$ include "seed7_05.s7i";
  include "draw.s7i";
  include "color.s7i";

const proc: writePPM (in string: fileName, in PRIMITIVE_WINDOW: aWindow) is func
  local
    var file: ppmFile is STD_NULL;
    var integer: x is 0;
    var integer: y is 0;
    var color: pixColor is black;
  begin
    ppmFile := open(fileName, "w");
    if ppmFile <> STD_NULL then
      writeln(ppmFile, "P6");
      writeln(ppmFile, width(aWindow) <& " " <& height(aWindow));
      writeln(ppmFile, "255");
      for y range 0 to pred(height(aWindow)) do
        for x range 0 to pred(width(aWindow)) do
          pixColor := getPixelColor(aWindow, x, y);
          write(ppmFile, str(chr(pixColor.redLight)) <& chr(pixColor.greenLight) <& chr(pixColor.blueLight));
        end for;
      end for;
      close(ppmFile);
    end if;
  end func;