Gtk+ versus Qt [LWN.net]

Gtk+ versus Qt

Posted Mar 22, 2007 21:22 UTC (Thu) by oak (guest, #2786)
In reply to: Gtk+ versus Qt by mmutz
Parent article: The road to freedom in the embedded world

IMHO Qt is mainly suited for cases where the project is either proprietary or open AND that doesn't change. The case where you have to pay the licencing fees in the ramp up phase while the code goes through legal and management clearances doesn't fly that well, especially if the code is eventually going to be Open Sourced (or that hasn't been decided yet). Gtk gives more freedom in deciding how & when the code depending on it is to be Open Sourced.

Another issue is that Qt doesn't really have a community developing the widget set like is with Gnome/Gtk, it's completely controlled by Trolltech (which is a commercial entity and could get bought out).

C++ ABI compatibility is still a minor issue too. The C++ ABI changed again between GCC 3.x and 4.x.

On the upsides, Qt for example has excellent documentation and something like Doxygen can produce much nicer class hierarchies etc. from C++ code than what gtk-doc can ever produce from Gobject stuff...

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Gtk+ versus Qt

Posted Mar 23, 2007 21:36 UTC (Fri) by oak (guest, #2786) [Link]

>> Another issue is that Qt doesn't really have a community developing
>> the widget set like is with Gnome/Gtk,
>
> You mean like the KDE devs

Don't they develope things atop Qt, instead developing Qt itself?
AFAIK Trolltech doesn't accept changes from others because they
need to have full ownership of everything in Qt to be able
to dual-license its code. Or do they offer also an option
of contributor resigning all the rights to his code to Trolltech?

> http://www.kde.org/whatiskde/kdefreeqtfoundation.php

Yes, the code will be freed if Trolltech is bought, but the
foundation doesn't come with the Qt developers currently in
the Trolltech payroll. Code without a proper knowledge transfer
from the previous maintainers (or without clear owner / decision
process in technical matters) is much harder to maintain. I don't
know whether this would be a problem in practice. It depends a bit
what would happen with Trolltech and its employees and how much
involvement e.g. current KDE devs have with Qt.

Gtk+ versus Qt

Posted Mar 29, 2007 23:19 UTC (Thu) by Duncan (guest, #6647) [Link]

There is, however, rather more to this picture. Trolltech has very
deliberately "poison-pilled" any hostile buyout or takeover attempt.
(Unlike many smaller companies here in the US, it seems they value their
independence and are /not/ simply there to eventually be bought out.) The
currently active licensing arrangement for Qt is GPL/QPL/proprietary. In
practice, what this does is ensure people contribute back to the community
either with code, or if they don't want to do that, at least with money,
so they can take their work built on top proprietary, but in the process
fund the base that's dual licensed GPL as well, thus contributing to
further development of the free software side with money if they refuse to
contribute to it with code. =8^)

This of course has so far done a good job of keeping Trolltech financially
viable, as well as providing a technically great toolkit for use both in
freedomware and in proprietaryware. The "poison-pill" aspect of the
FreeQTFoundation, however, is that should it be triggered, the code would
*NOT* just be "freed" (there's no need for that, it's already free as in
freedom to anyone wishing to make their own code likewise), but would be
BSD-style licensed, thus allowing commercial use without "giving back" in
the form of code or cash, as is now required. Since the code is the same
but for the license, this would immediately devalue the company in terms
of cash-out value, thus discouraging any action that might trigger the
release in the first place.

BTW, it should also be noted that the way the foundation is setup (two
board members each from Trolltech and KDE, with the KDE side ruling in
case of a tie vote), should Trolltech ever cease to act in the interest of
KDE, KDE has the upper hand. Not that they're likely to trigger it in
anything like the foreseeable future, since that would kill the mutually
beneficial relationship that has and continues to benefit KDE greatly, but
it's nice to know that one way or another, KDE has the legal trump card
should it ever be needed.

Duncan