js/reveal.js

   1 /*!
   2  * reveal.js
   3  * http://lab.hakim.se/reveal-js
   4  * MIT licensed
   5  *
   6  * Copyright (C) 2013 Hakim El Hattab, http://hakim.se
   7  */
   8 var Reveal = (function(){
   9
  10         'use strict';
  11
  12         var SLIDES_SELECTOR = '.reveal .slides section',
  13                 HORIZONTAL_SLIDES_SELECTOR = '.reveal .slides>section',
  14                 VERTICAL_SLIDES_SELECTOR = '.reveal .slides>section.present>section',
  15                 HOME_SLIDE_SELECTOR = '.reveal .slides>section:first-child',
  16
  17                 // Configurations defaults, can be overridden at initialization time
  18                 config = {
  19
  20                         // The "normal" size of the presentation, aspect ratio will be preserved
  21                         // when the presentation is scaled to fit different resolutions
  22                         width: 960,
  23                         height: 700,
  24
  25                         // Factor of the display size that should remain empty around the content
  26                         margin: 0.1,
  27
  28                         // Bounds for smallest/largest possible scale to apply to content
  29                         minScale: 0.2,
  30                         maxScale: 1.0,
  31
  32                         // Display controls in the bottom right corner
  33                         controls: true,
  34
  35                         // Display a presentation progress bar
  36                         progress: true,
  37
  38                         // Push each slide change to the browser history
  39                         history: false,
  40
  41                         // Enable keyboard shortcuts for navigation
  42                         keyboard: true,
  43
  44                         // Enable the slide overview mode
  45                         overview: true,
  46
  47                         // Vertical centring of slides
  48                         center: true,
  49
  50                         // Enables touch navigation on devices with touch input
  51                         touch: true,
  52
  53                         // Loop the presentation
  54                         loop: false,
  55
  56                         // Change the presentation direction to be RTL
  57                         rtl: false,
  58
  59                         // Number of milliseconds between automatically proceeding to the
  60                         // next slide, disabled when set to 0, this value can be overwritten
  61                         // by using a data-autoslide attribute on your slides
  62                         autoSlide: 0,
  63
  64                         // Enable slide navigation via mouse wheel
  65                         mouseWheel: false,
  66
  67                         // Apply a 3D roll to links on hover
  68                         rollingLinks: true,
  69
  70                         // Theme (see /css/theme)
  71                         theme: null,
  72
  73                         // Transition style
  74                         transition: 'default', // default/cube/page/concave/zoom/linear/fade/none
  75
  76                         // Script dependencies to load
  77                         dependencies: []
  78                 },
  79
  80                 // The current auto-slide duration
  81                 autoSlide = 0,
  82
  83                 // The horizontal and vertical index of the currently active slide
  84                 indexh = 0,
  85                 indexv = 0,
  86
  87                 // The previous and current slide HTML elements
  88                 previousSlide,
  89                 currentSlide,
  90
  91                 // Slides may hold a data-state attribute which we pick up and apply
  92                 // as a class to the body. This list contains the combined state of
  93                 // all current slides.
  94                 state = [],
  95
  96                 // The current scale of the presentation (see width/height config)
  97                 scale = 1,
  98
  99                 // Cached references to DOM elements
 100                 dom = {},
 101
 102                 // Detect support for CSS 3D transforms
 103                 supports3DTransforms =  'WebkitPerspective' in document.body.style ||
 104                                                                 'MozPerspective' in document.body.style ||
 105                                                                 'msPerspective' in document.body.style ||
 106                                                                 'OPerspective' in document.body.style ||
 107                                                                 'perspective' in document.body.style,
 108
 109                 // Detect support for CSS 2D transforms
 110                 supports2DTransforms =  'WebkitTransform' in document.body.style ||
 111                                                                 'MozTransform' in document.body.style ||
 112                                                                 'msTransform' in document.body.style ||
 113                                                                 'OTransform' in document.body.style ||
 114                                                                 'transform' in document.body.style,
 115
 116                 // Throttles mouse wheel navigation
 117                 mouseWheelTimeout = 0,
 118
 119                 // An interval used to automatically move on to the next slide
 120                 autoSlideTimeout = 0,
 121
 122                 // Delays updates to the URL due to a Chrome thumbnailer bug
 123                 writeURLTimeout = 0,
 124
 125                 // A delay used to activate the overview mode
 126                 activateOverviewTimeout = 0,
 127
 128                 // A delay used to deactivate the overview mode
 129                 deactivateOverviewTimeout = 0,
 130
 131                 // Flags if the interaction event listeners are bound
 132                 eventsAreBound = false,
 133
 134                 // Holds information about the currently ongoing touch input
 135                 touch = {
 136                         startX: 0,
 137                         startY: 0,
 138                         startSpan: 0,
 139                         startCount: 0,
 140                         handled: false,
 141                         threshold: 80
 142                 };
 143
 144         /**
 145          * Starts up the presentation if the client is capable.
 146          */
 147         function initialize( options ) {
 148
 149                 if( !supports2DTransforms && !supports3DTransforms ) {
 150                         document.body.setAttribute( 'class', 'no-transforms' );
 151
 152                         // If the browser doesn't support core features we won't be
 153                         // using JavaScript to control the presentation
 154                         return;
 155                 }
 156
 157                 // Force a layout when the whole page, incl fonts, has loaded
 158                 window.addEventListener( 'load', layout, false );
 159
 160                 // Copy options over to our config object
 161                 extend( config, options );
 162
 163                 // Hide the address bar in mobile browsers
 164                 hideAddressBar();
 165
 166                 // Loads the dependencies and continues to #start() once done
 167                 load();
 168
 169         }
 170
 171         /**
 172          * Finds and stores references to DOM elements which are
 173          * required by the presentation. If a required element is
 174          * not found, it is created.
 175          */
 176         function setupDOM() {
 177
 178                 // Cache references to key DOM elements
 179                 dom.theme = document.querySelector( '#theme' );
 180                 dom.wrapper = document.querySelector( '.reveal' );
 181                 dom.slides = document.querySelector( '.reveal .slides' );
 182
 183                 // Progress bar
 184                 if( !dom.wrapper.querySelector( '.progress' ) && config.progress ) {
 185                         var progressElement = document.createElement( 'div' );
 186                         progressElement.classList.add( 'progress' );
 187                         progressElement.innerHTML = '<span></span>';
 188                         dom.wrapper.appendChild( progressElement );
 189                 }
 190
 191                 // Arrow controls
 192                 if( !dom.wrapper.querySelector( '.controls' ) && config.controls ) {
 193                         var controlsElement = document.createElement( 'aside' );
 194                         controlsElement.classList.add( 'controls' );
 195                         controlsElement.innerHTML = '<div class="navigate-left"></div>' +
 196                                                                                 '<div class="navigate-right"></div>' +
 197                                                                                 '<div class="navigate-up"></div>' +
 198                                                                                 '<div class="navigate-down"></div>';
 199                         dom.wrapper.appendChild( controlsElement );
 200                 }
 201
 202                 // Presentation background element
 203                 if( !dom.wrapper.querySelector( '.state-background' ) ) {
 204                         var backgroundElement = document.createElement( 'div' );
 205                         backgroundElement.classList.add( 'state-background' );
 206                         dom.wrapper.appendChild( backgroundElement );
 207                 }
 208
 209                 // Overlay graphic which is displayed during the paused mode
 210                 if( !dom.wrapper.querySelector( '.pause-overlay' ) ) {
 211                         var pausedElement = document.createElement( 'div' );
 212                         pausedElement.classList.add( 'pause-overlay' );
 213                         dom.wrapper.appendChild( pausedElement );
 214                 }
 215
 216                 // Cache references to elements
 217                 dom.progress = document.querySelector( '.reveal .progress' );
 218                 dom.progressbar = document.querySelector( '.reveal .progress span' );
 219
 220                 if ( config.controls ) {
 221                         dom.controls = document.querySelector( '.reveal .controls' );
 222
 223                         // There can be multiple instances of controls throughout the page
 224                         dom.controlsLeft = toArray( document.querySelectorAll( '.navigate-left' ) );
 225                         dom.controlsRight = toArray( document.querySelectorAll( '.navigate-right' ) );
 226                         dom.controlsUp = toArray( document.querySelectorAll( '.navigate-up' ) );
 227                         dom.controlsDown = toArray( document.querySelectorAll( '.navigate-down' ) );
 228                         dom.controlsPrev = toArray( document.querySelectorAll( '.navigate-prev' ) );
 229                         dom.controlsNext = toArray( document.querySelectorAll( '.navigate-next' ) );
 230                 }
 231
 232         }
 233
 234         /**
 235          * Hides the address bar if we're on a mobile device.
 236          */
 237         function hideAddressBar() {
 238
 239                 if( /iphone|ipod|android/gi.test( navigator.userAgent ) && !/crios/gi.test( navigator.userAgent ) ) {
 240                         // Events that should trigger the address bar to hide
 241                         window.addEventListener( 'load', removeAddressBar, false );
 242                         window.addEventListener( 'orientationchange', removeAddressBar, false );
 243                 }
 244
 245         }
 246
 247         /**
 248          * Loads the dependencies of reveal.js. Dependencies are
 249          * defined via the configuration option 'dependencies'
 250          * and will be loaded prior to starting/binding reveal.js.
 251          * Some dependencies may have an 'async' flag, if so they
 252          * will load after reveal.js has been started up.
 253          */
 254         function load() {
 255
 256                 var scripts = [],
 257                         scriptsAsync = [];
 258
 259                 for( var i = 0, len = config.dependencies.length; i < len; i++ ) {
 260                         var s = config.dependencies[i];
 261
 262                         // Load if there's no condition or the condition is truthy
 263                         if( !s.condition || s.condition() ) {
 264                                 if( s.async ) {
 265                                         scriptsAsync.push( s.src );
 266                                 }
 267                                 else {
 268                                         scripts.push( s.src );
 269                                 }
 270
 271                                 // Extension may contain callback functions
 272                                 if( typeof s.callback === 'function' ) {
 273                                         head.ready( s.src.match( /([\w\d_\-]*)\.?js$|[^\\\/]*$/i )[0], s.callback );
 274                                 }
 275                         }
 276                 }
 277
 278                 // Called once synchronous scripts finish loading
 279                 function proceed() {
 280                         if( scriptsAsync.length ) {
 281                                 // Load asynchronous scripts
 282                                 head.js.apply( null, scriptsAsync );
 283                         }
 284
 285                         start();
 286                 }
 287
 288                 if( scripts.length ) {
 289                         head.ready( proceed );
 290
 291                         // Load synchronous scripts
 292                         head.js.apply( null, scripts );
 293                 }
 294                 else {
 295                         proceed();
 296                 }
 297
 298         }
 299
 300         /**
 301          * Starts up reveal.js by binding input events and navigating
 302          * to the current URL deeplink if there is one.
 303          */
 304         function start() {
 305
 306                 // Make sure we've got all the DOM elements we need
 307                 setupDOM();
 308
 309                 // Updates the presentation to match the current configuration values
 310                 configure();
 311
 312                 // Read the initial hash
 313                 readURL();
 314
 315                 // Notify listeners that the presentation is ready but use a 1ms
 316                 // timeout to ensure it's not fired synchronously after #initialize()
 317                 setTimeout( function() {
 318                         dispatchEvent( 'ready', {
 319                                 'indexh': indexh,
 320                                 'indexv': indexv,
 321                                 'currentSlide': currentSlide
 322                         } );
 323                 }, 1 );
 324
 325         }
 326
 327         /**
 328          * Applies the configuration settings from the config object.
 329          */
 330         function configure( options ) {
 331
 332                 dom.wrapper.classList.remove( config.transition );
 333
 334                 // New config options may be passed when this method
 335                 // is invoked through the API after initialization
 336                 if( typeof options === 'object' ) extend( config, options );
 337
 338                 // Force linear transition based on browser capabilities
 339                 if( supports3DTransforms === false ) config.transition = 'linear';
 340
 341                 dom.wrapper.classList.add( config.transition );
 342
 343                 if( dom.controls ) {
 344                         dom.controls.style.display = ( config.controls && dom.controls ) ? 'block' : 'none';
 345                 }
 346
 347                 if( dom.progress ) {
 348                         dom.progress.style.display = ( config.progress && dom.progress ) ? 'block' : 'none';
 349                 }
 350
 351                 if( config.rtl ) {
 352                         dom.wrapper.classList.add( 'rtl' );
 353                 }
 354                 else {
 355                         dom.wrapper.classList.remove( 'rtl' );
 356                 }
 357
 358                 if( config.center ) {
 359                         dom.wrapper.classList.add( 'center' );
 360                 }
 361                 else {
 362                         dom.wrapper.classList.remove( 'center' );
 363                 }
 364
 365                 if( config.mouseWheel ) {
 366                         document.addEventListener( 'DOMMouseScroll', onDocumentMouseScroll, false ); // FF
 367                         document.addEventListener( 'mousewheel', onDocumentMouseScroll, false );
 368                 }
 369                 else {
 370                         document.removeEventListener( 'DOMMouseScroll', onDocumentMouseScroll, false ); // FF
 371                         document.removeEventListener( 'mousewheel', onDocumentMouseScroll, false );
 372                 }
 373
 374                 // 3D links
 375                 if( config.rollingLinks ) {
 376                         enable3DLinks();
 377                 }
 378                 else {
 379                         disable3DLinks();
 380                 }
 381
 382                 // Load the theme in the config, if it's not already loaded
 383                 if( config.theme && dom.theme ) {
 384                         var themeURL = dom.theme.getAttribute( 'href' );
 385                         var themeFinder = /[^\/]*?(?=\.css)/;
 386                         var themeName = themeURL.match(themeFinder)[0];
 387
 388                         if(  config.theme !== themeName ) {
 389                                 themeURL = themeURL.replace(themeFinder, config.theme);
 390                                 dom.theme.setAttribute( 'href', themeURL );
 391                         }
 392                 }
 393
 394                 postConfigure();
 395
 396         }
 397
 398         /**
 399          * Updates various parts of the presentatio after the
 400          * configuration has changed.
 401          */
 402         function postConfigure() {
 403
 404                 // Subscribe to input
 405                 removeEventListeners();
 406                 addEventListeners();
 407
 408                 // Force a layout to make sure the current config is accounted for
 409                 layout();
 410
 411                 // Reflect the current autoSlide value
 412                 autoSlide = config.autoSlide;
 413
 414                 // Start auto-sliding if it's enabled
 415                 cueAutoSlide();
 416
 417         }
 418
 419         /**
 420          * Binds all event listeners.
 421          */
 422         function addEventListeners() {
 423
 424                 eventsAreBound = true;
 425
 426                 window.addEventListener( 'hashchange', onWindowHashChange, false );
 427                 window.addEventListener( 'resize', onWindowResize, false );
 428
 429                 if( config.touch ) {
 430                         dom.wrapper.addEventListener( 'touchstart', onTouchStart, false );
 431                         dom.wrapper.addEventListener( 'touchmove', onTouchMove, false );
 432                         dom.wrapper.addEventListener( 'touchend', onTouchEnd, false );
 433
 434                         // Support pointer-style touch interaction as well
 435                         if( window.navigator.msPointerEnabled ) {
 436                                 dom.wrapper.addEventListener( 'MSPointerDown', onPointerDown, false );
 437                                 dom.wrapper.addEventListener( 'MSPointerMove', onPointerMove, false );
 438                                 dom.wrapper.addEventListener( 'MSPointerUp', onPointerUp, false );
 439                         }
 440                 }
 441
 442                 if( config.keyboard ) {
 443                         document.addEventListener( 'keydown', onDocumentKeyDown, false );
 444                 }
 445
 446                 if ( config.progress && dom.progress ) {
 447                         dom.progress.addEventListener( 'click', onProgressClicked, false );
 448                 }
 449
 450                 if ( config.controls && dom.controls ) {
 451                         [ 'touchstart', 'click' ].forEach( function( eventName ) {
 452                                 dom.controlsLeft.forEach( function( el ) { el.addEventListener( eventName, onNavigateLeftClicked, false ); } );
 453                                 dom.controlsRight.forEach( function( el ) { el.addEventListener( eventName, onNavigateRightClicked, false ); } );
 454                                 dom.controlsUp.forEach( function( el ) { el.addEventListener( eventName, onNavigateUpClicked, false ); } );
 455                                 dom.controlsDown.forEach( function( el ) { el.addEventListener( eventName, onNavigateDownClicked, false ); } );
 456                                 dom.controlsPrev.forEach( function( el ) { el.addEventListener( eventName, onNavigatePrevClicked, false ); } );
 457                                 dom.controlsNext.forEach( function( el ) { el.addEventListener( eventName, onNavigateNextClicked, false ); } );
 458                         } );
 459                 }
 460
 461         }
 462
 463         /**
 464          * Unbinds all event listeners.
 465          */
 466         function removeEventListeners() {
 467
 468                 eventsAreBound = false;
 469
 470                 document.removeEventListener( 'keydown', onDocumentKeyDown, false );
 471                 window.removeEventListener( 'hashchange', onWindowHashChange, false );
 472                 window.removeEventListener( 'resize', onWindowResize, false );
 473
 474                 dom.wrapper.removeEventListener( 'touchstart', onTouchStart, false );
 475                 dom.wrapper.removeEventListener( 'touchmove', onTouchMove, false );
 476                 dom.wrapper.removeEventListener( 'touchend', onTouchEnd, false );
 477
 478                 if( window.navigator.msPointerEnabled ) {
 479                         dom.wrapper.removeEventListener( 'MSPointerDown', onPointerDown, false );
 480                         dom.wrapper.removeEventListener( 'MSPointerMove', onPointerMove, false );
 481                         dom.wrapper.removeEventListener( 'MSPointerUp', onPointerUp, false );
 482                 }
 483
 484                 if ( config.progress && dom.progress ) {
 485                         dom.progress.removeEventListener( 'click', onProgressClicked, false );
 486                 }
 487
 488                 if ( config.controls && dom.controls ) {
 489                         [ 'touchstart', 'click' ].forEach( function( eventName ) {
 490                                 dom.controlsLeft.forEach( function( el ) { el.removeEventListener( eventName, onNavigateLeftClicked, false ); } );
 491                                 dom.controlsRight.forEach( function( el ) { el.removeEventListener( eventName, onNavigateRightClicked, false ); } );
 492                                 dom.controlsUp.forEach( function( el ) { el.removeEventListener( eventName, onNavigateUpClicked, false ); } );
 493                                 dom.controlsDown.forEach( function( el ) { el.removeEventListener( eventName, onNavigateDownClicked, false ); } );
 494                                 dom.controlsPrev.forEach( function( el ) { el.removeEventListener( eventName, onNavigatePrevClicked, false ); } );
 495                                 dom.controlsNext.forEach( function( el ) { el.removeEventListener( eventName, onNavigateNextClicked, false ); } );
 496                         } );
 497                 }
 498
 499         }
 500
 501         /**
 502          * Extend object a with the properties of object b.
 503          * If there's a conflict, object b takes precedence.
 504          */
 505         function extend( a, b ) {
 506
 507                 for( var i in b ) {
 508                         a[ i ] = b[ i ];
 509                 }
 510
 511         }
 512
 513         /**
 514          * Converts the target object to an array.
 515          */
 516         function toArray( o ) {
 517
 518                 return Array.prototype.slice.call( o );
 519
 520         }
 521
 522         /**
 523          * Measures the distance in pixels between point a
 524          * and point b.
 525          *
 526          * @param {Object} a point with x/y properties
 527          * @param {Object} b point with x/y properties
 528          */
 529         function distanceBetween( a, b ) {
 530
 531                 var dx = a.x - b.x,
 532                         dy = a.y - b.y;
 533
 534                 return Math.sqrt( dx*dx + dy*dy );
 535
 536         }
 537
 538         /**
 539          * Causes the address bar to hide on mobile devices,
 540          * more vertical space ftw.
 541          */
 542         function removeAddressBar() {
 543
 544                 if( window.orientation === 0 ) {
 545                         document.documentElement.style.overflow = 'scroll';
 546                         document.body.style.height = '120%';
 547                 }
 548                 else {
 549                         document.documentElement.style.overflow = '';
 550                         document.body.style.height = '100%';
 551                 }
 552
 553                 setTimeout( function() {
 554                         window.scrollTo( 0, 1 );
 555                 }, 10 );
 556
 557         }
 558
 559         /**
 560          * Dispatches an event of the specified type from the
 561          * reveal DOM element.
 562          */
 563         function dispatchEvent( type, properties ) {
 564
 565                 var event = document.createEvent( "HTMLEvents", 1, 2 );
 566                 event.initEvent( type, true, true );
 567                 extend( event, properties );
 568                 dom.wrapper.dispatchEvent( event );
 569
 570         }
 571
 572         /**
 573          * Wrap all links in 3D goodness.
 574          */
 575         function enable3DLinks() {
 576
 577                 if( supports3DTransforms && !( 'msPerspective' in document.body.style ) ) {
 578                         var anchors = document.querySelectorAll( SLIDES_SELECTOR + ' a:not(.image)' );
 579
 580                         for( var i = 0, len = anchors.length; i < len; i++ ) {
 581                                 var anchor = anchors[i];
 582
 583                                 if( anchor.textContent && !anchor.querySelector( '*' ) && ( !anchor.className || !anchor.classList.contains( anchor, 'roll' ) ) ) {
 584                                         var span = document.createElement('span');
 585                                         span.setAttribute('data-title', anchor.text);
 586                                         span.innerHTML = anchor.innerHTML;
 587
 588                                         anchor.classList.add( 'roll' );
 589                                         anchor.innerHTML = '';
 590                                         anchor.appendChild(span);
 591                                 }
 592                         }
 593                 }
 594
 595         }
 596
 597         /**
 598          * Unwrap all 3D links.
 599          */
 600         function disable3DLinks() {
 601
 602                 var anchors = document.querySelectorAll( SLIDES_SELECTOR + ' a.roll' );
 603
 604                 for( var i = 0, len = anchors.length; i < len; i++ ) {
 605                         var anchor = anchors[i];
 606                         var span = anchor.querySelector( 'span' );
 607
 608                         if( span ) {
 609                                 anchor.classList.remove( 'roll' );
 610                                 anchor.innerHTML = span.innerHTML;
 611                         }
 612                 }
 613
 614         }
 615
 616         /**
 617          * Return a sorted fragments list, ordered by an increasing
 618          * "data-fragment-index" attribute.
 619          *
 620          * Fragments will be revealed in the order that they are returned by
 621          * this function, so you can use the index attributes to control the
 622          * order of fragment appearance.
 623          *
 624          * To maintain a sensible default fragment order, fragments are presumed
 625          * to be passed in document order. This function adds a "fragment-index"
 626          * attribute to each node if such an attribute is not already present,
 627          * and sets that attribute to an integer value which is the position of
 628          * the fragment within the fragments list.
 629          */
 630         function sortFragments( fragments ) {
 631
 632                 var a = toArray( fragments );
 633
 634                 a.forEach( function( el, idx ) {
 635                         if( !el.hasAttribute( 'data-fragment-index' ) ) {
 636                                 el.setAttribute( 'data-fragment-index', idx );
 637                         }
 638                 } );
 639
 640                 a.sort( function( l, r ) {
 641                         return l.getAttribute( 'data-fragment-index' ) - r.getAttribute( 'data-fragment-index');
 642                 } );
 643
 644                 return a;
 645
 646         }
 647
 648         /**
 649          * Applies JavaScript-controlled layout rules to the
 650          * presentation.
 651          */
 652         function layout() {
 653
 654                 if( dom.wrapper ) {
 655
 656                         // Available space to scale within
 657                         var availableWidth = dom.wrapper.offsetWidth,
 658                                 availableHeight = dom.wrapper.offsetHeight;
 659
 660                         // Reduce available space by margin
 661                         availableWidth -= ( availableHeight * config.margin );
 662                         availableHeight -= ( availableHeight * config.margin );
 663
 664                         // Dimensions of the content
 665                         var slideWidth = config.width,
 666                                 slideHeight = config.height;
 667
 668                         // Slide width may be a percentage of available width
 669                         if( typeof slideWidth === 'string' && /%$/.test( slideWidth ) ) {
 670                                 slideWidth = parseInt( slideWidth, 10 ) / 100 * availableWidth;
 671                         }
 672
 673                         // Slide height may be a percentage of available height
 674                         if( typeof slideHeight === 'string' && /%$/.test( slideHeight ) ) {
 675                                 slideHeight = parseInt( slideHeight, 10 ) / 100 * availableHeight;
 676                         }
 677
 678                         dom.slides.style.width = slideWidth + 'px';
 679                         dom.slides.style.height = slideHeight + 'px';
 680
 681                         // Determine scale of content to fit within available space
 682                         scale = Math.min( availableWidth / slideWidth, availableHeight / slideHeight );
 683
 684                         // Respect max/min scale settings
 685                         scale = Math.max( scale, config.minScale );
 686                         scale = Math.min( scale, config.maxScale );
 687
 688                         // Prefer applying scale via zoom since Chrome blurs scaled content
 689                         // with nested transforms
 690                         if( typeof dom.slides.style.zoom !== 'undefined' && !navigator.userAgent.match( /(iphone|ipod|ipad|android)/gi ) ) {
 691                                 dom.slides.style.zoom = scale;
 692                         }
 693                         // Apply scale transform as a fallback
 694                         else {
 695                                 var transform = 'translate(-50%, -50%) scale('+ scale +') translate(50%, 50%)';
 696
 697                                 dom.slides.style.WebkitTransform = transform;
 698                                 dom.slides.style.MozTransform = transform;
 699                                 dom.slides.style.msTransform = transform;
 700                                 dom.slides.style.OTransform = transform;
 701                                 dom.slides.style.transform = transform;
 702                         }
 703
 704                         // Select all slides, vertical and horizontal
 705                         var slides = toArray( document.querySelectorAll( SLIDES_SELECTOR ) );
 706
 707                         for( var i = 0, len = slides.length; i < len; i++ ) {
 708                                 var slide = slides[ i ];
 709
 710                                 // Don't bother updating invisible slides
 711                                 if( slide.style.display === 'none' ) {
 712                                         continue;
 713                                 }
 714
 715                                 if( config.center ) {
 716                                         // Vertical stacks are not centred since their section
 717                                         // children will be
 718                                         if( slide.classList.contains( 'stack' ) ) {
 719                                                 slide.style.top = 0;
 720                                         }
 721                                         else {
 722                                                 slide.style.top = Math.max( - ( slide.offsetHeight / 2 ) - 20, -slideHeight / 2 ) + 'px';
 723                                         }
 724                                 }
 725                                 else {
 726                                         slide.style.top = '';
 727                                 }
 728
 729                         }
 730
 731                 }
 732
 733         }
 734
 735         /**
 736          * Stores the vertical index of a stack so that the same
 737          * vertical slide can be selected when navigating to and
 738          * from the stack.
 739          *
 740          * @param {HTMLElement} stack The vertical stack element
 741          * @param {int} v Index to memorize
 742          */
 743         function setPreviousVerticalIndex( stack, v ) {
 744
 745                 if( typeof stack === 'object' && typeof stack.setAttribute === 'function' ) {
 746                         stack.setAttribute( 'data-previous-indexv', v || 0 );
 747                 }
 748
 749         }
 750
 751         /**
 752          * Retrieves the vertical index which was stored using
 753          * #setPreviousVerticalIndex() or 0 if no previous index
 754          * exists.
 755          *
 756          * @param {HTMLElement} stack The vertical stack element
 757          */
 758         function getPreviousVerticalIndex( stack ) {
 759
 760                 if( typeof stack === 'object' && typeof stack.setAttribute === 'function' && stack.classList.contains( 'stack' ) ) {
 761                         return parseInt( stack.getAttribute( 'data-previous-indexv' ) || 0, 10 );
 762                 }
 763
 764                 return 0;
 765
 766         }
 767
 768         /**
 769          * Displays the overview of slides (quick nav) by
 770          * scaling down and arranging all slide elements.
 771          *
 772          * Experimental feature, might be dropped if perf
 773          * can't be improved.
 774          */
 775         function activateOverview() {
 776
 777                 // Only proceed if enabled in config
 778                 if( config.overview ) {
 779
 780                         // Don't auto-slide while in overview mode
 781                         cancelAutoSlide();
 782
 783                         var wasActive = dom.wrapper.classList.contains( 'overview' );
 784
 785                         dom.wrapper.classList.add( 'overview' );
 786                         dom.wrapper.classList.remove( 'exit-overview' );
 787
 788                         clearTimeout( activateOverviewTimeout );
 789                         clearTimeout( deactivateOverviewTimeout );
 790
 791                         // Not the pretties solution, but need to let the overview
 792                         // class apply first so that slides are measured accurately
 793                         // before we can position them
 794                         activateOverviewTimeout = setTimeout( function(){
 795
 796                                 var horizontalSlides = document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR );
 797
 798                                 for( var i = 0, len1 = horizontalSlides.length; i < len1; i++ ) {
 799                                         var hslide = horizontalSlides[i],
 800                                                 htransform = 'translateZ(-2500px) translate(' + ( ( i - indexh ) * 105 ) + '%, 0%)';
 801
 802                                         hslide.setAttribute( 'data-index-h', i );
 803                                         hslide.style.display = 'block';
 804                                         hslide.style.WebkitTransform = htransform;
 805                                         hslide.style.MozTransform = htransform;
 806                                         hslide.style.msTransform = htransform;
 807                                         hslide.style.OTransform = htransform;
 808                                         hslide.style.transform = htransform;
 809
 810                                         if( hslide.classList.contains( 'stack' ) ) {
 811
 812                                                 var verticalSlides = hslide.querySelectorAll( 'section' );
 813
 814                                                 for( var j = 0, len2 = verticalSlides.length; j < len2; j++ ) {
 815                                                         var verticalIndex = i === indexh ? indexv : getPreviousVerticalIndex( hslide );
 816
 817                                                         var vslide = verticalSlides[j],
 818                                                                 vtransform = 'translate(0%, ' + ( ( j - verticalIndex ) * 105 ) + '%)';
 819
 820                                                         vslide.setAttribute( 'data-index-h', i );
 821                                                         vslide.setAttribute( 'data-index-v', j );
 822                                                         vslide.style.display = 'block';
 823                                                         vslide.style.WebkitTransform = vtransform;
 824                                                         vslide.style.MozTransform = vtransform;
 825                                                         vslide.style.msTransform = vtransform;
 826                                                         vslide.style.OTransform = vtransform;
 827                                                         vslide.style.transform = vtransform;
 828
 829                                                         // Navigate to this slide on click
 830                                                         vslide.addEventListener( 'click', onOverviewSlideClicked, true );
 831                                                 }
 832
 833                                         }
 834                                         else {
 835
 836                                                 // Navigate to this slide on click
 837                                                 hslide.addEventListener( 'click', onOverviewSlideClicked, true );
 838
 839                                         }
 840                                 }
 841
 842                                 layout();
 843
 844                                 if( !wasActive ) {
 845                                         // Notify observers of the overview showing
 846                                         dispatchEvent( 'overviewshown', {
 847                                                 'indexh': indexh,
 848                                                 'indexv': indexv,
 849                                                 'currentSlide': currentSlide
 850                                         } );
 851                                 }
 852
 853                         }, 10 );
 854
 855                 }
 856
 857         }
 858
 859         /**
 860          * Exits the slide overview and enters the currently
 861          * active slide.
 862          */
 863         function deactivateOverview() {
 864
 865                 // Only proceed if enabled in config
 866                 if( config.overview ) {
 867
 868                         clearTimeout( activateOverviewTimeout );
 869                         clearTimeout( deactivateOverviewTimeout );
 870
 871                         dom.wrapper.classList.remove( 'overview' );
 872
 873                         // Temporarily add a class so that transitions can do different things
 874                         // depending on whether they are exiting/entering overview, or just
 875                         // moving from slide to slide
 876                         dom.wrapper.classList.add( 'exit-overview' );
 877
 878                         deactivateOverviewTimeout = setTimeout( function () {
 879                                 dom.wrapper.classList.remove( 'exit-overview' );
 880                         }, 10);
 881
 882                         // Select all slides
 883                         var slides = toArray( document.querySelectorAll( SLIDES_SELECTOR ) );
 884
 885                         for( var i = 0, len = slides.length; i < len; i++ ) {
 886                                 var element = slides[i];
 887
 888                                 element.style.display = '';
 889
 890                                 // Resets all transforms to use the external styles
 891                                 element.style.WebkitTransform = '';
 892                                 element.style.MozTransform = '';
 893                                 element.style.msTransform = '';
 894                                 element.style.OTransform = '';
 895                                 element.style.transform = '';
 896
 897                                 element.removeEventListener( 'click', onOverviewSlideClicked, true );
 898                         }
 899
 900                         slide( indexh, indexv );
 901
 902                         cueAutoSlide();
 903
 904                         // Notify observers of the overview hiding
 905                         dispatchEvent( 'overviewhidden', {
 906                                 'indexh': indexh,
 907                                 'indexv': indexv,
 908                                 'currentSlide': currentSlide
 909                         } );
 910
 911                 }
 912         }
 913
 914         /**
 915          * Toggles the slide overview mode on and off.
 916          *
 917          * @param {Boolean} override Optional flag which overrides the
 918          * toggle logic and forcibly sets the desired state. True means
 919          * overview is open, false means it's closed.
 920          */
 921         function toggleOverview( override ) {
 922
 923                 if( typeof override === 'boolean' ) {
 924                         override ? activateOverview() : deactivateOverview();
 925                 }
 926                 else {
 927                         isOverview() ? deactivateOverview() : activateOverview();
 928                 }
 929
 930         }
 931
 932         /**
 933          * Checks if the overview is currently active.
 934          *
 935          * @return {Boolean} true if the overview is active,
 936          * false otherwise
 937          */
 938         function isOverview() {
 939
 940                 return dom.wrapper.classList.contains( 'overview' );
 941
 942         }
 943
 944         /**
 945          * Handling the fullscreen functionality via the fullscreen API
 946          *
 947          * @see http://fullscreen.spec.whatwg.org/
 948          * @see https://developer.mozilla.org/en-US/docs/DOM/Using_fullscreen_mode
 949          */
 950         function enterFullscreen() {
 951
 952                 var element = document.body;
 953
 954                 // Check which implementation is available
 955                 var requestMethod = element.requestFullScreen ||
 956                                                         element.webkitRequestFullScreen ||
 957                                                         element.mozRequestFullScreen ||
 958                                                         element.msRequestFullScreen;
 959
 960                 if( requestMethod ) {
 961                         requestMethod.apply( element );
 962                 }
 963
 964         }
 965
 966         /**
 967          * Enters the paused mode which fades everything on screen to
 968          * black.
 969          */
 970         function pause() {
 971
 972                 var wasPaused = dom.wrapper.classList.contains( 'paused' );
 973
 974                 cancelAutoSlide();
 975                 dom.wrapper.classList.add( 'paused' );
 976
 977                 if( wasPaused === false ) {
 978                         dispatchEvent( 'paused' );
 979                 }
 980
 981         }
 982
 983         /**
 984          * Exits from the paused mode.
 985          */
 986         function resume() {
 987
 988                 var wasPaused = dom.wrapper.classList.contains( 'paused' );
 989                 dom.wrapper.classList.remove( 'paused' );
 990
 991                 cueAutoSlide();
 992
 993                 if( wasPaused ) {
 994                         dispatchEvent( 'resumed' );
 995                 }
 996
 997         }
 998
 999         /**
1000          * Toggles the paused mode on and off.
1001          */
1002         function togglePause() {
1003
1004                 if( isPaused() ) {
1005                         resume();
1006                 }
1007                 else {
1008                         pause();
1009                 }
1010
1011         }
1012
1013         /**
1014          * Checks if we are currently in the paused mode.
1015          */
1016         function isPaused() {
1017
1018                 return dom.wrapper.classList.contains( 'paused' );
1019
1020         }
1021
1022         /**
1023          * Steps from the current point in the presentation to the
1024          * slide which matches the specified horizontal and vertical
1025          * indices.
1026          *
1027          * @param {int} h Horizontal index of the target slide
1028          * @param {int} v Vertical index of the target slide
1029          * @param {int} f Optional index of a fragment within the
1030          * target slide to activate
1031          * @param {int} o Optional origin for use in multimaster environments
1032          */
1033         function slide( h, v, f, o ) {
1034
1035                 // Remember where we were at before
1036                 previousSlide = currentSlide;
1037
1038                 // Query all horizontal slides in the deck
1039                 var horizontalSlides = document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR );
1040
1041                 // If no vertical index is specified and the upcoming slide is a
1042                 // stack, resume at its previous vertical index
1043                 if( v === undefined ) {
1044                         v = getPreviousVerticalIndex( horizontalSlides[ h ] );
1045                 }
1046
1047                 // If we were on a vertical stack, remember what vertical index
1048                 // it was on so we can resume at the same position when returning
1049                 if( previousSlide && previousSlide.parentNode && previousSlide.parentNode.classList.contains( 'stack' ) ) {
1050                         setPreviousVerticalIndex( previousSlide.parentNode, indexv );
1051                 }
1052
1053                 // Remember the state before this slide
1054                 var stateBefore = state.concat();
1055
1056                 // Reset the state array
1057                 state.length = 0;
1058
1059                 var indexhBefore = indexh,
1060                         indexvBefore = indexv;
1061
1062                 // Activate and transition to the new slide
1063                 indexh = updateSlides( HORIZONTAL_SLIDES_SELECTOR, h === undefined ? indexh : h );
1064                 indexv = updateSlides( VERTICAL_SLIDES_SELECTOR, v === undefined ? indexv : v );
1065
1066                 layout();
1067
1068                 // Apply the new state
1069                 stateLoop: for( var i = 0, len = state.length; i < len; i++ ) {
1070                         // Check if this state existed on the previous slide. If it
1071                         // did, we will avoid adding it repeatedly
1072                         for( var j = 0; j < stateBefore.length; j++ ) {
1073                                 if( stateBefore[j] === state[i] ) {
1074                                         stateBefore.splice( j, 1 );
1075                                         continue stateLoop;
1076                                 }
1077                         }
1078
1079                         document.documentElement.classList.add( state[i] );
1080
1081                         // Dispatch custom event matching the state's name
1082                         dispatchEvent( state[i] );
1083                 }
1084
1085                 // Clean up the remains of the previous state
1086                 while( stateBefore.length ) {
1087                         document.documentElement.classList.remove( stateBefore.pop() );
1088                 }
1089
1090                 // If the overview is active, re-activate it to update positions
1091                 if( isOverview() ) {
1092                         activateOverview();
1093                 }
1094
1095                 // Update the URL hash after a delay since updating it mid-transition
1096                 // is likely to cause visual lag
1097                 writeURL( 1500 );
1098
1099                 // Find the current horizontal slide and any possible vertical slides
1100                 // within it
1101                 var currentHorizontalSlide = horizontalSlides[ indexh ],
1102                         currentVerticalSlides = currentHorizontalSlide.querySelectorAll( 'section' );
1103
1104                 // Store references to the previous and current slides
1105                 currentSlide = currentVerticalSlides[ indexv ] || currentHorizontalSlide;
1106
1107
1108                 // Show fragment, if specified
1109                 if( typeof f !== 'undefined' ) {
1110                         var fragments = sortFragments( currentSlide.querySelectorAll( '.fragment' ) );
1111
1112                         toArray( fragments ).forEach( function( fragment, indexf ) {
1113                                 if( indexf < f ) {
1114                                         fragment.classList.add( 'visible' );
1115                                 }
1116                                 else {
1117                                         fragment.classList.remove( 'visible' );
1118                                 }
1119                         } );
1120                 }
1121
1122                 // Dispatch an event if the slide changed
1123                 if( indexh !== indexhBefore || indexv !== indexvBefore ) {
1124                         dispatchEvent( 'slidechanged', {
1125                                 'indexh': indexh,
1126                                 'indexv': indexv,
1127                                 'previousSlide': previousSlide,
1128                                 'currentSlide': currentSlide,
1129                                 'origin': o
1130                         } );
1131                 }
1132                 else {
1133                         // Ensure that the previous slide is never the same as the current
1134                         previousSlide = null;
1135                 }
1136
1137                 // Solves an edge case where the previous slide maintains the
1138                 // 'present' class when navigating between adjacent vertical
1139                 // stacks
1140                 if( previousSlide ) {
1141                         previousSlide.classList.remove( 'present' );
1142
1143                         // Reset all slides upon navigate to home
1144                         // Issue: #285
1145                         if ( document.querySelector( HOME_SLIDE_SELECTOR ).classList.contains( 'present' ) ) {
1146                                 // Launch async task
1147                                 setTimeout( function () {
1148                                         var slides = toArray( document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR + '.stack') ), i;
1149                                         for( i in slides ) {
1150                                                 if( slides[i] ) {
1151                                                         // Reset stack
1152                                                         setPreviousVerticalIndex( slides[i], 0 );
1153                                                 }
1154                                         }
1155                                 }, 0 );
1156                         }
1157                 }
1158
1159                 updateControls();
1160                 updateProgress();
1161
1162         }
1163
1164         /**
1165          * Updates one dimension of slides by showing the slide
1166          * with the specified index.
1167          *
1168          * @param {String} selector A CSS selector that will fetch
1169          * the group of slides we are working with
1170          * @param {Number} index The index of the slide that should be
1171          * shown
1172          *
1173          * @return {Number} The index of the slide that is now shown,
1174          * might differ from the passed in index if it was out of
1175          * bounds.
1176          */
1177         function updateSlides( selector, index ) {
1178
1179                 // Select all slides and convert the NodeList result to
1180                 // an array
1181                 var slides = toArray( document.querySelectorAll( selector ) ),
1182                         slidesLength = slides.length;
1183
1184                 if( slidesLength ) {
1185
1186                         // Should the index loop?
1187                         if( config.loop ) {
1188                                 index %= slidesLength;
1189
1190                                 if( index < 0 ) {
1191                                         index = slidesLength + index;
1192                                 }
1193                         }
1194
1195                         // Enforce max and minimum index bounds
1196                         index = Math.max( Math.min( index, slidesLength - 1 ), 0 );
1197
1198                         for( var i = 0; i < slidesLength; i++ ) {
1199                                 var element = slides[i];
1200
1201                                 // Optimization; hide all slides that are three or more steps
1202                                 // away from the present slide
1203                                 if( isOverview() === false ) {
1204                                         // The distance loops so that it measures 1 between the first
1205                                         // and last slides
1206                                         var distance = Math.abs( ( index - i ) % ( slidesLength - 3 ) ) || 0;
1207
1208                                         element.style.display = distance > 3 ? 'none' : 'block';
1209                                 }
1210
1211                                 slides[i].classList.remove( 'past' );
1212                                 slides[i].classList.remove( 'present' );
1213                                 slides[i].classList.remove( 'future' );
1214
1215                                 if( i < index ) {
1216                                         // Any element previous to index is given the 'past' class
1217                                         slides[i].classList.add( 'past' );
1218                                 }
1219                                 else if( i > index ) {
1220                                         // Any element subsequent to index is given the 'future' class
1221                                         slides[i].classList.add( 'future' );
1222                                 }
1223
1224                                 // If this element contains vertical slides
1225                                 if( element.querySelector( 'section' ) ) {
1226                                         slides[i].classList.add( 'stack' );
1227                                 }
1228                         }
1229
1230                         // Mark the current slide as present
1231                         slides[index].classList.add( 'present' );
1232
1233                         // If this slide has a state associated with it, add it
1234                         // onto the current state of the deck
1235                         var slideState = slides[index].getAttribute( 'data-state' );
1236                         if( slideState ) {
1237                                 state = state.concat( slideState.split( ' ' ) );
1238                         }
1239
1240                         // If this slide has a data-autoslide attribtue associated use this as
1241                         // autoSlide value otherwise use the global configured time
1242                         var slideAutoSlide = slides[index].getAttribute( 'data-autoslide' );
1243                         if( slideAutoSlide ) {
1244                                 autoSlide = parseInt( slideAutoSlide, 10 );
1245                         }
1246                         else {
1247                                 autoSlide = config.autoSlide;
1248                         }
1249
1250                 }
1251                 else {
1252                         // Since there are no slides we can't be anywhere beyond the
1253                         // zeroth index
1254                         index = 0;
1255                 }
1256
1257                 return index;
1258
1259         }
1260
1261         /**
1262          * Updates the progress bar to reflect the current slide.
1263          */
1264         function updateProgress() {
1265
1266                 // Update progress if enabled
1267                 if( config.progress && dom.progress ) {
1268
1269                         var horizontalSlides = toArray( document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) );
1270
1271                         // The number of past and total slides
1272                         var totalCount = document.querySelectorAll( SLIDES_SELECTOR + ':not(.stack)' ).length;
1273                         var pastCount = 0;
1274
1275                         // Step through all slides and count the past ones
1276                         mainLoop: for( var i = 0; i < horizontalSlides.length; i++ ) {
1277
1278                                 var horizontalSlide = horizontalSlides[i];
1279                                 var verticalSlides = toArray( horizontalSlide.querySelectorAll( 'section' ) );
1280
1281                                 for( var j = 0; j < verticalSlides.length; j++ ) {
1282
1283                                         // Stop as soon as we arrive at the present
1284                                         if( verticalSlides[j].classList.contains( 'present' ) ) {
1285                                                 break mainLoop;
1286                                         }
1287
1288                                         pastCount++;
1289
1290                                 }
1291
1292                                 // Stop as soon as we arrive at the present
1293                                 if( horizontalSlide.classList.contains( 'present' ) ) {
1294                                         break;
1295                                 }
1296
1297                                 // Don't count the wrapping section for vertical slides
1298                                 if( horizontalSlide.classList.contains( 'stack' ) === false ) {
1299                                         pastCount++;
1300                                 }
1301
1302                         }
1303
1304                         dom.progressbar.style.width = ( pastCount / ( totalCount - 1 ) ) * window.innerWidth + 'px';
1305
1306                 }
1307
1308         }
1309
1310         /**
1311          * Updates the state of all control/navigation arrows.
1312          */
1313         function updateControls() {
1314
1315                 if ( config.controls && dom.controls ) {
1316
1317                         var routes = availableRoutes();
1318
1319                         // Remove the 'enabled' class from all directions
1320                         dom.controlsLeft.concat( dom.controlsRight )
1321                                                         .concat( dom.controlsUp )
1322                                                         .concat( dom.controlsDown )
1323                                                         .concat( dom.controlsPrev )
1324                                                         .concat( dom.controlsNext ).forEach( function( node ) {
1325                                 node.classList.remove( 'enabled' );
1326                         } );
1327
1328                         // Add the 'enabled' class to the available routes
1329                         if( routes.left ) dom.controlsLeft.forEach( function( el ) { el.classList.add( 'enabled' );     } );
1330                         if( routes.right ) dom.controlsRight.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1331                         if( routes.up ) dom.controlsUp.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1332                         if( routes.down ) dom.controlsDown.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1333
1334                         // Prev/next buttons
1335                         if( routes.left || routes.up ) dom.controlsPrev.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1336                         if( routes.right || routes.down ) dom.controlsNext.forEach( function( el ) { el.classList.add( 'enabled' ); } );
1337
1338                 }
1339
1340         }
1341
1342         /**
1343          * Determine what available routes there are for navigation.
1344          *
1345          * @return {Object} containing four booleans: left/right/up/down
1346          */
1347         function availableRoutes() {
1348
1349                 var horizontalSlides = document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ),
1350                         verticalSlides = document.querySelectorAll( VERTICAL_SLIDES_SELECTOR );
1351
1352                 return {
1353                         left: indexh > 0 || config.loop,
1354                         right: indexh < horizontalSlides.length - 1 || config.loop,
1355                         up: indexv > 0,
1356                         down: indexv < verticalSlides.length - 1
1357                 };
1358
1359         }
1360
1361         /**
1362          * Reads the current URL (hash) and navigates accordingly.
1363          */
1364         function readURL() {
1365
1366                 var hash = window.location.hash;
1367
1368                 // Attempt to parse the hash as either an index or name
1369                 var bits = hash.slice( 2 ).split( '/' ),
1370                         name = hash.replace( /#|\//gi, '' );
1371
1372                 // If the first bit is invalid and there is a name we can
1373                 // assume that this is a named link
1374                 if( isNaN( parseInt( bits[0], 10 ) ) && name.length ) {
1375                         // Find the slide with the specified name
1376                         var element = document.querySelector( '#' + name );
1377
1378                         if( element ) {
1379                                 // Find the position of the named slide and navigate to it
1380                                 var indices = Reveal.getIndices( element );
1381                                 slide( indices.h, indices.v );
1382                         }
1383                         // If the slide doesn't exist, navigate to the current slide
1384                         else {
1385                                 slide( indexh, indexv );
1386                         }
1387                 }
1388                 else {
1389                         // Read the index components of the hash
1390                         var h = parseInt( bits[0], 10 ) || 0,
1391                                 v = parseInt( bits[1], 10 ) || 0;
1392
1393                         slide( h, v );
1394                 }
1395
1396         }
1397
1398         /**
1399          * Updates the page URL (hash) to reflect the current
1400          * state.
1401          *
1402          * @param {Number} delay The time in ms to wait before
1403          * writing the hash
1404          */
1405         function writeURL( delay ) {
1406
1407                 if( config.history ) {
1408
1409                         // Make sure there's never more than one timeout running
1410                         clearTimeout( writeURLTimeout );
1411
1412                         // If a delay is specified, timeout this call
1413                         if( typeof delay === 'number' ) {
1414                                 writeURLTimeout = setTimeout( writeURL, delay );
1415                         }
1416                         else {
1417                                 var url = '/';
1418
1419                                 // If the current slide has an ID, use that as a named link
1420                                 if( currentSlide && typeof currentSlide.getAttribute( 'id' ) === 'string' ) {
1421                                         url = '/' + currentSlide.getAttribute( 'id' );
1422                                 }
1423                                 // Otherwise use the /h/v index
1424                                 else {
1425                                         if( indexh > 0 || indexv > 0 ) url += indexh;
1426                                         if( indexv > 0 ) url += '/' + indexv;
1427                                 }
1428
1429                                 window.location.hash = url;
1430                         }
1431                 }
1432
1433         }
1434
1435         /**
1436          * Retrieves the h/v location of the current, or specified,
1437          * slide.
1438          *
1439          * @param {HTMLElement} slide If specified, the returned
1440          * index will be for this slide rather than the currently
1441          * active one
1442          *
1443          * @return {Object} { h: <int>, v: <int> }
1444          */
1445         function getIndices( slide ) {
1446
1447                 // By default, return the current indices
1448                 var h = indexh,
1449                         v = indexv;
1450
1451                 // If a slide is specified, return the indices of that slide
1452                 if( slide ) {
1453                         var isVertical = !!slide.parentNode.nodeName.match( /section/gi );
1454                         var slideh = isVertical ? slide.parentNode : slide;
1455
1456                         // Select all horizontal slides
1457                         var horizontalSlides = toArray( document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) );
1458
1459                         // Now that we know which the horizontal slide is, get its index
1460                         h = Math.max( horizontalSlides.indexOf( slideh ), 0 );
1461
1462                         // If this is a vertical slide, grab the vertical index
1463                         if( isVertical ) {
1464                                 v = Math.max( toArray( slide.parentNode.querySelectorAll( 'section' ) ).indexOf( slide ), 0 );
1465                         }
1466                 }
1467
1468                 return { h: h, v: v };
1469
1470         }
1471
1472         /**
1473          * Navigate to the next slide fragment.
1474          *
1475          * @return {Boolean} true if there was a next fragment,
1476          * false otherwise
1477          */
1478         function nextFragment() {
1479
1480                 // Vertical slides:
1481                 if( document.querySelector( VERTICAL_SLIDES_SELECTOR + '.present' ) ) {
1482                         var verticalFragments = sortFragments( document.querySelectorAll( VERTICAL_SLIDES_SELECTOR + '.present .fragment:not(.visible)' ) );
1483
1484                         if( verticalFragments.length ) {
1485                                 verticalFragments[0].classList.add( 'visible' );
1486
1487                                 // Notify subscribers of the change
1488                                 dispatchEvent( 'fragmentshown', { fragment: verticalFragments[0] } );
1489                                 return true;
1490                         }
1491                 }
1492                 // Horizontal slides:
1493                 else {
1494                         var horizontalFragments = sortFragments( document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR + '.present .fragment:not(.visible)' ) );
1495
1496                         if( horizontalFragments.length ) {
1497                                 horizontalFragments[0].classList.add( 'visible' );
1498
1499                                 // Notify subscribers of the change
1500                                 dispatchEvent( 'fragmentshown', { fragment: horizontalFragments[0] } );
1501                                 return true;
1502                         }
1503                 }
1504
1505                 return false;
1506
1507         }
1508
1509         /**
1510          * Navigate to the previous slide fragment.
1511          *
1512          * @return {Boolean} true if there was a previous fragment,
1513          * false otherwise
1514          */
1515         function previousFragment() {
1516
1517                 // Vertical slides:
1518                 if( document.querySelector( VERTICAL_SLIDES_SELECTOR + '.present' ) ) {
1519                         var verticalFragments = sortFragments( document.querySelectorAll( VERTICAL_SLIDES_SELECTOR + '.present .fragment.visible' ) );
1520
1521                         if( verticalFragments.length ) {
1522                                 verticalFragments[ verticalFragments.length - 1 ].classList.remove( 'visible' );
1523
1524                                 // Notify subscribers of the change
1525                                 dispatchEvent( 'fragmenthidden', { fragment: verticalFragments[ verticalFragments.length - 1 ] } );
1526                                 return true;
1527                         }
1528                 }
1529                 // Horizontal slides:
1530                 else {
1531                         var horizontalFragments = sortFragments( document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR + '.present .fragment.visible' ) );
1532
1533                         if( horizontalFragments.length ) {
1534                                 horizontalFragments[ horizontalFragments.length - 1 ].classList.remove( 'visible' );
1535
1536                                 // Notify subscribers of the change
1537                                 dispatchEvent( 'fragmenthidden', { fragment: horizontalFragments[ horizontalFragments.length - 1 ] } );
1538                                 return true;
1539                         }
1540                 }
1541
1542                 return false;
1543
1544         }
1545
1546         /**
1547          * Cues a new automated slide if enabled in the config.
1548          */
1549         function cueAutoSlide() {
1550
1551                 clearTimeout( autoSlideTimeout );
1552
1553                 // Cue the next auto-slide if enabled
1554                 if( autoSlide && !isPaused() && !isOverview() ) {
1555                         autoSlideTimeout = setTimeout( navigateNext, autoSlide );
1556                 }
1557
1558         }
1559
1560         /**
1561          * Cancels any ongoing request to auto-slide.
1562          */
1563         function cancelAutoSlide() {
1564
1565                 clearTimeout( autoSlideTimeout );
1566
1567         }
1568
1569         function navigateLeft() {
1570
1571                 // Prioritize hiding fragments
1572                 if( availableRoutes().left && ( isOverview() || previousFragment() === false ) ) {
1573                         slide( indexh - 1 );
1574                 }
1575
1576         }
1577
1578         function navigateRight() {
1579
1580                 // Prioritize revealing fragments
1581                 if( availableRoutes().right && ( isOverview() || nextFragment() === false ) ) {
1582                         slide( indexh + 1 );
1583                 }
1584
1585         }
1586
1587         function navigateUp() {
1588
1589                 // Prioritize hiding fragments
1590                 if( availableRoutes().up && isOverview() || previousFragment() === false ) {
1591                         slide( indexh, indexv - 1 );
1592                 }
1593
1594         }
1595
1596         function navigateDown() {
1597
1598                 // Prioritize revealing fragments
1599                 if( availableRoutes().down && isOverview() || nextFragment() === false ) {
1600                         slide( indexh, indexv + 1 );
1601                 }
1602
1603         }
1604
1605         /**
1606          * Navigates backwards, prioritized in the following order:
1607          * 1) Previous fragment
1608          * 2) Previous vertical slide
1609          * 3) Previous horizontal slide
1610          */
1611         function navigatePrev() {
1612
1613                 // Prioritize revealing fragments
1614                 if( previousFragment() === false ) {
1615                         if( availableRoutes().up ) {
1616                                 navigateUp();
1617                         }
1618                         else {
1619                                 // Fetch the previous horizontal slide, if there is one
1620                                 var previousSlide = document.querySelector( HORIZONTAL_SLIDES_SELECTOR + '.past:nth-child(' + indexh + ')' );
1621
1622                                 if( previousSlide ) {
1623                                         indexv = ( previousSlide.querySelectorAll( 'section' ).length + 1 ) || undefined;
1624                                         indexh --;
1625                                         slide();
1626                                 }
1627                         }
1628                 }
1629
1630         }
1631
1632         /**
1633          * Same as #navigatePrev() but navigates forwards.
1634          */
1635         function navigateNext() {
1636
1637                 // Prioritize revealing fragments
1638                 if( nextFragment() === false ) {
1639                         availableRoutes().down ? navigateDown() : navigateRight();
1640                 }
1641
1642                 // If auto-sliding is enabled we need to cue up
1643                 // another timeout
1644                 cueAutoSlide();
1645
1646         }
1647
1648
1649         // --------------------------------------------------------------------//
1650         // ----------------------------- EVENTS -------------------------------//
1651         // --------------------------------------------------------------------//
1652
1653
1654         /**
1655          * Handler for the document level 'keydown' event.
1656          *
1657          * @param {Object} event
1658          */
1659         function onDocumentKeyDown( event ) {
1660
1661                 // Check if there's a focused element that could be using
1662                 // the keyboard
1663                 var activeElement = document.activeElement;
1664                 var hasFocus = !!( document.activeElement && ( document.activeElement.type || document.activeElement.href || document.activeElement.contentEditable !== 'inherit' ) );
1665
1666                 // Disregard the event if there's a focused element or a
1667                 // keyboard modifier key is present
1668                 if( hasFocus || (event.shiftKey && event.keyCode !== 32) || event.altKey || event.ctrlKey || event.metaKey ) return;
1669
1670                 var triggered = true;
1671
1672                 // while paused only allow "unpausing" keyboard events (b and .)
1673                 if( isPaused() && [66,190,191].indexOf( event.keyCode ) === -1 ) {
1674                         return false;
1675                 }
1676
1677                 switch( event.keyCode ) {
1678                         // p, page up
1679                         case 80: case 33: navigatePrev(); break;
1680                         // n, page down
1681                         case 78: case 34: navigateNext(); break;
1682                         // h, left
1683                         case 72: case 37: navigateLeft(); break;
1684                         // l, right
1685                         case 76: case 39: navigateRight(); break;
1686                         // k, up
1687                         case 75: case 38: navigateUp(); break;
1688                         // j, down
1689                         case 74: case 40: navigateDown(); break;
1690                         // home
1691                         case 36: slide( 0 ); break;
1692                         // end
1693                         case 35: slide( Number.MAX_VALUE ); break;
1694                         // space
1695                         case 32: isOverview() ? deactivateOverview() : event.shiftKey ? navigatePrev() : navigateNext(); break;
1696                         // return
1697                         case 13: isOverview() ? deactivateOverview() : triggered = false; break;
1698                         // b, period, Logitech presenter tools "black screen" button
1699                         case 66: case 190: case 191: togglePause(); break;
1700                         // f
1701                         case 70: enterFullscreen(); break;
1702                         default:
1703                                 triggered = false;
1704                 }
1705
1706                 // If the input resulted in a triggered action we should prevent
1707                 // the browsers default behavior
1708                 if( triggered ) {
1709                         event.preventDefault();
1710                 }
1711                 else if ( event.keyCode === 27 && supports3DTransforms ) {
1712                         toggleOverview();
1713
1714                         event.preventDefault();
1715                 }
1716
1717                 // If auto-sliding is enabled we need to cue up
1718                 // another timeout
1719                 cueAutoSlide();
1720
1721         }
1722
1723         /**
1724          * Handler for the 'touchstart' event, enables support for
1725          * swipe and pinch gestures.
1726          */
1727         function onTouchStart( event ) {
1728
1729                 touch.startX = event.touches[0].clientX;
1730                 touch.startY = event.touches[0].clientY;
1731                 touch.startCount = event.touches.length;
1732
1733                 // If there's two touches we need to memorize the distance
1734                 // between those two points to detect pinching
1735                 if( event.touches.length === 2 && config.overview ) {
1736                         touch.startSpan = distanceBetween( {
1737                                 x: event.touches[1].clientX,
1738                                 y: event.touches[1].clientY
1739                         }, {
1740                                 x: touch.startX,
1741                                 y: touch.startY
1742                         } );
1743                 }
1744
1745         }
1746
1747         /**
1748          * Handler for the 'touchmove' event.
1749          */
1750         function onTouchMove( event ) {
1751
1752                 // Each touch should only trigger one action
1753                 if( !touch.handled ) {
1754                         var currentX = event.touches[0].clientX;
1755                         var currentY = event.touches[0].clientY;
1756
1757                         // If the touch started off with two points and still has
1758                         // two active touches; test for the pinch gesture
1759                         if( event.touches.length === 2 && touch.startCount === 2 && config.overview ) {
1760
1761                                 // The current distance in pixels between the two touch points
1762                                 var currentSpan = distanceBetween( {
1763                                         x: event.touches[1].clientX,
1764                                         y: event.touches[1].clientY
1765                                 }, {
1766                                         x: touch.startX,
1767                                         y: touch.startY
1768                                 } );
1769
1770                                 // If the span is larger than the desire amount we've got
1771                                 // ourselves a pinch
1772                                 if( Math.abs( touch.startSpan - currentSpan ) > touch.threshold ) {
1773                                         touch.handled = true;
1774
1775                                         if( currentSpan < touch.startSpan ) {
1776                                                 activateOverview();
1777                                         }
1778                                         else {
1779                                                 deactivateOverview();
1780                                         }
1781                                 }
1782
1783                                 event.preventDefault();
1784
1785                         }
1786                         // There was only one touch point, look for a swipe
1787                         else if( event.touches.length === 1 && touch.startCount !== 2 ) {
1788
1789                                 var deltaX = currentX - touch.startX,
1790                                         deltaY = currentY - touch.startY;
1791
1792                                 if( deltaX > touch.threshold && Math.abs( deltaX ) > Math.abs( deltaY ) ) {
1793                                         touch.handled = true;
1794                                         navigateLeft();
1795                                 }
1796                                 else if( deltaX < -touch.threshold && Math.abs( deltaX ) > Math.abs( deltaY ) ) {
1797                                         touch.handled = true;
1798                                         navigateRight();
1799                                 }
1800                                 else if( deltaY > touch.threshold ) {
1801                                         touch.handled = true;
1802                                         navigateUp();
1803                                 }
1804                                 else if( deltaY < -touch.threshold ) {
1805                                         touch.handled = true;
1806                                         navigateDown();
1807                                 }
1808
1809                                 event.preventDefault();
1810
1811                         }
1812                 }
1813                 // There's a bug with swiping on some Android devices unless
1814                 // the default action is always prevented
1815                 else if( navigator.userAgent.match( /android/gi ) ) {
1816                         event.preventDefault();
1817                 }
1818
1819         }
1820
1821         /**
1822          * Handler for the 'touchend' event.
1823          */
1824         function onTouchEnd( event ) {
1825
1826                 touch.handled = false;
1827
1828         }
1829
1830         /**
1831          * Convert pointer down to touch start.
1832          */
1833         function onPointerDown( event ) {
1834
1835                 if( event.pointerType === event.MSPOINTER_TYPE_TOUCH ) {
1836                         event.touches = [{ clientX: event.clientX, clientY: event.clientY }];
1837                         onTouchStart( event );
1838                 }
1839
1840         }
1841
1842         /**
1843          * Convert pointer move to touch move.
1844          */
1845         function onPointerMove( event ) {
1846
1847                 if( event.pointerType === event.MSPOINTER_TYPE_TOUCH ) {
1848                         event.touches = [{ clientX: event.clientX, clientY: event.clientY }];
1849                         onTouchMove( event );
1850                 }
1851
1852         }
1853
1854         /**
1855          * Convert pointer up to touch end.
1856          */
1857         function onPointerUp( event ) {
1858
1859                 if( event.pointerType === event.MSPOINTER_TYPE_TOUCH ) {
1860                         event.touches = [{ clientX: event.clientX, clientY: event.clientY }];
1861                         onTouchEnd( event );
1862                 }
1863
1864         }
1865
1866         /**
1867          * Handles mouse wheel scrolling, throttled to avoid skipping
1868          * multiple slides.
1869          */
1870         function onDocumentMouseScroll( event ) {
1871
1872                 clearTimeout( mouseWheelTimeout );
1873
1874                 mouseWheelTimeout = setTimeout( function() {
1875                         var delta = event.detail || -event.wheelDelta;
1876                         if( delta > 0 ) {
1877                                 navigateNext();
1878                         }
1879                         else {
1880                                 navigatePrev();
1881                         }
1882                 }, 100 );
1883
1884         }
1885
1886         /**
1887          * Clicking on the progress bar results in a navigation to the
1888          * closest approximate horizontal slide using this equation:
1889          *
1890          * ( clickX / presentationWidth ) * numberOfSlides
1891          */
1892         function onProgressClicked( event ) {
1893
1894                 event.preventDefault();
1895
1896                 var slidesTotal = toArray( document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) ).length;
1897                 var slideIndex = Math.floor( ( event.clientX / dom.wrapper.offsetWidth ) * slidesTotal );
1898
1899                 slide( slideIndex );
1900
1901         }
1902
1903         /**
1904          * Event handler for navigation control buttons.
1905          */
1906         function onNavigateLeftClicked( event ) { event.preventDefault(); navigateLeft(); }
1907         function onNavigateRightClicked( event ) { event.preventDefault(); navigateRight(); }
1908         function onNavigateUpClicked( event ) { event.preventDefault(); navigateUp(); }
1909         function onNavigateDownClicked( event ) { event.preventDefault(); navigateDown(); }
1910         function onNavigatePrevClicked( event ) { event.preventDefault(); navigatePrev(); }
1911         function onNavigateNextClicked( event ) { event.preventDefault(); navigateNext(); }
1912
1913         /**
1914          * Handler for the window level 'hashchange' event.
1915          */
1916         function onWindowHashChange( event ) {
1917
1918                 readURL();
1919
1920         }
1921
1922         /**
1923          * Handler for the window level 'resize' event.
1924          */
1925         function onWindowResize( event ) {
1926
1927                 layout();
1928
1929         }
1930
1931         /**
1932          * Invoked when a slide is and we're in the overview.
1933          */
1934         function onOverviewSlideClicked( event ) {
1935
1936                 // TODO There's a bug here where the event listeners are not
1937                 // removed after deactivating the overview.
1938                 if( eventsAreBound && isOverview() ) {
1939                         event.preventDefault();
1940
1941                         var element = event.target;
1942
1943                         while( element && !element.nodeName.match( /section/gi ) ) {
1944                                 element = element.parentNode;
1945                         }
1946
1947                         if( element && !element.classList.contains( 'disabled' ) ) {
1948
1949                                 deactivateOverview();
1950
1951                                 if( element.nodeName.match( /section/gi ) ) {
1952                                         var h = parseInt( element.getAttribute( 'data-index-h' ), 10 ),
1953                                                 v = parseInt( element.getAttribute( 'data-index-v' ), 10 );
1954
1955                                         slide( h, v );
1956                                 }
1957
1958                         }
1959                 }
1960
1961         }
1962
1963
1964         // --------------------------------------------------------------------//
1965         // ------------------------------- API --------------------------------//
1966         // --------------------------------------------------------------------//
1967
1968
1969         return {
1970                 initialize: initialize,
1971                 configure: configure,
1972
1973                 // Navigation methods
1974                 slide: slide,
1975                 left: navigateLeft,
1976                 right: navigateRight,
1977                 up: navigateUp,
1978                 down: navigateDown,
1979                 prev: navigatePrev,
1980                 next: navigateNext,
1981                 prevFragment: previousFragment,
1982                 nextFragment: nextFragment,
1983
1984                 // Deprecated aliases
1985                 navigateTo: slide,
1986                 navigateLeft: navigateLeft,
1987                 navigateRight: navigateRight,
1988                 navigateUp: navigateUp,
1989                 navigateDown: navigateDown,
1990                 navigatePrev: navigatePrev,
1991                 navigateNext: navigateNext,
1992
1993                 // Forces an update in slide layout
1994                 layout: layout,
1995
1996                 // Returns an object with the available routes as booleans (left/right/top/bottom)
1997                 availableRoutes: availableRoutes,
1998
1999                 // Toggles the overview mode on/off
2000                 toggleOverview: toggleOverview,
2001
2002                 // Toggles the "black screen" mode on/off
2003                 togglePause: togglePause,
2004
2005                 // State checks
2006                 isOverview: isOverview,
2007                 isPaused: isPaused,
2008
2009                 // Adds or removes all internal event listeners (such as keyboard)
2010                 addEventListeners: addEventListeners,
2011                 removeEventListeners: removeEventListeners,
2012
2013                 // Returns the indices of the current, or specified, slide
2014                 getIndices: getIndices,
2015
2016                 // Returns the slide at the specified index, y is optional
2017                 getSlide: function( x, y ) {
2018                         var horizontalSlide = document.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR )[ x ];
2019                         var verticalSlides = horizontalSlide && horizontalSlide.querySelectorAll( 'section' );
2020
2021                         if( typeof y !== 'undefined' ) {
2022                                 return verticalSlides ? verticalSlides[ y ] : undefined;
2023                         }
2024
2025                         return horizontalSlide;
2026                 },
2027
2028                 // Returns the previous slide element, may be null
2029                 getPreviousSlide: function() {
2030                         return previousSlide;
2031                 },
2032
2033                 // Returns the current slide element
2034                 getCurrentSlide: function() {
2035                         return currentSlide;
2036                 },
2037
2038                 // Returns the current scale of the presentation content
2039                 getScale: function() {
2040                         return scale;
2041                 },
2042
2043                 // Returns the current configuration object
2044                 getConfig: function() {
2045                         return config;
2046                 },
2047
2048                 // Helper method, retrieves query string as a key/value hash
2049                 getQueryHash: function() {
2050                         var query = {};
2051
2052                         location.search.replace( /[A-Z0-9]+?=(\w*)/gi, function(a) {
2053                                 query[ a.split( '=' ).shift() ] = a.split( '=' ).pop();
2054                         } );
2055
2056                         return query;
2057                 },
2058
2059                 // Returns true if we're currently on the first slide
2060                 isFirstSlide: function() {
2061                         return document.querySelector( SLIDES_SELECTOR + '.past' ) == null ? true : false;
2062                 },
2063
2064                 // Returns true if we're currently on the last slide
2065                 isLastSlide: function() {
2066                         if( currentSlide && currentSlide.classList.contains( '.stack' ) ) {
2067                                 return currentSlide.querySelector( SLIDES_SELECTOR + '.future' ) == null ? true : false;
2068                         }
2069                         else {
2070                                 return document.querySelector( SLIDES_SELECTOR + '.future' ) == null ? true : false;
2071                         }
2072                 },
2073
2074                 // Forward event binding to the reveal DOM element
2075                 addEventListener: function( type, listener, useCapture ) {
2076                         if( 'addEventListener' in window ) {
2077                                 ( dom.wrapper || document.querySelector( '.reveal' ) ).addEventListener( type, listener, useCapture );
2078                         }
2079                 },
2080                 removeEventListener: function( type, listener, useCapture ) {
2081                         if( 'addEventListener' in window ) {
2082                                 ( dom.wrapper || document.querySelector( '.reveal' ) ).removeEventListener( type, listener, useCapture );
2083                         }
2084                 }
2085         };
2086
2087 })();