1 files changed, 189 insertions, 46 deletions

diff --git a/js/reveal.js b/js/reveal.js
index 6f572b0..0eebeb6 100644
--- a/js/reveal.js
+++ b/js/reveal.js
@@ -180,6 +180,13 @@
 			// - false:  No media will autoplay, regardless of individual setting
 			autoPlayMedia: null,
 
+			// Global override for preloading lazy-loaded iframes
+			// - null:   Iframes with data-src AND data-preload will be loaded when within
+			//           the viewDistance, iframes with only data-src will be loaded when visible
+			// - true:   All iframes with data-src will be loaded when within the viewDistance
+			// - false:  All iframes with data-src will be loaded only when visible
+			preloadIframes: null,
+
 			// Controls automatic progression to the next slide
 			// - 0:      Auto-sliding only happens if the data-autoslide HTML attribute
 			//           is present on the current slide or fragment
@@ -319,6 +326,12 @@
 		// Cached references to DOM elements
 		dom = {},
 
+		// A list of registered reveal.js plugins
+		plugins = {},
+
+		// List of asynchronously loaded reveal.js dependencies
+		asyncDependencies = [],
+
 		// Features supported by the browser, see #checkCapabilities()
 		features = {},
 
@@ -422,7 +435,7 @@
 		// Hide the address bar in mobile browsers
 		hideAddressBar();
 
-		// Loads the dependencies and continues to #start() once done
+		// Loads dependencies and continues to #start() once done
 		load();
 
 	}
@@ -477,37 +490,22 @@
 	function load() {
 
 		var scripts = [],
-			scriptsAsync = [],
-			scriptsToPreload = 0;
-
-		// Called once synchronous scripts finish loading
-		function afterSynchronousScriptsLoaded() {
-			// Load asynchronous scripts
-			if( scriptsAsync.length ) {
-				scriptsAsync.forEach( function( s ) {
-					loadScript( s.src, s.callback );
-				} );
-			}
-
-			start();
-		}
-
-		for( var i = 0, len = config.dependencies.length; i < len; i++ ) {
-			var s = config.dependencies[i];
+			scriptsToLoad = 0;
 
+		config.dependencies.forEach( function( s ) {
 			// Load if there's no condition or the condition is truthy
 			if( !s.condition || s.condition() ) {
 				if( s.async ) {
-					scriptsAsync.push( s );
+					asyncDependencies.push( s );
 				}
 				else {
 					scripts.push( s );
 				}
 			}
-		}
+		} );
 
 		if( scripts.length ) {
-			scriptsToPreload = scripts.length;
+			scriptsToLoad = scripts.length;
 
 			// Load synchronous scripts
 			scripts.forEach( function( s ) {
@@ -515,22 +513,82 @@
 
 					if( typeof s.callback === 'function' ) s.callback();
 
-					if( --scriptsToPreload === 0 ) {
-
-						afterSynchronousScriptsLoaded();
-
+					if( --scriptsToLoad === 0 ) {
+						initPlugins();
 					}
 
 				} );
 			} );
 		}
 		else {
-			afterSynchronousScriptsLoaded();
+			initPlugins();
 		}
 
 	}
 
 	/**
+	 * Initializes our plugins and waits for them to be ready
+	 * before proceeding.
+	 */
+	function initPlugins() {
+
+		var pluginsToInitialize = Object.keys( plugins ).length;
+
+		// If there are no plugins, skip this step
+		if( pluginsToInitialize === 0 ) {
+			loadAsyncDependencies();
+		}
+		// ... otherwise initialize plugins
+		else {
+
+			var afterPlugInitialized = function() {
+				if( --pluginsToInitialize === 0 ) {
+					loadAsyncDependencies();
+				}
+			};
+
+			for( var i in plugins ) {
+
+				var plugin = plugins[i];
+
+				// If the plugin has an 'init' method, invoke it
+				if( typeof plugin.init === 'function' ) {
+					var callback = plugin.init();
+
+					// If the plugin returned a Promise, wait for it
+					if( callback && typeof callback.then === 'function' ) {
+						callback.then( afterPlugInitialized );
+					}
+					else {
+						afterPlugInitialized();
+					}
+				}
+				else {
+					afterPlugInitialized();
+				}
+
+			}
+
+		}
+
+	}
+
+	/**
+	 * Loads all async reveal.js dependencies.
+	 */
+	function loadAsyncDependencies() {
+
+		if( asyncDependencies.length ) {
+			asyncDependencies.forEach( function( s ) {
+				loadScript( s.src, s.callback );
+			} );
+		}
+
+		start();
+
+	}
+
+	/**
 	 * Loads a JavaScript file from the given URL and executes it.
 	 *
 	 * @param {string} url Address of the .js file to load
@@ -1520,6 +1578,53 @@
 	}
 
 	/**
+	 * Registers a new plugin with this reveal.js instance.
+	 *
+	 * reveal.js waits for all regisered plugins to initialize
+	 * before considering itself ready, as long as the plugin
+	 * is registered before calling `Reveal.initialize()`.
+	 */
+	function registerPlugin( id, plugin ) {
+
+		if( plugins[id] === undefined ) {
+			plugins[id] = plugin;
+
+			// If a plugin is registered after reveal.js is loaded,
+			// initialize it right away
+			if( loaded && typeof plugin.init === 'function' ) {
+				plugin.init();
+			}
+		}
+		else {
+			console.warn( 'reveal.js: "'+ id +'" plugin has already been registered' );
+		}
+
+	}
+
+	/**
+	 * Checks if a specific plugin has been registered.
+	 *
+	 * @param {String} id Unique plugin identifier
+	 */
+	function hasPlugin( id ) {
+
+		return !!plugins[id];
+
+	}
+
+	/**
+	 * Returns the specific plugin instance, if a plugin
+	 * with the given ID has been registered.
+	 *
+	 * @param {String} id Unique plugin identifier
+	 */
+	function getPlugin( id ) {
+
+		return plugins[id];
+
+	}
+
+	/**
 	 * Add a custom key binding with optional description to
 	 * be added to the help screen.
 	 */
@@ -1837,15 +1942,6 @@
 	}
 
 	/**
-	 * Check if this instance is being used to print a PDF with fragments.
-	 */
-	function isPrintingPDFFragments() {
-
-		return ( /print-pdf-fragments/gi ).test( window.location.search );
-
-	}
-
-	/**
 	 * Hides the address bar if we're on a mobile device.
 	 */
 	function hideAddressBar() {
@@ -2935,6 +3031,9 @@
 	 */
 	function syncSlide( slide ) {
 
+		// Default to the current slide
+		slide = slide || currentSlide;
+
 		syncBackground( slide );
 		syncFragments( slide );
 
@@ -2951,10 +3050,14 @@
 	 * after reveal.js has already initialized.
 	 *
 	 * @param {HTMLElement} slide
+	 * @return {Array} a list of the HTML fragments that were synced
 	 */
 	function syncFragments( slide ) {
 
-		sortFragments( slide.querySelectorAll( '.fragment' ) );
+		// Default to the current slide
+		slide = slide || currentSlide;
+
+		return sortFragments( slide.querySelectorAll( '.fragment' ) );
 
 	}
 
@@ -3606,6 +3709,26 @@
 	}
 
 	/**
+	 * Should the given element be preloaded?
+	 * Decides based on local element attributes and global config.
+	 *
+	 * @param {HTMLElement} element
+	 */
+	function shouldPreload( element ) {
+
+		// Prefer an explicit global preload setting
+		var preload = config.preloadIframes;
+
+		// If no global setting is available, fall back on the element's
+		// own preload setting
+		if( typeof preload !== 'boolean' ) {
+			preload = element.hasAttribute( 'data-preload' );
+		}
+
+		return preload;
+	}
+
+	/**
 	 * Called when the given slide is within the configured view
 	 * distance. Shows the slide element and loads any content
 	 * that is set to load lazily (data-src).
@@ -3620,10 +3743,12 @@
 		slide.style.display = config.display;
 
 		// Media elements with data-src attributes
-		toArray( slide.querySelectorAll( 'img[data-src], video[data-src], audio[data-src]' ) ).forEach( function( element ) {
-			element.setAttribute( 'src', element.getAttribute( 'data-src' ) );
-			element.setAttribute( 'data-lazy-loaded', '' );
-			element.removeAttribute( 'data-src' );
+		toArray( slide.querySelectorAll( 'img[data-src], video[data-src], audio[data-src], iframe[data-src]' ) ).forEach( function( element ) {
+			if( element.tagName !== 'IFRAME' || shouldPreload( element ) ) {
+				element.setAttribute( 'src', element.getAttribute( 'data-src' ) );
+				element.setAttribute( 'data-lazy-loaded', '' );
+				element.removeAttribute( 'data-src' );
+			}
 		} );
 
 		// Media elements with <source> children
@@ -3741,7 +3866,7 @@
 		}
 
 		// Reset lazy-loaded media elements with src attributes
-		toArray( slide.querySelectorAll( 'video[data-lazy-loaded][src], audio[data-lazy-loaded][src]' ) ).forEach( function( element ) {
+		toArray( slide.querySelectorAll( 'video[data-lazy-loaded][src], audio[data-lazy-loaded][src], iframe[data-lazy-loaded][src]' ) ).forEach( function( element ) {
 			element.setAttribute( 'data-src', element.getAttribute( 'src' ) );
 			element.removeAttribute( 'src' );
 		} );
@@ -4131,7 +4256,7 @@
 
 		}
 
-		return pastCount / ( totalCount - 1 );
+		return Math.min( pastCount / ( totalCount - 1 ), 1 );
 
 	}
 
@@ -4224,11 +4349,21 @@
 			writeURLTimeout = setTimeout( writeURL, delay );
 		}
 		else if( currentSlide ) {
+			// If we're configured to push to history OR the history
+			// API is not avaialble.
 			if( config.history || !window.history ) {
 				window.location.hash = locationHash();
 			}
+			// If we're configured to refelct the current slide in the
+			// URL without pushing to history.
 			else if( config.hash ) {
-				window.history.replaceState(null, null, '#' + locationHash());
+				window.history.replaceState( null, null, '#' + locationHash() );
+			}
+			// If history and hash are both disabled, a hash may still
+			// be added to the URL by clicking on a href with a hash
+			// target. Counter this by always removing the hash.
+			else {
+				window.history.replaceState( null, null, window.location.pathname + window.location.search );
 			}
 		}
 
@@ -5811,6 +5946,11 @@
 			return dom.wrapper || document.querySelector( '.reveal' );
 		},
 
+		// Returns a hash with all registered plugins
+		getPlugins: function() {
+			return plugins;
+		},
+
 		// Returns true if we're currently on the first slide
 		isFirstSlide: function() {
 			return ( indexh === 0 && indexv === 0 );
@@ -5861,12 +6001,15 @@
 			}
 		},
 
-		// Adds a custom key binding
+		// Adds/remvoes a custom key binding
 		addKeyBinding: addKeyBinding,
-
-		// Removes a custom key binding
 		removeKeyBinding: removeKeyBinding,
 
+		// API for registering and retrieving plugins
+		registerPlugin: registerPlugin,
+		hasPlugin: hasPlugin,
+		getPlugin: getPlugin,
+
 		// Programatically triggers a keyboard event
 		triggerKey: function( keyCode ) {
 			onDocumentKeyDown( { keyCode: keyCode } );