From octave-graphics-request at bevo dot che dot wisc dot edu Thu Jun 27 11:56:44 2002
Subject: Re: GTK and Octave
From: =?iso-8859-10?q?Jo=E3o=20Cardoso?= <jcard at fe dot up dot pt>
To: octave-graphics at bevo dot che dot wisc dot edu
Date: Thu, 27 Jun 2002 17:55:46 +0100

On Tuesday 25 June 2002 00:12, Ben Sapp wrote:
| Hello,
|
| I have written a class and some DLD functions to accompany the class
| that allow a person to bring up most GTK widgets from within Octave. 
|  I also have a callback implementation working.

Hi,

I didn't compile your gtk_octave, only quickly browse the code.

Again an Octave deficiency arises, as the gtk main loop is only called 
during "Octave idle time", i.e., while Octave (actually readline) waits 
for user keyboard input:

/* This is called during octave idle time */
extern int
event_hook()
{
  while (gtk_events_pending())
    gtk_main_iteration_do(FALSE);

  return 0;
}

What happens if the user hits a button which deploys a lengthly 
calculation that afterwards the user wants to cancel hitting another 
button? Nothing, the current calculation has to finish until the new 
button is recognized (or the user code has to check regularly for the 
new gtk event, which is not a very clean approach)

This can be avoided only if event_hook() is also called during Octave 
processing. Without knowing enough about Octave "insides", it looks to 
me that the only "safe" way of doing this is for Octave to call 
event_hook() when the parser hits a "terminal symbol".
What do you think about this?

Joao