springGraph edge Renderer

package controls
{
	import com.adobe.flex.extras.controls.springgraph.Graph;
	import com.adobe.flex.extras.controls.springgraph.IEdgeRenderer;
	import com.adobe.flex.extras.controls.springgraph.Item;
	
	import flash.display.BitmapData;
	import flash.display.Graphics;
	import flash.geom.Matrix;
	import flash.text.TextFieldAutoSize;
	
	import mx.core.IDataRenderer;
	import mx.core.UIComponent;
	import mx.core.UITextField;
	import mx.graphics.ImageSnapshot;

	public class CusEdge implements IEdgeRenderer
	{
		private var thickness:int=2;
		private var lineColor:uint=0x232323;
		private var arrowSize:int=5;
		
		public function CusEdge()
		{
		}
		
		/** 实现画线接口 **/
		public function draw(g:Graphics, fromView:UIComponent, toView:UIComponent, fX:int, fY:int, tX:int, tY:int, graph:Graph):Boolean
		{
			var fromItem: Item = (fromView as IDataRenderer).data as Item;
			var toItem: Item = (toView as IDataRenderer).data as Item;
			var node:Object=graph.getLinkData(fromItem,toItem);
			if (node.@fromID!=(fromView as CusNode).id && node.@fromID==(toView as CusNode).id)
			{
				return drawNew(g,toView,fromView,tX,tY,fX,fY,graph);
			}	
			else
			{
				return drawNew(g,fromView,toView,fX,fY,tX,tY,graph);
			}
			return true;
		}
		
		/** 画线函数 **/
		public function drawNew(g:Graphics, fromView:UIComponent, toView:UIComponent, fX:int, fY:int, tX:int, tY:int, graph:Graph):Boolean
		{
			var fromX:int;
			var fromY:int;
			var toX:int;
			var toY:int;
			var totoX:int;
			var totoY:int;
			var eid:String;
			
			var halfFromH:Number=fromView.height/2;
			var halfFromW:Number=fromView.width/2;
			var halfToH:Number=toView.height/2;
			var halfToW:Number=toView.width/2;
			
			var angle:Number  = getAngle( fX, fY, tX, tY);			
			var toAngle:Number=Math.atan2(halfToH,halfToW)*(180/Math.PI);
			var fromAngle:Number=Math.atan2(halfFromH,halfFromW)*(180/Math.PI);
			var k:Number=Math.tan(angle*(Math.PI/180));
			
			///to坐标换算
			if (angle>=0 && angle<90)//1象限
			{
				if (angle>toAngle)
				{
					toX=tX - halfToH / k;
					toY=tY + halfToH;				
				}
				else
				{
					toX=tX - halfToW;
					toY=tY + halfToW * k;
				}
			}
			if (angle>=90 && angle<=180)//2象限
			{
				if (angle+toAngle>180)
				{
					toX=tX + halfToW ;
					toY=tY - halfToW * k;				
				}
				else
				{
					toX=tX - halfToH / k;
					toY=tY + halfToH;	
				}
			}
			if (angle>=-90 && angle<0)//4象限
			{
				if (Math.abs(angle)>toAngle)
				{
					toX=tX + halfToH / k;					
					toY=tY - halfToH;				
				}
				else
				{
					toX=tX - halfToW;
					toY=tY + halfToW * k;
				}
			}
			if (angle<-90 && angle>=-180)//3象限
			{
				if (angle+180>toAngle)
				{
					toX=tX + halfToH / k;
					toY=tY - halfToH;				
				}
				else
				{
					toX=tX + halfToW;
					toY=tY - halfToW * k;	
				}
			}
			///from坐标换算
			if (angle>0 && angle<=90)
			{			
				if (angle>fromAngle)
				{
					fromX=fX + halfFromH / k;
					fromY=fY - halfFromH;
				}
				else
				{
					fromX=fX + halfFromW;
					fromY=fY - halfFromW * k;
				}
			}
			if (angle>90 && angle<=180)
			{
				if (angle+fromAngle>180)
				{
					fromX=fX - halfFromW;
					fromY=fY + halfFromW * k;			
				}
				else
				{
					fromX=fX + halfFromH / k;
					fromY=fY - halfFromH;
				}
			}
			if (angle>=-90 && angle<=0)
			{
				if (Math.abs(angle)>fromAngle)
				{
					fromX=fX - halfFromH / k;
					fromY=fY + halfFromH;
				}
				else
				{
					fromX=fX + halfFromW;
					fromY=fY - halfFromW * k;
				}
			}
			if (angle<-90 && angle>=-180)
			{
				if (angle+180>fromAngle)
				{
					fromX=fX - halfFromH / k;
					fromY=fY + halfFromH;
				}
				else
				{
					fromX=fX - halfFromW;
					fromY=fY + halfFromW * k;
				}
			}
			
			
			
			totoX=toX - arrowSize * Math.cos(angle*(Math.PI/180));
			totoY=toY + arrowSize * Math.sin(angle*(Math.PI/180));
			
			g.lineStyle(thickness,lineColor);
			g.moveTo(fromX,fromY);			
			g.lineTo(totoX,totoY);

			
			var fromItem: Item = (fromView as IDataRenderer).data as Item;
			var toItem: Item = (toView as IDataRenderer).data as Item;
			var node:Object=graph.getLinkData(fromItem,toItem);
			if (node!=null)
			{
				if (node.@id)			
					eid=node.@prop;
//				if (node.width)
//					weight=node.width;
//				if (node.bytewidth)
//					bytewidth=node.bytewidth;
			}
			var uit:UITextField = new UITextField();
			uit.textColor = lineColor;
			uit.text = eid;
			uit.autoSize =   TextFieldAutoSize.LEFT;
			var textBitmapData:BitmapData = ImageSnapshot.captureBitmapData(uit);
			var sizeMatrix:Matrix = new Matrix();
			var coef:Number = Math.min(uit.measuredWidth/textBitmapData.width,uit.measuredHeight/textBitmapData.height);
			sizeMatrix.a = coef;
			sizeMatrix.d = coef;
			textBitmapData = ImageSnapshot.captureBitmapData(uit,sizeMatrix);
			g.lineStyle(0,0,0);
			var sm:Matrix = new Matrix();
			sm.tx = (fromX+toX)/2;
			sm.ty = (fromY+toY)/2;
			g.beginBitmapFill(textBitmapData,sm,false);
			g.drawRect((fromX+toX)/2,(fromY+toY)/2,uit.measuredWidth,uit.measuredHeight);
			g.endFill();
			
			
			drawArrowHead(fromX,fromY,toX,toY,g);
			return true;
		}
		
		/** 画箭头 **/
		private function drawArrowHead(startX:int,startY:int,endX:int,endY:int,graphics:Graphics):void{
			//得到箭头的角度
			var angle:Number  = this.getAngle(startX,startY,endX,endY);
			var centerX:Number = endX - arrowSize * Math.cos(angle*(Math.PI/180));
			var centerY:Number = endY + arrowSize * Math.sin(angle*(Math.PI/180));
			
			var leftX:Number = centerX + arrowSize * Math.cos((angle+120)*(Math.PI/180));
			var leftY:Number = centerY - arrowSize * Math.sin((angle+120)*(Math.PI/180));
			var rightX:Number = centerX + arrowSize * Math.cos((angle+240)*(Math.PI/180));
			var rightY:Number = centerY - arrowSize * Math.sin((angle+240)*(Math.PI/180)); 
			
			graphics.lineStyle(2,lineColor,1);
			graphics.beginFill(lineColor);
			graphics.moveTo(endX,endY);
			
			graphics.lineTo(leftX,leftY);
			graphics.lineTo(centerX,centerY);
			
			graphics.lineTo(rightX,rightY);
			graphics.lineTo(endX,endY);
			graphics.endFill();
		}
		
		/** 得到箭头的角度 **/
		private function getAngle(startX:int,startY:int,endX:int,endY:int):Number{
			var temX:Number = endX - startX;
			var temY:Number = startY - endY;
			var angle:Number = Math.atan2(temY,temX)*(180/Math.PI);
			return angle;
		}
	}
}