自动旋转和UIImageView动画的问题

Question

I am rotating a UIImageView in place periodically. My view is very basic, a view inside of a UITabBar view set. If I happen to rotate my iPad while my rotation is animating then my image becomes skewed. I have checked everything I can think of in my xib file for my image, the autoresizing is turned completely off and I am not auto-resizing subviews on the parent view.

Here is my animation code:

            [UIView beginAnimations:nil context:nil];
            [UIView setAnimationDuration:0.5];
            [UIView setAnimationDelay:0.0];
            transform = CGAffineTransformMakeRotation(convertToRadian(myDegrees));
            myImage.transform = transform;  
            [UIView commitAnimations];

If I take my animation out then everything works as I would expect. This rotation code appears to work fine if I do not rotate my device.

What can I do to keep the built-in rotation animation from altering my animation and skewing my images?

Answer 1

After many different attempts, what I ended up doing here is adding a clear view with my rotating images inside of it and setting the "auto-resize sub views" to off in interface builder. You can also do this in code as needed. I had to add the UIView placeholder because the super view containing my rotating images needed to auto-resize other view objects on rotation, but this fixed the funky skewing of my images due to animation of orientation change at the same time as animating a manual rotation in place.

Hope this helps someone.

Answer 2

The coordinate system gets changed. I've figured this much out too... thought I had a bug. If you save the CG ... GState, then you can revert back to the coordinate system initially used. This is in Deitel and Deitel's book. I just found it. Wanted to post it for anyone also looking.

You got a clever trick though! I might use it if this won't work.