[Haskell-cafe] webcam library on github

. ch.gosch at googlemail.com
Fri May 25 09:07:41 CEST 2012

On Fri, 2012-05-25 at 08:24 +0800, Conrad Parker wrote:

> I've downloaded and built this. I had to also download Claude
> Heiland-Allen's v4l2 source from gitorious, as that package does not
> seem to be on hackage (though his other related packages are). I guess
> your package won't build on hackage until v4l2 is uploaded ...

You're right, I remember I had to do that too when I first started the

> In any case I was able to run "cabal sdist". It gave a warning about
> no Setup.hs file; I've sent you a pull request which adds this, and
> also relaxes some library constraints in the cabal file.

Thanks! I will add your suggestions (probably tonight) with pleasure.

> Two questions:
> * you've set the license to GPL3, but the C libraries it builds on are
> LGPL-2.1 (libv4l2) and repa and the haskell bindings it uses are BSD3.
> GPL3 seems a bit restrictive for a library.

The gpl is sort of my default license. I know it is a little
restrictive, so if that keeps people (if any) from contributing, I will
change the license. As far as I can see, I would be able to change it to
lgpl then, but not to bsd.

> * the name hsimage is fairly broad, I'd suggest a simpler name like
> repa-v4l2. If you want to support other device APIs or add other
> software image processing routines, I think it would make more sense
> to put those in separate packages.

That was indeed my intent. I first wanted something for image
processing, but seeing that there was nothing like I wanted for webcams,
I started doing that.
I think your suggestion for a simpler name makes sense, will probably
also do that.

BTW, I could not find any "more or less standard" way to represent
images in Haskell. Is there anything like that? I don't know if that
would make sense except being able to interact with different potential
imaging packages. Maybe it's good enough to just copy image data over in
most cases.

Thanks again for all your suggestions, that was very helpful!

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