[SciPy-user] Re[2]: ANN: Veusz 0.5 - a scientific plotting package

[Robert Kern]

Gerard Vermeulen wrote:
> On Mon, 18 Apr 2005 21:53:45 -0700
> Robert Kern <rkern at ucsd.edu> wrote:
> 
> 
>>Robert Kern wrote:
>>
>>>Gerard Vermeulen wrote:
>>
>>>>If you do not use commercial licensed releases of PyQt and Qt, you
>>>>are using the GPL versions.  This implies that you have to release
>>>>your software based on PyQt also under the GPL license.
>>>>
>>>>The modified BSD being compatible with the GPL does not mean that
>>>>you can release GPL derived works under the BSD license.
>>>
>>>
>>>The work as a whole must be distributed under the terms of the GPL. 
>>>However, Jeremy's code can be under whatever license he wishes as long 
>>>as it is compatible with the GPL. If he chose the modified BSD license, 
>>>one could take pieces of that code, inasmuch as they are separable from 
>>>PyQt, and incorporate them into matplotlib. Just because the 
>>>BSD-licensed code is combined with GPL-licensed code doesn't mean that 
>>>the BSD-licensed code is not BSD-licensed.
>>
>> >
>> > Or if he feels like avoiding this silliness, Jeremy could, if he
>> > wanted to, just separately license the bits that other people want to
>> > use in BSDish-licensed, non-PyQt projects.
>>
>>C.f. http://www.opensource.org/licenses/gpl-license.php
>>Section 2
>>
>>"""These requirements apply to the modified work as a whole. If 
>>identifiable sections of that work are not derived from the Program, and 
>>can be reasonably considered independent and separate works in 
>>themselves, then this License, and its terms, do not apply to those 
>>sections when you distribute them as separate works. But when you 
>>distribute the same sections as part of a whole which is a work based on 
>>the Program, the distribution of the whole must be on the terms of this 
>>License, whose permissions for other licensees extend to the entire 
>>whole, and thus to each and every part regardless of who wrote it.
>>"""
>>
> 
> 
> If you write a Python script for PyQt you do not modify PyQt or Qt,
> but you use it.

The "modified work as a whole" would be Veusz+PyQt+Qt. There is no 
distinction here.

> The intent of the GPL is clarified in the GPL-FAQ. Here
> http://www.gnu.org/licenses/gpl-faq.html#IfLibraryIsGPL
> applies:
> 
> """If a library is released under the GPL (not the LGPL), does that
> mean that any program which uses it has to be under the GPL?
> 
> Yes, because the program as it is actually run includes the library.
> """

Yes, it's a pat answer that glosses over the full details, and it is 
intended to further the FSF's goal of getting more software under the 
GPL and not non-copyleft licenses. A fuller answer would use the words 
"as a whole" to modify the word "program" just like the full license 
does. The "program as a whole" must be offered under the GPL because one 
of its components is GPLed. But if the work can be broken down into 
separable components, then such components that aren't derived from that 
already-GPLed code can also be offered under a different license.

The license text itself is quite clear about this issue and is the 
really only thing that matters.

> The business model of Trolltech which also sells commercial licenses
> for Qt is based on this answer.

No, the business model is to sell commercial licenses to people who want 
to incorporate Qt into proprietary products. It is not to sell 
commercial licenses to people who want to use Qt as a library with other 
Free, GPL-compatible code.

Regardless, neither their business model nor a pat FAQ answer overrides 
the plain text of the license.

Of course all of this discussion is moot if Jeremy does not wish to 
offer his code under a freer license even if he feels that he is allowed to.

Now, I am not a lawyer, but I listen to them from time to time. 
Specifically, Chapter 6 of Larry Rosen's book is quite helpful here:

   http://www.rosenlaw.com/oslbook.htm

-- 
Robert Kern
rkern at ucsd.edu

"In the fields of hell where the grass grows high
  Are the graves of dreams allowed to die."
   -- Richard Harter