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.




PGraphics bitmap = createGraphics(100,100); // Create the bitmap
bitmap.beginDraw();
bitmap.background(255, 0, 0); // Fill bitmap with red rgb color
bitmap.endDraw();
image(bitmap, 0, 0); // Place bitmap on screen.
color b = color(0, 0, 255); // Define a blue rgb color
set(50, 50, b); // Set blue colored pixel in the middle of the screen
color c = get(50, 50); // Get the color of same pixel
if(b == c) print("Color changed correctly"); // Verify
 