Created
April 11, 2019 08:27
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Replace pixels in UIImage (white or black. For other colours require some adjustment in terms of CGFloat converting)
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| extension UIImage { | |
| func replaceColor(_ color: UIColor, with: UIColor) -> UIImage? { | |
| guard let fromRGB = color.rgb(), let toRGB = with.rgb() else { return self } | |
| let rect = CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height) | |
| UIGraphicsBeginImageContextWithOptions(rect.size, false, self.scale) | |
| UIRectFill(rect) | |
| draw(in: rect, blendMode: .copy, alpha: 1) | |
| guard let contextRef = UIGraphicsGetCurrentContext() else { return self } | |
| var data = contextRef.data?.assumingMemoryBound(to: UInt8.self) | |
| if data == nil { return self } | |
| let bytesPerRow = contextRef.bytesPerRow | |
| let rowsCount = contextRef.height | |
| let pEnd = data! + (bytesPerRow * rowsCount) | |
| while data! < pEnd { | |
| if data![0] == fromRGB.b && data![1] == fromRGB.g && data![2] == fromRGB.r { | |
| data![0] = toRGB.b | |
| data![1] = toRGB.g | |
| data![2] = toRGB.r | |
| } | |
| data! += 4 | |
| } | |
| let newImage = UIGraphicsGetImageFromCurrentImageContext() | |
| UIGraphicsEndImageContext() | |
| return newImage | |
| } | |
| } | |
| private extension UIColor { | |
| func rgb() -> (r: UInt8, g: UInt8, b: UInt8)? { | |
| var fRedComp: CGFloat = 0, fGreenComp: CGFloat = 0, fBlueComp: CGFloat = 0, fAlpha: CGFloat = 0 | |
| guard self.getRed(&fRedComp, green: &fGreenComp, blue: &fBlueComp, alpha: &fAlpha) else { return nil } | |
| return (r: UInt8(fRedComp * 255), g: UInt8(fGreenComp * 255), b: UInt8(fBlueComp * 255)) | |
| } | |
| } |
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