Themes: Improve a11y and extendability of custom video headers.

This adds play/pause controls to video headers, along with voice
assistance, using `wp.a11y.speak`, to make custom video headers more
accessible. To make styling the play/pause button easier for themes,
CSS has been omitted from the default implementation.

This also includes a refactor of the `wp.customHeader` code to introduce
a `BaseHandler` class, which can be extended by plugins and themes to modify
or enhance the default video handlers.

Props davidakennedy, afercia, bradyvercher, joemcgill, adamsilverstein, rianrietveld.
Fixes #38678.

git-svn-id: https://develop.svn.wordpress.org/trunk@39272 602fd350-edb4-49c9-b593-d223f7449a82
This commit is contained in:
Joe McGill 2016-11-16 23:25:28 +00:00
parent ac9a74eff5
commit b5563ef917
4 changed files with 414 additions and 117 deletions

View File

@ -3596,7 +3596,7 @@ final class WP_Customize_Manager {
$this->add_setting( 'external_header_video', array(
'theme_supports' => array( 'custom-header', 'video' ),
'transport' => 'postMessage',
'sanitize_callback' => 'esc_url',
'sanitize_callback' => 'esc_url_raw',
'validate_callback' => array( $this, '_validate_external_header_video' ),
) );

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@ -1,155 +1,446 @@
(function( window, settings ) {
/* global YT */
( function( window, settings ) {
var NativeHandler, YouTubeHandler;
window.wp = window.wp || {};
// Fail gracefully in unsupported browsers.
if ( ! ( 'addEventListener' in window ) ) {
// Fail gracefully in unsupported browsers.
return;
}
function wpCustomHeader() {
var handlers = {
nativeVideo: {
test: function( settings ) {
var video = document.createElement( 'video' );
return video.canPlayType( settings.mimeType );
},
callback: nativeHandler
},
youtube: {
test: function( settings ) {
return 'video/x-youtube' === settings.mimeType;
},
callback: youtubeHandler
}
/**
* Trigger an event.
*
* @param {Element} target HTML element to dispatch the event on.
* @param {string} name Event name.
*/
function trigger( target, name ) {
var evt;
if ( 'function' === typeof window.Event ) {
evt = new Event( name );
} else {
evt = document.createEvent( 'Event' );
evt.initEvent( name, true, true );
}
target.dispatchEvent( evt );
}
/**
* Create a custom header instance.
*
* @class CustomHeader
*/
function CustomHeader() {
this.handlers = {
nativeVideo: new NativeHandler(),
youtube: new YouTubeHandler()
};
}
function initialize() {
settings.container = document.getElementById( 'wp-custom-header' );
CustomHeader.prototype = {
/**
* Initalize the custom header.
*
* If the environment supports video, loops through registered handlers
* until one is found that can handle the video.
*/
initialize: function() {
if ( this.supportsVideo() ) {
for ( var id in this.handlers ) {
var handler = this.handlers[ id ];
if ( supportsVideo() ) {
for ( var id in handlers ) {
var handler = handlers[ id ];
if ( handlers.hasOwnProperty( id ) && handler.test( settings ) ) {
handler.callback( settings );
// Set up and dispatch custom event when the video is loaded.
if ( 'dispatchEvent' in window ) {
var videoLoaded = new Event( 'wp-custom-header-video-loaded' );
document.dispatchEvent( videoLoaded );
}
if ( 'test' in handler && handler.test( settings ) ) {
this.activeHandler = handler.initialize.call( handler, settings );
// Dispatch custom event when the video is loaded.
trigger( document, 'wp-custom-header-video-loaded' );
break;
}
}
}
}
},
function supportsVideo() {
/**
* Determines if the current environment supports video.
*
* Themes and plugins can override this method to change the criteria.
*
* @return {boolean}
*/
supportsVideo: function() {
// Don't load video on small screens. @todo: consider bandwidth and other factors.
if ( window.innerWidth < settings.minWidth || window.innerHeight < settings.minHeight ) {
if ( window.innerWidth < settings.minWidth || window.innerHeight < settings.minHeight ) {
return false;
}
return true;
}
},
return {
handlers: handlers,
initialize: initialize,
supportsVideo: supportsVideo
};
}
/**
* Base handler for custom handlers to extend.
*
* @type {BaseHandler}
*/
BaseVideoHandler: BaseHandler
};
function nativeHandler( settings ) {
var video = document.createElement( 'video' );
/**
* Create a video handler instance.
*
* @class BaseHandler
*/
function BaseHandler() {}
video.id = 'wp-custom-header-video';
video.autoplay = 'autoplay';
video.loop = 'loop';
video.muted = 'muted';
video.width = settings.width;
video.height = settings.height;
BaseHandler.prototype = {
/**
* Initialize the video handler.
*
* @param {object} settings Video settings.
*/
initialize: function( settings ) {
var handler = this,
button = document.createElement( 'button' );
video.addEventListener( 'click', function() {
if ( video.paused ) {
video.play();
} else {
video.pause();
}
});
this.settings = settings;
this.container = document.getElementById( 'wp-custom-header' ),
this.button = button;
settings.container.innerHTML = '';
settings.container.appendChild( video );
video.src = settings.videoUrl;
}
button.setAttribute( 'type', 'button' );
button.setAttribute( 'id', 'wp-custom-header-video-button' );
button.setAttribute( 'class', 'wp-custom-header-video-button wp-custom-header-video-play' );
button.innerHTML = settings.l10n.play;
function youtubeHandler( settings ) {
// @link http://stackoverflow.com/a/27728417
var VIDEO_ID_REGEX = /^.*(?:(?:youtu\.be\/|v\/|vi\/|u\/\w\/|embed\/)|(?:(?:watch)?\?v(?:i)?=|\&v(?:i)?=))([^#\&\?]*).*/,
videoId = settings.videoUrl.match( VIDEO_ID_REGEX )[1];
function loadVideo() {
var YT = window.YT || {};
YT.ready(function() {
var video = document.createElement( 'div' );
video.id = 'wp-custom-header-video';
settings.container.innerHTML = '';
settings.container.appendChild( video );
new YT.Player( video, {
height: settings.height,
width: settings.width,
videoId: videoId,
events: {
onReady: function( e ) {
e.target.mute();
},
onStateChange: function( e ) {
if ( YT.PlayerState.ENDED === e.data ) {
e.target.playVideo();
}
}
},
playerVars: {
autoplay: 1,
controls: 0,
disablekb: 1,
fs: 0,
iv_load_policy: 3,
loop: 1,
modestbranding: 1,
//origin: '',
playsinline: 1,
rel: 0,
showinfo: 0
}
});
// Toggle video playback when the button is clicked.
button.addEventListener( 'click', function() {
if ( handler.isPaused() ) {
handler.play();
} else {
handler.pause();
}
});
// Update the button class and text when the video state changes.
this.container.addEventListener( 'play', function() {
button.className = 'wp-custom-header-video-button wp-custom-header-video-play';
button.innerHTML = settings.l10n.pause;
if ( 'a11y' in window.wp ) {
window.wp.a11y.speak( settings.l10n.playSpeak);
}
});
this.container.addEventListener( 'pause', function() {
button.className = 'wp-custom-header-video-button wp-custom-header-video-pause';
button.innerHTML = settings.l10n.play;
if ( 'a11y' in window.wp ) {
window.wp.a11y.speak( settings.l10n.pauseSpeak);
}
});
this.ready();
},
/**
* Ready method called after a handler is initialized.
*
* @abstract
*/
ready: function() {},
/**
* Whether the video is paused.
*
* @abstract
* @return {boolean}
*/
isPaused: function() {},
/**
* Pause the video.
*
* @abstract
*/
pause: function() {},
/**
* Play the video.
*
* @abstract
*/
play: function() {},
/**
* Append a video node to the header container.
*
* @param {Element} node HTML element.
*/
setVideo: function( node ) {
var editShortcutNode,
editShortcut = this.container.getElementsByClassName( 'customize-partial-edit-shortcut' );
if ( editShortcut.length ) {
editShortcutNode = this.container.removeChild( editShortcut[0] );
}
this.container.innerHTML = '';
this.container.appendChild( node );
if ( editShortcutNode ) {
this.container.appendChild( editShortcutNode );
}
},
/**
* Show the video controls.
*
* Appends a play/pause button to header container.
*/
showControls: function() {
if ( ! this.container.contains( this.button ) ) {
this.container.appendChild( this.button );
}
},
/**
* Whether the handler can process a video.
*
* @abstract
* @param {object} settings Video settings.
* @return {boolean}
*/
test: function() {
return false;
},
/**
* Trigger an event on the header container.
*
* @param {string} name Event name.
*/
trigger: function( name ) {
trigger( this.container, name );
}
};
/**
* Create a custom handler.
*
* @param {object} protoProps Properties to apply to the prototype.
* @return CustomHandler The subclass.
*/
BaseHandler.extend = function( protoProps ) {
var prop;
function CustomHandler() {
var result = BaseHandler.apply( this, arguments );
return result;
}
if ( 'YT' in window ) {
loadVideo();
} else {
var tag = document.createElement( 'script' );
tag.src = 'https://www.youtube.com/player_api';
tag.onload = function () { loadVideo(); };
document.getElementsByTagName( 'head' )[0].appendChild( tag );
CustomHandler.prototype = Object.create( BaseHandler.prototype );
CustomHandler.prototype.constructor = CustomHandler;
for ( prop in protoProps ) {
CustomHandler.prototype[ prop ] = protoProps[ prop ];
}
}
window.wp = window.wp || {};
window.wp.customHeader = new wpCustomHeader();
document.addEventListener( 'DOMContentLoaded', window.wp.customHeader.initialize, false );
return CustomHandler;
};
/**
* Native video handler.
*
* @class NativeHandler
*/
NativeHandler = BaseHandler.extend({
/**
* Whether the native handler supports a video.
*
* @param {object} settings Video settings.
* @return {boolean}
*/
test: function( settings ) {
var video = document.createElement( 'video' );
return video.canPlayType( settings.mimeType );
},
/**
* Set up a native video element.
*/
ready: function() {
var handler = this,
video = document.createElement( 'video' );
video.id = 'wp-custom-header-video';
video.autoplay = 'autoplay';
video.loop = 'loop';
video.muted = 'muted';
video.width = this.settings.width;
video.height = this.settings.height;
video.addEventListener( 'play', function() {
handler.trigger( 'play' );
});
video.addEventListener( 'pause', function() {
handler.trigger( 'pause' );
});
video.addEventListener( 'canplay', function() {
handler.showControls();
});
this.video = video;
handler.setVideo( video );
video.src = this.settings.videoUrl;
},
/**
* Whether the video is paused.
*
* @return {boolean}
*/
isPaused: function() {
return this.video.paused;
},
/**
* Pause the video.
*/
pause: function() {
this.video.pause();
},
/**
* Play the video.
*/
play: function() {
this.video.play();
}
});
/**
* YouTube video handler.
*
* @class YouTubeHandler
*/
YouTubeHandler = BaseHandler.extend({
/**
* Whether the handler supports a video.
*
* @param {object} settings Video settings.
* @return {boolean}
*/
test: function( settings ) {
return 'video/x-youtube' === settings.mimeType;
},
/**
* Set up a YouTube iframe.
*
* Loads the YouTube IFrame API if the 'YT' global doesn't exist.
*/
ready: function() {
var handler = this;
if ( 'YT' in window ) {
YT.ready( handler.loadVideo.bind( handler ) );
} else {
var tag = document.createElement( 'script' );
tag.src = 'https://www.youtube.com/iframe_api';
tag.onload = function () {
YT.ready( handler.loadVideo.bind( handler ) );
};
document.getElementsByTagName( 'head' )[0].appendChild( tag );
}
},
/**
* Load a YouTube video.
*/
loadVideo: function() {
var handler = this,
video = document.createElement( 'div' ),
// @link http://stackoverflow.com/a/27728417
VIDEO_ID_REGEX = /^.*(?:(?:youtu\.be\/|v\/|vi\/|u\/\w\/|embed\/)|(?:(?:watch)?\?v(?:i)?=|\&v(?:i)?=))([^#\&\?]*).*/;
video.id = 'wp-custom-header-video';
handler.setVideo( video );
handler.player = new YT.Player( video, {
height: this.settings.height,
width: this.settings.width,
videoId: this.settings.videoUrl.match( VIDEO_ID_REGEX )[1],
events: {
onReady: function( e ) {
e.target.mute();
handler.showControls();
},
onStateChange: function( e ) {
if ( YT.PlayerState.PLAYING === e.data ) {
handler.trigger( 'play' );
} else if ( YT.PlayerState.PAUSED === e.data ) {
handler.trigger( 'pause' );
} else if ( YT.PlayerState.ENDED === e.data ) {
e.target.playVideo();
}
}
},
playerVars: {
autoplay: 1,
controls: 0,
disablekb: 1,
fs: 0,
iv_load_policy: 3,
loop: 1,
modestbranding: 1,
playsinline: 1,
rel: 0,
showinfo: 0
}
});
},
/**
* Whether the video is paused.
*
* @return {boolean}
*/
isPaused: function() {
return YT.PlayerState.PAUSED === this.player.getPlayerState();
},
/**
* Pause the video.
*/
pause: function() {
this.player.pauseVideo();
},
/**
* Play the video.
*/
play: function() {
this.player.playVideo();
}
});
// Initialize the custom header when the DOM is ready.
window.wp.customHeader = new CustomHeader();
document.addEventListener( 'DOMContentLoaded', window.wp.customHeader.initialize.bind( window.wp.customHeader ), false );
// Selective refresh support in the Customizer.
if ( 'customize' in window.wp ) {
wp.customize.selectiveRefresh.bind( 'render-partials-response', function( response ) {
window.wp.customize.selectiveRefresh.bind( 'render-partials-response', function( response ) {
if ( 'custom_header_settings' in response ) {
settings = response.custom_header_settings;
}
});
wp.customize.selectiveRefresh.bind( 'partial-content-rendered', function( placement ) {
window.wp.customize.selectiveRefresh.bind( 'partial-content-rendered', function( placement ) {
if ( 'custom_header' === placement.partial.id ) {
window.wp.customHeader.initialize();
}

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@ -481,7 +481,7 @@ function wp_default_scripts( &$scripts ) {
$scripts->add( 'customize-nav-menus', "/wp-admin/js/customize-nav-menus$suffix.js", array( 'jquery', 'wp-backbone', 'customize-controls', 'accordion', 'nav-menu' ), false, 1 );
$scripts->add( 'customize-preview-nav-menus', "/wp-includes/js/customize-preview-nav-menus$suffix.js", array( 'jquery', 'wp-util', 'customize-preview', 'customize-selective-refresh' ), false, 1 );
$scripts->add( 'wp-custom-header', "/wp-includes/js/wp-custom-header$suffix.js", array(), false, 1 );
$scripts->add( 'wp-custom-header', "/wp-includes/js/wp-custom-header$suffix.js", array( 'wp-a11y' ), false, 1 );
$scripts->add( 'accordion', "/wp-admin/js/accordion$suffix.js", array( 'jquery' ), false, 1 );

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@ -1381,6 +1381,12 @@ function get_header_video_settings() {
'height' => absint( $header->height ),
'minWidth' => 900,
'minHeight' => 500,
'l10n' => array(
'pause' => __( 'Pause' ),
'play' => __( 'Play' ),
'pauseSpeak' => __( 'Video is paused.'),
'playSpeak' => __( 'Video is playing.'),
),
);
if ( preg_match( '#^https?://(?:www\.)?(?:youtube\.com/watch|youtu\.be/)#', $video_url ) ) {