procedure DrawLine(var Bitmap : Integer; X1, Y1, X2, Y2 : Integer; Color : Integer);
var
  X, Dist, W, H : Integer;
  Angle : Extended;
  P : TPoint;
begin
  GetBitmapSize(Bitmap, W, H);
  Angle := ArcTan2(Y2-Y1, X2-X1);
  Dist := Distance(X1, Y1, X2, Y2);
  for X := 1 to Dist do
  begin
    P := Point(X1 + X, Y1);
    P := RotatePoint(P, Angle, X1, Y1);
    if (P.X < 1) or (P.X > W-2) or (P.Y < 1) or (P.Y > H-1) then Continue;
    FastSetPixel(Bitmap, P.X, P.Y, Color);
    FastSetPixel(Bitmap, P.X+1, P.Y, Color);
  end;
end;