Animating custom views that draw with Core Graphics

I've got a complex UIScrollView hierarchy with a few synchronized views that layer on top of the main UIScrollView content (so their contents can be repositioned, but so they draw at the same screen size regardless of UIScrollView zoom).


One of these auxiliary views is a grid view. It works fine, except during device rotation. In this case, the new grid is redrawn at the new size, but with the bounds rect based on the original dimensions. As the rotation animation procedes, the bounds are properly scaled (and rotated) such that the grid ends up in the right place, but its movement doesn't track during the animation proper.


I can't quite figure out where the breakdown happens. I'd like to redraw the grid at the right scale at the start of the animation so that the lines and intersections track everything else.


Any suggestions? Thanks!