CGIImage is nil after a segue

Question

I have a prepareForSegue that passes an image like this to the next viewController

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
  WizardPreview *controller = [segue destinationViewController];
  controller.myPicture = myPicture;
}

On the viewWillAppear of the viewController being presented I have a like like this

CGImageRef imageRef = [self.myPicture CGImage];

the result is nil

The strange part is that self.myPicture is not nil, but self.myPicture.CGImage is.

Any reason for that?

NOTE: myPicture is not nil when it is passed and even from viewWillAppear , I test and I see that self.myPicture is not nil.

NOTE 2: this is a code compiled for iOS 7 running on an iPhone with iOS 8.

Answer 1

You haven't posted enough code to say for sure. The three most likely options are:

1. If myPicture is nil in the prepareForSegure:sender: method
2. If WizardPreview 's myPicture property is weak
3. If the UIImage is not backed by a CGImage (for example, if it's backed by a CIImage )

If #3 is true, you can create a CGImage directly from a CIImage ( sample code here ).