动态绘制扇形实例

动态绘制扇形实例:

/****
* DrawSectorTest
* 动态绘制扇形实例（拖拽绘制）
****/
package fengzi.drawing
{
	import flash.display.Shape;
	import flash.display.Sprite;
	import flash.events.MouseEvent;


	public class DrawSectorTest extends Sprite
	{
		private var _sector:Sprite;
		private var _dragSp:Sprite;
		private var _radian:Number;//弧度
		private var _radius:uint;//半径
		private var _angle:Number;//初始角度

		/***
		* DrawSectorTest     构造
		* @param             radius     半径
		* @param             angle      初始角度
		***/

		public function DrawSectorTest(radius:uint=100,angle:Number=60)
		{
			_radius=radius
			_angle=angle
			_sector = new Sprite();
			_dragSp = new Sprite();
			_sector.x = _dragSp.x = stage.stageWidth * 0.5;
			_sector.y = _dragSp.y = stage.stageHeight * 0.5;
			this.addChild(_sector);
			this.addChild(_dragSp);


			_dragSp.graphics.beginFill(0,.2);
			_dragSp.graphics.drawRect(0,-5,_radius,10);
			_dragSp.graphics.endFill();

			drawSector(_sector,0,0,_radius,_angle,0);
			_dragSp.rotation = _angle;
			_dragSp.addEventListener(MouseEvent.MOUSE_DOWN,onDragDown);
		}
		private function onDragDown(e:MouseEvent):void
		{
			stage.addEventListener(MouseEvent.MOUSE_MOVE,onDragMove);
			stage.addEventListener(MouseEvent.MOUSE_UP,onDragOut);
		}
		private function onDragMove(e:MouseEvent):void
		{
			_dragSp.rotation = Math.atan2(_dragSp.parent.mouseY - _dragSp.y,_dragSp.parent.mouseX - _dragSp.x) * 180 / Math.PI;
			_radian = (_dragSp.rotation) * Math.PI / 180;
			/*
			这是关键，因为rotation的区间是[0,180][0,-180],如果直接用_dragSp.rotation会导致拖拽绘制扇形错误
			*/
			if (_dragSp.rotation > 180)
			{
				_radian = _radian + Math.PI;
			}
			if (_radian < 0)
			{
				_radian = _radian + 2 * Math.PI;
			}
			drawSector(_sector,0,0,_radius,_radian*180/Math.PI,0);
		}
		private function onDragOut(e:MouseEvent):void
		{
			stage.removeEventListener(MouseEvent.MOUSE_MOVE,onDragMove);
			stage.removeEventListener(MouseEvent.MOUSE_UP,onDragOut);

		}
		/***
		* 绘制扇形
		* @param    mc 承载扇形的对象
		* @param    x 圆心角x
		* @param    y 圆心角y
		* @param    r 半径
		* @param    angle 绘制角度
		* @param    startAngle 起始角度
		* @param    color 填充颜色
		* @param    hasFrame 是否填充边框
		***/
		private function drawSector(sp:Sprite,x:Number=0,y:Number=0,r:Number=100,angle:Number=60,startAngle:Number=0,color:Number=0xff0000,hasFrame:Boolean=true):void
		{
			sp.graphics.clear();
			if (hasFrame)
			{
				sp.graphics.lineStyle(0,0xffff00);
			}
			sp.graphics.beginFill(color,1);
			sp.graphics.moveTo(x,y);
			angle=(Math.abs(angle)>360)?360:angle;
			var n:Number = Math.ceil(Math.abs(angle) / 45);
			var angleA:Number = angle / n;
			angleA = angleA * Math.PI / 180;
			startAngle = startAngle * Math.PI / 180;
			sp.graphics.lineTo(x+r*Math.cos(startAngle),y+r*Math.sin(startAngle));
			for (var i:int=1; i<=n; i++)
			{
				startAngle +=  angleA;
				var angleMid:Number = startAngle - angleA / 2;
				var bx:Number=x+r/Math.cos(angleA/2)*Math.cos(angleMid);
				var by:Number=y+r/Math.cos(angleA/2)*Math.sin(angleMid);
				var cx:Number = x + r * Math.cos(startAngle);
				var cy:Number = y + r * Math.sin(startAngle);
				sp.graphics.curveTo(bx,by,cx,cy);
			}
			if (angle!=360)
			{
				sp.graphics.lineTo(x,y);
			}
			sp.graphics.endFill();
		}
	}
}