图像遮罩在iOS10 beta3上失败

Question

For some time now we use the following code to mask a grayscale image without transparency to a coloured image.

This always worked fine until Apple released iOS 10 beta 3. Suddenly the mask is not applied anymore resulting in just a square box being returned with te given color.

The logic behind this can be found at https://developer.apple.com/library/mac/documentation/GraphicsImaging/Conceptual/drawingwithquartz2d/dq_images/dq_images.html

under the header Masking an Image with an Image Mask

The logic of this code: * Take an grayscale image without alpha * Create an solid image with the given color * Create a mask from the given image * Mask the solid image with the created mask * Output is a masked image with also respect for colors in between (gray might be light red ie).

Has anyone an idea how to fix this function? If you have XCode 8 beta 3 you can run this code and on a simulator lower than iOS 10 this will work correct and on iOS 10 it will just create a square box

Example image:

    public static func image(maskedWith color: UIColor, imageNamed imageName: String) -> UIImage? {

    guard let image = UIImage(named: imageName)?.withRenderingMode(.alwaysOriginal) else {
        return nil
    }

    guard image.size != CGSize.zero else {
        return nil
    }

    guard
        let maskRef = image.cgImage,
        let colorImage = self.image(with: color, size: image.size),
        let cgColorImage = colorImage.cgImage,
        let dataProvider = maskRef.dataProvider
        else {
        return nil
    }

    guard
        let mask = CGImage(maskWidth: maskRef.width, height: maskRef.height, bitsPerComponent: maskRef.bitsPerComponent, bitsPerPixel: maskRef.bitsPerPixel, bytesPerRow: maskRef.bytesPerRow, provider: dataProvider, decode: nil, shouldInterpolate: true),
        let masked = cgColorImage.masking(mask)
        else {
        return nil
    }

    let result = UIImage(cgImage: masked, scale: UIScreen.main().scale, orientation: image.imageOrientation)

    return result
}

public static func image(with color: UIColor, size: CGSize) -> UIImage? {

    guard size != CGSize.zero else {
        return nil
    }

    let rect = CGRect(origin: CGPoint.zero, size: size)

    UIGraphicsBeginImageContextWithOptions(size, false, UIScreen.main().scale)

    defer {
        UIGraphicsEndImageContext()
    }

    guard let context = UIGraphicsGetCurrentContext() else {
        return nil
    }

    context.setFillColor(color.cgColor)
    context.fill(rect)

    let image = UIGraphicsGetImageFromCurrentImageContext()

    return image;
}

Answer 1

此问题已在iOS10 beta 4中解决。