Writing PNG with pure Python

[Paul Boddie]

Johann C. Rocholl wrote:
> The MIT license is enticingly short and simple, thank you for the tip.
>
> I have now decided to license my project (including the pure python PNG
> library) under the Apache License 2.0 which is less restrictive than
> the GPL in terms of sublicensing.

But it is also incompatible with the GPL:

http://www.fsf.org/licensing/licenses/index_html#GPLIncompatibleLicenses

It's obviously your decision about how you license your own code, but
I'd advise you to disregard the "Pythonic license" rhetoric, whatever
that means: Python's original licence was regarded as not being enough
of a licence by some lawyers (that's what some people refer to as the
original Python licence); subsequent licences aren't recommended for
application to any other works (like various licences of the Python
code over the years); despite advocacy for permissive licences by some
parties, there exist numerous successful GPL'd and LGPL'd Python
projects (meaning that projects licensed in such a way are not lesser
members of the community). Moreover, any licensing gymnastics
undertaken by the PSF did involve various extra somersaults to remain
GPL-compatible, meaning that even people who favour permissive licences
regard "licence interoperability" positively.

If you're convinced that a permissive licence suits your code best,
please consider something whose side-effects you understand. If the
additional patent grant or licence termination clauses (which the FSF
don't regard as a bad thing, just something incompatible with the
current GPL/LGPL) are specifically what you want, then the Apache
Licence may be what you're after; otherwise, you should choose
something less baroque and better understood, perhaps from this list:

http://www.fsf.org/licensing/licenses/index_html#GPLCompatibleLicenses

Yes, one of the best places to find out about non-FSF licences is
actually the FSF themselves, undermining various myths some people like
to put forward.

Paul