reveal.js

	}

	/**
	 * Handler for the window level 'resize' event.
	 */
	function onWindowResize( event ) {

		layout();

	}

	/**
	 * Handle for the window level 'visibilitychange' event.
	 */
	function onPageVisibilityChange( event ) {

		var isHidden =  document.webkitHidden ||
						document.msHidden ||
						document.hidden;

		// If, after clicking a link or similar and we're coming back,
		// focus the document.body to ensure we can use keyboard shortcuts
		if( isHidden === false && document.activeElement !== document.body ) {
			document.activeElement.blur();
			document.body.focus();
		}

	}

	/**
	 * Invoked when a slide is and we're in the overview.
	 */
	function onOverviewSlideClicked( event ) {

		// TODO There's a bug here where the event listeners are not
		// removed after deactivating the overview.
		if( eventsAreBound && isOverview() ) {
			event.preventDefault();

			var element = event.target;

			while( element && !element.nodeName.match( /section/gi ) ) {
				element = element.parentNode;
			}

			if( element && !element.classList.contains( 'disabled' ) ) {

				deactivateOverview();

				if( element.nodeName.match( /section/gi ) ) {
					var h = parseInt( element.getAttribute( 'data-index-h' ), 10 ),
						v = parseInt( element.getAttribute( 'data-index-v' ), 10 );

					slide( h, v );
				}

			}
		}

	}

	/**
	 * Handles clicks on links that are set to preview in the
	 * iframe overlay.
	 */
	function onPreviewLinkClicked( event ) {

		if( event.currentTarget && event.currentTarget.hasAttribute( 'href' ) ) {
			var url = event.currentTarget.getAttribute( 'href' );
			if( url ) {
				showPreview( url );
				event.preventDefault();
			}
		}

	}

	/**
	 * Handles click on the auto-sliding controls element.
	 */
	function onAutoSlidePlayerClick( event ) {

		// Replay
		if( Reveal.isLastSlide() && config.loop === false ) {
			slide( 0, 0 );
			resumeAutoSlide();
		}
		// Resume
		else if( autoSlidePaused ) {
			resumeAutoSlide();
		}
		// Pause
		else {
			pauseAutoSlide();
		}

	}


	// --------------------------------------------------------------------//
	// ------------------------ PLAYBACK COMPONENT ------------------------//
	// --------------------------------------------------------------------//


	/**
	 * Constructor for the playback component, which displays
	 * play/pause/progress controls.
	 *
	 * @param {HTMLElement} container The component will append
	 * itself to this
	 * @param {Function} progressCheck A method which will be
	 * called frequently to get the current progress on a range
	 * of 0-1
	 */
	function Playback( container, progressCheck ) {

		// Cosmetics
		this.diameter = 50;
		this.thickness = 3;

		// Flags if we are currently playing
		this.playing = false;

		// Current progress on a 0-1 range
		this.progress = 0;

		// Used to loop the animation smoothly
		this.progressOffset = 1;

		this.container = container;
		this.progressCheck = progressCheck;

		this.canvas = document.createElement( 'canvas' );
		this.canvas.className = 'playback';
		this.canvas.width = this.diameter;
		this.canvas.height = this.diameter;
		this.context = this.canvas.getContext( '2d' );

		this.container.appendChild( this.canvas );

		this.render();

	}

	Playback.prototype.setPlaying = function( value ) {

		var wasPlaying = this.playing;

		this.playing = value;

		// Start repainting if we weren't already
		if( !wasPlaying && this.playing ) {
			this.animate();
		}
		else {
			this.render();
		}

	};

	Playback.prototype.animate = function() {

		var progressBefore = this.progress;

		this.progress = this.progressCheck();

		// When we loop, offset the progress so that it eases
		// smoothly rather than immediately resetting
		if( progressBefore > 0.8 && this.progress < 0.2 ) {
			this.progressOffset = this.progress;
		}

		this.render();

		if( this.playing ) {
			features.requestAnimationFrameMethod.call( window, this.animate.bind( this ) );
		}

	};

	/**
	 * Renders the current progress and playback state.
	 */
	Playback.prototype.render = function() {

		var progress = this.playing ? this.progress : 0,
			radius = ( this.diameter / 2 ) - this.thickness,
			x = this.diameter / 2,
			y = this.diameter / 2,
			iconSize = 14;

		// Ease towards 1
		this.progressOffset += ( 1 - this.progressOffset ) * 0.1;

		var endAngle = ( - Math.PI / 2 ) + ( progress * ( Math.PI * 2 ) );
		var startAngle = ( - Math.PI / 2 ) + ( this.progressOffset * ( Math.PI * 2 ) );

		this.context.save();
		this.context.clearRect( 0, 0, this.diameter, this.diameter );

		// Solid background color
		this.context.beginPath();
		this.context.arc( x, y, radius + 2, 0, Math.PI * 2, false );
		this.context.fillStyle = 'rgba( 0, 0, 0, 0.4 )';
		this.context.fill();

		// Draw progress track
		this.context.beginPath();
		this.context.arc( x, y, radius, 0, Math.PI * 2, false );
		this.context.lineWidth = this.thickness;
		this.context.strokeStyle = '#666';
		this.context.stroke();

		if( this.playing ) {
			// Draw progress on top of track
			this.context.beginPath();
			this.context.arc( x, y, radius, startAngle, endAngle, false );
			this.context.lineWidth = this.thickness;
			this.context.strokeStyle = '#fff';
			this.context.stroke();
		}

		this.context.translate( x - ( iconSize / 2 ), y - ( iconSize / 2 ) );

		// Draw play/pause icons
		if( this.playing ) {
			this.context.fillStyle = '#fff';
			this.context.fillRect( 0, 0, iconSize / 2 - 2, iconSize );
			this.context.fillRect( iconSize / 2 + 2, 0, iconSize / 2 - 2, iconSize );
		}
		else {
			this.context.beginPath();
			this.context.translate( 2, 0 );
			this.context.moveTo( 0, 0 );
			this.context.lineTo( iconSize - 2, iconSize / 2 );
			this.context.lineTo( 0, iconSize );
			this.context.fillStyle = '#fff';
			this.context.fill();
		}

		this.context.restore();

	};

	Playback.prototype.on = function( type, listener ) {
		this.canvas.addEventListener( type, listener, false );
	};

	Playback.prototype.off = function( type, listener ) {
		this.canvas.removeEventListener( type, listener, false );
	};

	Playback.prototype.destroy = function() {

		this.playing = false;

		if( this.canvas.parentNode ) {
			this.container.removeChild( this.canvas );
		}

	};


	// --------------------------------------------------------------------//
	// ------------------------------- API --------------------------------//
	// --------------------------------------------------------------------//


	Reveal = {
		initialize: initialize,
		configure: configure,
		sync: sync,

		// Navigation methods
		slide: slide,
		left: navigateLeft,
		right: navigateRight,
		up: navigateUp,
		down: navigateDown,
		prev: navigatePrev,
		next: navigateNext,

		// Fragment methods
		navigateFragment: navigateFragment,
		prevFragment: previousFragment,
		nextFragment: nextFragment,

		// Deprecated aliases
		navigateTo: slide,
		navigateLeft: navigateLeft,
		navigateRight: navigateRight,
		navigateUp: navigateUp,
		navigateDown: navigateDown,
		navigatePrev: navigatePrev,
		navigateNext: navigateNext,

		// Forces an update in slide layout
		layout: layout,

		// Returns an object with the available routes as booleans (left/right/top/bottom)
		availableRoutes: availableRoutes,

		// Returns an object with the available fragments as booleans (prev/next)
		availableFragments: availableFragments,

		// Toggles the overview mode on/off
		toggleOverview: toggleOverview,

		// Toggles the "black screen" mode on/off
		togglePause: togglePause,

		// Toggles the auto slide mode on/off
		toggleAutoSlide: toggleAutoSlide,

		// State checks
		isOverview: isOverview,
		isPaused: isPaused,
		isAutoSliding: isAutoSliding,

		// Adds or removes all internal event listeners (such as keyboard)
		addEventListeners: addEventListeners,
		removeEventListeners: removeEventListeners,

		// Facility for persisting and restoring the presentation state
		getState: getState,
		setState: setState,

		// Presentation progress on range of 0-1
		getProgress: getProgress,

		// Returns the indices of the current, or specified, slide
		getIndices: getIndices,

		getTotalSlides: getTotalSlides,

		// Returns the slide element at the specified index
		getSlide: getSlide,

		// Returns the slide background element at the specified index
		getSlideBackground: getSlideBackground,

		// Returns the previous slide element, may be null
		getPreviousSlide: function() {
			return previousSlide;
		},

		// Returns the current slide element
		getCurrentSlide: function() {
			return currentSlide;
		},

		// Returns the current scale of the presentation content
		getScale: function() {
			return scale;
		},

		// Returns the current configuration object
		getConfig: function() {
			return config;
		},

		// Helper method, retrieves query string as a key/value hash
		getQueryHash: function() {
			var query = {};

			location.search.replace( /[A-Z0-9]+?=([\w\.%-]*)/gi, function(a) {
				query[ a.split( '=' ).shift() ] = a.split( '=' ).pop();
			} );

			// Basic deserialization
			for( var i in query ) {
				var value = query[ i ];

				query[ i ] = deserialize( unescape( value ) );
			}

			return query;
		},

		// Returns true if we're currently on the first slide
		isFirstSlide: function() {
			return ( indexh === 0 && indexv === 0 );
		},

		// Returns true if we're currently on the last slide
		isLastSlide: function() {
			if( currentSlide ) {
				// Does this slide has next a sibling?
				if( currentSlide.nextElementSibling ) return false;

				// If it's vertical, does its parent have a next sibling?
				if( isVerticalSlide( currentSlide ) && currentSlide.parentNode.nextElementSibling ) return false;

				return true;
			}

			return false;
		},

		// Checks if reveal.js has been loaded and is ready for use
		isReady: function() {
			return loaded;
		},

		// Forward event binding to the reveal DOM element
		addEventListener: function( type, listener, useCapture ) {
			if( 'addEventListener' in window ) {
				( dom.wrapper || document.querySelector( '.reveal' ) ).addEventListener( type, listener, useCapture );
			}
		},
		removeEventListener: function( type, listener, useCapture ) {
			if( 'addEventListener' in window ) {
				( dom.wrapper || document.querySelector( '.reveal' ) ).removeEventListener( type, listener, useCapture );
			}
		},

		// Programatically triggers a keyboard event
		triggerKey: function( keyCode ) {
			onDocumentKeyDown( { keyCode: keyCode } );
		}
	};

	return Reveal;

}));