Resize image via CGBitmap

resize.txt

extension UIImage {
    
    func resize(size: CGSize) -> UIImage! {
            if let colorSpace = CGColorSpaceCreateDeviceRGB() {
            let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.PremultipliedLast.rawValue)
            let context = CGBitmapContextCreate(nil, Int(size.width), Int(size.height), 8, 0, colorSpace, bitmapInfo.rawValue)
            CGContextClearRect(context, CGRectMake(0, 0, size.width, size.height))
            
            switch self.imageOrientation
            {
            case .Up, .UpMirrored:
                CGContextDrawImage(context, CGRectMake(0, 0, size.width, size.height), self.CGImage)
                
            case .Left, .LeftMirrored:
                CGContextRotateCTM(context, CGFloat(M_PI_2))
                CGContextTranslateCTM(context, 0.0, -size.width)
                CGContextDrawImage(context, CGRectMake(0, 0, size.height, size.width), self.CGImage)
                
            case .Right, .RightMirrored:
                CGContextRotateCTM(context, CGFloat(-M_PI_2))
                CGContextTranslateCTM(context, -size.height, 0.0)
                CGContextDrawImage(context, CGRectMake(0, 0, size.height, size.width), self.CGImage)
                
            case .Down, .DownMirrored:
                CGContextRotateCTM(context, CGFloat(M_PI));
                CGContextTranslateCTM(context, -size.width, -size.height)
                CGContextDrawImage(context, CGRectMake(0, 0, size.width, size.height), self.CGImage)
            }
            
            if let scaledImage = CGBitmapContextCreateImage(context) {
                return  UIImage(CGImage: scaledImage)
            }
        }

        return nil
    }
}