[cairo] Cairo and Mozilla licensing

[Mike Shaver]

I'm not sure I have time to keep up with a thread on this but I
wanted to step in and clarify a few things, because there has been a lot
of talk about this issue, and some of it seems to be a little off-track.

Please don't take this as Official Mozilla Foundation Policy; I'm
writing quickly, and don't like speaking for the MF about licensing even
when I have a lot of time to get myself in trouble.

Quoting Bryce Harrington:
> If they're serious about using external code from the community, then
> they'll need to come to grips with the fact that open source projects
> use (L)GPL moreso than the MPL.  I think you've got a good point that
> changing the world to suit one app is unrealistic.  A more easily
> scalable solution for them would be for Mozilla to figure out how to
> include (L)GPL code.

It would indeed be nice if we could magically include LGPL code in our
build -- note that we're not just talking about depending on it on a
platform that might already have it installed, as we do with GTK and
other such apps.  There are a lot of complications for us, including a
multi-year history of providing all of our products under the MPL (in
addition to other licenses, like the GPL/LGPL, in fact).  There are a
number of companies, for example, who distribute Mozilla technology and
who are not at all comfortable with the LGPL at present.  This is not to
say that it's impossible to convince them that the LGPL is acceptable
for their use, but it's not trivial, and it requires a fair bit of
lawyer time, historically.

One of the things that attracted us to Cairo initially -- we'd been
using libart for SVG on Linux -- was the license, which was a no-brainer
for us in terms of building a strong dependency on it.  Now it's no
longer a no-brainer, and those of us in the Mozilla camp who are
pro-Cairo have to contend with another barrier to deep adoption of it.

Maybe this is just a Mozilla problem, but I think that having Cairo
adopted as the graphics layer for Mozilla -- on all our platforms--
would be a win for Cairo too, which is why I've been discussing this
licensing issue off and on with Carl since desktopcon.  (I wish I'd had
more time to spend on it, but I've been pretty busy.)  Without intending
to sound (too :) ) egotistical, I think we're a little more than "just
one app" in this discussion, given our multi-million user installed base
and cross-platform commitment, etc.

> (I admittedly deserve part of the blame for this - I was involved with
> the discussions that resulted in the MPL and wish I'd faught harder to
> make it more GPL-compatible; there were other considerations at the time
> though.)

LGPL-compatibility of the MPL isn't an issue here, at all; the MPL and
LGPL are compatible in terms of their ability to be combined in the same
work without violating the license terms of either.  (Though
"foo"-compatible in licensing discussions usually means "can be
distributed under the terms of", and it's hard, maybe impossible to have
a GPL-compatible license that is a) not the GPL, and b) has any copyleft
elements in it.  I'm not sure if that's considered a bug or feature in
the GPL, but here we are.)

Even if Mozilla were MIT-licensed, which license is utterly
GPL-compatible, this would still be a problem for us -- perhaps more so,
because there would be no copyleft expectations at _all_ in our existing
distributor/developer base -- because it would be a major change in the
license policy as seen by our distributors and downstream developers.

(I don't recall you from the MPL-creation days, but it was all a blur.
Good to run into you again, still!)

So, yeah.

All that to say that we really do want to find a way to use Cairo, and
probably even help with it as with Stuart's GDI(+) work; that it looks
like an excellent technical and "cultural" fit; and that it's just this
licensing bump that's keeping us from throwing a parade.  I sincerely
hope that we can work it out, however that ends up being, because I'd
really like to get back to making some software.

Mike