Re: [Update REQ 6854]: Geomview - Praise

[munzner at cs.stanford.edu]

> For the 'stop/start' problem I have not yet found a solution. But I
> found that a similar problem also exitst when geomview reads a file
> from disk. I attach an example file to this mail. This is about the
> complexity of geometrical structures I would like to display.
> 
> If I start geomview like this:
> 
> geomview xtest2.dat
> 
> it will show in the browser that it loaded one or two (out of two)
> objects but displays none directly. I have to send an X event (e.g.
> mouse movement) to one of the geomview windows, then geomview will
> do the remaining work. In this case it is not a problem, but this
> may be the same case when my programme write into the pipe. And if
> geomview does not empty the pipe it will overfill as yous suggested.
> 
> I am not sure wheter you can reproduce this problem, as it may
> depend on window manager settings. I am using FVWM and I let the
> window manger place the windows on the screen.

Aha - now I see the problem, thanks to your test file. Yes, your
problem is both reproducible and easily fixable. If you insert
"(progn" at the top of the file and ")" at the bottom of the file
everything should load properly. Whenever you want Geomview to execute
an entire block of commands all at once you need to wrap them in a
progn, otherwise it will just execute one per frame (which is
sometimes a desired behavior). 

This issue is mentioned in the documentation in the external modules example 
section, but it's pretty easy to miss:

http://www.geom.umn.edu/software/geomview/geomview_8.html#SEC52

 The code begins by defining procedures progn() and endprogn() which
 begin and end a Geomview progn group. The purpose of the Geomview
 progn command is to group commands together and cause Geomview to
 execute them all at once, without refreshing any graphics windows
 until the end. It is a good idea to group blocks of commands that a
 module sends to Geomview like this so that the user sees their
 cumulative effect all at once.


TM