Create.js拖拽事件处理机制

直接上代码 ，怕自己忘记

sheetContainer.on("mousedown", function (evt) {
this.parent.addChild(this);
this.offset = {x: this.x - evt.stageX, y: this.y - evt.stageY};
});
sheetContainer.on("pressmove", function (evt) {
this.x = evt.stageX + this.offset.x;
this.y = evt.stageY + this.offset.y;
// indicate that the stage should be updated on the next tick:
update = true;
});