function im = create_rgb_image(w, h)
  im = zeros(w, h, 3, "uint8");
endfunction

function set_background(im, colorvector)
  im(:,:,1) = colorvector(1);
  im(:,:,2) = colorvector(2);
  im(:,:,3) = colorvector(3);
endfunction

function set_pixel(im, coord, colorvector)
  im(coord(1), coord(2), 1) = colorvector(1);
  im(coord(1), coord(2), 2) = colorvector(2);
  im(coord(1), coord(2), 3) = colorvector(3);
endfunction

function [r, g, b] = get_pixel(im, coord)
  r = im(coord(1), coord(2), 1)
  g = im(coord(1), coord(2), 2)
  b = im(coord(1), coord(2), 3)
endfunction