http://blog.chinaunix.net/space.php?uid=143884&do=blog&id=2815256
[Quote]if (extendDirtyRegion(c, x, y, w, h)){ //在接受这次请求的时候,可能还有一些请求没有被调度处理,
//要考虑过去的请求中是否有同组件的请求,如果有,直接合并
//即可,合并成功即可返回。
// Component was already marked as dirty, region has been
// extended, no need to continue.
return;
} [/Quote]