scaling without getting outside the frame ...

hi, list;

spent some time on that problem now and couldn't find exactly what i was looking for in
the archives, so i dare posting this question now. sorry if it's brought on before:

i want to zoom in and scroll around inside an image/a movie using the "scale" and
"position" messages on a [jit.gl.videoplane] object - is there an EASY way to make sure
that i'm never getting into the black area (= outside the picture).

is there a better or more convenient way to achieve this scrolling like effect like in
adobe photoshop ? i gave the "srcdim" and "dstdim" messages a try but they don't really do
what i'm looking for and it seems quite difficult to get a distinct zoom-like effect using
them.

precisely what i want to do is: to zoom into a picture, scroll around, then zoom even more
into it - staying in the last position. then zoom out again and, regardless what position
i have, never getting into the black.

if somebody has already made an effort on this - please give advice or post a patch

thank you

oliver