imread/write (Was: Re: Moving functions from octave to octave-forge?)

[Søren Hauberg]

David Bateman skrev:
> should definitely be looked at for importation, though the issue with
> the odepkg/mex-files and the Imagemagick dependency on imread/imwrite
> needs addressing. The ones in my "too hard" basket depend on someone
> going to the effort of importing them.
The current implementation of imread checks if jpgread and pngread is 
available and uses them if possible. So, the ImageMagick dependency 
isn't that hard. If you don't have it, but do have lib[png|jpeg] you 
will still be able to read most files. We could rewrite the imwrite 
function to work in the same way. That way the user can read/write the 
following formats:

  * png, if libpng is installed.
  * jpeg, if libjpeg is installed.
  * ppm, for writing (always), and I guess we could write a ppm reader.
  * everything else, if ImageMagick is installed.

I mostly work with image processing and I'd guess that 99% of the images 
I read is in png, so no need for ImageMagick for me.

On an ImageMagick related note: perhaps we should use GraphicsMagick 
(http://www.graphicsmagick.org/) instead. It's a fork of ImageMagick 
that tries to keep the interface stable, making it easier to maintain 
code that links against *Magick.

Søren