incremental redisplay

["Andreas C. Lemke" <andreas@sigi.colorado.edu>]

Hi,
 I'm trying to understand Genera's incremental redisplay facility
(e.g.  dw:redisplayer, dw:with-redisplayable-output).  From what I
read in the documentation, it is the thing to use for changeable
displays that contain presentations if you don't want to refresh
the entire window every time.

 My experiments with it have been very negative so far, i.e., the
the displays get messed up in all but the trivial cases.

 Another problem is that it does not work properly if the redisplay
piece is not completely visible (e.g., try redisplay-test-1 from
sys:examples;incremental-redisplay.lisp and scroll it up to the top
of the screen as far as possible).  Should I not use it for redisplay
pieces that are larger than the window?  What should I use then?

 What I am actually trying to do is something like the File System, i.e.,
an indented tree showing a variable amount of detail.

 If I can't use incremental redisplay, then I need some other way to
move presentations.  How do I do that?  This problem also cropped up
when we were building a graph editor whose nodes were presentations.

 Is there anybody out there who has made successful use of incremental
redisplay?  Any feedback would be greatly appreciated.

..................
... andreas ..:-).
..................