ヘキサを整数へ変換、カラーコードからUIColorを作る準備

foo.swift

import Foundation
var hex = "ABCDEF"
// remove space located at header, trailer
let cString:String = hex.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).uppercaseString
//whitespaceAndNewlineCharacterSet, space, linefeed 

if ((cString as String).characters.count != 6) {
  print("Error")
}
// picking up 2 chars
let rString = (cString as NSString).substringWithRange(NSRange(location: 0, length: 2))
let gString = (cString as NSString).substringWithRange(NSRange(location: 2, length: 2))
let bString = (cString as NSString).substringWithRange(NSRange(location: 4, length: 2))

var r:CUnsignedInt = 0, g:CUnsignedInt = 0, b:CUnsignedInt = 0;
// class culster for conversion from String to various type
NSScanner(string: rString).scanHexInt(&r)
NSScanner(string: gString).scanHexInt(&g)
NSScanner(string: bString).scanHexInt(&b)
print(r, g, b) //171 205 239                                                                     


// Key Point
// 1. NSString.stringByTrimmingCharactersInSet、空白改行除去
// 2. NSString.substringWithRange、部分文字列除去
// 3. NSScanner.scanHexInt、Hex2Intヘキサを数字へ変換                
~