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