extension UIImage{    /**    获取图片中的像素颜色值    - parameter pos: 图片中的位置    - returns: 颜色值    */    func getPixelColor(pos:CGPoint)->(alpha: CGFloat, red: CGFloat, green: CGFloat,blue:CGFloat){        let pixelData=http://www.mamicode.com/CGDataProviderCopyData(CGImageGetDataProvider(self.CGImage))        let data:UnsafePointer<UInt8> = CFDataGetBytePtr(pixelData)        let pixelInfo: Int = ((Int(self.size.width) * Int(pos.y)) + Int(pos.x)) * 4        let r = CGFloat(data[pixelInfo]) / CGFloat(255.0)        let g = CGFloat(data[pixelInfo+1]) / CGFloat(255.0)        let b = CGFloat(data[pixelInfo+2]) / CGFloat(255.0)        let a = CGFloat(data[pixelInfo+3]) / CGFloat(255.0)        return (a,r,g,b)    }}

swift获取图片像素颜色值