dojo/dnd/TimedMoveable.js

Dojo core is a powerful, lightweight library that makes common tasks quicker and easier. Animate elements, manipulate the DOM, and query with easy CSS syntax, all without sacrificing performance.

define(["../_base/declare", "./Moveable" /*=====, "./Mover" =====*/], function(declare, Moveable /*=====, Mover =====*/){
	// module:
	//		dojo/dnd/TimedMoveable

	/*=====
	var __TimedMoveableArgs = declare([Moveable.__MoveableArgs], {
		// timeout: Number
		//		delay move by this number of ms,
		//		accumulating position changes during the timeout
		timeout: 0
	});
	=====*/

	// precalculate long expressions
	var oldOnMove = Moveable.prototype.onMove;

	return declare("dojo.dnd.TimedMoveable", Moveable, {
		// summary:
		//		A specialized version of Moveable to support an FPS throttling.
		//		This class puts an upper restriction on FPS, which may reduce
		//		the CPU load. The additional parameter "timeout" regulates
		//		the delay before actually moving the moveable object.

		// object attributes (for markup)
		timeout: 40,	// in ms, 40ms corresponds to 25 fps

		constructor: function(node, params){
			// summary:
			//		an object that makes a node moveable with a timer
			// node: Node||String
			//		a node (or node's id) to be moved
			// params: __TimedMoveableArgs
			//		object with additional parameters.

			// sanitize parameters
			if(!params){ params = {}; }
			if(params.timeout && typeof params.timeout == "number" && params.timeout >= 0){
				this.timeout = params.timeout;
			}
		},

		onMoveStop: function(/*Mover*/ mover){
			if(mover._timer){
				// stop timer
				clearTimeout(mover._timer);
				// reflect the last received position
				oldOnMove.call(this, mover, mover._leftTop);
			}
			Moveable.prototype.onMoveStop.apply(this, arguments);
		},
		onMove: function(/*Mover*/ mover, /*Object*/ leftTop){
			mover._leftTop = leftTop;
			if(!mover._timer){
				var _t = this;	// to avoid using dojo.hitch()
				mover._timer = setTimeout(function(){
					// we don't have any pending requests
					mover._timer = null;
					// reflect the last received position
					oldOnMove.call(_t, mover, mover._leftTop);
				}, this.timeout);
			}
		}
	});
});