/**
* FD.widget.Scroll
*
* 滚动类
* 限制：
* 		1、container 必须是一个<ul>
* 		2、必须包含js/core/fdev.js和js/core/yui/animation-min.js两个js文件
* 调用方法：
* 		……
*		<ul id="scroll1">
*			<li><a href="#">内容1内容1内容1内容1内容1</a></li>
*			<li><a href="#">内容2内容2内容2内容2内容2</a></li>
*			<li><a href="#">内容3内容3内容3内容3内容3</a></li>
*		</ul>
*		……
*		<script type="text/javascript">
*			FD.widget.Scroll.init('scroll1',{});
*		</script>
*
* @author 	yaosl<happyyaosl@gmail.com>
* @link    http://www.fdev-lib.cn/
*/
FD.widget.Scroll = new function() {
var defConfig = {
delay: 2,
speed: 20,
startDelay: 2,
direction: 'vertical',	/* 'horizontal(h)' or 'vertical(v)'. defaults to vertical. */
disableAutoPlay: false,
distance: 'auto',
scrollItemCount: 1  	/* 随同一行滚动的li数量，默认1 */
}
/**
* decorate 开始滚动
* @param {Object} container 必须是一个ul
* @param {Object} config
*/
this.init = function(container, config) {
container = $(container);
config = FD.common.applyIf(config||{}, defConfig);
var step = 2;
if (config.speed < 20) {
step = 5;
}
if (config.lineHeight) {
config.distance = config.lineHeight;
}
var scrollTimeId = null, startTimeId = null, startDelayTimeId = null;
/* 是否横向滚动 */
var isHorizontal = (config.direction.toLowerCase() == 'horizontal') || (config.direction.toLowerCase() == 'h');
/* 返回给调用者的控制器，只包含对调用者可见的方法/属性 */
var handle = {};
handle._distance = 0;
/* 空间上能否还可以滚动 */
handle.scrollable = true;
/* 本次预计滚动的距离 */
handle.distance = config.distance;
/* 每次滚动的距离 */
handle._distance = 0;
/* 鼠标移动上去时暂停 */
handle.suspend = false;
/* 暂停 */
handle.paused = false;
/* 内部使用事件 */
var _onScrollEvent = new $Y.CustomEvent("_onScroll", handle, false, $Y.CustomEvent.FLAT);
_onScrollEvent.subscribe(function() {
var curLi = container.getElementsByTagName('li')[0];
if (!curLi) {
this.scrollable = false;
return;
}
this.distance = (config.distance == 'auto')?curLi[isHorizontal?'offsetWidth':'offsetHeight']:config.distance;
with(container) {
if (isHorizontal)
this.scrollable = (scrollWidth - scrollLeft - offsetWidth) >= this.distance;
else
this.scrollable = (scrollHeight - scrollTop - offsetHeight) >= this.distance;
}
});
/* 公开事件 */
var onScrollEvent = new $Y.CustomEvent("onScroll", handle, false, $Y.CustomEvent.FLAT);
if (config.onScroll) {
onScrollEvent.subscribe(config.onScroll);
} else {
onScrollEvent.subscribe(function() {
for (var i = 0; i < config.scrollItemCount; i++) {
container.appendChild(container.getElementsByTagName('li')[0]);
}
container[isHorizontal?'scrollLeft':'scrollTop'] = 0;
});
}
var scroll = function() {
if (handle.suspend) return;
handle._distance += step;
var _d;
if ((_d = handle._distance % handle.distance) < step) {
container[isHorizontal?'scrollLeft':'scrollTop'] += (step - _d);
clearInterval(scrollTimeId);
onScrollEvent.fire();
_onScrollEvent.fire();
startTimeId = null;
if (handle.scrollable && !handle.paused) handle.play();
}else{
container[isHorizontal?'scrollLeft':'scrollTop'] += step;
}
}
var start = function() {
if (handle.paused) return;
handle._distance = 0;
scrollTimeId = setInterval(scroll, config.speed);
}
$E.on(container, 'mouseover', function(){handle.suspend=true;});
$E.on(container, 'mouseout', function(){handle.suspend=false;});
FD.common.apply(handle, {
subscribeOnScroll: function(func, override) {
if (override === true && onScrollEvent.subscribers.length > 0)
onScrollEvent.unsubscribeAll();
onScrollEvent.subscribe(func);
},
pause: function() {
this.paused = true;
clearTimeout(startTimeId);
startTimeId = null;
},
play: function() {
this.paused = false;
if (startDelayTimeId) {clearTimeout(startDelayTimeId);}
if (!startTimeId) {
startTimeId = setTimeout(start, config.delay*1000);
}
}
});
handle.onScroll = handle.subscribeOnScroll;
/** 初始化移动距离并判断是否可滚动 */
_onScrollEvent.fire();
/** 自动开始滚动 */
if (!config.disableAutoPlay) {
startDelayTimeId = setTimeout(function(){handle.play();}, config.startDelay*1000);
}
return handle;
}
};