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Swift UIColor extension that parses a hexadecimal color string
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| extension UIColor { | |
| enum Error: ErrorType { | |
| case Parsing(String) | |
| } | |
| convenience init(hex input: String) throws { | |
| let hex = input.stringByTrimmingCharactersInSet(NSCharacterSet.alphanumericCharacterSet().invertedSet) | |
| var int = UInt32() | |
| guard NSScanner(string: hex).scanHexInt(&int) else { | |
| throw Error.Parsing("Unable to scan hexadecimal integer") | |
| } | |
| let a, r, g, b: UInt32 | |
| switch hex.characters.count { | |
| case 3: // RGB (12-bit) | |
| (a, r, g, b) = (255, (int >> 8) * 17, (int >> 4 & 0xF) * 17, (int & 0xF) * 17) | |
| case 6: // RGB (24-bit) | |
| (a, r, g, b) = (255, int >> 16, int >> 8 & 0xFF, int & 0xFF) | |
| case 8: // ARGB (32-bit) | |
| (a, r, g, b) = (int >> 24, int >> 16 & 0xFF, int >> 8 & 0xFF, int & 0xFF) | |
| default: | |
| throw Error.Parsing("Invalid hexadecimal size: \(hex.characters.count)") | |
| } | |
| self.init(red: CGFloat(r) / 255, green: CGFloat(g) / 255, blue: CGFloat(b) / 255, alpha: CGFloat(a) / 255) | |
| } | |
| } |
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