Re: [Update REQ 6867]: `Pause until key is pressed'

[gartside at maths.ox.ac.uk]

Tamara,

Thank you for your reply to my earlier question.
I would not wish to unecessarily take up your time...
But I have added a bit of background to the question.


The set up is that I am giving the talk with `Magicpoint'.
Magicpoint is a line based presentation package.

At the relevant points in the talk, there is a line in the magicpoint
file:
%system "geomview -ogl -nopanels <gcl file>"

This behaves just as one would expect. I have added `window <position>
commands at the beginning of the gcl files to position the camera 
in the right place on the screen.
-----------
Your `freeze' suggestion has the problem (as you say) that execution
continues.

The soluution with loading in the files would seem to work. I guess my
objections
to this, are 1) the file panel takes up a lot of space on the screen,  2)
I 
have no doubt I will feel nervous giving my talk, and pressing various
buttons 
etc, surely multiplies the possibilities for errors, and 3) the process of 
loading up files will interrupt the flow of the talk.

I have had three ideas for possible solutions.

1) Just break up the gcl files into  the relevant sections, and having
in the magicpoint file:
%system "geomview ... filePart 1"
%pause     (which is a command to magicpoint to stop until a key is
pressed)
%system "geomview ... filePart 2"

The disadvantage of this is the nasty flicker caused by opening and
closing the geomview camera windows. This is particularly pronounced
because geomview, by default, opens the camera window in the `wrong'
place. (I can not get the -wpos option working.)
   
2) I thought I could add a `shell (read n)' command to the gcl file at the
point where I want a pause. This, I imagined, would mean execution
gcl file would stop until something was typed in. But in fact the camera
window
goes grey and everthing grinds to a halt!
-I dont much (anything?!) about command shells etc. I dont know what
going on here...

3) In the man pages for geomview I noticed the geomview -M option and the
`togeo
mview' command. This, it seems, might give a better version to solution
1).
-I should have lines:

%system "geomview -M filePart 1"  (loads the objects and does something)
%Pause    (wait until key presses)
%system "togeomview filePart 2"  (send geomview more gcl commands to the
object
s already in the camera window)

in my magicpoint file. This would be better, because there would be no
need too
pen and close windows, and to reload the objects.
--But I cant sort this out! All this stuff about pipes... ho hum.
I will try to track down our `local expert' tomorrow.
But if you do have any suggestions, I would be most grateful to hear them.

With thanks!

Paul.