Re: Qt Theming being a GPL violation

On Sat, 2004-06-19 at 17:50, Rhys Weatherley wrote:
> The moral of the story is this: we need to add some information to the 
> documentation that the Qt themer can only be used with applications whose 
> licenses are compatible with the GPL.  If a user uses the Qt themer to run a 
> non-compatible application, then the user has caused a violation to occur.


Users can't violate the GPL, only distributors can. If a user runs a
non-GPL SWF application using pnet and they turn on the Qt themer, they
have not caused a violation of the GPL because the combination of
GPL+non-GPL code is not distributed to anyone; it occurs only on the end
user's system. Because the GPL only covers distribution, this is not a
violation of the GPL by the end-user. An example of this is proprietary
Nvidia drivers being used by an X server upon which Qt-based
applications are running; the end user makes the connections between the
GPL and non-GPL components, so there is no license violation.

So long as the Qt themer is distributed separately from pnetlib (at
least for source distribution, where keeping GPL+LE is desired), and so
long as pnetlib itself has no direct, hardcoded, knowledge of the Qt
themer, there shouldn't be a problem. If pnetlib's theming system were
to have some hardcoded setting for the Qt themer, this would be making
the connection in pnetlib code, whereas such a connection can only
legally be made by the end user (so long as we want to keep pnetlib
GPL+LE). This means we need some kind of system to load themes
dynamically and the part of the system which actually makes the Qt
themer known to the ThemeManager must be distributed with the Qt themer
rather than with pnetlib. A workable example would be a configuration
file which is read by the ThemeManager, and is set to use the
DefaultThemePainter by default, but which can be modified by the Qt
themer's installation scripts to inform the ThemeManager of the Qt
themer's existence and its location on the system.


Rich