UIImage from CALayer in iOS

Solution 1:

Sounds like you want to render your layer into a UIImage. In that case, the method below should do the trick. Just add this to your view or controller class, or create a category on CALayer.

Obj-C

- (UIImage *)imageFromLayer:(CALayer *)layer
{
  UIGraphicsBeginImageContextWithOptions(layer.frame.size, NO, 0);

  [layer renderInContext:UIGraphicsGetCurrentContext()];
  UIImage *outputImage = UIGraphicsGetImageFromCurrentImageContext();

  UIGraphicsEndImageContext();

  return outputImage;
}

Swift

func imageFromLayer(layer:CALayer) -> UIImage {
    UIGraphicsBeginImageContextWithOptions(layer.frame.size, layer.isOpaque, 0)
    layer.render(in: UIGraphicsGetCurrentContext()!)
    let outputImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return outputImage!
}

Solution 2:

Todd's answer is correct, however for retina screens there should be a little difference:

- (UIImage *)imageFromLayer:(CALayer *)layer
{

    if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)])
        UIGraphicsBeginImageContextWithOptions([layer frame].size, NO, [UIScreen mainScreen].scale);
    else
        UIGraphicsBeginImageContext([layer frame].size);

    [layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *outputImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return outputImage;
}