As the sun rises and the forest mist clears, and the clouds return and the caves darken, these changes of light and shadow are the morning and evening in the mountains. Wildflowers bloom with their subtle fragrance, fine trees flourish with their dense shade, the wind and frost are pure and clean, and the water recedes to reveal the rocks—these are the four seasons in the mountains. Going out in the morning and returning in the evening, the scenery of the four seasons is different, and the joy is endless.至于负者歌于途,行者休于树,前者呼,后者应,伛偻提携,往来而不绝者,滁人游也。临溪而渔,溪深而鱼肥,酿泉为酒,泉香而酒洌,山肴野蔌,杂然而前陈者,太守宴也。宴酣之乐,非丝非竹,射者中,弈者胜,觥筹交错,起坐而喧哗者,众宾欢也。苍颜白发,颓然乎其间者,太守醉也。
/**
* @output wp-includes/js/wp-custom-header.js
*/
/* global YT */
(function( window, settings ) {
var NativeHandler, YouTubeHandler;
/** @namespace wp */
window.wp = window.wp || {};
// Fail gracefully in unsupported browsers.
if ( ! ( 'addEventListener' in window ) ) {
return;
}
/**
* 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.
*
* @memberOf wp
*
* @class
*/
function CustomHeader() {
this.handlers = {
nativeVideo: new NativeHandler(),
youtube: new YouTubeHandler()
};
}
CustomHeader.prototype = {
/**
* Initialize 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 ( '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;
}
}
}
},
/**
* 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 ) {
return false;
}
return true;
},
/**
* Base handler for custom handlers to extend.
*
* @type {BaseHandler}
*/
BaseVideoHandler: BaseHandler
};
/**
* Create a video handler instance.
*
* @memberOf wp
*
* @class
*/
function BaseHandler() {}
BaseHandler.prototype = {
/**
* Initialize the video handler.
*
* @param {Object} settings Video settings.
*/
initialize: function( settings ) {
var handler = this,
button = document.createElement( 'button' );
this.settings = settings;
this.container = document.getElementById( 'wp-custom-header' );
this.button = button;
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;
// 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.
*
* @memberOf wp
*
* @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;
}
CustomHandler.prototype = Object.create( BaseHandler.prototype );
CustomHandler.prototype.constructor = CustomHandler;
for ( prop in protoProps ) {
CustomHandler.prototype[ prop ] = protoProps[ prop ];
}
return CustomHandler;
};
/**
* Native video handler.
*
* @memberOf wp
*
* @class
*/
NativeHandler = BaseHandler.extend(/** @lends wp.NativeHandler.prototype */{
/**
* 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 = true;
video.loop = true;
video.muted = true;
video.playsInline = true;
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.
*
* @memberOf wp
*
* @class wp.YouTubeHandler
*/
YouTubeHandler = BaseHandler.extend(/** @lends wp.YouTubeHandler.prototype */{
/**
* 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 ) {
window.wp.customize.selectiveRefresh.bind( 'render-partials-response', function( response ) {
if ( 'custom_header_settings' in response ) {
settings = response.custom_header_settings;
}
});
window.wp.customize.selectiveRefresh.bind( 'partial-content-rendered', function( placement ) {
if ( 'custom_header' === placement.partial.id ) {
window.wp.customHeader.initialize();
}
});
}
})( window, window._wpCustomHeaderSettings || {} );