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Qt/PyQt license confusion

P: n/a
OK, so I'm at the stage where I want to make a choice between wxPython
and PyQt.

Currently I'm using wxPython mainly due to the fact that it has GPL
Linux and Windows versions.

I prefer Qt to wxWindows, but am confused with all the Windows
licensing issues.

For the moment this is just for my own tinkering and utility apps, but
I wouldn't mind being able to distribute them too - freeware/GPL or
whatever, not commercially.

It seems there are numerous sources of a Windows license:

C++ GUI Programming with Qt 3 book (includes Qt 3.2 "book license",
32usd)

TheKompany's BlackAdder (comes with PyQt and Qt limited to Python
license - not C++, "personal use", 80usd)

PyQt license from Riverbank (250usd only supports Qt commercial, not
non-commercial or even evaluation!)

Qt Windows commercial license from Trolltech (1550usd or 2500usd for
Win+Lin)

So it's looking like BlackAdder is the best choice, although I'm still
not sure if that includes a PyQt license as BA is commercial, so is it
stupid enough to not include a commercial PyQt license?! And if it's
limited to "personal use" whatever that is, then surely it's not a
commercial license of either tool?

I don't know what kinda of license comes with the book - if it's not
commercial then PyQt won't support it anyway - maybe it's a kind of
education license?

I'm not paying 1550+250usd just to write Windows apps for myself, and
even if I bought a 250usd PyQt license, I'd still not be able to
evaluate Qt before paying the 1550usd!

So how does everyone else do it - you can't just be writing Linux apps
using PyQt - what's the point of a cross-platform GUI toolkit that you
can only afford to use on one platform?!

Also, can I even use py2exe or McMillan Installer to distribute
commercial versions of anything, as they are GPL tool IIRC...?
Jul 18 '05 #1
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8 Replies


P: n/a
simo wrote:
OK, so I'm at the stage where I want to make a choice between wxPython
and PyQt.
I use wxPython. I couldn't get PyQt to even work, much less to develop
with it. Other people have said the same thing about wxPython, so
perhaps it is a 'depends on the user' thing.
Also, can I even use py2exe or McMillan Installer to distribute
commercial versions of anything, as they are GPL tool IIRC...?


I am not a lawyer, but here is what I believe to be the case:

If you modify a piece of GPL'd software and distribute it, you must
distribute the source of the modified GPL'd software.

If you /use/ a piece of GPL'd software to create 'something else', and
the 'something else' gets distributed, you have used the GPL'd software
as a tool - and are /not required/ to license your 'something else' with
the GPL.

Corrections always appreciated,
- Josiah
Jul 18 '05 #2

P: n/a
Josiah Carlson wrote:
If you /use/ a piece of GPL'd software to create 'something else', and
the 'something else' gets distributed, you have used the GPL'd software
as a tool - and are /not required/ to license your 'something else' with
the GPL.


No, I'm pretty sure you would have to GPL your software then too. Isn't
that the difference between the GPL and LGPL?
Jul 18 '05 #3

P: n/a
Leif K-Brooks <eu*****@ecritters.biz> writes:
If you /use/ a piece of GPL'd software to create 'something else',
and the 'something else' gets distributed, you have used the GPL'd
software as a tool - and are /not required/ to license your
'something else' with the GPL.


No, I'm pretty sure you would have to GPL your software then
too. Isn't that the difference between the GPL and LGPL?


I think he's talking about a different situation than using GPL'd code
in your application. I read it as "Editing your program with GNU
Emacs doesn't mean you then have to distribute the program under the GPL."
Jul 18 '05 #4

P: n/a
On Wed, 04 Feb 2004 13:08:44 -0800, Josiah Carlson wrote:
If you modify a piece of GPL'd software and distribute it, you must
distribute the source of the modified GPL'd software.

If you /use/ a piece of GPL'd software to create 'something else', and
the 'something else' gets distributed, you have used the GPL'd software
as a tool - and are /not required/ to license your 'something else' with
the GPL.


More precisely, you only create a derivative work if your work is based
on the copyrightable part of the original work. Using a tool (such as a
text editor) that doesn't include parts of itself in the result, is not
creating a derivative work of the tool.

This question is covered in the GPL FAQ at the GNU website:

<http://www.gnu.org/licenses/gpl-faq.html#CanIUseGPLToolsForNF>

--
\ "I must say that I find television very educational. The minute |
`\ somebody turns it on, I go to the library and read a book." -- |
_o__) Groucho Marx |
Ben Finney <http://bignose.squidly.org/>
Jul 18 '05 #5

P: n/a
> I think he's talking about a different situation than using GPL'd code
in your application. I read it as "Editing your program with GNU
Emacs doesn't mean you then have to distribute the program under the GPL."


What you say is what I meant.

- Josiah
Jul 18 '05 #6

P: n/a
simo wrote:

For the moment this is just for my own tinkering and utility apps, but
I wouldn't mind being able to distribute them too - freeware/GPL or
whatever, not commercially.

It seems there are numerous sources of a Windows license:

C++ GUI Programming with Qt 3 book (includes Qt 3.2 "book license",
32usd)

TheKompany's BlackAdder (comes with PyQt and Qt limited to Python
license - not C++, "personal use", 80usd)

PyQt license from Riverbank (250usd only supports Qt commercial, not
non-commercial or even evaluation!)

So it's looking like BlackAdder is the best choice, although I'm still
not sure if that includes a PyQt license as BA is commercial, so is it
stupid enough to not include a commercial PyQt license?! And if it's
limited to "personal use" whatever that is, then surely it's not a
commercial license of either tool?

Yes, I aggree is confusing, here's how I understand (some of)it...

BlackAdder is best deal around,

personal version (win/linux), $80 includes both Qt/PyQt lic.
for personal use. Personal use means your free to use
for your own use. Can not distribute, commercially, or
use in a business setting, even for your own use.

Business/Commercial version (win/linux), $380? includes both Qt/PyQt
commercial lic. per developer with rights to distribute.

Here's the confusing part....
If you package up any of the above....

Under windows personal, you can only give the code
to another user, friend etc., they would have to have
thier own Qt/PyQt personal lic. to run it on windows.

Under windows commercial, you could distribute, but...
it has to been done in a way that does not allow
user direct access to the underlying Qt/Pyqt base
code. So they could not use to create there own programs.
I don't know what kinda of license comes with the book - if it's not
commercial then PyQt won't support it anyway - maybe it's a kind of
education license?

Non-Commercial lic., PyQt is still deciding wether they
are going to release a win non-commercial version to coinside
with the new Trolltech non-commercial win release.
They did with the older Qt 2.3 win non-commerial.

I personally think people get to caught up in all this
and try to cover everything from tinkering to commercial
distribution before they even start programming.

It's free to tinker with on linux and distribute
code gpl'd.

Then if you want to tinker on windows, you
could probally still find the old Qt/PyQt win
non-commercial 2.3 version around or wait until
PyQt release a win non-commercial version to
go with the new Qt win non-commercial release
or pay $80 for BlackAdder.

If all that goes so well, you would like
to use/distribute programs written with
Qt/PyQt, $400 seems like a small investment.

I went through the same thing, going back
and forth with wxpy/pyqt, installed and have
used both. I'm staying in the PyQt camp and
have found very little use (none yet) for win
or commercial use. The little tool kit one
can put together is outstanding.....
Qt, Qt Assistant, Qt Designer,
PyQt, pyuic, eric3, etc......



Jul 18 '05 #7

P: n/a
Ken Godee <ke*@perfect-image.com> wrote

[snip]
BlackAdder is best deal around,

personal version (win/linux), $80 includes both Qt/PyQt lic.
for personal use. Personal use means your free to use
for your own use. Can not distribute, commercially, or
use in a business setting, even for your own use.
Yes, as far as I can tell after talking to Riverbank, The Kompany and
Trolltech, BA Personal is literally for your own non-commercial use
with NO DISTRIBUTION at all for Windows, but the Linux stuff is still
GPL.
Business/Commercial version (win/linux), $380? includes both Qt/PyQt
commercial lic. per developer with rights to distribute.
$400 and yes, looks like unlimited (even commercial) rights to
distribute Qt/PyQt apps, but as you say.....
Under windows personal, you can only give the code
to another user, friend etc., they would have to have
thier own Qt/PyQt personal lic. to run it on windows.
Yes, looks like users would have to source their own DLL's to run it,
from what Riverbank said, which means owning BA/Qt/PyQt etc.
Under windows commercial, you could distribute, but...
it has to been done in a way that does not allow
user direct access to the underlying Qt/Pyqt base
code. So they could not use to create there own programs.
Does this mean I couldn't distribute the Qt/PyQT DLL's still as they
could be used to run other Py[Qt] apps, I guess static (McMillan
Installer) binaries would be OK....

[book] Non-Commercial lic., PyQt is still deciding wether they
are going to release a win non-commercial version to coinside
with the new Trolltech non-commercial win release.
They did with the older Qt 2.3 win non-commerial.
Yup, Riverbank basically said they're undecided, I don't know if
that's because it might compromise BlackAdder sales, also the Qt 3.2.1
with the book won't work with the commercial PyQt either, and 2.3 is
now unsupported too.

I wonder if it might be worth getting BA for the PyQt license and the
book for the full Qt license (i.e. it works with C++ too) although
that's $110+ now....
I personally think people get to caught up in all this
and try to cover everything from tinkering to commercial
distribution before they even start programming.

It's free to tinker with on linux and distribute
code gpl'd.
Well that's what I'm currently doing, but I'd like to use Windows
versions myself too. The only option I see is to distribute Linux
versions, with source code under the GPL that Windows users could use
if they had the PyQt/Qt licenses.

[...] If all that goes so well, you would like
to use/distribute programs written with
Qt/PyQt, $400 seems like a small investment.
I'm never going to write applications that would make it worth my
while to buy a $400 license just for Windows versions!
I went through the same thing, going back
and forth with wxpy/pyqt, installed and have
used both. I'm staying in the PyQt camp and
have found very little use (none yet) for win
or commercial use. The little tool kit one
can put together is outstanding.....
Qt, Qt Assistant, Qt Designer,
PyQt, pyuic, eric3, etc......


Well I'm not a very "visual" style programmer so Designer/pyuic are
not really for me, but the Python version of Assistant looks very
promising (as I hate the C++ docs, when you're coding Python!)
Jul 18 '05 #8

P: n/a
>>Under windows commercial, you could distribute, but...
it has to been done in a way that does not allow
user direct access to the underlying Qt/Pyqt base
code. So they could not use to create there own programs.
Does this mean I couldn't distribute the Qt/PyQT DLL's still as they
could be used to run other Py[Qt] apps, I guess static (McMillan
Installer) binaries would be OK....

The PyQt site has some Howto's on how to package up your
apps under win/linux.
I wonder if it might be worth getting BA for the PyQt license and the
book for the full Qt license (i.e. it works with C++ too) although
that's $110+ now....


If you buy the BA lic. you get current version
of Qt/PyQt combo for win/linux.
$80.00

If you buy the book, you get NON-COMMERCIAL Qt only, which
you already got with BA.

I've got a copy of the book coming as we speak, $31 @ amazon
I think $31 just to have the book as a reference by itself
is worth the money and as far as these types of books go, that's a very
resonable price. Wanna buy a shelf full of Perl books?
I went through the same thing, going back
and forth with wxpy/pyqt, installed and have
used both. I'm staying in the PyQt camp and
have found very little use (none yet) for win
or commercial use. The little tool kit one
can put together is outstanding.....
Qt, Qt Assistant, Qt Designer,
PyQt, pyuic, eric3, etc......

Well I'm not a very "visual" style programmer so Designer/pyuic are
not really for me, but the Python version of Assistant looks very
promising (as I hate the C++ docs, when you're coding Python!)


I tell ya, using Designer/pyuic one can belt out a pretty
complex form in a fraction of the time. If you haven't atleast
gave it a good go, you should.

I'm sure you know already, but you can buy just the Qt c++ docs
converted to PyQt for $20 as a stand alone.

Jul 18 '05 #9

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