Team:NKU CHINA/page js7

function bgfader(images, _options){ var options = { speed: 3000, timeout: 3000, opacity: 0.5 } images = images && images.length ? images : [ ] var isPlaying = true var to = null var inTransition = false

var $container = $(this) var originalContainerStyle = { }

var $imageSet = $('

', {

'id': 'bgfader_imageset_' + $('.bgfader').length, 'class': 'bgfader' }) $imageSet.data('no', $('.bgfader').length)

var $overlay = $('

', {

'class': 'bgfader-overlay' })

options = $.extend({ }, options, _options)

var _createImageTag = function(url){

var $image = $('

', {

'class': 'image' }) return $image }

var _getBackgroundUrl = function($image) { return $image.css('background-image') } var _setBackgroundUrl = function($image) { if(typeof $image.data('loading-image') !== 'undefined') return $image if(_isLoading($image)) return $image

$image.data('loading-image', true) var index = _getImageIndex($image)

if(index === -1) return $image

$('<img>').attr('src', images[index]).load(function(){ $image.css('background-image', 'url(' + images[index] + ')') $image.data('loading-image', false) $(this).remove() }) return $image }

var _isLoading = function($image) { return $image.data('loading-image') === true }

var _hasBackgroundImage = function($image){ return $image.css('background-image') !== 'none' }

var _getImageIndex = function($image) { return $('.image').index($image) }

var _set = function(){ originalContainerStyle = { 'position': $container.css('position'), 'z-index': $container.css('z-index') } $container.css({ 'position': 'relative', 'z-index': 0 })

$overlay.css('background', 'rgba(0, 0, 0, ' + options.opacity + ')') $container.append($imageSet).append($overlay) $imageSet.show()

$.each(images, function(index, url) { var $imageTag = _createImageTag(url) $imageSet.append($imageTag) }) }

var _getVisibleImage = function() { return $imageSet.find('.image:visible') }

var _getLastImage = function() { return $imageSet.find('.image:last') }

var _getFirstImage = function() { return $imageSet.find('.image:first') }

var _next = function(image){ if(image.next().length){ _show(image.next()) }else{ start() } return this }

var _prev = function(image) { if(image.prev().length){ _show(image.prev()) }else{ _show(_getLastImage()) } return this }

var _setBg = function($image){ $imageSet.css('background-image', $image.css('background-image')) }

var _show = function(image) { if(!inTransition){ _getVisibleImage().hide() inTransition = true image = _setBackgroundUrl(image) image.fadeIn(options.speed, function(){ if(_hasBackgroundImage(image)){ _setBg(image) } var nextImage = image.next() if(!_hasBackgroundImage(nextImage)){ _setBackgroundUrl(nextImage) } inTransition = false if(isPlaying){ to = setTimeout(function() { _next(image) }, options.timeout); } }) } }

var start = function(){ isPlaying = true _show(_getFirstImage()) return this }

var stop = function() { isPlaying = false clearTimeout(to) return this }

var next = function() { stop() _next(_getVisibleImage()) return this }

var prev = function() { stop() _prev(_getVisibleImage()) return this }

var destroy = function() { stop() $overlay.remove() $imageSet.remove() $container.css(originalContainerStyle) return null }

_set() return { 'next': next, 'prev': prev, 'start': start, 'stop': stop, 'destroy': destroy } }

jQuery.fn.extend({ 'bgfader': bgfader

})