RE: [GRASS-dev] v.digit: Qt or wxWidgets

John_Gillette1 · May 19, 2006, 11:17pm

From: Michael Barton

I can offer a couple of answers, though Glynn and others can
fill in richer details.

(2) wxWidgets is an interface building platform, like TclTk,
QT, and GTK. It can be used with C.

(3) I think that this is answered in (2)

(4) wxWidgets, like QT and TclTk has versions that run
natively across platforms--inlcuding most *nix flavors, Mac
OS X, and Windows. GTK runs primarily in X11 (though there
are experimental versions under development for other
platforms I understand).

Michael

This probably answers most of my questions. Obviously wxWidgets
is a C++ program which would call the C grass libraries. I was
confused by the relationship of GTK+ and wxWidgets on Linux.
wxWidgets "sits on top of GTK+" to use GTK+ as the native GUI
on Linux (only). So based on Michael's answer above, wxWidgets
would make it easier to port GUI programs to other systems while
doing away with the X11 requirement. This also avoids licensing
issues with Qt.

So ... wxWidgets?

John

cmbarton · May 20, 2006, 6:46am

My understanding is that, as of last summer, there are open source versions
of QT for all platforms.

Same for TclTk and wxWidgets

Michael
__________________________________________
Michael Barton, Professor of Anthropology
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton

From: John Gillette <JGillette@rfmd.com>
Date: Fri, 19 May 2006 19:17:52 -0400
To: Michael Barton <michael.barton@asu.edu>, Glynn Clements
<glynn@gclements.plus.com>
Cc: <grass-dev@grass.itc.it>
Conversation: [GRASS-dev] v.digit: Qt or wxWidgets
Subject: RE: [GRASS-dev] v.digit: Qt or wxWidgets

From: Michael Barton

I can offer a couple of answers, though Glynn and others can
fill in richer details.

(2) wxWidgets is an interface building platform, like TclTk,
QT, and GTK. It can be used with C.

(3) I think that this is answered in (2)

(4) wxWidgets, like QT and TclTk has versions that run
natively across platforms--inlcuding most *nix flavors, Mac
OS X, and Windows. GTK runs primarily in X11 (though there
are experimental versions under development for other
platforms I understand).

Michael

This probably answers most of my questions. Obviously wxWidgets
is a C++ program which would call the C grass libraries. I was
confused by the relationship of GTK+ and wxWidgets on Linux.
wxWidgets "sits on top of GTK+" to use GTK+ as the native GUI
on Linux (only). So based on Michael's answer above, wxWidgets
would make it easier to port GUI programs to other systems while
doing away with the X11 requirement. This also avoids licensing
issues with Qt.

So ... wxWidgets?

John

Benjamin_Ducke3 · May 20, 2006, 9:44am

Wxwidgets does not currently seem to have C support, but that
is not so important:
it is not uncommon for a large software project to use different
programming languages for different parts of the project.
It seems that an objected-oriented language is better suited for
modern day GUI development as it is easy and clean to map GUI
interactions and widgets to classes and methods with a toolkit in C++ or Java.
A good GUI, though looking simple can become a very complex issue due
to the many levels of interactions with the user, OS etc. A good OO
framework can help a lot here.

On the other hand, C is still the language of choice for computationally intensive algorithms.

So there is nothing that speaks against continuing the low-level GIS
programming in C and putting a C++ GUI toolkit on top of it.

I like Wxwidgets because it is truly open source and has bindings
for many high-level languages (perl, python, .NET, ...). It also uses
native GUI widgets on each platform, so on any OS, the user will
feel comfortable with a Wxwidgets GUI. Plus it has excellent
documentation, API stability and user base support.

Qt is a nice toolkit too, but it is not as open as Wxwidgets. There are
subtle but maybe relevant differences in the licensing scheme and it
seems that there is always a difference between the open source and the
commercial versions. But I think Radim is more qualified to judge this.

Well, that's my thoughts on it.

Benjamin

Michael Barton wrote:

My understanding is that, as of last summer, there are open source versions
of QT for all platforms.

Same for TclTk and wxWidgets

Michael
__________________________________________
Michael Barton, Professor of Anthropology
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton

From: John Gillette <JGillette@rfmd.com>
Date: Fri, 19 May 2006 19:17:52 -0400
To: Michael Barton <michael.barton@asu.edu>, Glynn Clements
<glynn@gclements.plus.com>
Cc: <grass-dev@grass.itc.it>
Conversation: [GRASS-dev] v.digit: Qt or wxWidgets
Subject: RE: [GRASS-dev] v.digit: Qt or wxWidgets

From: Michael Barton

I can offer a couple of answers, though Glynn and others can
fill in richer details.

(2) wxWidgets is an interface building platform, like TclTk,
QT, and GTK. It can be used with C.

(3) I think that this is answered in (2)

(4) wxWidgets, like QT and TclTk has versions that run
natively across platforms--inlcuding most *nix flavors, Mac
OS X, and Windows. GTK runs primarily in X11 (though there
are experimental versions under development for other
platforms I understand).

Michael

This probably answers most of my questions. Obviously wxWidgets
is a C++ program which would call the C grass libraries. I was
confused by the relationship of GTK+ and wxWidgets on Linux.
wxWidgets "sits on top of GTK+" to use GTK+ as the native GUI
on Linux (only). So based on Michael's answer above, wxWidgets
would make it easier to port GUI programs to other systems while
doing away with the X11 requirement. This also avoids licensing
issues with Qt.

So ... wxWidgets?

John

_______________________________________________
grass-dev mailing list
grass-dev@grass.itc.it
http://grass.itc.it/mailman/listinfo/grass-dev

--
Benjamin Ducke, M.A.
Archäoinformatik
(Archaeoinformation Science)
Institut für Ur- und Frühgeschichte
(Inst. of Prehistoric and Historic Archaeology)
Christian-Albrechts-Universität zu Kiel
Johanna-Mestorf-Straße 2-6
D 24098 Kiel
Germany

Tel.: ++49 (0)431 880-3378 / -3379
Fax : ++49 (0)431 880-7300
www.uni-kiel.de/ufg

H_B · May 21, 2006, 6:00am

> (4) wxWidgets, like QT and TclTk has versions that run
> natively across platforms--inlcuding most *nix flavors, Mac
> OS X, and Windows. GTK runs primarily in X11 (though there
> are experimental versions under development for other
> platforms I understand).

FWIW, WinGIMP uses GTK on windows & works quite well.

Also consider where GTK+ (or any other toolkit in active development)
will be on the Mac not now, but when the software will be written/ready.
If in 6 months GTK will likely be ready for the Mac, I don't see that as
a blocker. Plan for the long term..

Hamish

H_B · May 21, 2006, 6:03am

This also avoids licensing issues with Qt.

I don't think these issues exist anymore. AFAIU, the version for Windows
is no longer restricted.

Hamish

Glynn_Clements1 · May 21, 2006, 7:08am

Hamish wrote:

> > (4) wxWidgets, like QT and TclTk has versions that run
> > natively across platforms--inlcuding most *nix flavors, Mac
> > OS X, and Windows. GTK runs primarily in X11 (though there
> > are experimental versions under development for other
> > platforms I understand).

FWIW, WinGIMP uses GTK on windows & works quite well.

The Windows port isn't an issue. I use several GTK programs on Windows
(Pan, XChat, GIMP) and they work almost as well as on Linux.

I'm more concerned about the Mac. In particular, the fact that you can
use the Unix/X11 version of GTK with an X server allows developers to
"cop out" and risks reducing the motivation to develop the native
version.

Also consider where GTK+ (or any other toolkit in active development)
will be on the Mac not now, but when the software will be written/ready.
If in 6 months GTK will likely be ready for the Mac, I don't see that as
a blocker. Plan for the long term..

Part of the problem there is that it might be quite simple to produce
a version which "mostly" works on the Mac yet much harder to actually
finish the job. Looking at the "todo" list for the Mac port suggests
that some of the outstanding tasks might be quite hard. I'm also
quite worried about this:

Menus/pop up windows

* These are currently buggy and need fixing. (medium)

Most of the other items on that list aren't critical, as they relate
to things we don't particularly need. But we will need menus and
pop-up windows, and they'll need to work well enough for the
application to be usable.

--
Glynn Clements <glynn@gclements.plus.com>

Radim_Blazek3 · May 22, 2006, 8:31am

On 5/20/06, John Gillette <JGillette@rfmd.com> wrote:

This also avoids licensing issues with Qt.

???

Radim

Radim_Blazek3 · May 22, 2006, 8:47am

On 5/20/06, Benjamin Ducke <benjamin.ducke@ufg.uni-kiel.de> wrote:

Qt is a nice toolkit too, but it is not as open as Wxwidgets.

What do you mean exactly. It is GPL on all platforms.

There are
subtle but maybe relevant differences in the licensing scheme and it
seems that there is always a difference between the open source and the
commercial versions. But I think Radim is more qualified to judge this.

I cannot say if there are differences, but I don't believe.
We are using GPL version on all platforms.
There are some additional packages (QSA, Qt Solutions, Teambuilder)
which are not available under GPL on all platforms but the Qt, Qtopia
and Qtopia SDK will be most probably the same on all platforms
and under all licenses.

http://www.trolltech.com/products/qt/licenses/licensing/matrix

I don't care which toolkit you choose. I just don't like to see
that some people for some strange reasons repeat to say that
Qt is not free, which is not true.

Radim

Glynn_Clements1 · May 22, 2006, 3:20pm

Radim Blazek wrote:

What do you mean exactly. It is GPL on all platforms.

> There are
> subtle but maybe relevant differences in the licensing scheme and it
> seems that there is always a difference between the open source and the
> commercial versions. But I think Radim is more qualified to judge this.

I cannot say if there are differences, but I don't believe.
We are using GPL version on all platforms.
There are some additional packages (QSA, Qt Solutions, Teambuilder)
which are not available under GPL on all platforms but the Qt, Qtopia
and Qtopia SDK will be most probably the same on all platforms
and under all licenses.

http://www.trolltech.com/products/qt/licenses/licensing/matrix

I don't care which toolkit you choose. I just don't like to see
that some people for some strange reasons repeat to say that
Qt is not free, which is not true.

The licensing information on the TrollTech site suggests that the
licence for the Open Source edition isn't actually the GPL, but a
requirement that you publish your code under the terms of the GPL.

The GPL itself does not require that you publish your code at all. You
are free to create derivative works and not publish them at all. /If/
you publish them, you must do so under the terms of the GPL.

TrollTech's site suggests that you cannot develop "in-house"
applications using the Qt Open Source edition (and you can't obtain a
commercial licence for software which was originally developed using
the Open Source edition). In which case, the licence isn't even
GPL-compatible.

--
Glynn Clements <glynn@gclements.plus.com>

Laurent_C · May 22, 2006, 3:50pm

2006/5/22, Glynn Clements <glynn@gclements.plus.com>:

Radim Blazek wrote:

What do you mean exactly. It is GPL on all platforms.

There are
subtle but maybe relevant differences in the licensing scheme and it
seems that there is always a difference between the open source and the
commercial versions. But I think Radim is more qualified to judge this.

I cannot say if there are differences, but I don’t believe.
We are using GPL version on all platforms.
There are some additional packages (QSA, Qt Solutions, Teambuilder)
which are not available under GPL on all platforms but the Qt, Qtopia
and Qtopia SDK will be most probably the same on all platforms
and under all licenses.

http://www.trolltech.com/products/qt/licenses/licensing/matrix

I don’t care which toolkit you choose. I just don’t like to see
that some people for some strange reasons repeat to say that
Qt is not free, which is not true.

The licensing information on the TrollTech site suggests that the
licence for the Open Source edition isn’t actually the GPL, but a
requirement that you publish your code under the terms of the GPL.

The GPL itself does not require that you publish your code at all. You
are free to create derivative works and not publish them at all. /If/
you publish them, you must do so under the terms of the GPL.

TrollTech’s site suggests that you cannot develop “in-house”
applications using the Qt Open Source edition (and you can’t obtain a
commercial licence for software which was originally developed using
the Open Source edition). In which case, the licence isn’t even
GPL-compatible.

–
Glynn Clements < glynn@gclements.plus.com>

grass-dev mailing list
grass-dev@grass.itc.it
http://grass.itc.it/mailman/listinfo/grass-dev

From Trolltech’s website :

“Trolltech’s dual license policy provides versions of Qt under the terms of the GNU General Public License (GPL).”

I don’t think there are lincensing problems with Qt.

Radim_Blazek3 · May 22, 2006, 3:56pm

On 5/22/06, Glynn Clements <glynn@gclements.plus.com> wrote:

Radim Blazek wrote:

> What do you mean exactly. It is GPL on all platforms.
>
> > There are
> > subtle but maybe relevant differences in the licensing scheme and it
> > seems that there is always a difference between the open source and the
> > commercial versions. But I think Radim is more qualified to judge this.
>
> I cannot say if there are differences, but I don't believe.
> We are using GPL version on all platforms.
> There are some additional packages (QSA, Qt Solutions, Teambuilder)
> which are not available under GPL on all platforms but the Qt, Qtopia
> and Qtopia SDK will be most probably the same on all platforms
> and under all licenses.
>
> http://www.trolltech.com/products/qt/licenses/licensing/matrix
>
> I don't care which toolkit you choose. I just don't like to see
> that some people for some strange reasons repeat to say that
> Qt is not free, which is not true.

The licensing information on the TrollTech site suggests that the
licence for the Open Source edition isn't actually the GPL, but a
requirement that you publish your code under the terms of the GPL.

The GPL itself does not require that you publish your code at all. You
are free to create derivative works and not publish them at all. /If/
you publish them, you must do so under the terms of the GPL.

TrollTech's site suggests that you cannot develop "in-house"
applications using the Qt Open Source edition (and you can't obtain a
commercial licence for software which was originally developed using
the Open Source edition). In which case, the licence isn't even
GPL-compatible.

I cannot find anything like that. The opensource package is licenced under
GPL and I don't see any exception. Where is written that you
must publish your code even if you do not distribute the application
or that you cannot develop and use "in-house" application using open source
edition of Qt?

Radim

--
Glynn Clements <glynn@gclements.plus.com>

Laurent_C · May 22, 2006, 4:13pm

2006/5/22, Radim Blazek <radim.blazek@gmail.com>:

On 5/22/06, Glynn Clements <glynn@gclements.plus.com> wrote:

Radim Blazek wrote:

What do you mean exactly. It is GPL on all platforms.

There are
subtle but maybe relevant differences in the licensing scheme and it
seems that there is always a difference between the open source and the
commercial versions. But I think Radim is more qualified to judge this.

I cannot say if there are differences, but I don’t believe.
We are using GPL version on all platforms.
There are some additional packages (QSA, Qt Solutions, Teambuilder)
which are not available under GPL on all platforms but the Qt, Qtopia
and Qtopia SDK will be most probably the same on all platforms
and under all licenses.

http://www.trolltech.com/products/qt/licenses/licensing/matrix

I don’t care which toolkit you choose. I just don’t like to see
that some people for some strange reasons repeat to say that
Qt is not free, which is not true.

The licensing information on the TrollTech site suggests that the
licence for the Open Source edition isn’t actually the GPL, but a
requirement that you publish your code under the terms of the GPL.

The GPL itself does not require that you publish your code at all. You
are free to create derivative works and not publish them at all. /If/
you publish them, you must do so under the terms of the GPL.

TrollTech’s site suggests that you cannot develop “in-house”
applications using the Qt Open Source edition (and you can’t obtain a
commercial licence for software which was originally developed using
the Open Source edition). In which case, the licence isn’t even
GPL-compatible.

I cannot find anything like that. The opensource package is licenced under
GPL and I don’t see any exception. Where is written that you
must publish your code even if you do not distribute the application
or that you cannot develop and use “in-house” application using open source
edition of Qt?

Radim

There is something like that here (http://www.trolltech.com/products/qt/licenses/licensing/opensource )

“If you wish to use the Qt Open Source Edition, you must contribute all your source code to the open source community in accordance with the GPL when your application is distributed.”

“when your application is distributed”. There are no licensing problems for me.
I’ve just dowloaded the package and the lincense packaged is the GPL.

Radim_Blazek3 · May 22, 2006, 4:27pm

On 5/22/06, Laurent C. <lrntct@gmail.com> wrote:

2006/5/22, Radim Blazek <radim.blazek@gmail.com>:
> On 5/22/06, Glynn Clements <glynn@gclements.plus.com> wrote:
> >
> > Radim Blazek wrote:
> >
> > > What do you mean exactly. It is GPL on all platforms.
> > >
> > > > There are
> > > > subtle but maybe relevant differences in the licensing scheme and it
> > > > seems that there is always a difference between the open source and
the
> > > > commercial versions. But I think Radim is more qualified to judge
this.
> > >
> > > I cannot say if there are differences, but I don't believe.
> > > We are using GPL version on all platforms.
> > > There are some additional packages (QSA, Qt Solutions, Teambuilder)
> > > which are not available under GPL on all platforms but the Qt, Qtopia
> > > and Qtopia SDK will be most probably the same on all platforms
> > > and under all licenses.
> > >
http://www.trolltech.com/products/qt/licenses/licensing/matrix
> > >
> > > I don't care which toolkit you choose. I just don't like to see
> > > that some people for some strange reasons repeat to say that
> > > Qt is not free, which is not true.
> >
> > The licensing information on the TrollTech site suggests that the
> > licence for the Open Source edition isn't actually the GPL, but a
> > requirement that you publish your code under the terms of the GPL.
> >
> > The GPL itself does not require that you publish your code at all. You
> > are free to create derivative works and not publish them at all. /If/
> > you publish them, you must do so under the terms of the GPL.
> >
> > TrollTech's site suggests that you cannot develop "in-house"
> > applications using the Qt Open Source edition (and you can't obtain a
> > commercial licence for software which was originally developed using
> > the Open Source edition). In which case, the licence isn't even
> > GPL-compatible.
>
> I cannot find anything like that. The opensource package is licenced under
> GPL and I don't see any exception. Where is written that you
> must publish your code even if you do not distribute the application
> or that you cannot develop and use "in-house" application using open
source
> edition of Qt?
>
> Radim

There is something like that here
(http://www.trolltech.com/products/qt/licenses/licensing/opensource
)

"If you wish to use the Qt Open Source Edition, you must contribute all your
source code to the open source community in accordance with the GPL when
your application is distributed."
"when your application is distributed". There are no licensing problems for
me.
I've just dowloaded the package and the lincense packaged is the GPL.

Yes, "when your application is distributed" and "in accordance with the GPL"
so it is GPL, nothing more.

Radim

Glynn_Clements1 · May 22, 2006, 7:26pm

Radim Blazek wrote:

> > I don't care which toolkit you choose. I just don't like to see
> > that some people for some strange reasons repeat to say that
> > Qt is not free, which is not true.
>
> The licensing information on the TrollTech site suggests that the
> licence for the Open Source edition isn't actually the GPL, but a
> requirement that you publish your code under the terms of the GPL.
>
> The GPL itself does not require that you publish your code at all. You
> are free to create derivative works and not publish them at all. /If/
> you publish them, you must do so under the terms of the GPL.
>
> TrollTech's site suggests that you cannot develop "in-house"
> applications using the Qt Open Source edition (and you can't obtain a
> commercial licence for software which was originally developed using
> the Open Source edition). In which case, the licence isn't even
> GPL-compatible.

I cannot find anything like that. The opensource package is licenced under
GPL and I don't see any exception. Where is written that you
must publish your code even if you do not distribute the application
or that you cannot develop and use "in-house" application using open source
edition of Qt?

http://www.trolltech.com/products/qt/licenses/licensing

  You must purchase a Qt Commercial License from Trolltech or
  from any of its authorized resellers before you start
  developing proprietary software. The Commercial license does
  not allow the incorporation of code developed with the Open
  Source Edition of Qt into a proprietary product.

http://www.trolltech.com/products/qt/licenses/licensing/opensource

  Based on the "Quid Pro Quo" principle, if you wish to derive a
  commercial advantage by not releasing your application under
  an open source license, you must purchase an appropriate
  number of commercial licenses from Trolltech. By purchasing
  commercial licenses, you are no longer obliged to publish your
  source code.

http://www.trolltech.com/developer/downloads/qt/faq

  If you are working in a commercial environment and are
  required to keep the source code of your product closed, you
  must use the commercial version instead. Trolltech's
  commercial license terms do not allow you to start developing
  proprietary software using the Open Source edition.

http://www.trolltech.com/developer/downloads/qt/x11

  If you are writing proprietary/commercial software, or if you
  plan to commercialize the software you are writing with Qt,
  you must use a commercial version of Qt. Please refer to the
  Open Source Downloads info page for reasons why.

Now, all of these could be considered mistakes in wording, based upon
the assumption that the software will ultimately be distributed. Or
they could be the result of TrollTech misunderstanding the
consequences of releasing Qt under the GPL. Or they could be a
calculated attempt to sell more commercial licences by misleading
users as to the scope of the rights granted by the GPL.

If the only licence which is included in the official Qt Open Source
version distributed by TrollTech is a copy of the GPL, then there's no
problem. You have the rights stated there regardless of TrollTech's
interpretation of them.

--
Glynn Clements <glynn@gclements.plus.com>

Radim_Blazek3 · May 23, 2006, 7:02am

On 5/22/06, Glynn Clements <glynn@gclements.plus.com> wrote:

Radim Blazek wrote:

> > > I don't care which toolkit you choose. I just don't like to see
> > > that some people for some strange reasons repeat to say that
> > > Qt is not free, which is not true.
> >
> > The licensing information on the TrollTech site suggests that the
> > licence for the Open Source edition isn't actually the GPL, but a
> > requirement that you publish your code under the terms of the GPL.
> >
> > The GPL itself does not require that you publish your code at all. You
> > are free to create derivative works and not publish them at all. /If/
> > you publish them, you must do so under the terms of the GPL.
> >
> > TrollTech's site suggests that you cannot develop "in-house"
> > applications using the Qt Open Source edition (and you can't obtain a
> > commercial licence for software which was originally developed using
> > the Open Source edition). In which case, the licence isn't even
> > GPL-compatible.
>
> I cannot find anything like that. The opensource package is licenced under
> GPL and I don't see any exception. Where is written that you
> must publish your code even if you do not distribute the application
> or that you cannot develop and use "in-house" application using open source
> edition of Qt?

http://www.trolltech.com/products/qt/licenses/licensing

        You must purchase a Qt Commercial License from Trolltech or
        from any of its authorized resellers before you start
        developing proprietary software. The Commercial license does
        not allow the incorporation of code developed with the Open
        Source Edition of Qt into a proprietary product.

http://www.trolltech.com/products/qt/licenses/licensing/opensource

        Based on the "Quid Pro Quo" principle, if you wish to derive a
        commercial advantage by not releasing your application under
        an open source license, you must purchase an appropriate
        number of commercial licenses from Trolltech. By purchasing
        commercial licenses, you are no longer obliged to publish your
        source code.

http://www.trolltech.com/developer/downloads/qt/faq

        If you are working in a commercial environment and are
        required to keep the source code of your product closed, you
        must use the commercial version instead. Trolltech's
        commercial license terms do not allow you to start developing
        proprietary software using the Open Source edition.

http://www.trolltech.com/developer/downloads/qt/x11

        If you are writing proprietary/commercial software, or if you
        plan to commercialize the software you are writing with Qt,
        you must use a commercial version of Qt. Please refer to the
        Open Source Downloads info page for reasons why.

Now, all of these could be considered mistakes in wording, based upon
the assumption that the software will ultimately be distributed. Or
they could be the result of TrollTech misunderstanding the
consequences of releasing Qt under the GPL. Or they could be a
calculated attempt to sell more commercial licences by misleading
users as to the scope of the rights granted by the GPL.

IMO it is quite clear, they just say in other words what is written
in detail in their licenses: you can only use open source edition
to develop open source software. If you have doubts about
in-house applications you can read GPL.

If the only licence which is included in the official Qt Open Source
version distributed by TrollTech is a copy of the GPL, then there's no
problem. You have the rights stated there regardless of TrollTech's
interpretation of them.

I think so.

Radim

--
Glynn Clements <glynn@gclements.plus.com>

Ron_Yorston · May 23, 2006, 9:49am

Glynn Clements <glynn@gclements.plus.com> wrote:

http://www.trolltech.com/products/qt/licenses/licensing

You must purchase a Qt Commercial License from Trolltech or
from any of its authorized resellers before you start
developing proprietary software. The Commercial license does
not allow the incorporation of code developed with the Open
Source Edition of Qt into a proprietary product.

http://www.trolltech.com/products/qt/licenses/licensing/opensource

Based on the "Quid Pro Quo" principle, if you wish to derive a
commercial advantage by not releasing your application under
an open source license, you must purchase an appropriate
number of commercial licenses from Trolltech. By purchasing
commercial licenses, you are no longer obliged to publish your
source code.

http://www.trolltech.com/developer/downloads/qt/faq

If you are working in a commercial environment and are
required to keep the source code of your product closed, you
must use the commercial version instead. Trolltech's
commercial license terms do not allow you to start developing
proprietary software using the Open Source edition.

http://www.trolltech.com/developer/downloads/qt/x11

If you are writing proprietary/commercial software, or if you
plan to commercialize the software you are writing with Qt,
you must use a commercial version of Qt. Please refer to the
Open Source Downloads info page for reasons why.

Now, all of these could be considered mistakes in wording, based upon
the assumption that the software will ultimately be distributed. Or
they could be the result of TrollTech misunderstanding the
consequences of releasing Qt under the GPL. Or they could be a
calculated attempt to sell more commercial licences by misleading
users as to the scope of the rights granted by the GPL.

If the only licence which is included in the official Qt Open Source
version distributed by TrollTech is a copy of the GPL, then there's no
problem. You have the rights stated there regardless of TrollTech's
interpretation of them.

I think TrollTech have a very clear understanding of the GPL and its
consequences.

The items quoted from their website all say in different ways that
'you must' use a commercially licensed version of Qt if you want to
distribute your software and keep the source code closed. This is
not something you could do under the GPL.

The leverage TrollTech have which allows them to say 'you must'
behave in a particular way is that they can refuse to sell you a
commercial licence. If you want to buy your way out of the GPL's
obligation to publish source you have to do so on TrollTech's terms.

This has no affect on your rights under the GPL.

Ron

Glynn_Clements1 · May 23, 2006, 7:24pm

Ron Yorston wrote:

> http://www.trolltech.com/products/qt/licenses/licensing
>
> You must purchase a Qt Commercial License from Trolltech or
> from any of its authorized resellers before you start
> developing proprietary software. The Commercial license does
> not allow the incorporation of code developed with the Open
> Source Edition of Qt into a proprietary product.
>
> http://www.trolltech.com/products/qt/licenses/licensing/opensource
>
> Based on the "Quid Pro Quo" principle, if you wish to derive a
> commercial advantage by not releasing your application under
> an open source license, you must purchase an appropriate
> number of commercial licenses from Trolltech. By purchasing
> commercial licenses, you are no longer obliged to publish your
> source code.
>
> http://www.trolltech.com/developer/downloads/qt/faq
>
> If you are working in a commercial environment and are
> required to keep the source code of your product closed, you
> must use the commercial version instead. Trolltech's
> commercial license terms do not allow you to start developing
> proprietary software using the Open Source edition.
>
> http://www.trolltech.com/developer/downloads/qt/x11
>
> If you are writing proprietary/commercial software, or if you
> plan to commercialize the software you are writing with Qt,
> you must use a commercial version of Qt. Please refer to the
> Open Source Downloads info page for reasons why.
>
> Now, all of these could be considered mistakes in wording, based upon
> the assumption that the software will ultimately be distributed. Or
> they could be the result of TrollTech misunderstanding the
> consequences of releasing Qt under the GPL. Or they could be a
> calculated attempt to sell more commercial licences by misleading
> users as to the scope of the rights granted by the GPL.
>
> If the only licence which is included in the official Qt Open Source
> version distributed by TrollTech is a copy of the GPL, then there's no
> problem. You have the rights stated there regardless of TrollTech's
> interpretation of them.

I think TrollTech have a very clear understanding of the GPL and its
consequences.

The items quoted from their website all say in different ways that
'you must' use a commercially licensed version of Qt if you want to
distribute your software and keep the source code closed.

No they don't.

That may be what was intended, but it isn't what is actually said
above. All of those quotes omit the "distribute your software" part;
i.e. they say that you must use the commercial version if you want to
keep the source closed, with no mention of distribution.

Assuming that the above are due simply to a poor choice of wording[1],
they wouldn't be the first to make that mistake. Netscape made a
similar error with the original draft of the Mozilla Public Licence,
stating that "you must publish the modified version under the terms of
this licence", rather than "if you publish the modified version, you
must do so under the terms of this licence".

[1] If Qt's licencing terms really did require you to publish
"private" derivative works, I think that the FSF would have said
something by now.

--
Glynn Clements <glynn@gclements.plus.com>

H_B · May 24, 2006, 3:09am

[1] If Qt's licencing terms really did require you to publish
"private" derivative works, I think that the FSF would have said
something by now.

let's just go to the source..

wget http://wftp.tu-chemnitz.de/pub/Qt/qt/source/qt-win-opensource-src-4.1.3.zip

$ unzip qt-win-opensource-src-4.1.3.zip

$ head LICENSE.GPL

You may use, distribute and copy the Qt GUI Toolkit under the terms of
GNU General Public License version 2, which is displayed below.

-------------------------------------------------------------------------

GNU GENERAL PUBLIC LICENSE
Version 2, June 1991

$ head -22 src/winmain/qtmain_win.cpp
/****************************************************************************
**
** Copyright (C) 1992-2006 Trolltech AS. All rights reserved.
**
** This file is part of the window classes of the Qt Toolkit.
**
** This file may be used under the terms of the GNU General Public
** License version 2.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of
** this file. Please review the following information to ensure GNU
** General Public Licensing requirements will be met:
** http://www.trolltech.com/products/qt/opensource.html
**
** If you are unsure which license is appropriate for your use, please
** review the following information:
** http://www.trolltech.com/products/qt/licensing.html or contact the
** sales department at sales@trolltech.com.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
****************************************************************************/

$ less OPENSOURCE-NOTICE.TXT
[attached]

Hamish

(attachments)

OPENSOURCE-NOTICE.TXT (2.64 KB)