haxe
    private var _downPos:Point = null;
    @:bind(canvas, MouseEvent.MOUSE_DOWN)
    private function onCanvasMouseDown(event:MouseEvent) {
        _downPos = new Point(event.localX, event.localY);
        canvas.componentGraphics.moveTo(_downPos.x, _downPos.y);
    }

    @:bind(canvas, MouseEvent.MOUSE_MOVE)
    private function onCanvasMouseMove(event:MouseEvent) {
        if (_downPos == null) {
            return;
        }
        canvas.componentGraphics.lineTo(event.localX, event.localY);
        _downPos = new Point(event.localX, event.localY);
    }
    
    @:bind(canvas, MouseEvent.MOUSE_UP)
    private function onCanvasMouseUp(event:MouseEvent) {
        _downPos = null;
    }