I'm trying to animate the exposure value of a Drawable as part of a transition. In this same transition I'm adjusting the saturation via a ColorFilter. I'm wondering if there are any ways to mimic adjusting this value that would be compatible with a ColorMatrix or other quick transformation. The values would need to be calculated in the middle of a draw() method, so there's not enough time to calculate gamma correction (unless you know of a quick way that can operate on a Drawable and not a Bitmap). At the same time, the frame will be shown for a small enough time that getting it perfect isn't important as long as it's smooth.
The full effect I'm going for is described at http://www.google.com/design/spec/patterns/imagery-treatment.html#imagery-treatment-image-load
