let cs = CGColorSpaceCreateDeviceRGB()
let bytes : CMutableVoidPointer = nil
let bitmapInfo = CGBitmapInfo(CGImageAlphaInfo.PremultipliedFirst.toRaw()) | CGBitmapInfo.ByteOrder32Little
let context = CGBitmapContextCreate(bytes, 128, 128, 8, 512, cs, bitmapInfo)
assert(context)
println("context: \(context)")

出来るもんだな