Fill Rectangle Pixel Method

procedure TForm1.BitBtn4Click(Sender: TObject);
//fill bm pixel by pixel
var x,y : byte;
k : integer;
begin
t1 := gettickcount;
with bm do with canvas do
for k := 1 to 100 do
for y := 0 to 99 do
for x := 0 to 99 do
pixels[x,y] := $ff0000;
t2 :=gettickcount;
showtime(1000000);
end;