swift 2.0之后的CGBitmapInfo alpha掩码

Question

我正在使用来自此github repo https://github.com/Haneke/HanekeSwift的库来缓存从服务器下载的图像.更新到swift 2.0后,一切都搞砸了.

我已经能够解决所有问题,但这个功能:

func hnk_decompressedImage() -> UIImage! {
    let originalImageRef = self.CGImage
    let originalBitmapInfo = CGImageGetBitmapInfo(originalImageRef)
    let alphaInfo = CGImageGetAlphaInfo(originalImageRef)

    // See: http://stackoverflow.com/questions/23723564/which-cgimagealphainfo-should-we-use
    var bitmapInfo = originalBitmapInfo
    switch (alphaInfo) {
    case .None:
        bitmapInfo &= ~CGBitmapInfo.AlphaInfoMask
        bitmapInfo |= CGBitmapInfo(rawValue: CGImageAlphaInfo.NoneSkipFirst.rawValue)
    case .PremultipliedFirst, .PremultipliedLast, .NoneSkipFirst, .NoneSkipLast:
        break
    case .Only, .Last, .First: // Unsupported
        return self
    }

    let colorSpace = CGColorSpaceCreateDeviceRGB()
    let pixelSize = CGSizeMake(self.size.width * self.scale, self.size.height * self.scale)
    if let context = CGBitmapContextCreate(nil, Int(ceil(pixelSize.width)), Int(ceil(pixelSize.height)), CGImageGetBitsPerComponent(originalImageRef), 0, colorSpace, bitmapInfo) {

        let imageRect = CGRectMake(0, 0, pixelSize.width, pixelSize.height)
        UIGraphicsPushContext(context)

        // Flip coordinate system. See: http://stackoverflow.com/questions/506622/cgcontextdrawimage-draws-image-upside-down-when-passed-uiimage-cgimage
        CGContextTranslateCTM(context, 0, pixelSize.height)
        CGContextScaleCTM(context, 1.0, -1.0)

        // UIImage and drawInRect takes into account image orientation, unlike CGContextDrawImage.
        self.drawInRect(imageRect)
        UIGraphicsPopContext()
        let decompressedImageRef = CGBitmapContextCreateImage(context)

        let scale = UIScreen.mainScreen().scale
        let image = UIImage(CGImage: decompressedImageRef, scale:scale, orientation:UIImageOrientation.Up)

        return image

    } else {
        return self
    }
}

具体来说,这是抛出错误的代码行:

bitmapInfo &= ~CGBitmapInfo.AlphaInfoMask
        bitmapInfo |= CGBitmapInfo(rawValue: CGImageAlphaInfo.NoneSkipFirst.rawValue)

错误:一元运算符'〜'不能应用于CGBitmapInfo类型的操作数

bitmapInfo |= CGBitmapInfo(rawValue: CGImageAlphaInfo.NoneSkipFirst.rawValue)

错误:二进制运算符'| ='不能应用于'CGBitmapInfo'类型的操作数

if let context = CGBitmapContextCreate(nil, Int(ceil(pixelSize.width)), Int(ceil(pixelSize.height)), CGImageGetBitsPerComponent(originalImageRef), 0, colorSpace, bitmapInfo)

错误:无法将类型为"CGBitmapInfo"的值转换为类型为UInt32的预期参数

Answer 1

错误:无法将类型为"CGBitmapInfo"的值转换为类型为UInt32的预期参数

Swift 2.0实际上需要UInt32而不是CGBitMapInfo对象,所以你应该在CGBitMapInfo中取出一个UInt32变量.

CGBitmapContextCreate(
    nil, 
    Int(ceil(pixelSize.width)), 
    Int(ceil(pixelSize.height)), 
    CGImageGetBitsPerComponent(originalImageRef), 
    0, 
    colorSpace, 
    bitmapInfo.rawValue)

https://developer.apple.com/library/ios/documentation/GraphicsImaging/Reference/CGBitmapContext/#//apple_ref/c/func/CGBitmapContextCreate