RGB arrays

[g03092@n1.usna.navy.mil (Raymond Lee)]

Dear Friends:
     I do colorimetric analysis using 24-bit color, and I'm trying
to build RGB integer arrays from PICTs that are displayed in
MCL2.0b color windows.  At the moment, I'm using _GetCPixel and
scanning windows pixel-by-pixel, but this is hardly satisfactory
(or elegant) because I often have to scale PICTs that are larger
than my monitor's pixel dimensions.
     How could I build, say, a 400-by-300-by-3 integer array of RGB
values (0 - 255) from a 400-by-300 pixel PICT?  I assume that if I
use something like a :pixmap, then the PICT doesn't need to be
displayed in the top-level window (or even be completely on-screen) 
in order for me to access all pixel RGB values.
     Please excuse the novice's LISP syntax; I'll be glad to help
any MCLers with colorimetry or color perception issues.
 
          Thanks,
          Raymond Lee
          Oceanography Department, U. S.  Naval Academy