SegmentBresenham := proc (img, x0, y0, x1, y1)
    local deltax, deltay, x, y, ystep, steep, err, img2, x02, y02, x12, y12;
    x02, x12, y02, y12 := y0, y1, x0, x1;
    steep := abs(x12 - x02) < abs(y12 - y02);
    img2 := copy(img);
    if steep then
        x02, y02 := y02, x02;
        x12, y12 := y12, x12;
    end if;
    if x12 < x02 then
        x02, x12 := x12, x02;
        y02, y12 := y12, y02;
    end if;
    deltax := x12 - x02;
    deltay := abs(y12 - y02);
    err := deltax / 2;
    y := y02;
    if y02 < y12 then
        ystep := 1
    else
        ystep := -1
    end if;
    for x from x02 to x12 do
        if steep then
            img2[y, x] := 0
        else
            img2[x, y] := 0
        end if;
        err := err - deltay;
        if err < 0 then
            y := y + ystep;
            err := err + deltax
        end if;
    end do;
    return img2;
end proc: