true color animation implementation

[David A Copperman +1 908 949 9075]

I have placed the file anim.tar.Z (compressed tar file) in grass/incoming on
moon.cecer.army.mil.  This package contains an implementation of true color
animation in GRASS.  It integrates the GRASS 4.0 monitor with InterViews 2.6.
InterViews is a public domain X Window toolkit package, written in C++.  It
has been in the public domain for approximately six years, and is the precursor
to Fresco, the MIT X Consortium C++ alternative to Xt, planned for release
with X11R6.

The main idea of the implementation is that using InterViews, your code can
maintain a complete in-core image of the state of the screen.  In that way,
as animation operations occur, the code can recognize (in spatially optimal
fashion) what parts of the screen were affected.  So parts of the GIS map
that have been animated can be restored to their prior GIS values.  This is
in contrast to the exclusive-or method of the standard GRASS release.

Publication of a high-level description of the implementation, with a
discussion of the general animation problem, is pending in the proceedings
of the upcoming (3/94) GRASS GIS Users Conference.  Title of the paper is
"True Color Animation in GRASS - Implementation and Observations."

While the code that I have supplied is really pretty simple, there is a
fairly steep learning curve to get comfortable with InterViews.  It is not
well-documented.  Like GRASS, you can get its complete source code, and go
to town reading the stuff, as I had already done with the GRASS monitor.
But my code will hopefully ease the way for you a bit.  I'll also note
that my code modifies the monitor in that it makes it part of a larger
program, rather than standalone as in the standard GRASS release.  This is
not necessary for the implementation, but was simply preferable for the
project in which this work was done.

InterViews may be obtained via anonymous ftp at interviews.stanford.edu
(IP 36.22.0.175).  Once logged in, type "binary" and then "get pub/3.1.tar.Z".
InterViews documentation is available in pub/papers.tar.Z.  And the usenet
group comp.windows.interviews is an excellent place to get help.

(Note the release number 3.1 on the tar file.  3.1 is the latest release of
InterViews; 2.6 is compatible with it, in that 2.6 was modified to use the
base class for InterViews 3.1 "widgets", the Glyph, at the time of the 3.1
release.)

David Copperman
AT&T Bell Laboratories
dac at hoqaa.att.com