How to style a button to have transparent text?

Question

I am currently working on the welcome page and I came across this interesting design:

I am trying to make a button below using text passing through a translucent view behind it. I tried the following code, but it does not seem to work:

let transparent = UIColor(red: 0, green: 0, blue: 0, alpha: 0)
let semiwhite = UIColor(red: 1.0, green: 1.0, blue: 1.0, alpha: 0.15)        
bottomView.backgroundColor = semiwhite
loginButton.backgroundColor = semiwhite
loginButton.setTitleColor(transparent, forState: .Normal)
loginButton.layer.cornerRadius = 10
loginButton.layer.masksToBounds = true
loginButton.layer.borderWidth = 2.5
loginButton.layer.borderColor = transparent.CGColor

Does anyone know how to do this?

Answer 1

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override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()

    let image1 = maskedImage(size: button1.bounds.size, text: "Sign in with Facebook")
    button1.setImage(image1, for: .normal)

    let image2 = maskedImage(size: button2.bounds.size, text: "Sign-up with Email")
    button2.setImage(image2, for: .normal)
}

func maskedImage(size: CGSize, text: String) -> UIImage? {
    UIGraphicsBeginImageContextWithOptions(size, true, 0)

    let context = UIGraphicsGetCurrentContext()
    context?.scaleBy(x: 1, y: -1)
    context?.translateBy(x: 0, y: -size.height)

    // draw rounded rectange inset of the button entire dimensions

    UIColor.white.setStroke()
    let pathRect = CGRect(origin: .zero, size: size).insetBy(dx: 10, dy: 10)
    let path = UIBezierPath(roundedRect: pathRect, cornerRadius: 5)
    path.lineWidth = 4
    path.stroke()

    // draw the text

    let attributes: [NSAttributedStringKey: Any] = [
        .font: UIFont.preferredFont(forTextStyle: .caption1),
        .foregroundColor: UIColor.white
    ]
    let textSize = text.size(withAttributes: attributes)
    let point = CGPoint(x: (size.width - textSize.width) / 2, y: (size.height - textSize.height) / 2)
    text.draw(at: point, withAttributes: attributes)

    // capture the image and end context

    let maskImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

    // create image mask

    guard let cgimage = maskImage?.cgImage, let dataProvider = cgimage.dataProvider else { return nil }

    let bytesPerRow = cgimage.bytesPerRow
    let bitsPerPixel = cgimage.bitsPerPixel
    let width = cgimage.width
    let height = cgimage.height
    let bitsPerComponent = cgimage.bitsPerComponent

    guard let mask = CGImage(maskWidth: width, height: height, bitsPerComponent: bitsPerComponent, bitsPerPixel: bitsPerPixel, bytesPerRow: bytesPerRow, provider: dataProvider, decode: nil, shouldInterpolate: false) else { return nil }

    // create the actual image

    let rect = CGRect(origin: .zero, size: size)
    UIGraphicsBeginImageContextWithOptions(size, false, 0)
    UIGraphicsGetCurrentContext()?.clip(to: rect, mask: mask)
    UIColor.white.withAlphaComponent(0.9).setFill()
    UIBezierPath(rect: rect).fill()
    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

    // return image

    return image
}

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Answer 2

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Answer 3

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, :)