Get average color of UIImage in Swift

Question

I was recently attempting to convert the code from here into Swift. However, I keep getting a white color, no matter the image. Here\'s my code:

// Playgroun         


        

Answer 1

Swift 3:

func areaAverage() -> UIColor {

    var bitmap = [UInt8](repeating: 0, count: 4)

    let context = CIContext(options: nil)
    let cgImg = context.createCGImage(CoreImage.CIImage(cgImage: self.cgImage!), from: CoreImage.CIImage(cgImage: self.cgImage!).extent)

    let inputImage = CIImage(cgImage: cgImg!)
    let extent = inputImage.extent
    let inputExtent = CIVector(x: extent.origin.x, y: extent.origin.y, z: extent.size.width, w: extent.size.height)
    let filter = CIFilter(name: "CIAreaAverage", withInputParameters: [kCIInputImageKey: inputImage, kCIInputExtentKey: inputExtent])!
    let outputImage = filter.outputImage!
    let outputExtent = outputImage.extent
    assert(outputExtent.size.width == 1 && outputExtent.size.height == 1)

    // Render to bitmap.
    context.render(outputImage, toBitmap: &bitmap, rowBytes: 4, bounds: CGRect(x: 0, y: 0, width: 1, height: 1), format: kCIFormatRGBA8, colorSpace: CGColorSpaceCreateDeviceRGB())

    // Compute result.
    let result = UIColor(red: CGFloat(bitmap[0]) / 255.0, green: CGFloat(bitmap[1]) / 255.0, blue: CGFloat(bitmap[2]) / 255.0, alpha: CGFloat(bitmap[3]) / 255.0)
    return result
}