package {
          import com.foed.Vector2D;
          
          import flash.display.Sprite;
          import flash.display.StageAlign;
          import flash.display.StageScaleMode;
          import flash.events.MouseEvent;
          import flash.text.TextField;
  
          [SWF (backgroundColor=0xffffff)]
          public class @ax-lib-flex-animation-code-02-Steering extends Sprite
          {
                  private var sA:Sprite;
                  private var sB:Sprite;
                  private var sC:Sprite;
                  private var tf:TextField;
                  
                  
                  
                  public function @ax-lib-flex-animation-code-02-Steering()
                  {
                          stage.align = StageAlign.TOP_LEFT;
                          stage.scaleMode = StageScaleMode.NO_SCALE;
                          
                          sA = makeHandle(100, 100, "A");
                          sB = makeHandle(200, 100, "B");
                          sC = makeHandle(200, 200, "C");
                          draw();
                          
                          tf = new TextField();
                          tf.selectable = false;
                          addChild(tf);
                  }
                  
                  
                  private function makeHandle(xpos:Number, ypos:Number, label:String):Sprite
                  {
                          var s:Sprite = new Sprite();
                          s.graphics.beginFill(0x999999);
                          s.graphics.drawCircle(0, 0, 10);
                          s.addEventListener(MouseEvent.MOUSE_DOWN, onMouseDown);
                          s.x = xpos;
                          s.y = ypos;
                          var lab:TextField = new TextField();
                          lab.selectable = false;
                          lab.text = label;
                          lab.x = -6;
                          lab.y = -7;
                          lab.width = 12;
                          lab.height = 14;
                          lab.mouseEnabled = false;
                          s.addChild(lab);
                          
                          addChild(s);
                          return s;
                  }
                  
                  private function onMouseDown(event:MouseEvent):void
                  {
                          event.target.startDrag();
                          stage.addEventListener(MouseEvent.MOUSE_UP, onMouseUp);
                          stage.addEventListener(MouseEvent.MOUSE_MOVE, onMouseMove);
                  }
                  
                  private function onMouseUp(event:MouseEvent):void
                  {
                          stopDrag();
                          stage.removeEventListener(MouseEvent.MOUSE_UP, onMouseUp);
                          stage.removeEventListener(MouseEvent.MOUSE_MOVE, onMouseMove);
                  }
                  
                  private function onMouseMove(event:MouseEvent):void
                  {
                          draw();
                          calculate();
                  }
                  
                  private function draw():void
                  {
                          graphics.clear();
                          graphics.lineStyle(0);
                          graphics.moveTo(sB.x, sB.y);
                          graphics.lineTo(sA.x, sA.y);
                          graphics.lineTo(sC.x, sC.y);
                  }
                  
                  private function calculate():void
                  {
                          var v1:Vector2D = new Vector2D(sB.x - sA.x, sB.y - sA.y);
                          var v2:Vector2D = new Vector2D(sC.x - sA.x, sC.y - sA.y);
                          var degrees:Number = Vector2D.angleBetween(v1, v2) * 180 / Math.PI;
                          tf.text = (degrees * v1.sign(v2)).toString();
                  }
          }
  }