[jitter] dstdim multi screen

i'm trying to figure out how to use dstdimstart and dstdimend to slide a small image fluidly from one jit.window to another (using named matrices). as the small image approches the borders it squishes up, the dstdims don't allow you to specify start and end dims that go beyond the frame of the main matrix. any suggestions for keeping the original shape of the small image as it passes from one screen to another? hope my question is clear... thanks in advance.