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