Re: Defining 'preferred form for making modifications'

[tb@becket.net (Thomas Bushnell, BSG)]

Henning Makholm <henning@makholm.net> writes:

> > What?  Who on earth said it was illegal to edit things other than the
> > preferred form?
> 
> The GPL says that. It says that you mustn't distribute anything
> without giving the preferred form for it, and if we go by your premise
> that gifs are not the preferred form, then my modified gifs have no
> preferred form at all. Hence it is impossible for me to distribute
> them legally.

I have never said that gifs are not the preferred form.  I said that
it is *contextual*, and depends on a particular history.

The history you were considering was a .xcf (or the like), which
someone then modified a few parts of in its gif output.  The result is
certainly within the terms of the GPL, and I believe you would be
obligated to distribute both the xcf and the gif.

The point is *exactly* the same as for a program: nothing about the
GPL says that you cannot program in machine language; nothing says
that you must modify things in C rather than machine language.  

> > Nothing in the GPL says that, but the fact that you have edited them
> > means that you consider them, for the purpose of that edit, to be
> > preferred.
> 
> But you just claimed that the xcf is the preferred form "for
> everyone". Please make up your mind.

Precisely when the xcf is the exact source of the actual gif in
question.  If the gif has been modified on its own, then the source is
now the combination of both the xcf and the gif.

> The xcf may be source for somethine, but there is no way it can be
> source for the modified gifs. The latter pictures look entirely
> different from the xcfs.

Yes, it's not the sole source.

> > The reason is quite clear: because otherwise one could very trivially
> > escape the GPL's requirements entirely,
> 
> I don't think that a "loophole" argument is a convincing argument for
> fixing an unreasonable interpretation of "preferred form".

So far you don't understand my interpretation, because you misstate it
each time you try and reproduce it....