Re: Double buffering and canvases.

Steve Lamont (
Wed, 4 Dec 96 08:26:27 PST

To subscribers of the xforms list from (Steve Lamont) :

> > > When i put fl_set_form_dblbuffer( ..form.., 1) imediatelly after the form's
> > > creation i get:
> > >
> > > X Error of failed request: BadWindow (invalid Window parameter)
> > > Major opcode of failed request: 10 (X_UnmapWindow)
> > > Resource id in failed request: 0x2400038
> > > Serial number of failed request: 4541
> > > Current serial number in output stream: 4543
> > >
> > > Any suggestions?????
> If i understood ok, you are saying to use fl_set_form_dblbuffer before
> fl_show_form. This is what i am doing. ( Did i mentioned that my form
> has a canvas???? If i did, im sorry, my form has 2 free objects on it...)

Sorry. I probably misinterpreted your posting.

In any case, I just concocted a test case and was unable to reproduce
the problem.

It may be helpful to run your program in synchronous mode in order to
localize the source of error (by default, XForms derived programs and
most other X applications run in asynchronous mode, meaning that
requests are batched up and sent in one great glob and responses are
sent more or less in the same way, to minimize the number of round
trips to the X server). You can put your application into synchronous
mode by using the comand flag '-sync'.

You might also try setting the debug level (with '-debug N', where 'N'
is the debug level) to see if that tells you anything.

> Also I haven't manage to deactivate my form yet while drawing. Any
> suggestions about this????

fl_deactivate_form() should do the job. I just crufted up a quick
test program and it worked as I expected. What sort of objects are in
the form? What sort of objects get bogus events? What are the

Can you reduce the problem to a minimal test program?

To unsubscribe, send the message "unsubscribe" to or see