Re: extending pstricks terminal driver

[Ethan M. <merritt@u.washington.edu>]

On Wednesday 10 December 2008 08:42:21 Petr Mikulik wrote:
> > 
> > One question: is "with image" already able to read png images? I had
> > an impression that it was only able to read some
> > unusual binary formats (3 bytes per pixel).
> 
> Ethan has shown it works this way:
> 
>     plot '<convert table.png avs:-' binary filetype=avs with rgbimage
> 
> Nowadays gnuplot is typically compiled with the gd library. Therefore it 
> should be pretty easy to use the gd-library to load png/gif/jpg images 
> directly. I think it may not be too much code in breaders.c. Could somebody 
> contribute this feature?

I honestly don't see quite how that would work.
Using libgd, or libpng for that matter, will result in an in-memory copy
of the bitmap image.  But that's not exactly what the binary file input code
wants; it expects to read a stream of binary data on the input fd, so that it
can filter, re-map, combine fields, etc.  It seems to me that one would
have to write a new input layer that dummies up access to an in-memory
bitmap as successive reads to a fake pipe.  

What would we gain by adding all this extra code? Isn't it much better to let
an external utility do this for us, as in the example you quote?

-- 
Ethan A Merritt
Biomolecular Structure Center
University of Washington, Seattle 98195-7742