使用自定义 UIBezierPath 屏蔽图像 swift

Question

我创建了带有自定义形状的 UIBezierPath，然后我需要将其作为图像的遮罩，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，最后创建了我的蒙版，但它不起作用

这里是图片，我需要将它屏蔽掉 dropbox。com/s/tnxgx7g1uvb1zj7/TeethMask.png?dl=0 这里是 UIBazier 路径 dropbox。com/s/nz93n1vgvj6c6y0/… 我需要在这个路径中屏蔽这张图片输出是这样的 https://www.dropbox.com/s/gueyhdmmdcfvyiq/image.png?dl=0

这里是ViewControllerclass

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
        }


    }

}

这里是 ShapeView class

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

嗯，你做错了几件事...

您链接的 "teeth" 图片：

的原始大小为 461 x 259。所以，我将使用 200 x 112.

的比例 "target" 大小

首先，形状图层在左上角使用 0,0。您的原始点数组：

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),
]

给出这个形状：

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),
]

我们得到这个形状：

如果你的形状像那样偏移，将很难正确地 "line up"，所以我们可以 "normalize" 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)

我们到了：

唯一剩下的就是将其用作图像的遮罩。

我建议使用 subclassing UIImageView 而不是 UIView ... 这样你就可以设置 .image 属性需要添加另一个视图作为子视图。此外，我认为您会发现在控制器代码中管理自定义蒙版图像的大小比在自定义 class.

中管理要容易得多。

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

    }

}

当您运行该代码并点击视图时，您将得到：

使用自定义 UIBezierPath 屏蔽图像 swift

Mask Image with custom UIBazierPath swift

ios

uibezierpath

image-masking

swift