使用形状蒙版Swift隐藏文本

Question

我尝试在文本上绘制一个三角形，并在与文本相交的位置绘制形状。

当我尝试应用蒙版时，文字就会消失。 这是代码：

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var messageLabel: UILabel!
    let maskLayer = CAShapeLayer()

    override func viewDidLoad() {
        super.viewDidLoad()

        drawMask()
        messageLabel.layer.mask = maskLayer
    }

    func drawMask(){

        let path = UIBezierPath()

        let xMsgLbl = messageLabel.center.x-80
        let yMsgLbl = messageLabel.center.y-25

        path.moveToPoint(CGPointMake(xMsgLbl,yMsgLbl))
        path.addLineToPoint(CGPointMake(xMsgLbl+80, yMsgLbl+80))
        path.addLineToPoint(CGPointMake(xMsgLbl-80,yMsgLbl+80))
        path.addLineToPoint(CGPointMake(xMsgLbl,yMsgLbl))
        path.closePath()

        maskLayer.fillColor = UIColor.blueColor().CGColor
        maskLayer.path = path.CGPath

        view.layer.addSublayer(maskLayer)


    }
}

Answer 1

所以我想出了如何做到这一点。但它对我来说感觉不对。必须有更好的方法来实现它。

我添加了UIView并将其放入文本中，然后将蒙版应用于视图。它奏效了。但为什么它首先不起作用。

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var textView: UIView!
    @IBOutlet weak var messageLabel: UILabel!

    let maskLayer = CAShapeLayer()
    let path = UIBezierPath()

    override func viewDidLoad() {
        super.viewDidLoad()

        drawMask()

        maskLayer.opacity = 1.0
        view.layer.addSublayer(maskLayer)

        textView.layer.addSublayer(messageLabel.layer)
        messageLabel.layer.position.x = CGFloat(view.layer.position.x)+4

        messageLabel.layer.mask = maskLayer
        messageLabel.layer.masksToBounds = true

        textView.layer.mask = maskLayer
        textView.layer.masksToBounds = true

    }

    func drawMask(){

        let xMin = CGFloat(view.center.x)
        let yMin = CGFloat(view.center.y)-120

        path.moveToPoint(CGPointMake(xMin,yMin))
        path.addLineToPoint(CGPointMake(xMin+80, yMin+120))
        path.addLineToPoint(CGPointMake(xMin-80,yMin+120))
        path.addLineToPoint(CGPointMake(xMin,yMin))
        path.closePath()

        maskLayer.fillColor = UIColor.blackColor().CGColor
        maskLayer.path = path.CGPath

    }
}