source: Dev/trunk/src/client/dojox/gfx/Mover.js

define(["dojo/_base/lang","dojo/_base/array", "dojo/_base/declare", "dojo/on", "dojo/touch", "dojo/_base/event"],
  function(lang, arr, declare, on, touch, event){
        return declare("dojox.gfx.Mover", null, {
                constructor: function(shape, e, host){
                        // summary:
                        //              an object, which makes a shape follow the mouse,
                        //              used as a default mover, and as a base class for custom movers
                        // shape: dojox/gfx.Shape
                        //              a shape object to be moved
                        // e: Event
                        //              a mouse event, which started the move;
                        //              only clientX and clientY properties are used
                        // host: Object?
                        //              object which implements the functionality of the move,
                        //               and defines proper events (onMoveStart and onMoveStop)
                        this.shape = shape;
                        this.lastX = e.clientX;
                        this.lastY = e.clientY;
                        var h = this.host = host, d = document,
                                firstEvent = on(d, touch.move, lang.hitch(this, "onFirstMove"));
                        this.events = [
                                on(d, touch.move, lang.hitch(this, "onMouseMove")),
                                on(d, touch.release, lang.hitch(this, "destroy")),
                                // cancel text selection and text dragging
                                on(d, "dragstart",   lang.hitch(event, "stop")),
                                on(d, "selectstart", lang.hitch(event, "stop")),
                                firstEvent
                        ];
                        // notify that the move has started
                        if(h && h.onMoveStart){
                                h.onMoveStart(this);
                        }
                },
                // mouse event processors
                onMouseMove: function(e){
                        // summary:
                        //              event processor for onmousemove
                        // e: Event
                        //              mouse event
                        var x = e.clientX;
                        var y = e.clientY;
                        this.host.onMove(this, {dx: x - this.lastX, dy: y - this.lastY});
                        this.lastX = x;
                        this.lastY = y;
                        event.stop(e);
                },
                // utilities
                onFirstMove: function(){
                        // summary:
                        //              it is meant to be called only once
                        this.host.onFirstMove(this);
                        this.events.pop().remove();
                },
                destroy: function(){
                        // summary:
                        //              stops the move, deletes all references, so the object can be garbage-collected
                        arr.forEach(this.events, function(handle){
                                handle.remove();
                        });
                        // undo global settings
                        var h = this.host;
                        if(h && h.onMoveStop){
                                h.onMoveStop(this);
                        }
                        // destroy objects
                        this.events = this.shape = null;
                }
        });
});