Re: [Texmacs-dev] Qt-TeXmacs: segfault with KDE-Oxygen

[Norbert Nemec]

Thanks, Gubinelli, for this detailed explanation. I can understand the 
difficulties that you experienced. TeXmacs certainly is a tricky beast 
to marry with any toolkit...

After solving the problem with the KDE style, I have now been using 
Qt-TeXmacs for a day and am very happy about it. In general, it works 
much smoother than the original TeXmacs X11-GUI.

The only noticeable quirk that remains for me is, that Qt-TeXmacs does 
not quit cleanly. When I run it from the console, it does not finish 
after closing the last window, so I have to press Ctrl-C to regain 
control of the console. I don't know how exactly the event-loop is 
supposed to finish. At the moment, it is an infinite loop without any 
break statement...

Greetings,
Norbert



Gubinelli Massimiliano wrote:
> Hi Norbert,
>
>  the status of the Qt port under Linux is not ideal. The main reason 
> is that I'm developing the port under Mac and currently, due to lack 
> of time, I'm not able to cross-test under Linux. I should mention that 
> the Qt port works under mac and windows (in the sense that it does not 
> segfaults like it does on linux). I've done some experimentations with 
> different versions of Qt/X11 under Linux and for example the port 
> works fine with the 4.4/debug version of the libraries. I don't thinks 
> there is a real bug. I tend to think that the use of the Qt framework 
> forced by TeXmacs structure is a bit unconventional and produce 
> fragile code.
>
> As far as the run-loop is concerned we tried different alternatives 
> (both in Qt port and in the Cocoa port) the main constraint we have to 
> face is that there should be some order in the call to 
> the_interpose_handler (see qt_gui.cpp for example) which perform the 
> update of internal TeXmacs structures after some inputs and the 
> refresh of the exposed widgets. In the X11 port everything is 
> carefully crafted by exaclty prescribing the order of operations : 
> input handling, update, refresh. In modern GUIs like Qt or Cocoa 
> usually the run-loop is controlled by the library and we haven't fund 
> canonical ways to correclty sequence the calls to TeXmac internal 
> functions (both for updating and refreshing).
>
> I should mention also the fact that we have a cario renderer available 
> and that if the problems with the Qt port cannot be reasonably 
> resolved (for example now I found a bug apparently due to Qt) we 
> should evaluate the option to shift to other cross-platform libraries 
> like Gtk+ or wxWidgets, or the like.
>
> Any suggestion to improve the status of the Qt port under linux is 
> welcome.
>
> Best,
> Massimiliano
>
> On 19 avr. 09, at 19:21, Norbert Nemec wrote:
>
> > Hi there,
> >
> > I just tracked down the segfaults of Qt-TeXmacs to the use of the 
> > Oxygen style in KDE. When I have that style active, TeXmacs crashes 
> > as soon as I click on a menu that contains sub-menus. Menus without 
> > sub-menus work fine.
> >
> > The simple solution: use a different style.
> >
> > I fear the bug really sits in TeXmacs not in the style. I have never 
> > experienced problems with the style in any other setting. My guess 
> > would be that the menus are set up in some strange way that usually 
> > works but does not really follow the standards and causes problems in 
> > this special case.
> >
> > Greetings,
> > Norbert
> >
> >
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>
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