CAShapeLayer 中的多条路径

Question

我想知道是否有可能让 CAShapeLayer 笔触不止一条路径，因为实际上它只需要一条路径作为参数，例如：

CAShapeLayer* myLayer=[CAShapeLayer layer];
myLayer.path=myBezierPath

但是如果我想在该层上绘制多个路径怎么办？

Answer 1

使用

void CGPathAddPath (
  CGMutablePathRef path1,     // The mutable path to change.
  const CGAffineTransform *m, // A pointer to an affine transformation matrix, or NULL if no transformation is needed. If specified, Quartz applies the transformation to path2 before it is added to path1.
  CGPathRef path2             // The path to add.
);

代码示例：

CGMutablePathRef combinedPath = CGPathCreateMutableCopy(path.CGPath);
CGPathAddPath(combinedPath, NULL, path2.CGPath);
CGPathAddPath(combinedPath, NULL, path3.CGPath);
CGPathAddPath(combinedPath, NULL, path4.CGPath);
myLayer.path = combinedPath;

Answer 2

Swift 4.1 版本的@Kjuly's answer

在 Swift 中你可以使用CGMutablePath

代码示例：

let combinedPath = CGMutablePath()
combinedPath.addPath(path1)
combinedPath.addPath(path2)
....
combinedPath.addPath(path_n)

myLayer.path = combinedPath

Answer 3

另一种方法是像这样附加路径......

UIBezierPath *left_path = [UIBezierPath bezierPathWithRect:frame_left];
UIBezierPath *right_path = [UIBezierPath bezierPathWithRect:frame_right];

[left_path appendPath:right_path];

CAShapeLayer *shapeLayer = [CAShapeLayer layer];
shapeLayer.path = left_path.CGPath;

Answer 4

好的，我自己发现了。可以做到以下几点：

CGMutablePathRef combinedPath= CGPathCreateMutableCopy(path.CGPath); 
CGPathAddPath(combinedPath, NULL, path2.CGPath); 
CGPathAddPath(combinedPath, NULL, path3.CGPath); 
CGPathAddPath(combinedPath, NULL, path4.CGPath); 
myLayer.path=combinedPath;

Answer 5

import UIKit
import QuartzCore
import CoreGraphics

class ViewController: UIViewController,UIGestureRecognizerDelegate {
var btnview : UIButton!
var buttonCenter = CGPoint.zero
var firstlayerpoint = CGPoint.zero
var firstLayer = CAShapeLayer()
var secondLayer = CAShapeLayer()
var thirdLayer = CAShapeLayer()
var initialPosition = CGRect()
let label = UILabel()
@IBOutlet weak var nameLabel: UILabel!
@IBOutlet weak var blueLabel: UILabel!
@IBOutlet weak var greenLabel: UILabel!
@IBOutlet weak var redLabel: UILabel!
    override func viewDidLoad() {
    super.viewDidLoad()


        firstLayer = self.createCircleWithBounds(bounds: CGRect(x:0, y:0, width:100,height:100), Position: self.view.center, StrokeColor: UIColor.blue, LineWidth: 20.0)
        firstLayer.strokeStart = 0.00
        firstLayer.strokeEnd = 0.33

        self.view.layer.addSublayer(firstLayer)


        secondLayer = self.createCircleWithBounds(bounds: CGRect(x:0, y:0, width:100,height:100), Position: self.view.center, StrokeColor: UIColor.red, LineWidth: 20.0)
        secondLayer.strokeStart = 0.33
        secondLayer.strokeEnd = 0.66
        self.view.layer.addSublayer(secondLayer)


        thirdLayer = self.createCircleWithBounds(bounds:  CGRect(x:0, y:0, width:100,height:100), Position: self.view.center, StrokeColor: UIColor.green, LineWidth: 20.0)
        thirdLayer.strokeStart = 0.66
        thirdLayer.strokeEnd = 1.00
        self.view.layer.addSublayer(thirdLayer)

    btnview = UIButton(frame: CGRect(x: self.view.center.x - 20 , y: self.view.center.y - 20 , width: 40, height: 40))
    btnview.backgroundColor = UIColor.gray
    btnview.isUserInteractionEnabled = true
    let panGesture = UIPanGestureRecognizer(target: self, action: #selector(self.panButton(panGesture:)))
    // panGesture.minimumNumberOfTouches = 1

    btnview.addGestureRecognizer(panGesture)

    self.view.addSubview(btnview)
    // Do any additional setup after loading the view, typically from a nib.
        nameLabel.isHidden = true
        blueLabel.isHidden = true
        greenLabel.isHidden = true
        redLabel.isHidden = true
}


func panButton(panGesture: UIPanGestureRecognizer) {

    //let translation = panGesture.translation(in: self.btnview)
    panGesture.view!.center =  btnview.center
    panGesture.setTranslation(CGPoint.zero, in: self.view)
    // var point = CGPoint.zero
    //  point = firstLayer.frame.size.center


    if panGesture.state == .began {


        label.isHidden = false
        buttonCenter = btnview.center // store old button center
    }
    else if panGesture.state == .ended || panGesture.state == .failed || panGesture.state == .cancelled {

        print(btnview.frame.origin.x)
        print(greenLabel.frame.origin.x)
        if btnview.frame.origin.x > greenLabel.frame.origin.x
        {
            //    lblflayer.isHidden = false
            //    lblsecondlayer.isHidden = true
            //    lblthirdlayer.isHidden = true
            nameLabel.isHidden = false
            nameLabel.text = "Blue"
            nameLabel.backgroundColor = UIColor.blue

        }
        else if btnview.frame.origin.x > blueLabel.frame.origin.x
        {
            // print(btnview.frame.origin.x)
            //  print(lblsecondlayer.frame.origin.x)
            //     lblsecondlayer.isHidden = false
            //   lblflayer.isHidden = true
            //    lblthirdlayer.isHidden = true
            nameLabel.isHidden = false
            nameLabel.text = "Red"
            nameLabel.backgroundColor = UIColor.red

        }

        else  if btnview.frame.origin.x > redLabel.frame.origin.x
        {
            print(btnview.frame.origin.x)
            print(redLabel.frame.origin.x)
            greenLabel.isHidden = true
            //  lblsecondlayer.isHidden = true
            //  lblthirdlayer.isHidden = false

            nameLabel.isHidden = false
            nameLabel.text = "Green"
            nameLabel.backgroundColor = UIColor.green
        }
        else
        {
            nameLabel.isHidden = true
            // lblflayer.isHidden = true
            // lblsecondlayer.isHidden = true
            //  lblthirdlayer.isHidden = true
        }

        btnview.center = buttonCenter // restore button center
    }
    else
    {
        let location = panGesture.location(in: view) // get pan location
        btnview.center = location // set button to where finger is
    }


}



func createCircleWithBounds(bounds: CGRect, Position position: CGPoint, StrokeColor color: UIColor, LineWidth lineWidth: CGFloat) -> CAShapeLayer {
    //let shapelayer = CAShapeLayer.layer
    let shapelayer = CAShapeLayer()
    shapelayer.strokeColor = color.cgColor
    shapelayer.fillColor = UIColor.clear.cgColor
    shapelayer.path = UIBezierPath(roundedRect: bounds, cornerRadius: bounds.width / 2).cgPath
    shapelayer.bounds = bounds
    shapelayer.position = position
    shapelayer.lineCap = kCALineCapButt
    shapelayer.lineWidth = lineWidth
    return shapelayer
}

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

}