On Mon, Nov 22, 2010 at 11:10 PM, Knapp <magick.c...@gmail.com> wrote:
> http://en.wikipedia.org/wiki/PyQt > > PyQt is developed by the British firm Riverbank Computing. It is > available under similar terms to Qt versions older than 4.5; this > means a variety of licenses including GNU General Public License (GPL) > and commercial license, but not the GNU Lesser General Public License > (LGPL). > Right. In both of these cases they are using the GPL to provide a free version to the community for only GPL software development, attempting to assure closed-source software development must license their commercial version. Remember that while GPL software can "incorporate a closed source library as a library exception", the GPL makes no such provision for a piece of software to "incorporate GPL code without becoming GPL". If you depend on details of GPL code and link against GPL code, then you must be GPL. Since PyQt is a development framework, it's impractical for you to use it as a development framework without depending on it's details and linking against it. Relating this to our discussion... Someone could write a GPL open-source application UI which depended on the GPL PyQT, but which called out to a closed-source library which did some special functions. All code which depended on GPL PyQt would need to be GPL, but the closed-source library would be independent and depend on no details. For some commercial applications, this would mean a huge amount of their code would be open-source (i.e. if they are mostly UI), and if the company didn't want to release all that code, they would need to license the commercial PyQt to keep it closed. This is analogous to GPL Blender today. As long as all pieces of code that depend on blender details (UI, RNA manipulation, operator implementations) are all GPL open-source, you're fine. Core-algorithms (such as something that takes an array of points and modifies it in some way), can be closed source. As the code which depends on blender details becomes substantial, companies are less happy open-sourcing that part of the code. If PyQt were offered under the LGPL, it would negate their attempt to use dual-licensing as a revenue model, as any company would be free to link the LGPL code into their closed-source code and distribute. The LGPL would merely require them to release the complete source to the version of PyQt they used, including any modifications or improvements. Their code built around PyQt could remain closed under any liecnse they desired. _______________________________________________ Bf-committers mailing list Bf-committers@blender.org http://lists.blender.org/mailman/listinfo/bf-committers