ) * 105 ) + '%)';
 617
 618                                                         vslide.setAttribute( 'data-index-h', i );
 619                                                         vslide.setAttribute( 'data-index-v', j );
 620                                                         vslide.style.display = 'block';
 621                                                         vslide.style.WebkitTransform = vtransform;
 622                                                         vslide.style.MozTransform = vtransform;
 623                                                         vslide.style.msTransform = vtransform;
 624                                                         vslide.style.OTransform = vtransform;
 625                                                         vslide.style.transform = vtransform;
 626
 627                                                         // Navigate to this slide on click
 628                                                         vslide.addEventListener( 'click', onOverviewSlideClicked, true );
 629                                                 }
 630
 631                                         }
 632                                         else {
 633
 634                                                 // Navigate to this slide on click
 635                                                 hslide.addEventListener( 'click', onOverviewSlideClicked, true );
 636
 637                                         }
 638                                 }
 639
 640                                 layout();
 641
 642                         }, 10 );
 643
 644                 }
 645
 646         }
 647
 648         /**
 649          * Exits the slide overview and enters the currently
 650          * active slide.
 651          */
 652         function deactivateOverview() {
 653
 654                 // Only proceed if enabled in config
 655                 if( config.overview ) {
 656
 657                         clearTimeout( activateOverviewTimeout );
 658
 659                         dom.wrapper.classList.remove( 'overview' );
 660
 661                         // Select all slides
 662                         var slides = toArray( document.querySelectorAll( SLIDES_SELECTOR ) );
 663
 664                         for( var i = 0, len = slides.length; i < len; i++ ) {
 665                                 var element = slides[i];
 666
 667                                 element.style.display = '';
 668
 669                                 // Resets all transforms to use the external styles
 670                                 element.style.WebkitTransform = '';
 671                                 element.style.MozTransform = '';
 672                                 element.style.msTransform = '';
 673                                 element.style.OTransform = '';
 674                                 element.style.transform = '';
 675
 676                                 element.removeEventListener( 'click', onOverviewSlideClicked, true );
 677                         }
 678
 679                         slide( indexh, indexv );
 680
 681                 }
 682         }
 683
 684         /**
 685          * Toggles the slide overview mode on and off.
 686          *
 687          * @param {Boolean} override Optional flag which overrides the
 688          * toggle logic and forcibly sets the desired state. True means
 689          * overview is open, false means it's closed.
 690          */
 691         function toggleOverview( override ) {
 692                 if( typeof override === 'boolean' ) {
 693                         override ? activateOverview() : deactivateOverview();
 694                 }
 695                 else {
 696                         isOverviewActive() ? deactivateOverview() : activateOverview();
 697                 }
 698         }
 699
 700         /**
 701          * Checks if the overview is currently active.
 702          *
 703          * @return {Boolean} true if the overview is active,
 704          * false otherwise
 705          */
 706         function isOverviewActive() {
 707                 return dom.wrapper.classList.contains( 'overview' );
 708         }
 709
 710         /**
 711          * Handling the fullscreen functionality via the fullscreen API
 712          *
 713          * @see http://fullscreen.spec.whatwg.org/
 714          * @see https://developer.mozilla.org/en-US/docs/DOM/Using_fullscreen_mode
 715          */
 716         function enterFullscreen() {
 717                 var element = document.body;
 718
 719                 // Check which implementation is available
 720                 var requestMethod = element.requestFullScreen ||
 721                                                         element.webkitRequestFullScreen ||
 722                                                         element.mozRequestFullScreen ||
 723                                                         element.msRequestFullScreen;
 724
 725                 if( requestMethod ) {
 726                         requestMethod.apply( element );
 727                 }
 728         }
 729
 730         /**
 731          * Enters the paused mode which fades everything on screen to
 732          * black.
 733          */
 734         function pause() {
 735                 dom.wrapper.classList.add( 'paused' );
 736         }
 737
 738         /**
 739          * Exits from the paused mode.
 740          */
 741         function resume() {
 742                 dom.wrapper.classList.remove( 'paused' );
 743         }
 744
 745         /**
 746          * Toggles the paused mode on and off.
 747          */
 748         function togglePause() {
 749                 if( isPaused() ) {
 750                         resume();
 751                 }
 752                 else {
 753                         pause();
 754                 }
 755         }
 756
 757         /**
 758          * Checks if we are currently in the paused mode.
 759          */
 760         function isPaused() {
 761                 return dom.wrapper.classList.contains( 'paused' );
 762         }
 763
 764         /**
 765          * Steps from the current point in the presentation to the
 766          * slide which matches the specified horizontal and vertical
 767          * indices.
 768          *
 769          * @param {int} h Horizontal index of the target slide
 770          * @param {int} v Vertical index of the target slide
 771          * @param {int} f Optional index of a fragment within the
 772          * target slide to activate
 773          */
 774         function slide( h, v, f ) {
 775                 // Remember where we were at before
 776                 previousSlide = currentSlide;
 777
 778                 // Query all horizontal slides in the deck
 779                 var horizontalSlides = document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR );
 780
 781                 // If no vertical index is specified and the upcoming slide is a
 782                 // stack, resume at its previous vertical index
 783                 if( v === undefined ) {
 784                         v = getPreviousVerticalIndex( horizontalSlides[ h ] );
 785                 }
 786
 787                 // If we were on a vertical stack, remember what vertical index
 788                 // it was on so we can resume at the same position when returning
 789                 if( previousSlide && previousSlide.parentNode && previousSlide.parentNode.classList.contains( 'stack' ) ) {
 790                         setPreviousVerticalIndex( previousSlide.parentNode, indexv );
 791                 }
 792
 793                 // Remember the state before this slide
 794                 var stateBefore = state.concat();
 795
 796                 // Reset the state array
 797                 state.length = 0;
 798
 799                 var indexhBefore = indexh,
 800                         indexvBefore = indexv;
 801
 802                 // Activate and transition to the new slide
 803                 indexh = updateSlides( HORIZONTAL_SLIDES_SELECTOR, h === undefined ? indexh : h );
 804                 indexv = updateSlides( VERTICAL_SLIDES_SELECTOR, v === undefined ? indexv : v );
 805
 806                 layout();
 807
 808                 // Apply the new state
 809                 stateLoop: for( var i = 0, len = state.length; i < len; i++ ) {
 810                         // Check if this state existed on the previous slide. If it
 811                         // did, we will avoid adding it repeatedly
 812                         for( var j = 0; j < stateBefore.length; j++ ) {
 813                                 if( stateBefore[j] === state[i] ) {
 814                                         stateBefore.splice( j, 1 );
 815                                         continue stateLoop;
 816                                 }
 817                         }
 818
 819                         document.documentElement.classList.add( state[i] );
 820
 821                         // Dispatch custom event matching the state's name
 822                         dispatchEvent( state[i] );
 823                 }
 824
 825                 // Clean up the remaints of the previous state
 826                 while( stateBefore.length ) {
 827                         document.documentElement.classList.remove( stateBefore.pop() );
 828                 }
 829
 830                 // If the overview is active, re-activate it to update positions
 831                 if( isOverviewActive() ) {
 832                         activateOverview();
 833                 }
 834
 835                 // Update the URL hash after a delay since updating it mid-transition
 836                 // is likely to cause visual lag
 837                 writeURL( 1500 );
 838
 839                 // Find the current horizontal slide and any possible vertical slides
 840                 // within it
 841                 var currentHorizontalSlide = horizontalSlides[ indexh ],
 842                         currentVerticalSlides = currentHorizontalSlide.querySelectorAll( 'section' );
 843
 844                 // Store references to the previous and current slides
 845                 currentSlide = currentVerticalSlides[ indexv ] || currentHorizontalSlide;
 846
 847
 848                 // Show fragment, if specified
 849                 if( typeof f !== 'undefined' ) {
 850                         var fragments = currentSlide.querySelectorAll( '.fragment' );
 851
 852                         toArray( fragments ).forEach( function( fragment, indexf ) {
 853                                 if( indexf < f ) {
 854                                         fragment.classList.add( 'visible' );
 855                                 }
 856                                 else {
 857                                         fragment.classList.remove( 'visible' );
 858                                 }
 859                         } );
 860                 }
 861
 862                 // Dispatch an event if the slide changed
 863                 if( indexh !== indexhBefore || indexv !== indexvBefore ) {
 864                         dispatchEvent( 'slidechanged', {
 865                                 'indexh': indexh,
 866                                 'indexv': indexv,
 867                                 'previousSlide': previousSlide,
 868                                 'currentSlide': currentSlide
 869                         } );
 870                 }
 871                 else {
 872                         // Ensure that the previous slide is never the same as the current
 873                         previousSlide = null;
 874                 }
 875
 876                 // Solves an edge case where the previous slide maintains the
 877                 // 'present' class when navigating between adjacent vertical
 878                 // stacks
 879                 if( previousSlide ) {
 880                         previousSlide.classList.remove( 'present' );
 881
 882             // Reset all slides upon navigate to home
 883             // Issue: #285
 884             if ( document.querySelector( HOME_SLIDE_SELECTOR ).classList.contains( 'present' ) ) {
 885                 // Launch async task
 886                 setTimeout( function () {
 887                     var slides = toArray( document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR + '.stack') ), i;
 888                     for( i in slides ) {
 889                         if( slides[i] ) {
 890                             // Reset stack
 891                             setPreviousVerticalIndex( slides[i], 0 );
 892                         }
 893                     }
 894                 }, 0 );
 895             }
 896                 }
 897
 898                 updateControls();
 899                 updateProgress();
 900         }
 901
 902         /**
 903          * Updates one dimension of slides by showing the slide
 904          * with the specified index.
 905          *
 906          * @param {String} selector A CSS selector that will fetch
 907          * the group of slides we are working with
 908          * @param {Number} index The index of the slide that should be
 909          * shown
 910          *
 911          * @return {Number} The index of the slide that is now shown,
 912          * might differ from the passed in index if it was out of
 913          * bounds.
 914          */
 915         function updateSlides( selector, index ) {
 916                 // Select all slides and convert the NodeList result to
 917                 // an array
 918                 var slides = toArray( document.querySelectorAll( selector ) ),
 919                         slidesLength = slides.length;
 920
 921                 if( slidesLength ) {
 922
 923                         // Should the index loop?
 924                         if( config.loop ) {
 925                                 index %= slidesLength;
 926
 927                                 if( index < 0 ) {
 928                                         index = slidesLength + index;
 929                                 }
 930                         }
 931
 932                         // Enforce max and minimum index bounds
 933                         index = Math.max( Math.min( index, slidesLength - 1 ), 0 );
 934
 935                         for( var i = 0; i < slidesLength; i++ ) {
 936                                 var element = slides[i];
 937
 938                                 // Optimization; hide all slides that are three or more steps
 939                                 // away from the present slide
 940                                 if( isOverviewActive() === false ) {
 941                                         // The distance loops so that it measures 1 between the first
 942                                         // and last slides
 943                                         var distance = Math.abs( ( index - i ) % ( slidesLength - 3 ) ) || 0;
 944
 945                                         element.style.display = distance > 3 ? 'none' : 'block';
 946                                 }
 947
 948                                 slides[i].classList.remove( 'past' );
 949                                 slides[i].classList.remove( 'present' );
 950                                 slides[i].classList.remove( 'future' );
 951
 952                                 if( i < index ) {
 953                                         // Any element previous to index is given the 'past' class
 954                                         slides[i].classList.add( 'past' );
 955                                 }
 956                                 else if( i > index ) {
 957                                         // Any element subsequent to index is given the 'future' class
 958                                         slides[i].classList.add( 'future' );
 959                                 }
 960
 961                                 // If this element contains vertical slides
 962                                 if( element.querySelector( 'section' ) ) {
 963                                         slides[i].classList.add( 'stack' );
 964                                 }
 965                         }
 966
 967                         // Mark the current slide as present
 968                         slides[index].classList.add( 'present' );
 969
 970                         // If this slide has a state associated with it, add it
 971                         // onto the current state of the deck
 972                         var slideState = slides[index].getAttribute( 'data-state' );
 973                         if( slideState ) {
 974                                 state = state.concat( slideState.split( ' ' ) );
 975                         }
 976
 977                         // If this slide has a data-autoslide attribtue associated use this as
 978                         // autoSlide value otherwise use the global configured time
 979                         var slideAutoSlide = slides[index].getAttribute( 'data-autoslide' );
 980                         if( slideAutoSlide ) {
 981                                 autoSlide = parseInt( slideAutoSlide, 10 );
 982                         }
 983                         else {
 984                                 autoSlide = config.autoSlide;
 985                         }
 986
 987                 }
 988                 else {
 989                         // Since there are no slides we can't be anywhere beyond the
 990                         // zeroth index
 991                         index = 0;
 992                 }
 993
 994                 return index;
 995
 996         }
 997
 998         /**
 999          * Updates the progress bar to reflect the current slide.
1000          */
1001         function updateProgress() {
1002                 // Update progress if enabled
1003                 if( config.progress && dom.progress ) {
1004
1005                         var horizontalSlides = toArray( document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) );
1006
1007                         // The number of past and total slides
1008                         var totalCount = document.querySelectorAll( SLIDES_SELECTOR + ':not(.stack)' ).length;
1009                         var pastCount = 0;
1010
1011                         // Step through all slides and count the past ones
1012                         mainLoop: for( var i = 0; i < horizontalSlides.length; i++ ) {
1013
1014                                 var horizontalSlide = horizontalSlides[i];
1015                                 var verticalSlides = toArray( horizontalSlide.querySelectorAll( 'section' ) );
1016
1017                                 for( var j = 0; j < verticalSlides.length; j++ ) {
1018
1019                                         // Stop as soon as we arrive at the present
1020                                         if( verticalSlides[j].classList.contains( 'present' ) ) {
1021                                                 break mainLoop;
1022                                         }
1023
1024                                         pastCount++;
1025
1026                                 }
1027
1028                                 // Stop as soon as we arrive at the present
1029                                 if( horizontalSlide.classList.contains( 'present' ) ) {
1030                                         break;
1031                                 }
1032
1033                                 // Don't count the wrapping section for vertical slides
1034                                 if( horizontalSlide.classList.contains( 'stack' ) === false ) {
1035                                         pastCount++;
1036                                 }
1037
1038                         }
1039
1040                         dom.progressbar.style.width = ( pastCount / ( totalCount - 1 ) ) * window.innerWidth + 'px';
1041
1042                 }
1043         }
1044
1045         /**
1046          * Updates the state of all control/navigation arrows.
1047          */
1048         function updateControls() {
1049                 if ( config.controls && dom.controls ) {
1050
1051                         var routes = availableRoutes();
1052
1053                         // Remove the 'enabled' class from all directions
1054                         dom.controlsLeft.concat( dom.controlsRight )
1055                                                         .concat( dom.controlsUp )
1056                                                         .concat( dom.controlsDown )
1057                                                         .concat( dom.controlsPrev )
1058                                                         .concat( dom.controlsNext ).forEach( function( node ) {
1059                                 node.classList.remove( 'enabled' );
1060                         } );
1061
1062                         // Add the 'enabled' class to the available routes
1063                         if( routes.left ) dom.controlsLeft.forEach( function( el ) { el.classList.add( 'enabled' );     } );
1064                         if( routes.right ) dom.controlsRight.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1065                         if( routes.up ) dom.controlsUp.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1066                         if( routes.down ) dom.controlsDown.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1067
1068                         // Prev/next buttons
1069                         if( routes.left || routes.up ) dom.controlsPrev.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1070                         if( routes.right || routes.down ) dom.controlsNext.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1071
1072                 }
1073         }
1074
1075         /**
1076          * Determine what available routes there are for navigation.
1077          *
1078          * @return {Object} containing four booleans: left/right/up/down
1079          */
1080         function availableRoutes() {
1081                 var horizontalSlides = document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ),
1082                         verticalSlides = document.querySelectorAll( VERTICAL_SLIDES_SELECTOR );
1083
1084                 return {
1085                         left: indexh > 0,
1086                         right: indexh < horizontalSlides.length - 1,
1087                         up: indexv > 0,
1088                         down: indexv < verticalSlides.length - 1
1089                 };
1090         }
1091
1092         /**
1093          * Reads the current URL (hash) and navigates accordingly.
1094          */
1095         function readURL() {
1096                 var hash = window.location.hash;
1097
1098                 // Attempt to parse the hash as either an index or name
1099                 var bits = hash.slice( 2 ).split( '/' ),
1100                         name = hash.replace( /#|\//gi, '' );
1101
1102                 // If the first bit is invalid and there is a name we can
1103                 // assume that this is a named link
1104                 if( isNaN( parseInt( bits[0], 10 ) ) && name.length ) {
1105                         // Find the slide with the specified name
1106                         var element = document.querySelector( '#' + name );
1107
1108                         if( element ) {
1109                                 // Find the position of the named slide and navigate to it
1110                                 var indices = Reveal.getIndices( element );
1111                                 slide( indices.h, indices.v );
1112                         }
1113                         // If the slide doesn't exist, navigate to the current slide
1114                         else {
1115                                 slide( indexh, indexv );
1116                         }
1117                 }
1118                 else {
1119                         // Read the index components of the hash
1120                         var h = parseInt( bits[0], 10 ) || 0,
1121                                 v = parseInt( bits[1], 10 ) || 0;
1122
1123                         slide( h, v );
1124                 }
1125         }
1126
1127         /**
1128          * Updates the page URL (hash) to reflect the current
1129          * state.
1130          *
1131          * @param {Number} delay The time in ms to wait before
1132          * writing the hash
1133          */
1134         function writeURL( delay ) {
1135                 if( config.history ) {
1136
1137                         // Make sure there's never more than one timeout running
1138                         clearTimeout( writeURLTimeout );
1139
1140                         // If a delay is specified, timeout this call
1141                         if( typeof delay === 'number' ) {
1142                                 writeURLTimeout = setTimeout( writeURL, delay );
1143                         }
1144                         else {
1145                                 var url = '/';
1146
1147                                 // If the current slide has an ID, use that as a named link
1148                                 if( currentSlide && typeof currentSlide.getAttribute( 'id' ) === 'string' ) {
1149                                         url = '/' + currentSlide.getAttribute( 'id' );
1150                                 }
1151                                 // Otherwise use the /h/v index
1152                                 else {
1153                                         if( indexh > 0 || indexv > 0 ) url += indexh;
1154                                         if( indexv > 0 ) url += '/' + indexv;
1155                                 }
1156
1157                                 window.location.hash = url;
1158                         }
1159                 }
1160         }
1161
1162         /**
1163          * Retrieves the h/v location of the current, or specified,
1164          * slide.
1165          *
1166          * @param {HTMLElement} slide If specified, the returned
1167          * index will be for this slide rather than the currently
1168          * active one
1169          *
1170          * @return {Object} { h: <int>, v: <int> }
1171          */
1172         function getIndices( slide ) {
1173                 // By default, return the current indices
1174                 var h = indexh,
1175                         v = indexv;
1176
1177                 // If a slide is specified, return the indices of that slide
1178                 if( slide ) {
1179                         var isVertical = !!slide.parentNode.nodeName.match( /section/gi );
1180                         var slideh = isVertical ? slide.parentNode : slide;
1181
1182                         // Select all horizontal slides
1183                         var horizontalSlides = toArray( document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) );
1184
1185                         // Now that we know which the horizontal slide is, get its index
1186                         h = Math.max( horizontalSlides.indexOf( slideh ), 0 );
1187
1188                         // If this is a vertical slide, grab the vertical index
1189                         if( isVertical ) {
1190                                 v = Math.max( toArray( slide.parentNode.querySelectorAll( 'section' ) ).indexOf( slide ), 0 );
1191                         }
1192                 }
1193
1194                 return { h: h, v: v };
1195         }
1196
1197         /**
1198          * Navigate to the next slide fragment.
1199          *
1200          * @return {Boolean} true if there was a next fragment,
1201          * false otherwise
1202          */
1203         function nextFragment() {
1204                 // Vertical slides:
1205                 if( document.querySelector( VERTICAL_SLIDES_SELECTOR + '.present' ) ) {
1206                         var verticalFragments = document.querySelectorAll( VERTICAL_SLIDES_SELECTOR + '.present .fragment:not(.visible)' );
1207                         if( verticalFragments.length ) {
1208                                 verticalFragments[0].classList.add( 'visible' );
1209
1210                                 // Notify subscribers of the change
1211                                 dispatchEvent( 'fragmentshown', { fragment: verticalFragments[0] } );
1212                                 return true;
1213                         }
1214                 }
1215                 // Horizontal slides:
1216                 else {
1217                         var horizontalFragments = document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR + '.present .fragment:not(.visible)' );
1218                         if( horizontalFragments.length ) {
1219                                 horizontalFragments[0].classList.add( 'visible' );
1220
1221                                 // Notify subscribers of the change
1222                                 dispatchEvent( 'fragmentshown', { fragment: horizontalFragments[0] } );
1223                                 return true;
1224                         }
1225                 }
1226
1227                 return false;
1228         }
1229
1230         /**
1231          * Navigate to the previous slide fragment.
1232          *
1233          * @return {Boolean} true if there was a previous fragment,
1234          * false otherwise
1235          */
1236         function previousFragment() {
1237                 // Vertical slides:
1238                 if( document.querySelector( VERTICAL_SLIDES_SELECTOR + '.present' ) ) {
1239                         var verticalFragments = document.querySelectorAll( VERTICAL_SLIDES_SELECTOR + '.present .fragment.visible' );
1240                         if( verticalFragments.length ) {
1241                                 verticalFragments[ verticalFragments.length - 1 ].classList.remove( 'visible' );
1242
1243                                 // Notify subscribers of the change
1244                                 dispatchEvent( 'fragmenthidden', { fragment: verticalFragments[ verticalFragments.length - 1 ] } );
1245                                 return true;
1246                         }
1247                 }
1248                 // Horizontal slides:
1249                 else {
1250                         var horizontalFragments = document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR + '.present .fragment.visible' );
1251                         if( horizontalFragments.length ) {
1252                                 horizontalFragments[ horizontalFragments.length - 1 ].classList.remove( 'visible' );
1253
1254                                 // Notify subscribers of the change
1255                                 dispatchEvent( 'fragmenthidden', { fragment: horizontalFragments[ horizontalFragments.length - 1 ] } );
1256                                 return true;
1257                         }
1258                 }
1259
1260                 return false;
1261         }
1262
1263         /**
1264          * Cues a new automated slide if enabled in the config.
1265          */
1266         function cueAutoSlide() {
1267                 clearTimeout( autoSlideTimeout );
1268
1269                 // Cue the next auto-slide if enabled
1270                 if( autoSlide ) {
1271                         autoSlideTimeout = setTimeout( navigateNext, autoSlide );
1272                 }
1273         }
1274
1275         function navigateLeft() {
1276                 // Prioritize hiding fragments
1277                 if( availableRoutes().left && isOverviewActive() || previousFragment() === false ) {
1278                         slide( indexh - 1 );
1279                 }
1280         }
1281
1282         function navigateRight() {
1283                 // Prioritize revealing fragments
1284                 if( availableRoutes().right && isOverviewActive() || nextFragment() === false ) {
1285                         slide( indexh + 1 );
1286                 }
1287         }
1288
1289         function navigateUp() {
1290                 // Prioritize hiding fragments
1291                 if( availableRoutes().up && isOverviewActive() || previousFragment() === false ) {
1292                         slide( indexh, indexv - 1 );
1293                 }
1294         }
1295
1296         function navigateDown() {
1297                 // Prioritize revealing fragments
1298                 if( availableRoutes().down && isOverviewActive() || nextFragment() === false ) {
1299                         slide( indexh, indexv + 1 );
1300                 }
1301         }
1302
1303         /**
1304          * Navigates backwards, prioritized in the following order:
1305          * 1) Previous fragment
1306          * 2) Previous vertical slide
1307          * 3) Previous horizontal slide
1308          */
1309         function navigatePrev() {
1310                 // Prioritize revealing fragments
1311                 if( previousFragment() === false ) {
1312                         if( availableRoutes().up ) {
1313                                 navigateUp();
1314                         }
1315                         else {
1316                                 // Fetch the previous horizontal slide, if there is one
1317                                 var previousSlide = document.querySelector( HORIZONTAL_SLIDES_SELECTOR + '.past:nth-child(' + indexh + ')' );
1318
1319                                 if( previousSlide ) {
1320                                         indexv = ( previousSlide.querySelectorAll( 'section' ).length + 1 ) || undefined;
1321                                         indexh --;
1322                                         slide();
1323                                 }
1324                         }
1325                 }
1326         }
1327
1328         /**
1329          * Same as #navigatePrev() but navigates forwards.
1330          */
1331         function navigateNext() {
1332                 // Prioritize revealing fragments
1333                 if( nextFragment() === false ) {
1334                         availableRoutes().down ? navigateDown() : navigateRight();
1335                 }
1336
1337                 // If auto-sliding is enabled we need to cue up
1338                 // another timeout
1339                 cueAutoSlide();
1340         }
1341
1342
1343         // --------------------------------------------------------------------//
1344         // ----------------------------- EVENTS -------------------------------//
1345         // --------------------------------------------------------------------//
1346
1347
1348         /**
1349          * Handler for the document level 'keydown' event.
1350          *
1351          * @param {Object} event
1352          */
1353         function onDocumentKeyDown( event ) {
1354                 // Check if there's a focused element that could be using
1355                 // the keyboard
1356                 var activeElement = document.activeElement;
1357                 var hasFocus = !!( document.activeElement && ( document.activeElement.type || document.activeElement.href || document.activeElement.contentEditable !== 'inherit' ) );
1358
1359                 // Disregard the event if there's a focused element or a
1360                 // keyboard modifier key is present
1361                 if ( hasFocus || event.shiftKey || event.altKey || event.ctrlKey || event.metaKey ) return;
1362
1363                 var triggered = true;
1364
1365                 switch( event.keyCode ) {
1366                         // p, page up
1367                         case 80: case 33: navigatePrev(); break;
1368                         // n, page down
1369                         case 78: case 34: navigateNext(); break;
1370                         // h, left
1371                         case 72: case 37: navigateLeft(); break;
1372                         // l, right
1373                         case 76: case 39: navigateRight(); break;
1374                         // k, up
1375                         case 75: case 38: navigateUp(); break;
1376                         // j, down
1377                         case 74: case 40: navigateDown(); break;
1378                         // home
1379                         case 36: slide( 0 ); break;
1380                         // end
1381                         case 35: slide( Number.MAX_VALUE ); break;
1382                         // space
1383                         case 32: isOverviewActive() ? deactivateOverview() : navigateNext(); break;
1384                         // return
1385                         case 13: isOverviewActive() ? deactivateOverview() : triggered = false; break;
1386                         // b, period
1387                         case 66: case 190: togglePause(); break;
1388                         // f
1389                         case 70: enterFullscreen(); break;
1390                         default:
1391                                 triggered = false;
1392                 }
1393
1394                 // If the input resulted in a triggered action we should prevent
1395                 // the browsers default behavior
1396                 if( triggered ) {
1397                         event.preventDefault();
1398                 }
1399                 else if ( event.keyCode === 27 && supports3DTransforms ) {
1400                         toggleOverview();
1401
1402                         event.preventDefault();
1403                 }
1404
1405                 // If auto-sliding is enabled we need to cue up
1406                 // another timeout
1407                 cueAutoSlide();
1408
1409         }
1410
1411         /**
1412          * Handler for the document level 'touchstart' event,
1413          * enables support for swipe and pinch gestures.
1414          */
1415         function onDocumentTouchStart( event ) {
1416                 touch.startX = event.touches[0].clientX;
1417                 touch.startY = event.touches[0].clientY;
1418                 touch.startCount = event.touches.length;
1419
1420                 // If there's two touches we need to memorize the distance
1421                 // between those two points to detect pinching
1422                 if( event.touches.length === 2 && config.overview ) {
1423                         touch.startSpan = distanceBetween( {
1424                                 x: event.touches[1].clientX,
1425                                 y: event.touches[1].clientY
1426                         }, {
1427                                 x: touch.startX,
1428                                 y: touch.startY
1429                         } );
1430                 }
1431         }
1432
1433         /**
1434          * Handler for the document level 'touchmove' event.
1435          */
1436         function onDocumentTouchMove( event ) {
1437                 // Each touch should only trigger one action
1438                 if( !touch.handled ) {
1439                         var currentX = event.touches[0].clientX;
1440                         var currentY = event.touches[0].clientY;
1441
1442                         // If the touch started off with two points and still has
1443                         // two active touches; test for the pinch gesture
1444                         if( event.touches.length === 2 && touch.startCount === 2 && config.overview ) {
1445
1446                                 // The current distance in pixels between the two touch points
1447                                 var currentSpan = distanceBetween( {
1448                                         x: event.touches[1].clientX,
1449                                         y: event.touches[1].clientY
1450                                 }, {
1451                                         x: touch.startX,
1452                                         y: touch.startY
1453                                 } );
1454
1455                                 // If the span is larger than the desire amount we've got
1456                                 // ourselves a pinch
1457                                 if( Math.abs( touch.startSpan - currentSpan ) > touch.threshold ) {
1458                                         touch.handled = true;
1459
1460                                         if( currentSpan < touch.startSpan ) {
1461                                                 activateOverview();
1462                                         }
1463                                         else {
1464                                                 deactivateOverview();
1465                                         }
1466                                 }
1467
1468                                 event.preventDefault();
1469
1470                         }
1471                         // There was only one touch point, look for a swipe
1472                         else if( event.touches.length === 1 && touch.startCount !== 2 ) {
1473
1474                                 var deltaX = currentX - touch.startX,
1475                                         deltaY = currentY - touch.startY;
1476
1477                                 if( deltaX > touch.threshold && Math.abs( deltaX ) > Math.abs( deltaY ) ) {
1478                                         touch.handled = true;
1479                                         navigateLeft();
1480                                 }
1481                                 else if( deltaX < -touch.threshold && Math.abs( deltaX ) > Math.abs( deltaY ) ) {
1482                                         touch.handled = true;
1483                                         navigateRight();
1484                                 }
1485                                 else if( deltaY > touch.threshold ) {
1486                                         touch.handled = true;
1487                                         navigateUp();
1488                                 }
1489                                 else if( deltaY < -touch.threshold ) {
1490                                         touch.handled = true;
1491                                         navigateDown();
1492                                 }
1493
1494                                 event.preventDefault();
1495
1496                         }
1497                 }
1498                 // There's a bug with swiping on some Android devices unless
1499                 // the default action is always prevented
1500                 else if( navigator.userAgent.match( /android/gi ) ) {
1501                         event.preventDefault();
1502                 }
1503         }
1504
1505         /**
1506          * Handler for the document level 'touchend' event.
1507          */
1508         function onDocumentTouchEnd( event ) {
1509                 touch.handled = false;
1510         }
1511
1512         /**
1513          * Handles mouse wheel scrolling, throttled to avoid skipping
1514          * multiple slides.
1515          */
1516         function onDocumentMouseScroll( event ){
1517                 clearTimeout( mouseWheelTimeout );
1518
1519                 mouseWheelTimeout = setTimeout( function() {
1520                         var delta = event.detail || -event.wheelDelta;
1521                         if( delta > 0 ) {
1522                                 navigateNext();
1523                         }
1524                         else {
1525                                 navigatePrev();
1526                         }
1527                 }, 100 );
1528         }
1529
1530         /**
1531          * Clicking on the progress bar results in a navigation to the
1532          * closest approximate horizontal slide using this equation:
1533          *
1534          * ( clickX / presentationWidth ) * numberOfSlides
1535          */
1536         function onProgressClick( event ) {
1537                 var slidesTotal = toArray( document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) ).length;
1538                 var slideIndex = Math.floor( ( event.clientX / dom.wrapper.offsetWidth ) * slidesTotal );
1539
1540                 slide( slideIndex );
1541         }
1542
1543         /**
1544          * Handler for the window level 'hashchange' event.
1545          */
1546         function onWindowHashChange( event ) {
1547                 readURL();
1548         }
1549
1550         /**
1551          * Handler for the window level 'resize' event.
1552          */
1553         function onWindowResize( event ) {
1554                 layout();
1555         }
1556
1557         /**
1558          * Invoked when a slide is and we're in the overview.
1559          */
1560         function onOverviewSlideClicked( event ) {
1561                 // TODO There's a bug here where the event listeners are not
1562                 // removed after deactivating the overview.
1563                 if( isOverviewActive() ) {
1564                         event.preventDefault();
1565
1566                         deactivateOverview();
1567
1568                         var element = event.target;
1569
1570                         while( element && !element.nodeName.match( /section/gi ) ) {
1571                                 element = element.parentNode;
1572                         }
1573
1574                         if( element.nodeName.match( /section/gi ) ) {
1575                                 var h = parseInt( element.getAttribute( 'data-index-h' ), 10 ),
1576                                         v = parseInt( element.getAttribute( 'data-index-v' ), 10 );
1577
1578                                 slide( h, v );
1579                         }
1580                 }
1581         }
1582
1583
1584         // --------------------------------------------------------------------//
1585         // ------------------------------- API --------------------------------//
1586         // --------------------------------------------------------------------//
1587
1588
1589         return {
1590                 initialize: initialize,
1591
1592                 // Navigation methods
1593                 slide: slide,
1594                 left: navigateLeft,
1595                 right: navigateRight,
1596                 up: navigateUp,
1597                 down: navigateDown,
1598                 prev: navigatePrev,
1599                 next: navigateNext,
1600                 prevFragment: previousFragment,
1601                 nextFragment: nextFragment,
1602
1603                 // Deprecated aliases
1604                 navigateTo: slide,
1605                 navigateLeft: navigateLeft,
1606                 navigateRight: navigateRight,
1607                 navigateUp: navigateUp,
1608                 navigateDown: navigateDown,
1609                 navigatePrev: navigatePrev,
1610                 navigateNext: navigateNext,
1611
1612                 // Toggles the overview mode on/off
1613                 toggleOverview: toggleOverview,
1614
1615                 // Adds or removes all internal event listeners (such as keyboard)
1616                 addEventListeners: addEventListeners,
1617                 removeEventListeners: removeEventListeners,
1618
1619                 // Returns the indices of the current, or specified, slide
1620                 getIndices: getIndices,
1621
1622                 // Returns the previous slide element, may be null
1623                 getPreviousSlide: function() {
1624                         return previousSlide;
1625                 },
1626
1627                 // Returns the current slide element
1628                 getCurrentSlide: function() {
1629                         return currentSlide;
1630                 },
1631
1632                 // Helper method, retrieves query string as a key/value hash
1633                 getQueryHash: function() {
1634                         var query = {};
1635
1636                         location.search.replace( /[A-Z0-9]+?=(\w*)/gi, function(a) {
1637                                 query[ a.split( '=' ).shift() ] = a.split( '=' ).pop();
1638                         } );
1639
1640                         return query;
1641                 },
1642
1643                 // Forward event binding to the reveal DOM element
1644                 addEventListener: function( type, listener, useCapture ) {
1645                         if( 'addEventListener' in window ) {
1646                                 ( dom.wrapper || document.querySelector( '.reveal' ) ).addEventListener( type, listener, useCapture );
1647                         }
1648                 },
1649                 removeEventListener: function( type, listener, useCapture ) {
1650                         if( 'addEventListener' in window ) {
1651                                 ( dom.wrapper || document.querySelector( '.reveal' ) ).removeEventListener( type, listener, useCapture );
1652                         }
1653                 }
1654         };
1655
1656 })();