Question

我想绘制一些形状，如某人的签名或其他一些写意形状。我是UIBezierPath的新手。我尝试过以下代码，但它没有按我的意愿运行。

怎么可能？ TIA

   let path = UIBezierPath()
    path.move(to: from)
    path.addLine(to: to)


    let shapeLayer = CAShapeLayer()
    shapeLayer.path = path.cgPath
    shapeLayer.strokeColor = lineColor.cgColor
    shapeLayer.lineWidth = 1.0

    view.layer.addSublayer(shapeLayer)

Answer 1

你好@Rajinder为此你必须得到接触点，所以你必须使用以下方法。

override func touchesBegan(_ touches: Set<UITouch>, with event: 
UIEvent?) 
{
    let touch = event?.allTouches?.first
    let touchLocation: CGPoint? = touch?.location(in: self.view)
    //---Declare "from" globally  as CGPoint
    from = CGPoint(x: (touchLocation?.x)!, y: (touchLocation?.y)!)

}


override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {

    let touch = event?.allTouches?.first
    let touchLocation: CGPoint? = touch?.location(in: self.view)

    //--Get New touch point
    let to = CGPoint(x: (touchLocation?.x)!, y: (touchLocation?.y)!)

    //--Draw line
    drawLineFromPoint(from: from, to: to, ofColor: UIColor.red, inView: self.view)

    //--Save as older point
    from = to

}


func drawLineFromPoint(from : CGPoint, to:CGPoint, ofColor lineColor: UIColor, inView view:UIView)
 {

    //design the path
    let path = UIBezierPath()
    path.move(to: from)
    path.addLine(to: to)

    //design path in layer
    let shapeLayer = CAShapeLayer()
    shapeLayer.path = path.cgPath
    shapeLayer.strokeColor = lineColor.cgColor
    shapeLayer.lineWidth = 1.0

    view.layer.addSublayer(shapeLayer)
}

Answer 2

这是一个基本的绘图代码，你应该添加UIImageView来绘制它，基本上你需要在前一个触摸点和当前点之间画一条线，使用线帽.round

import UIKit

class BasicDrawingViewController: UIViewController {

    var lastPoint = CGPoint.zero
    var paintColor : UIColor = UIColor.black
    var lineWidth : CGFloat = 20.0
    @IBOutlet weak var imageView: UIImageView!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        self.navigationController?.setNavigationBarHidden(true, animated: false)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


}
//Draw logic
extension BasicDrawingViewController{

    func drawBetweenPoints(point1:CGPoint,point2:CGPoint){
        UIGraphicsBeginImageContext(self.imageView.bounds.size)
        let context = UIGraphicsGetCurrentContext()

        self.imageView.image?.draw(in: self.imageView.bounds)
        context?.move(to: point1)
        context?.addLine(to: point2)
        context?.setLineCap(.round)
        context?.setStrokeColor(self.paintColor.cgColor)
        context?.setLineWidth(lineWidth)
        context?.strokePath()
        self.imageView.image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
    }

    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        debugPrint("Began")
        if let touch = touches.first{
            let point = touch.location(in: self.imageView)
            self.drawBetweenPoints(point1: point, point2: point)
            self.lastPoint = point
        }
    }

    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
        debugPrint("Move")
        if let touch = touches.first{
            let newPoint = touch.location(in: self.imageView)
            self.drawBetweenPoints(point1: self.lastPoint, point2: newPoint)
            self.lastPoint = newPoint
        }

    }

    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        debugPrint("Ended")
        if let touch = touches.first{
            let point = touch.location(in: self.imageView)
            debugPrint(point)
        }
    }
}

故事板设置

<强>结果

在swift中绘制手绘形状

2 个答案: