[Haskell-cafe] webcam library on github

Conrad Parker conrad at metadecks.org
Fri May 25 02:24:34 CEST 2012

On 25 May 2012 06:20, . <ch.gosch at googlemail.com> wrote:
> Hello Cafe,
> since I haven't found anything like that, I wrote a small library [1] to
> read from a webcam in Haskell, using V4L on Linux. It uses the v4l2
> package and repa for images.
> Is anyone interested in contributing to that, or giving some hints on
> how it could be made faster (I am not sure if I use repa correctly for
> best performance at all times), or just in emitting any other
> constructive comments? If yes, please give me a shout.
> PS I would put the whole thing on hackage, but my cabal currently
> doesn't want to do an sdist.

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 ...

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.

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 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.



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