IOS 签名

有时候app上办理一些业务需要手动签名

分析：签名无非是把手指滑动屏幕的痕迹记录下来，手指在屏幕上滑动系统自带touchesBegan touchesMoved touchesEnded 等方法，把每次划过的痕迹及线条保存起来，在view中重新绘画

   //手指触屏开始
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        
    }
    //手指移动时候发出
    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
        
        if  let touch : UITouch = NSSet(set: touches).anyObject() as? UITouch{
            
             let point = touch.location(in:self)
            
            pointArray?.append(point)//每条线点的集合
            
            self.setNeedsDisplay()
        }
        
       
    }
    //MARK: - -手指离开屏幕
    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        
        if let array = pointArray{
            
             lineArray?.append(array)//线的集合
            widthArray?.append(widthCount)
            colorArray?.append(colorCount)
            
            pointArray?.removeAll()
        }
       
    }

 override func draw(_ rect: CGRect) {
        
        //获取上下文
        guard let context = UIGraphicsGetCurrentContext() else {
            
            return
        }
        
        context.beginPath()
        context.setLineWidth(4)
        //线条拐角的样式 设为平滑
        context.setLineJoin(CGLineJoin.round)
        //线条开始的样式 设为平滑
        context.setLineCap(CGLineCap.round)
        
        //查看lineArray数组里是否有线条，有就将之前画的重绘，没有只画当前线条
        if lineArray!.count > 0{
            
            for i in 0..<lineArray!.count{
                
                let array = lineArray![I]
                
                if array.count>0{
                    
                    context.beginPath()
                    let startPoint : CGPoint = array[0]
                    context.move(to: startPoint)
                    
                    for j in 1..<array.count{
                        
                        let myPoint : CGPoint = array[j]
                        
                        context.addLine(to: myPoint)
                    }
                     //获取colorArray数组里的要绘制线条的颜色
                    
                    let stroColor = colors![colorArray![I]]
                    context.setStrokeColor(stroColor.cgColor)
                    //获取WidthArray数组里的要绘制线条的宽度
                    
                     let lineWidth = widths![widthArray![I]]
                    context.setLineWidth(lineWidth)
                    //保存自己画的
                    context.strokePath()
                }
            }
            
        }
        //画当前的线
        if pointArray!.count>0{
            
            context.beginPath()
            let startPoint : CGPoint = pointArray![0]
                context.move(to: startPoint)
                             
                for j in 1..<pointArray!.count{
                                 
                    let myPoint : CGPoint = pointArray![j]
                                 
                    context.addLine(to: myPoint)
                }
                    
             let stroColor = colors![colorCount]
              context.setStrokeColor(stroColor.cgColor)
             let lineWidth = widths![widthCount]
              context.setLineWidth(lineWidth)
            //保存自己画的
            context.strokePath()
        }
        
    }

附有案例Demo