CAShapeLayer 描边问题

Question

我使用 CAShapeLayer 而不是 CALayer 的唯一原因是动画属性。

view.layer 的红色边框是参考。如果为 shapeLayer 设置 lineWidth 则此图层超出 red 框架。

但我希望它适合 red 框。（适合NSView）

代码：

CustomView.swift:

 class CustomView: NSView{
 
    let shapeLayer = CAShapeLayer()
    
    init(){
        super.init(frame: .zero)
        
        wantsLayer = true
 
        layer?.borderWidth = 1.0
        layer?.borderColor = NSColor.red.cgColor
        layer?.masksToBounds = false
 
        layer!.addSublayer(shapeLayer)
 
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
 
    override func draw(_ rect: NSRect) {
        super.draw(rect)
    
        let path = CGMutablePath()

        path.move(to: CGPoint.zero)
        path.addLine(to: CGPoint(x: rect.width/2, y:rect.height))
        path.addLine(to: CGPoint(x: rect.width, y: 0))
        path.closeSubpath()
        
        shapeLayer.path = path
        
        shapeLayer.lineWidth = 30
        shapeLayer.strokeColor = NSColor.lightGray.cgColor
        shapeLayer.fillColor = .white
 
     }
}

ViewController.swift

     class ViewController: NSViewController {
 
    private lazy var customView: CustomView = {
        
        let customView = CustomView()
        
        view.addSubview(customView)
        
        customView.translatesAutoresizingMaskIntoConstraints = false
        
        NSLayoutConstraint.activate([
        
            customView.centerYAnchor.constraint(equalTo: view.centerYAnchor),
            customView.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            customView.heightAnchor.constraint(equalToConstant: 144),
            customView.widthAnchor.constraint(equalToConstant: 144)
        ])
        
        return customView
 
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        customView.shapeLayer.fillColor = NSColor.systemGreen.cgColor
    }
   
}

截图：

更新：

根据对这个问题的回答和评论。我确实通过以下代码

更新了 override func draw(_ rect: NSRect)

override func draw(_ rect: NSRect) {
        super.draw(rect)
                
        let path = CGMutablePath()
        
        let lineWidth: CGFloat = 30
       
        path.move(to: .init(x: lineWidth/2, y: lineWidth/2))
        path.addLine(to: .init(x: rect.width/2, y: rect.height - lineWidth/2))
        path.addLine(to: .init(x: rect.width - lineWidth/2, y: lineWidth/2))
        
        path.closeSubpath()
        
        shapeLayer.path = path
        shapeLayer.lineWidth = lineWidth
     }

CustomView.init 是，

init(){
        super.init(frame: .zero)
        
        wantsLayer = true
 
        layer?.borderWidth = 1.0
        layer?.borderColor = NSColor.red.cgColor
        layer?.masksToBounds = false
 
        layer!.addSublayer(shapeLayer)
 
        shapeLayer.strokeColor = NSColor.lightGray.cgColor
        shapeLayer.fillColor = .white
 
    }

输出：

但是还是画不对

更新：

修改了路径中的第一行...所以整个路径将是，

let path = CGMutablePath()
    
    let lineWidth: CGFloat = 30
   
    path.move(to: .init(x: lineWidth/2, y: lineWidth/2))
    path.addLine(to: .init(x: rect.width/2, y: rect.height - lineWidth))
    path.addLine(to: .init(x: rect.width - lineWidth/2, y: lineWidth/2))
    
    path.closeSubpath()

输出：

现在，我对修改第二行感到困惑。我不知道如何解决它。请hint/help我来解决这个问题。提前致谢...

Answer 1

edit/update:

将线宽乘以 2 并为形状添加遮罩会更容易：

class Triangle: NSView {
    let shapeLayer = CAShapeLayer()
    var lineWidth: CGFloat
    var strokeColor: NSColor = .clear
    var fillColor: NSColor = .clear
    init(size: CGSize, lineWidth: CGFloat = 10, strokeColor: NSColor = .white,  fillColor: NSColor = .black) {
        self.lineWidth = lineWidth*2
        self.strokeColor = strokeColor
        self.fillColor = fillColor
        super.init(frame: .init(origin: .zero, size: size))
        wantsLayer = true
        let path = NSBezierPath()
        path.move(to: .zero)
        path.line(to: .init(x: size.width/2 , y: size.height))
        path.line(to: .init(x: size.width, y: .zero))
        path.close()
        let mask = CAShapeLayer()
        mask.path = path.cgPath
        shapeLayer.mask = mask
        shapeLayer.path = path.cgPath
        shapeLayer.lineWidth = self.lineWidth
        shapeLayer.strokeColor = strokeColor.cgColor
        shapeLayer.fillColor = fillColor.cgColor
//      layer?.borderWidth = 1
//      layer?.borderColor = NSColor.red.cgColor
        layer?.addSublayer(shapeLayer)
    }
    convenience init(width: CGFloat, height: CGFloat, lineWidth: CGFloat = 10, strokeColor: NSColor = .white, fillColor: NSColor = .black) {
        self.init(size: .init(width: width, height: height), lineWidth: lineWidth, strokeColor: strokeColor, fillColor: fillColor)
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

extension NSBezierPath {
    var cgPath: CGPath {
        let path = CGMutablePath()
        var points: [CGPoint] = .init(repeating: .zero, count: 3)
        for i in 0..<elementCount {
            switch element(at: i, associatedPoints: &points) {
            case .moveTo: path.move(to: points[0])
            case .lineTo: path.addLine(to: points[0])
            case .curveTo: path.addCurve(to: points[2], control1: points[0], control2: points[1])
            case .closePath: path.closeSubpath()
            @unknown default: fatalError()
            }
        }
        return path
    }

}

class ViewController: NSViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        let triangle = Triangle(width: 200, height: 200, lineWidth: 1)
        view.addSubview(triangle)
    }
}

Answer 2

我并没有真正开发 iOS 应用程序。但请看下面

// View controller //
class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let rect = CGRect(origin: CGPoint.zero, size: CGSize(width: 200, height: 200))
        let triangleView = TriangleView(frame: rect, backColor: UIColor.green, strokeColor: UIColor.blue, lineWidth: 10)
        view.addSubview(triangleView)
    }
}

// Subclass of UIView //
import UIKit

class TriangleView: UIView {
    var backColor: UIColor
    var strokeColor: UIColor
    var lineWidth: CGFloat
    
    init(frame: CGRect, backColor: UIColor, strokeColor: UIColor, lineWidth: CGFloat) {
        self.backColor = backColor
        self.strokeColor = strokeColor
        self.lineWidth = lineWidth
        super.init(frame: frame)
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func draw(_ rect: CGRect) {
        super.draw(rect)
        backColor.set()
        //UIRectFill(rect)
        
        let shapeLayer = CAShapeLayer()
        let path = UIBezierPath()
        path.move(to: CGPoint(x: rect.width/2.0, y: lineWidth/2.0))
        path.addLine(to: CGPoint(x: lineWidth/2.0, y: rect.height - lineWidth/2.0))
        path.addLine(to: CGPoint(x: rect.width - lineWidth/2.0, y: rect.height - lineWidth/2.0))
        path.addLine(to: CGPoint(x: rect.width/2.0, y: lineWidth/2.0))
        path.close()
        shapeLayer.path = path.cgPath
        shapeLayer.lineWidth = lineWidth
        shapeLayer.fillColor = backColor.cgColor
        shapeLayer.strokeColor = strokeColor.cgColor
        layer.insertSublayer(shapeLayer, at: 0)
        layer.masksToBounds = false
    }
}

以下为Cocoa版本

// View controller //
import Cocoa

class ViewController: NSViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let rect = CGRect(origin: CGPoint(x: 50, y: 50), size: CGSize(width: 200, height: 200))
        let myView = MyView(frame: rect, fillColor: NSColor.green, strokeColor: NSColor.red, lineWidth: 10.0)
        myView.wantsLayer = true
        view.addSubview(myView)
    }
}

// Subclass of NSView //
import Cocoa

class MyView: NSView {
    override var isFlipped: Bool { return true }
    
    var fillColor: NSColor
    var strokeColor: NSColor
    var lineWidth: CGFloat
    init(frame: CGRect, fillColor: NSColor, strokeColor: NSColor, lineWidth: CGFloat){
        self.fillColor = fillColor
        self.strokeColor = strokeColor
        self.lineWidth = lineWidth
        super.init(frame: frame)
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func draw(_ rect: NSRect) {
        super.draw(rect)
        
        let path = NSBezierPath()
        path.move(to: CGPoint(x: rect.width/2.0, y: lineWidth/2.0))
        path.line(to: CGPoint(x: lineWidth/2.0, y: rect.height - lineWidth/2.0))
        path.line(to: CGPoint(x: rect.width - lineWidth/2.0, y: rect.height - lineWidth/2.0))
        path.line(to: CGPoint(x: rect.width/2.0, y: lineWidth/2.0))
        path.close()
        fillColor.setFill()
        path.fill()
        path.lineWidth = lineWidth
        strokeColor.set()
        path.stroke()
    }
}

Answer 3

“带掩码的双线宽”实现的另一种变体：

class TriangleView: NSView {
    let lineWidth: CGFloat = 20

    private lazy var shapeLayer: CAShapeLayer = {
        let shapeLayer = CAShapeLayer()
        shapeLayer.fillColor = NSColor.clear.cgColor
        shapeLayer.strokeColor = NSColor.red.cgColor
        shapeLayer.lineWidth = lineWidth * 2
        return shapeLayer
    }()

    private let maskLayer: CAShapeLayer = {
        let shapeLayer = CAShapeLayer()
        shapeLayer.fillColor = NSColor.white.cgColor
        shapeLayer.strokeColor = NSColor.clear.cgColor
        shapeLayer.lineWidth = 0
        return shapeLayer
    }()

    override init(frame frameRect: NSRect = .zero) {
        super.init(frame: frameRect)
        configure()
    }

    required init?(coder: NSCoder) {
        super.init(coder: coder)
        configure()
    }

    func configure() {
        wantsLayer = true
        layer?.borderColor = NSColor.blue.cgColor
        layer?.borderWidth = 1
        layer?.addSublayer(shapeLayer)
    }

    override func layout() {
        super.layout()

        let path = CGMutablePath()
        path.move(to: NSPoint(x: bounds.midX, y: bounds.maxY))
        path.addLine(to: NSPoint(x: bounds.maxX, y: bounds.minY))
        path.addLine(to: NSPoint(x: bounds.minX, y: bounds.minY))
        path.closeSubpath()

        shapeLayer.path = path
        maskLayer.path = path
        shapeLayer.mask = maskLayer
    }
}

概念与接受的答案相同（重新加倍线宽和掩码）。

如您所见，当使用CAShapeLayer时，我们没有实现draw, but rather let the shape layer take care of the rendering. But we do want to respond to frame changes, so we set (and reset) the path in layout。

无论如何，结果是：

CAShapeLayer 描边问题

CAShapeLayer stroke issue

macos

cocoa

cashapelayer

swift