FLTK licensing change explained

David Rudder writes "Bill Spitzak sent me an email explaining the change of license for FLTK. As you may remember, FLTK was taken off the GPL recently." Click below to read on.

"Here's his email:"

I. History of fltk:

I wrote a very large compositing program ("Nuke") for Digital Domain. As a toolkit I used Forms (not XForms), with several modifications of my own, particularily the file chooser and menu system that is in fltk.

Fltk was written in order to port Nuke from it's origial Forms/GL implementation. For a lot of reasons (all of them stupid, imho) this version has still not been adopted as the primary version used for production. However this version was ported to DEC Unix and to Linux and was used for Titanic on those machines.

I originally decided that it would be nice if fltk was free back when it seemed that official software department policy was to switch to a commercial toolkit (Motif, RapidApp), leaving my work unused and thus wasted. I received permission from Wook, who was VP of technology and operations at Digital Domain at that time. He agreed and at that point I started writing on my own time some things that I thought would make it useful for the outside world such as documentation.

An unexpected bonus was that immediatly after leaving the employment of Digital Domain (on his own decision), Matt Melchier wrote a port of fltk to NT, which he sent to me. I further modified this and used it to port Nuke to NT. This involved considerable work on fltk on DD's time, and I think the resulting increase in quality plus the cross-platform nature suddenly made fltk's popularity increase significantly.

At this point a new VP of technology (Wook having left near the end of Titanic production) noticed it and asked me about it. I thought I had explained that the code had absolutely no monetary value and that we had recieved considerable value of input by making it public. He expressed doubts but let me continue. After about 5 months this same manager announced plans to leave Digital Domain to start his own company in five weeks. Two weeks later I was called into a meeting with him and his replacement and told that I had to remove it from the web site and discontinue work on it.

II. What parts of FLTK does DD own?

Officially DD owns all parts that I wrote of fltk, whether or not I did them on their or my own time. Most was developed using DD's equipment, and about half on paid hours by DD. The intellectual property agreement with DD says this. Less officially it seems DD's policy that stuff done on my own time is not under their control as long as I don't profit from it.

DD's time: the core of fltk including the event handling and the windows, all support of OpenGL graphics, the NT port, and the few widgets used by Nuke, in particular the menus and input text fields.

NOT DD's time: is the fluid user interface builder, about half the documentation, the web site and mailing list, the tile, scroll, pack, and tabs widgets, all "valuators" except the slider, the fl_draw_image image drawing code, pixmaps, bitmaps.

Everything else is kind of vague. A large chunk of documentation was written while waiting for Titanic images to render and thus on DD's time, but in my opinion I would otherwise be wasting this time thus DD lost nothing.

The NT port is based on code submitted by Matt Melchier, and he definately submitted it assumming he was contributing to an open source toolkit. Although much of this code has been modified by me it is still based on his work.

Several files from the original Forms library written by Mark Overmars are in there almost unchanged, such as the chart. Forms appears to be under a bsd-style license (unrelated to the strict XForms license).

Other people have written submitted widgets and bug fixes. The widgets are not being used by DD's in-house code. The bug fixes are of course...

III. What reasons were given to make FLTK non-public:

1. I was simply told that

2. Ed also thought DD might be liable in some way (yes I know this is total BS...)

There are *NO* plans to turn fltk into a commercial product or otherwise sell it or distribute it. I think everyone knows that is totally impossible and could not possible produce any income.

There are also no plans to use fltk in-house for any long term. Officially the software department wants to rewrite Nuke to use Java for the user interface. All other programs that potentially could use fltk will remain using the Forms library.

IV: Can development continue on the already-distributed version.

Yes, this is allowed under the LGPL. I don't think I myself risk work on it. I have stopped working on it in-house proprietary version until the matter of Matt's code can be resolved.

V. Do you believe that the previous public-ness/free-ness of fltk has made developing it more efficient

Probably the most important part of fltk (the NT port) was contributed due to the free nature. And fltk is far more robust and featurefull than it ever would be in-house.

Overall though I can't argue that the effect is any better than break-even. The amount of time spent answering mail and merging bug fixes that probably would not have affected in-house stuff may be equal to the time saved by those bug fixes.

Ed: Digital Domain is the same company that made Titanic (which did rather well financially) using Linux.