macro 'Change Sampling Pitch...';
{Generates a grayscale step function within the current selection.}
var
  width,height,nSteps,StepSize,i,j,k,l,x,y:integer;
  value:real;
begin
  SaveState;
  GetPicSize(width, height);
  StepSize:=GetNumber('Cell Size [pixels square]',16);
  Duplicate('Sampling');
  nSteps:=width div StepSize;
  x:=0;
  y:=0;
  for i:=0 to nSteps-1 do begin
    y:=i*StepSize;
    for j:=0 to nSteps-1 do begin
       x:=j*StepSize;
       value:=0;
       for k:=y to y+StepSize-1 do begin
  	   for l:=x to x+StepSize-1 do begin
		value:=value+GetPixel(l,k);
	   end;
       end;
       value:=value/(StepSize*StepSize);
       MakeRoi(x,y,StepSize,StepSize);
       SetForeground(round(value));
       fill;
    end;
  end;
  KillRoi;
  RestoreState;
end;