dojo_app/js/library/dojox/dgauges/CircularValueIndicator.js

define(["dojo/_base/declare", "dojox/gfx", "./ScaleIndicatorBase", "dojo/_base/event"], function(declare, gfx, ScaleIndicatorBase, eventUtil){
	return declare("dojox.dgauges.CircularValueIndicator", ScaleIndicatorBase, {
		// summary:
		//		The circular value indicator, typically used for creating needles.

		indicatorShapeFunc: function(group, indicator){
			// summary:
			//		Draws the indicator. The rotation center is at (0, 0).
			// group: dojox/gfx/Group
			//		A GFX group for drawing.
			// indicator: dojox/dgauges/IndicatorBase
			//		A reference to this indicator.
			// returns: dojox/gfx/shape.Shape
			//		A GFX shape retrievable using the getIndicatorRenderer method of the associated scale.
			return group.createLine({
				x1: 0,
				y1: 0,
				x2: 40,
				y2: 0
			}).setStroke({
				color: "black",
				width: 1
			});
		},

		refreshRendering: function(){
			this.inherited(arguments);
			if(this._gfxGroup === null || this.scale === null){
				return;
			}else{
				var v = isNaN(this._transitionValue) ? this.value : this._transitionValue;
				var angle = this.scale.positionForValue(v);

				this._gfxGroup.setTransform([{
					dx: this.scale.originX,
					dy: this.scale.originY
				}, gfx.matrix.rotateg(angle)]);
			}
		},

		_onMouseDown: function(event){
			// summary:
			//		Internal method.
			// tags:
			//		private
			this.inherited(arguments);
			var origin = this.scale._gauge._gaugeToPage(this.scale.originX, this.scale.originY);
			var angle = ((Math.atan2(event.pageY - origin.y, event.pageX - origin.x)) * 180) / (Math.PI);
			this.set("value", this.scale.valueForPosition(angle));

			// prevent the browser from selecting text
			eventUtil.stop(event);
		},

		_onMouseMove: function(event){
			// summary:
			//		Internal method.
			// tags:
			//		private
			this.inherited(arguments);
			var origin = this.scale._gauge._gaugeToPage(this.scale.originX, this.scale.originY);
			var angle = ((Math.atan2(event.pageY - origin.y, event.pageX - origin.x)) * 180) / (Math.PI);
			this.set("value", this.scale.valueForPosition(angle));
		}
	});
});