[Octave-bug-tracker] [bug #53682] Can't study blank figure while program is waiting for us (kbhit) to study the figure and hit a key.

[Mike Miller]

Follow-up Comment #4, bug #53682 (project octave):

I can reproduce on gnome if I do the following:

1. Using graphics_toolkit fltk, create a new blank figure, then move it onto a
different virtual desktop while still blank.
2. Go back to the octave prompt and run the script. If I switch to the desktop
with the figure, it will still be blank until a character is entered at the
prompt.

I should also mention I need to run 'more off' for the script to show the
'disp' prompt.

So this is really two problems:

1. The kbhit function does not use readline, so it does not allow the readline
background event loop to run, which means fltk has no chance to redraw until
the script is finished. With the qt toolkit, all drawing is done in a separate
thread from the interpreter. If we do want to keep fltk on par with qt, we
could add a new thread to octave-cli to handle fltk drawing without waiting
for the interpreter to be idle. But I think some maintainers feel that fltk
will eventually be obsolete and removed now that we have a more fully-featured
qt toolkit.

2. When I run the script in gnome, the figure is fully drawn while waiting for
a response at the kbhit prompt. Even moving the figure to a different desktop
or minimizing it does not make the figure window blank. I think this is
because gnome is a compositing window manager and does not require the client
window to redraw itself after it is obscured or minimized. I will try a
different window manager to see if I can reproduce that effect.

    _______________________________________________________

Reply to this item at:

  <http://savannah.gnu.org/bugs/?53682>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.gnu.org/