Show a basic storage type to handle a simple RGB raster graphics image,
and some primitive associated functions.

If possible provide a function to allocate an uninitialised image,
given its width and height, and provide 3 additional functions:

   one to fill an image with a plain RGB color,
   one to set a given pixel with a color,
   one to get the color of a pixel.


(If there are specificities about the storage or the allocation, explain those.)

These functions are used as a base for the articles in the category raster graphics operations, 
and a basic output function to check the results
is available in the article write ppm file.




(defpackage #:rgb-pixel-buffer
  (:use #:common-lisp)
  (:export #:rgb-pixel-component #:rgb-pixel #:rgb-pixel-buffer
           #:+red+ #:+green+ #:+blue+ #:+black+ #:+white+
           #:make-rgb-pixel #:make-rgb-pixel-buffer #:rgb-pixel-buffer-width
           #:rgb-pixel-buffer-height #:rgb-pixel-red #:rgb-pixel-green
           #:rgb-pixel-blue #:fill-rgb-pixel-buffer))