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I'm converting some Objective-C code to Swift and in it there's the following code:

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
unsigned char rgba[4];
CGContextRef context = CGBitmapContextCreate(rgba, 1, 1, 8, 4, colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);

CGContextDrawImage(context, CGRectMake(0, 0, 1, 1), image.CGImage);
CGColorSpaceRelease(colorSpace);
CGContextRelease(context);


UIColor *averageColor = [UIColor colorWithRed:((CGFloat)rgba[0])/255.0 green:((CGFloat)rgba[1])/255.0 blue:((CGFloat)rgba[2])/255.0 alpha:alpha];
averageColor = [averageColor colorWithMinimumSaturation:0.15];

I've managed to convert the colorSpace easily but how do I create unsigned chars in Swift 3?

I tried the following and it didn't work the compiler prompt the following error:

Cannot convert value of type '[CUnsignedChar]' to expected argument type 'UnsafeMutableRawPointer?'

and here's the code:

 let colorSpace: CGColorSpace = CGColorSpaceCreateDeviceRGB()
 let rgba = [CUnsignedChar](repeating: 0,count: 4)
 // error on this line because of the rgba     
 let context: CGContext = CGContext.init(data: rgba, width: 1, height: 1, bitsPerComponent: 8, bytesPerRow: 4, space: colorSpace, bitmapInfo: CGImageAlphaInfo.premultipliedLast | CGBitmapInfo.byteOrder32Big) 


context.draw(image.cgImage!, in: CGRect(x: 0, y: 0, width: 1, height: 1))

I couldn't go any further

Can someone help?

thank you

Ivan Cantarino
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1 Answers1

2

Try this..

let colorSpace: CGColorSpace = CGColorSpaceCreateDeviceRGB()
let data = UnsafeMutableRawPointer.allocate(bytes: 4, alignedTo: 1) // 4 unsigned char = 4 bytes
let context: CGContext = CGContext.init(data: data, width: 1, height: 1, bitsPerComponent: 8, bytesPerRow: 4, space: colorSpace, bitmapInfo: CGImageAlphaInfo.premultipliedLast | CGBitmapInfo.byteOrder32Big)
let rgba = Array(UnsafeBufferPointer(start: data.assumingMemoryBound(to: UInt8.self), count: 4))
//  .... other
Bilal
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