How to create a UIImage from the current graphics context?

Question

I\'d like to create a UIImage object from the current graphics context. More specifically, my use case is a view that the user can draw lines on. They may draw incremental

Answer 1

Swift Version

    func createImage(from view: UIView) -> UIImage {
        UIGraphicsBeginImageContext(view.bounds.size)
        view.layer.renderInContext(UIGraphicsGetCurrentContext()!)
        let viewImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return viewImage
    }

Answer 2

UIImage * image = UIGraphicsGetImageFromCurrentImageContext();

If you need to keep image around, be sure to retain it!

EDIT: If you want to save the output of drawRect to an image, just create a bitmap context using UIGraphicsBeginImageContext and call your drawRect function with the new context bound. It's easier to do than saving the CGContextRef you're working with within drawRect - because that context may not have bitmap information associated with it.

UIGraphicsBeginImageContext(view.bounds.size);
[view drawRect: [myView bounds]];
UIImage * image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

You can also use the approach that Kelvin mentioned. If you want to create an image from a more complex view like UIWebView, his method is faster. Drawing the view's layer does not require refreshing the layer, it just requires moving image data from one buffer to another!

Answer 3

You need to setup the graphics context first:

UIGraphicsBeginImageContext(myView.bounds.size);
[myView.layer renderInContext:UIGraphicsGetCurrentContext()];
viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();