Drawing arcs with AS3

package {
	import flash.display.Sprite;
	public class arc extends Sprite {
		var my_canvas:Sprite = new Sprite();
		var deg_to_rad=0.0174532925;
		public function arc() {
			addChild(my_canvas);
			my_canvas.graphics.lineStyle(20,0xff0000,1);
			draw_arc(my_canvas,250,200,150,14,180,1);
		}
		public function draw_arc(movieclip,center_x,center_y,radius,angle_from,angle_to,precision) {
			var angle_diff=angle_to-angle_from;
			var steps=Math.round(angle_diff*precision);
			var angle=angle_from;
			var px=center_x+radius*Math.cos(angle*deg_to_rad);
			var py=center_y+radius*Math.sin(angle*deg_to_rad);
			movieclip.graphics.moveTo(px,py);
			for (var i:int=1; i<=steps; i++) {
				angle=angle_from+angle_diff/steps*i;
				movieclip.graphics.lineTo(center_x+radius*Math.cos(angle*deg_to_rad),center_y+radius*Math.sin(angle*deg_to_rad));
			}
		}
	}
}

package {
	import flash.display.Sprite;
	import flash.events.MouseEvent;
	import flash.events.Event;
	public class arc extends Sprite {
		var my_canvas:Sprite = new Sprite();
		var deg_to_rad=0.0174532925;
		var charging:Boolean=false;
		var power:int=0;
		public function arc() {
			addChild(my_canvas);
			stage.addEventListener(MouseEvent.MOUSE_UP, shoot);
			stage.addEventListener(MouseEvent.MOUSE_DOWN,charge);
			addEventListener(Event.ENTER_FRAME, on_enter_frame);
		}
		public function draw_arc(movieclip,center_x,center_y,radius,angle_from,angle_to,precision) {
			var angle_diff=angle_to-angle_from;
			var steps=Math.round(angle_diff*precision);
			var angle=angle_from;
			var px=center_x+radius*Math.cos(angle*deg_to_rad);
			var py=center_y+radius*Math.sin(angle*deg_to_rad);
			movieclip.graphics.moveTo(px,py);
			for (var i:int=1; i<=steps; i++) {
				angle=angle_from+angle_diff/steps*i;
				movieclip.graphics.lineTo(center_x+radius*Math.cos(angle*deg_to_rad),center_y+radius*Math.sin(angle*deg_to_rad));
			}
		}
		public function charge(e:MouseEvent) {
			charging=true;
		}
		public function shoot(e:MouseEvent) {
			charging=false;
			my_canvas.graphics.clear();
			power=0;
		}
		public function on_enter_frame(e:Event) {
			if (charging) {
				power++;
				if (power>=120) {
					power-=120;
				}
				my_canvas.graphics.clear();
				my_canvas.graphics.lineStyle(20,0x000000,1);
				draw_arc(my_canvas,250,200,150,270,270+power*3,1);
			}
		}
	}
}