UIImagePixel

gistfile1.txt

func pixel(in image: UIImage, at point: CGPoint) -> (UInt8, UInt8, UInt8, UInt8)? {
    let width = Int(image.size.width)
    let height = Int(image.size.height)
    let x = Int(point.x)
    let y = Int(point.y)
    guard x < width && y < height else {
        return nil
    }
    guard let cfData:CFData = image.cgImage?.dataProvider?.data, let pointer = CFDataGetBytePtr(cfData) else {
        return nil
    }
    let bytesPerPixel = 4
    let offset = (x + y * width) * bytesPerPixel
    return (pointer[offset], pointer[offset + 1], pointer[offset + 2], pointer[offset + 3])
}

let image = UIImage(named: "t.png")!
if let (r,g,b,a) = pixel(in: image, at: CGPoint(x: 1, y:2)) {
    print ("Red: \(r), Green: \(g), Blue: \(b), Alpha: \(a)")
}