使用自定义UIBazierPath swift遮罩图像

Question

我创建了具有自定义形状的UIBezierPath，然后我总是将其屏蔽为图像，但我总是得到空图像 这是我的代码 首先，我创建了路径，然后创建了图像，最后创建了我的遮罩，但是它不起作用

这是图像，我需要对其进行遮罩dropbox.com/s/tnxgx7g1uvb1zj7/TeethMask.png?dl=0这是UIBazier路径dropbox.com/s/nz93n1vgvj6c6y0 / ...我需要在此路径中对该图像进行遮罩 输出是这样的 https://www.dropbox.com/s/gueyhdmmdcfvyiq/image.png?dl=0

这是ViewController类

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let tapGR = UITapGestureRecognizer(target: self, action: #selector(didTap))

        self.view.addGestureRecognizer(tapGR)
    }

    @objc func didTap(tapGR: UITapGestureRecognizer) {

        let tapPoint = tapGR.location(in: self.view)

        if #available(iOS 11.0, *) {
            let shapeView = ShapeView(origin: tapPoint)
             self.view.addSubview(shapeView)
        } else {
            // Fallback on earlier versions
        }


    }

}

这是ShapeView类

import UIKit

@available(iOS 11.0, *)
class ShapeView: UIView {

    let size: CGFloat = 150
    let lineWidth: CGFloat = 3
    var fillColor: UIColor!
    var path: UIBezierPath!

    init(origin: CGPoint) {
        super.init(frame: CGRect(x: 0.0, y: 0.0, width: size, height: size))
        self.fillColor = randomColor()
        self.path = mouthPath()
        self.center = origin
        self.backgroundColor = UIColor.clear
    }


    func randomColor() -> UIColor {
        let hue:CGFloat = CGFloat(Float(arc4random()) / Float(UINT32_MAX))
        return UIColor(hue: hue, saturation: 0.8, brightness: 1.0, alpha: 0.8)
    }


    func mouthPath() -> UIBezierPath{
        let pointsArray = [CGPoint(x:36 , y:36 ),CGPoint(x:41 , y:36 ),CGPoint(x:45 , y:36 ),CGPoint(x:49 , y:36 ),CGPoint(x:53 , y:36 ),CGPoint(x:58 , y: 37),CGPoint(x:64 , y:37 ),CGPoint(x:69 , y:36 ),CGPoint(x:65 , y:29 ),CGPoint(x:58 , y:24 ),CGPoint(x:50 , y:22 ),CGPoint(x:42 , y:23 ),CGPoint(x:36 , y:28 ),CGPoint(x:32 , y:35 )]

        let newPath = UIBezierPath()
        let factor:CGFloat = 10
        for i in 0...pointsArray.count - 1 { // last point is 0,0
            let point = pointsArray[i]
            let currentPoint1 = CGPoint(x: point.x  * factor , y: point.y * factor)
        if i == 0 {
            newPath.move(to: currentPoint1)
        } else {
            newPath.addLine(to: currentPoint1)

            }
            }
            newPath.addLine(to: CGPoint(x: pointsArray[0].x  * factor, y: pointsArray[0].y * factor))
            newPath.close()

        let imageTemplate = UIImageView()
        imageTemplate.image =  UIImage(named: "TeethMask")
        self.addSubview(imageTemplate)
        self.bringSubviewToFront(imageTemplate)
        imageTemplate.frame = self.frame

        let mask = CAShapeLayer(layer: self.layer)
        mask.frame = newPath.bounds
        mask.fillColor = UIColor.clear.cgColor
        mask.strokeColor = UIColor.black.cgColor
        mask.path = newPath.cgPath
        mask.shouldRasterize = true
        imageTemplate.layer.mask = mask
        imageTemplate.layer.addSublayer(mask)
    }
}

Answer 1

好吧，你做错了几件事...

您链接的“牙齿”图片：

的本机大小为461 x 259。因此，我将使用200 x 112的比例“目标”大小。

首先，形状图层在左上角使用0,0。您原始的点阵：

let pointsArray = [
    CGPoint(x: 36, y: 36),
    CGPoint(x: 41, y: 36),
    CGPoint(x: 45, y: 36),
    CGPoint(x: 49, y: 36),
    CGPoint(x: 53, y: 36),
    CGPoint(x: 58, y: 37),
    CGPoint(x: 64, y: 37),
    CGPoint(x: 69, y: 36),
    CGPoint(x: 65, y: 29),
    CGPoint(x: 58, y: 24),
    CGPoint(x: 50, y: 22),
    CGPoint(x: 42, y: 23),
    CGPoint(x: 36, y: 28),
    CGPoint(x: 32, y: 35),
]

采用这种形状：

如果我们反转y坐标：

let pointsArray = [
    CGPoint(x: 36.0, y: 23.0),
    CGPoint(x: 41.0, y: 23.0),
    CGPoint(x: 45.0, y: 23.0),
    CGPoint(x: 49.0, y: 23.0),
    CGPoint(x: 53.0, y: 23.0),
    CGPoint(x: 58.0, y: 22.0),
    CGPoint(x: 64.0, y: 22.0),
    CGPoint(x: 69.0, y: 23.0),
    CGPoint(x: 65.0, y: 30.0),
    CGPoint(x: 58.0, y: 35.0),
    CGPoint(x: 50.0, y: 37.0),
    CGPoint(x: 42.0, y: 36.0),
    CGPoint(x: 36.0, y: 31.0),
    CGPoint(x: 32.0, y: 24.0),
]

我们得到这样的形状：

如果您的形状像这样偏移，将很难使事情正确地“对齐”，因此我们可以“标准化”从左上角开始的点：

let pointsArray: [CGPoint] = [
    CGPoint(x: 4.0, y: 1.0),
    CGPoint(x: 9.0, y: 1.0),
    CGPoint(x: 13.0, y: 1.0),
    CGPoint(x: 17.0, y: 1.0),
    CGPoint(x: 21.0, y: 1.0),
    CGPoint(x: 26.0, y: 0.0),
    CGPoint(x: 32.0, y: 0.0),
    CGPoint(x: 37.0, y: 1.0),
    CGPoint(x: 33.0, y: 8.0),
    CGPoint(x: 26.0, y: 13.0),
    CGPoint(x: 18.0, y: 15.0),
    CGPoint(x: 10.0, y: 14.0),
    CGPoint(x: 4.0, y: 9.0),
    CGPoint(x: 0.0, y: 2.0),
]

导致：

但是，我们希望形状适合图像，因此我们可以将UIBezierPath缩放到imageView的边界：

    // need to scale the path to self.bounds
    let scaleW = bounds.width / pth.bounds.width
    let scaleH = bounds.height / pth.bounds.height

    let trans = CGAffineTransform(scaleX: scaleW, y: scaleH)
    pth.apply(trans)

我们在这里：

唯一剩下的就是将其用作图像的蒙版。

我建议使用UIImageView而不是UIView的子类...这样，您可以设置.image属性，而无需将其他视图添加为子视图。另外，我认为您会发现，在控制器代码中而不是在自定义类中管理自定义蒙版图像的大小要容易得多。

这是一个演示视图控制器和一个自定义MouthShapeView：

class TeethViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let tapGR = UITapGestureRecognizer(target: self, action: #selector(didTap))

        self.view.addGestureRecognizer(tapGR)
    }

    @objc func didTap(tapGR: UITapGestureRecognizer) {

        let tapPoint = tapGR.location(in: self.view)

        if #available(iOS 11.0, *) {

            // make sure you can load the image
            if let img = UIImage(named: "TeethMask") {
                // create custom ShapeView with image
                let shapeView = MouthShapeView(image: img)
                // if you want to use original image proportions
                // set the width you want and calculate a proportional height
                // based on the original image size
                let targetWidth: CGFloat = 200.0
                let targetHeight: CGFloat = img.size.height / img.size.width * targetWidth
                // set the frame size
                shapeView.frame.size = CGSize(width: targetWidth, height: targetHeight)
                // set the frame center
                shapeView.center = tapPoint
                // add it
                self.view.addSubview(shapeView)
            }

        } else {
            // Fallback on earlier versions
        }


    }
}

@available(iOS 11.0, *) class MouthShapeView: UIImageView {

    let pointsArray: [CGPoint] = [
        CGPoint(x: 4.0, y: 1.0),
        CGPoint(x: 9.0, y: 1.0),
        CGPoint(x: 13.0, y: 1.0),
        CGPoint(x: 17.0, y: 1.0),
        CGPoint(x: 21.0, y: 1.0),
        CGPoint(x: 26.0, y: 0.0),
        CGPoint(x: 32.0, y: 0.0),
        CGPoint(x: 37.0, y: 1.0),
        CGPoint(x: 33.0, y: 8.0),
        CGPoint(x: 26.0, y: 13.0),
        CGPoint(x: 18.0, y: 15.0),
        CGPoint(x: 10.0, y: 14.0),
        CGPoint(x: 4.0, y: 9.0),
        CGPoint(x: 0.0, y: 2.0),
    ]

    let maskLayer = CAShapeLayer()

    override init(image: UIImage?) {
        super.init(image: image)
        maskLayer.fillColor = UIColor.black.cgColor
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func layoutSubviews() {
        super.layoutSubviews()

        let newPath = UIBezierPath()

        pointsArray.forEach { p in
            if p == pointsArray.first {
                newPath.move(to: p)
            } else {
                newPath.addLine(to: p)
            }
        }

        newPath.close()

        // need to scale the path to self.bounds
        let scaleW = bounds.width / newPath.bounds.width
        let scaleH = bounds.height / newPath.bounds.height

        let trans = CGAffineTransform(scaleX: scaleW, y: scaleH)
        newPath.apply(trans)

        maskLayer.path = newPath.cgPath
        layer.mask = maskLayer

    }

}

运行该代码，然后点击视图，您将得到：