scrawl

simple ScrawlView, can select color and lineWidth custom ,support undo and redo actions ,can get draw rect finished

     //构建画板
    let drawView = DrawView.init(frame: CGRect.init(x: 0, y: 150, width: self.view.frame.size.width, height: self.view.frame.size.height - 100));
    drawView.layer.borderWidth = 1;
    drawView.delegate = self
    self.view.addSubview(drawView)
    self.drawView = drawView
    
    //撤销  返回是否还能撤销
    self.drawView?.backToLastStep()
    
    //回退  返回是否还能回退
    self.drawView?.forwardNextStep()
    
    /*
    *  DrawViewDelegate   开始画
    */
    func beginDraw() {
        self.backBtn!.isEnabled = true
        self.forwardBtn!.isEnabled = false
    
    }
    
    /*
    *  获取涂鸦相对于涂鸦版的范围
    *  
    *  self.drawView?.getDrawRect()
    */

     /*
     *  设置涂鸦的颜色和粗细
    *
    *  self.drawView?.penColor = .red
    *  self.drawView?.penWidth = 10.0
    */