In article <[email protected]>, Tord Romstad <[email protected]> wrote: > I am Tord Romstad, author of Glaurung, one of the strongest GPLed > chess programs. Recently, I ported my program to the Apple iPhone. A > couple of days ago, I was contacted by someone who wants to make a > commercial chess program based on my program. He understands that his > derived program must also be available under the GPL, and intends to > publish all changes he makes in my code, so everything is OK so far. > > The problem is that he plans to hire a professional graphics designer > to draw the piece images and some other graphics, and to keep these > graphical image files proprietary. He asks me whether the GPL allows > this, and I honestly don't know myself. Does anyone here know more > about this?
Wait...you are the author? Do you own the copyright on the program? If so, you can let him use the code on whatever terms you want. When you made it available under GPL, that did not preclude you also making it available on other terms (even closed source, proprietary terms). GPL is a copyright license. Here's how to think about copyright licensing. Copyright law says that there are certain things that only you (the copyright owner) and people authorized by you are allowed to do. The biggies here are copying, distributing, and making derivative works. If someone wants to do one of those things legally, they have to have your permission in some form. When you give person X permission in some form, that does not preclude you from giving person Y permission in some other form. (Well, you could have made a contract with X in which you promised not to give anyone else permission in some other form, of course, but I doubt you did that!). When you released the code under GPL, you were giving everyone permission if they followed the terms of the GPL. You are still free to continue to grant people permission on other terms, including even giving them permission to make closed source, proprietary versions of your code (and you can do that yourself, of course, because you don't need permission). The only limit on your ability to make your code available under non-GPL licenses is that if someone doesn't like the other licenses you might offer, they can fall back to the GPL version and use it under the terms of the GPL. So, if you objected to what he wants to do, and were hoping to stop him, then the GPL would be very relevant here, because if GPL allowed non-free graphics in a free program, he'd be able to go ahead against your wishes. However, it does not sound like you object. In that case, the simplest thing to do is give him permission. Give him an explicit license that says he may use the code under the terms of GPL, with the special exception that he may use proprietary graphics data files. People on this group can probably help with the exact wording. -- --Tim Smith _______________________________________________ gnu-misc-discuss mailing list [email protected] http://lists.gnu.org/mailman/listinfo/gnu-misc-discuss
