Parsing image pixels with lua

Parsing image pixels with lua

[Stefan Müller]

Hi list,

I'm trying to create a ConTeXt document that searches for image-files 
(png, jpg, any, whatever... that's not important) in the same directory 
and processes all found images in a certain way.  I'm pretty sure that 
parsing the directory should work with lua in ConTeXt, but I'm stuck at 
the part where I want lua to process the image.  Is it somehow possible 
to get the color of an arbitrary pixel in the image (file) given the 
vertical and horizontal position of the pixel?

I could process the images beforehand with another application (which 
does not yet exist) and write its output to ASCII files or something, 
but I rather avoid that.  If that's the only possibility, how would I 
call another application while processing a tex file with ConTeXt?

Thanks in advance for any hints,
Stefan
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________