From c09ce88749f4b6467a701a629b97663b29f628f1 Mon Sep 17 00:00:00 2001
From: Holger Teichert <post@complanar.de>
Date: Sat, 17 Mar 2018 15:33:34 +0100
Subject: [PATCH] New plugin: media (#676)

The media plugin can autoplay and autopause/autostop <audio> and <video> elements when entering and leaving a step.

Support for impressConsole: don't autoplay in preview window and play but mute clips in current window.
---
 .gitignore                                   |   3 +
 build.js                                     |   1 +
 js/impress.js                                | 251 ++++++++++++++++++-
 src/plugins/impressConsole/impressConsole.js |   2 +-
 src/plugins/media/media.js                   | 248 ++++++++++++++++++
 5 files changed, 503 insertions(+), 2 deletions(-)
 create mode 100644 src/plugins/media/media.js

diff --git a/.gitignore b/.gitignore
index 08db758..ea23cc4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,6 @@
 /node_modules
 /npm-debug.log
 /*.tgz
+
+# Files for editors and other tools
+/.brackets.json
diff --git a/build.js b/build.js
index 2aacc4b..7fa47c1 100644
--- a/build.js
+++ b/build.js
@@ -17,6 +17,7 @@ buildify()
            'src/plugins/goto/goto.js',
            'src/plugins/help/help.js',
            'src/plugins/impressConsole/impressConsole.js',
+           'src/plugins/media/media.js',
            'src/plugins/mobile/mobile.js',
            'src/plugins/mouse-timeout/mouse-timeout.js',
            'src/plugins/navigation/navigation.js',
diff --git a/js/impress.js b/js/impress.js
index f2131ef..db10001 100644
--- a/js/impress.js
+++ b/js/impress.js
@@ -2510,7 +2510,7 @@
             //Btw, you can also launch console automatically:
             //<div id="impress" data-console-autolaunch="true">
             if ( root.dataset.consoleAutolaunch === 'true' ) {
-                window.open();
+                open();
             }
         };
 
@@ -2706,6 +2706,255 @@
 
 } )( document, window );
 
+/**
+ * Media Plugin
+ *
+ * This plugin will do the following things:
+ *
+ *  - Add a special class when playing (body.impress-media-video-playing
+ *    and body.impress-media-video-playing) and pausing media (body.impress-media-video-paused
+ *    and body.impress-media-audio-paused) (removing them when ending).
+ *    This can be useful for example for darkening the background or fading out other elements
+ *    while a video is playing.
+ *    Only media at the current step are taken into account. All classes are removed when leaving
+ *    a step.
+ *
+ *  - Introduce the following new data attributes:
+ *
+ *    - data-media-autoplay="true": Autostart media when entering its step.
+ *    - data-media-autostop="true": Stop media (= pause and reset to start), when leaving its
+ *      step.
+ *    - data-media-autopause="true": Pause media but keep current time when leaving its step.
+ *
+ *    When these attributes are added to a step they are inherited by all media on this step.
+ *    Of course this setting can be overwritten by adding different attributes to inidvidual
+ *    media.
+ *
+ *    The same rule applies when this attributes is added to the root element. Settings can be
+ *    overwritten for individual steps and media.
+ *
+ *    Examples:
+ *    - data-media-autostart="true" data-media-autostop="true": start media on enter, stop on
+ *      leave, restart from beginning when re-entering the step.
+ *
+ *    - data-media-autostart="true" data-media-autopause="true": start media on enter, pause on
+ *      leave, resume on re-enter
+ *
+ *    - data-media-autostart="true" data-media-autostop="true" data-media-autopause="true": start
+ *      media on enter, stop on leave (stop overwrites pause).
+ *
+ *    - data-media-autostart="true" data-media-autopause="false": let media start automatically
+ *      when entering a step and let it play when leaving the step.
+ *
+ *    - <div id="impress" data-media-autostart="true"> ... <div class="step"
+ *      data-media-autostart="false">
+ *      All media is startet automatically on all steps except the one that has the
+ *      data-media-autostart="false" attribute.
+ *
+ *  - Pro tip: Use <audio onended="impress().next()"> or <video onended="impress().next()"> to
+ *    proceed to the next step automatically, when the end of the media is reached.
+ *
+ *
+ * Copyright 2018 Holger Teichert (@complanar)
+ * Released under the MIT license.
+ */
+/* global window, document */
+
+( function( document, window ) {
+    "use strict";
+    var root, api, gc, attributeTracker;
+
+    attributeTracker = [];
+
+    // Function names
+    var enhanceMediaNodes,
+        enhanceMedia,
+        removeMediaClasses,
+        onStepenterDetectImpressConsole,
+        onStepenter,
+        onStepleave,
+        onPlay,
+        onPause,
+        onEnded,
+        getMediaAttribute,
+        teardown;
+
+    document.addEventListener( "impress:init", function( event ) {
+        root = event.target;
+        api = event.detail.api;
+        gc = api.lib.gc;
+
+        enhanceMedia();
+
+        gc.pushCallback( teardown );
+    }, false );
+
+    teardown = function() {
+        var el, i;
+        removeMediaClasses();
+        for ( i = 0; i < attributeTracker.length; i += 1 ) {
+            el = attributeTracker[ i ];
+            el.node.removeAttribute( el.attr );
+        }
+        attributeTracker = [];
+    };
+
+    getMediaAttribute = function( attributeName, nodes ) {
+        var attrName, attrValue, i, node;
+        attrName = "data-media-" + attributeName;
+
+        // Look for attributes in all nodes
+        for ( i = 0; i < nodes.length; i += 1 ) {
+            node = nodes[ i ];
+
+            // First test, if the attribute exists, because some browsers may return
+            // an empty string for non-existing attributes - specs are not clear at that point
+            if ( node.hasAttribute( attrName ) ) {
+
+                // Attribute found, return their parsed boolean value, empty strings count as true
+                // to enable empty value booleans (common in html5 but not allowed in well formed
+                // xml).
+                attrValue = node.getAttribute( attrName );
+                if ( attrValue === "" || attrValue === "true" ) {
+                    return true;
+                } else {
+                    return false;
+                }
+            }
+
+            // No attribute found at current node, proceed with next round
+        }
+
+        // Last resort: no attribute found - return undefined to distiguish from false
+        return undefined;
+    };
+
+    onPlay = function( event ) {
+        var type = event.target.nodeName.toLowerCase();
+        document.body.classList.add( "impress-media-" + type + "-playing" );
+        document.body.classList.remove( "impress-media-" + type + "-paused" );
+    };
+
+    onPause = function( event ) {
+        var type = event.target.nodeName.toLowerCase();
+        document.body.classList.add( "impress-media-" + type + "-paused" );
+        document.body.classList.remove( "impress-media-" + type + "-playing" );
+    };
+
+    onEnded = function( event ) {
+        var type = event.target.nodeName.toLowerCase();
+        document.body.classList.remove( "impress-media-" + type + "-playing" );
+        document.body.classList.remove( "impress-media-" + type + "-paused" );
+    };
+
+    removeMediaClasses = function() {
+        var type, types;
+        types = [ "video", "audio" ];
+        for ( type in types ) {
+            document.body.classList.remove( "impress-media-" + types[ type ] + "-playing" );
+            document.body.classList.remove( "impress-media-" + types[ type ] + "-paused" );
+        }
+    };
+
+    enhanceMediaNodes = function() {
+        var i, id, media, mediaElement, type;
+
+        media = root.querySelectorAll( "audio, video" );
+        for ( i = 0; i < media.length; i += 1 ) {
+            type = media[ i ].nodeName.toLowerCase();
+
+            // Set an id to identify each media node - used e.g. for cross references by
+            // the consoleMedia plugin
+            mediaElement = media[ i ];
+            id = mediaElement.getAttribute( "id" );
+            if ( id === undefined || id === null ) {
+                mediaElement.setAttribute( "id", "media-" + type + "-" + i );
+                attributeTracker.push( { "node": mediaElement, "attr": "id" } );
+            }
+            gc.addEventListener( mediaElement, "play", onPlay );
+            gc.addEventListener( mediaElement, "playing", onPlay );
+            gc.addEventListener( mediaElement, "pause", onPause );
+            gc.addEventListener( mediaElement, "ended", onEnded );
+        }
+    };
+
+    enhanceMedia = function() {
+        var steps, stepElement, i;
+        enhanceMediaNodes();
+        steps = document.getElementsByClassName( "step" );
+        for ( i = 0; i < steps.length; i += 1 ) {
+            stepElement = steps[ i ];
+
+            gc.addEventListener( stepElement, "impress:stepenter", onStepenter );
+            gc.addEventListener( stepElement, "impress:stepleave", onStepleave );
+        }
+    };
+
+    onStepenterDetectImpressConsole = function() {
+        return {
+            "preview": ( window.frameElement !== null && window.frameElement.id === "preView" ),
+            "slideView": ( window.frameElement !== null && window.frameElement.id === "slideView" )
+        };
+    };
+
+    onStepenter = function( event ) {
+        var stepElement, media, mediaElement, i, onConsole, autoplay;
+        if ( ( !event ) || ( !event.target ) ) {
+            return;
+        }
+
+        stepElement = event.target;
+        removeMediaClasses();
+
+        media = stepElement.querySelectorAll( "audio, video" );
+        for ( i = 0; i < media.length; i += 1 ) {
+            mediaElement = media[ i ];
+
+            // Autoplay when (maybe inherited) autoplay setting is true,
+            // but only if not on preview of the next step in impressConsole
+            onConsole = onStepenterDetectImpressConsole();
+            autoplay = getMediaAttribute( "autoplay", [ mediaElement, stepElement, root ] );
+            if ( autoplay && !onConsole.preview ) {
+                if ( onConsole.slideView ) {
+                    mediaElement.muted = true;
+                }
+                mediaElement.play();
+            }
+        }
+    };
+
+    onStepleave = function( event ) {
+        var stepElement, media, i, mediaElement, autoplay, autopause, autostop;
+        if ( ( !event || !event.target ) ) {
+            return;
+        }
+
+        stepElement = event.target;
+        media = event.target.querySelectorAll( "audio, video" );
+        for ( i = 0; i < media.length; i += 1 ) {
+            mediaElement = media[ i ];
+
+            autoplay = getMediaAttribute( "autoplay", [ mediaElement, stepElement, root ] );
+            autopause = getMediaAttribute( "autopause", [ mediaElement, stepElement, root ] );
+            autostop = getMediaAttribute( "autostop",  [ mediaElement, stepElement, root ] );
+
+            // If both autostop and autopause are undefined, set it to the value of autoplay
+            if ( autostop === undefined && autopause === undefined ) {
+                autostop = autoplay;
+            }
+
+            if ( autopause || autostop ) {
+                mediaElement.pause();
+                if ( autostop ) {
+                    mediaElement.currentTime = 0;
+                }
+            }
+        }
+        removeMediaClasses();
+    };
+
+} )( document, window );
+
 /**
  * Mobile devices support
  *
diff --git a/src/plugins/impressConsole/impressConsole.js b/src/plugins/impressConsole/impressConsole.js
index 36cc126..bfabea5 100644
--- a/src/plugins/impressConsole/impressConsole.js
+++ b/src/plugins/impressConsole/impressConsole.js
@@ -555,7 +555,7 @@
             //Btw, you can also launch console automatically:
             //<div id="impress" data-console-autolaunch="true">
             if ( root.dataset.consoleAutolaunch === 'true' ) {
-                window.open();
+                open();
             }
         };
 
diff --git a/src/plugins/media/media.js b/src/plugins/media/media.js
new file mode 100644
index 0000000..a325bf0
--- /dev/null
+++ b/src/plugins/media/media.js
@@ -0,0 +1,248 @@
+/**
+ * Media Plugin
+ *
+ * This plugin will do the following things:
+ *
+ *  - Add a special class when playing (body.impress-media-video-playing
+ *    and body.impress-media-video-playing) and pausing media (body.impress-media-video-paused
+ *    and body.impress-media-audio-paused) (removing them when ending).
+ *    This can be useful for example for darkening the background or fading out other elements
+ *    while a video is playing.
+ *    Only media at the current step are taken into account. All classes are removed when leaving
+ *    a step.
+ *
+ *  - Introduce the following new data attributes:
+ *
+ *    - data-media-autoplay="true": Autostart media when entering its step.
+ *    - data-media-autostop="true": Stop media (= pause and reset to start), when leaving its
+ *      step.
+ *    - data-media-autopause="true": Pause media but keep current time when leaving its step.
+ *
+ *    When these attributes are added to a step they are inherited by all media on this step.
+ *    Of course this setting can be overwritten by adding different attributes to inidvidual
+ *    media.
+ *
+ *    The same rule applies when this attributes is added to the root element. Settings can be
+ *    overwritten for individual steps and media.
+ *
+ *    Examples:
+ *    - data-media-autostart="true" data-media-autostop="true": start media on enter, stop on
+ *      leave, restart from beginning when re-entering the step.
+ *
+ *    - data-media-autostart="true" data-media-autopause="true": start media on enter, pause on
+ *      leave, resume on re-enter
+ *
+ *    - data-media-autostart="true" data-media-autostop="true" data-media-autopause="true": start
+ *      media on enter, stop on leave (stop overwrites pause).
+ *
+ *    - data-media-autostart="true" data-media-autopause="false": let media start automatically
+ *      when entering a step and let it play when leaving the step.
+ *
+ *    - <div id="impress" data-media-autostart="true"> ... <div class="step"
+ *      data-media-autostart="false">
+ *      All media is startet automatically on all steps except the one that has the
+ *      data-media-autostart="false" attribute.
+ *
+ *  - Pro tip: Use <audio onended="impress().next()"> or <video onended="impress().next()"> to
+ *    proceed to the next step automatically, when the end of the media is reached.
+ *
+ *
+ * Copyright 2018 Holger Teichert (@complanar)
+ * Released under the MIT license.
+ */
+/* global window, document */
+
+( function( document, window ) {
+    "use strict";
+    var root, api, gc, attributeTracker;
+
+    attributeTracker = [];
+
+    // Function names
+    var enhanceMediaNodes,
+        enhanceMedia,
+        removeMediaClasses,
+        onStepenterDetectImpressConsole,
+        onStepenter,
+        onStepleave,
+        onPlay,
+        onPause,
+        onEnded,
+        getMediaAttribute,
+        teardown;
+
+    document.addEventListener( "impress:init", function( event ) {
+        root = event.target;
+        api = event.detail.api;
+        gc = api.lib.gc;
+
+        enhanceMedia();
+
+        gc.pushCallback( teardown );
+    }, false );
+
+    teardown = function() {
+        var el, i;
+        removeMediaClasses();
+        for ( i = 0; i < attributeTracker.length; i += 1 ) {
+            el = attributeTracker[ i ];
+            el.node.removeAttribute( el.attr );
+        }
+        attributeTracker = [];
+    };
+
+    getMediaAttribute = function( attributeName, nodes ) {
+        var attrName, attrValue, i, node;
+        attrName = "data-media-" + attributeName;
+
+        // Look for attributes in all nodes
+        for ( i = 0; i < nodes.length; i += 1 ) {
+            node = nodes[ i ];
+
+            // First test, if the attribute exists, because some browsers may return
+            // an empty string for non-existing attributes - specs are not clear at that point
+            if ( node.hasAttribute( attrName ) ) {
+
+                // Attribute found, return their parsed boolean value, empty strings count as true
+                // to enable empty value booleans (common in html5 but not allowed in well formed
+                // xml).
+                attrValue = node.getAttribute( attrName );
+                if ( attrValue === "" || attrValue === "true" ) {
+                    return true;
+                } else {
+                    return false;
+                }
+            }
+
+            // No attribute found at current node, proceed with next round
+        }
+
+        // Last resort: no attribute found - return undefined to distiguish from false
+        return undefined;
+    };
+
+    onPlay = function( event ) {
+        var type = event.target.nodeName.toLowerCase();
+        document.body.classList.add( "impress-media-" + type + "-playing" );
+        document.body.classList.remove( "impress-media-" + type + "-paused" );
+    };
+
+    onPause = function( event ) {
+        var type = event.target.nodeName.toLowerCase();
+        document.body.classList.add( "impress-media-" + type + "-paused" );
+        document.body.classList.remove( "impress-media-" + type + "-playing" );
+    };
+
+    onEnded = function( event ) {
+        var type = event.target.nodeName.toLowerCase();
+        document.body.classList.remove( "impress-media-" + type + "-playing" );
+        document.body.classList.remove( "impress-media-" + type + "-paused" );
+    };
+
+    removeMediaClasses = function() {
+        var type, types;
+        types = [ "video", "audio" ];
+        for ( type in types ) {
+            document.body.classList.remove( "impress-media-" + types[ type ] + "-playing" );
+            document.body.classList.remove( "impress-media-" + types[ type ] + "-paused" );
+        }
+    };
+
+    enhanceMediaNodes = function() {
+        var i, id, media, mediaElement, type;
+
+        media = root.querySelectorAll( "audio, video" );
+        for ( i = 0; i < media.length; i += 1 ) {
+            type = media[ i ].nodeName.toLowerCase();
+
+            // Set an id to identify each media node - used e.g. for cross references by
+            // the consoleMedia plugin
+            mediaElement = media[ i ];
+            id = mediaElement.getAttribute( "id" );
+            if ( id === undefined || id === null ) {
+                mediaElement.setAttribute( "id", "media-" + type + "-" + i );
+                attributeTracker.push( { "node": mediaElement, "attr": "id" } );
+            }
+            gc.addEventListener( mediaElement, "play", onPlay );
+            gc.addEventListener( mediaElement, "playing", onPlay );
+            gc.addEventListener( mediaElement, "pause", onPause );
+            gc.addEventListener( mediaElement, "ended", onEnded );
+        }
+    };
+
+    enhanceMedia = function() {
+        var steps, stepElement, i;
+        enhanceMediaNodes();
+        steps = document.getElementsByClassName( "step" );
+        for ( i = 0; i < steps.length; i += 1 ) {
+            stepElement = steps[ i ];
+
+            gc.addEventListener( stepElement, "impress:stepenter", onStepenter );
+            gc.addEventListener( stepElement, "impress:stepleave", onStepleave );
+        }
+    };
+
+    onStepenterDetectImpressConsole = function() {
+        return {
+            "preview": ( window.frameElement !== null && window.frameElement.id === "preView" ),
+            "slideView": ( window.frameElement !== null && window.frameElement.id === "slideView" )
+        };
+    };
+
+    onStepenter = function( event ) {
+        var stepElement, media, mediaElement, i, onConsole, autoplay;
+        if ( ( !event ) || ( !event.target ) ) {
+            return;
+        }
+
+        stepElement = event.target;
+        removeMediaClasses();
+
+        media = stepElement.querySelectorAll( "audio, video" );
+        for ( i = 0; i < media.length; i += 1 ) {
+            mediaElement = media[ i ];
+
+            // Autoplay when (maybe inherited) autoplay setting is true,
+            // but only if not on preview of the next step in impressConsole
+            onConsole = onStepenterDetectImpressConsole();
+            autoplay = getMediaAttribute( "autoplay", [ mediaElement, stepElement, root ] );
+            if ( autoplay && !onConsole.preview ) {
+                if ( onConsole.slideView ) {
+                    mediaElement.muted = true;
+                }
+                mediaElement.play();
+            }
+        }
+    };
+
+    onStepleave = function( event ) {
+        var stepElement, media, i, mediaElement, autoplay, autopause, autostop;
+        if ( ( !event || !event.target ) ) {
+            return;
+        }
+
+        stepElement = event.target;
+        media = event.target.querySelectorAll( "audio, video" );
+        for ( i = 0; i < media.length; i += 1 ) {
+            mediaElement = media[ i ];
+
+            autoplay = getMediaAttribute( "autoplay", [ mediaElement, stepElement, root ] );
+            autopause = getMediaAttribute( "autopause", [ mediaElement, stepElement, root ] );
+            autostop = getMediaAttribute( "autostop",  [ mediaElement, stepElement, root ] );
+
+            // If both autostop and autopause are undefined, set it to the value of autoplay
+            if ( autostop === undefined && autopause === undefined ) {
+                autostop = autoplay;
+            }
+
+            if ( autopause || autostop ) {
+                mediaElement.pause();
+                if ( autostop ) {
+                    mediaElement.currentTime = 0;
+                }
+            }
+        }
+        removeMediaClasses();
+    };
+
+} )( document, window );