[plt-scheme] Re: scrolling inside an editor-snip?

>> override `draw' to send a suitable `refresh' call to
>> the nested text% (to draw only the visible part, and with an offset
>> that starts drawing at the right line)

the refresh method, as it stands now just takes as an input an area of
the editor, specified in local editor coordinates, there is no option
for an offset. how is the absolute location of the drawing-area
determined by the editor?  the docs didn't seem to have an
explanation. (there was a local to global method in the text% class,
but i guess i shouldn't be overriding this). do i need to override any
methods in the administrator of the text% object?