除了这个功能,我已经能够修复一切：

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

    // See: https://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),colorSpace,bitmapInfo) {

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

        // Flip coordinate system. See: https://stackoverflow.com/questions/506622/cgcontextdrawimage-draws-image-upside-down-when-passed-uiimage-cgimage
        CGContextTranslateCTM(context,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’| =’不能应用于类型为’CGBitmapInfo’的操作数

if let context = CGBitmapContextCreate(nil,bitmapInfo)

错误：无法将类型“CGBitmapInfo”的值转换为UInt32类型的预期参数