Draw UIView into image from static class method

gistfile1.txt

 static func buildImageForSize(size:CGSize) -> UIImage?
    {
        if size.height == 0 || size.width == 0 {
            return .None
        }
        
        var sigRect = CGRectZero
        sigRect.size = size
        
        // The following does NOT work
        //let space = CGColorSpaceCreateDeviceRGB();
        //let ctx = CGBitmapContextCreate(nil, Int(size.width), Int(size.height), 8, Int(size.width) * 4, space, CGImageAlphaInfo.PremultipliedLast.rawValue);
        
        UIGraphicsBeginImageContextWithOptions(size, false , 1.0)
        let ctx = UIGraphicsGetCurrentContext()
        
        let useView = UIView(frame: sigRect)
        useView.backgroundColor = UIColor.redColor()
        
        
        // Convert populated signature view to UIImage
        
        // There is no real current context, so make one so we can turn the view into an image
        var image : UIImage? = .None
        if let context = ctx {
            useView.layer.renderInContext(context)
            image = UIGraphicsGetImageFromCurrentImageContext()
        }

        UIGraphicsEndImageContext()
      
        return image
    }