swift - Swift 2 中 Pixel 的颜色

Question

这个问题已经有答案了:

CGBitmapContextCreate: unsupported parameter combination. How to pass kCGImageAlphaNoneSkipFirst [duplicate] (1 个回答)

已关闭 7 年前。

当我向此函数提供坐标时，我在尝试确定图像中某个位置的颜色时遇到问题

 func getColourFromPoint(point:CGPoint) -> UIColor {
    let colorSpace:CGColorSpace = CGColorSpaceCreateDeviceRGB()!
    let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.PremultipliedLast.rawValue)
    var pixelData:[UInt8] = [0, 0, 0, 0]
    let context = CGBitmapContextCreate(&pixelData, 1, 1, 8, 4, colorSpace, bitmapInfo)
    CGContextTranslateCTM(context, -point.x, -point.y);
    self.layer.renderInContext(context)

    var red:CGFloat = CGFloat(pixelData[0])/CGFloat(255.0)
    var green:CGFloat = CGFloat(pixelData[1])/CGFloat(255.0)
    var blue:CGFloat = CGFloat(pixelData[2])/CGFloat(255.0)
    var alpha:CGFloat = CGFloat(pixelData[3])/CGFloat(255.0)

    var color:UIColor = UIColor(red: red, green: green, blue: blue, alpha: alpha)
    return color
}

我得到的是一个错误“无法将“CGBitmapInfo”类型的值转换为预期的参数类型“UInt32”

据我所知，bitmapInfo是 UInt32，所以我很困惑。

Answer 1

现在看来是一个符合OptionSetType的结构体。尝试原始值...

let context = CGBitmapContextCreate(&pixelData, 1, 1, 8, 4, colorSpace, bitmapInfo.rawValue)