Re: [Boost-users] [boost] Review of Generic Image Library (GIL) begins today, Oct5, 2006

From: Thorsten Behrens (th.behrens_at_[hidden])
Date: 2006-10-08 21:17:21

Johan Oudinet <johan.oudinet <at> gmail.com> writes:

> On 10/5/06, Tom Brinkman <reportbase <at> gmail.com> wrote:
> > The review of Generic Image Library (GIL) begins today,
> > October 5, 2006, and continues through October 15, 2006.
> >
> > Please download the library at: http://opensource.adobe.com/gil.
> > Minor change are being made regularly (daily), so check the site
> > often for
> > updates.
> >
> > [snip]
> 
> I think you might look at the Olena project:
> http://olena.lrde.epita.fr
> 
Right. And maybe also Vigra's
(http://kogs-www.informatik.uni-hamburg.de/koethe/vigra) accessor concept and
type promotion traits might deserve a second glance.

Pixel accessors make explicit what's worked-around by GIL's
PixelDereferenceAdaptor, namely that getting to the place where the pixel is
stored and operating on the content of that in-memory representation are
orthogonal concepts. Vigra algorithms take a pair of pixel iterators and
accessors for source and destination. Thus, to be able to work on a 565 packed
RGB pixel type, one can reuse the int16 pixel iterator, and provide a 565 pixel
accessor. Very easy, very clean.

When it comes to image processing algorithms (I know that this is currently kind
of a weak spot for GIL - but ultimately, of how much use is this lib without at
least some basic processing functionality), I'd love to see promotion traits
used. Otherwise, supporting mixed types (float and int, etc) for color channels
generically would become rather hard...

Cheers,

-- Thorsten