procedure TPACentralize(var TPA: TPointArray; area: TBox);
var
  o: TPoint;
  b: TBox;
begin
  if (Length(TPA) > 0) then
  begin
    b := GetTPABounds(TPA);
    o := Point(((Round(area.X1 + ((area.X2 - area.X1) / 2)) - (((b.X2 - b.X1) + 1) div 2)) - b.X1), ((Round(area.Y1 + ((area.Y2 - area.Y1) / 2)) - (((b.Y2 - b.Y1) + 1) div 2)) - b.Y1));
    OffsetTPA(TPA, o);
  end;
end;

procedure ZoomTPA(var TPA: TPointArray; Times: Integer);
var
  w, h, l, i, x, y, width, height: Integer;
  m: array of TBoolArray;
  b: TBox;
begin
  if (times <> 0) then
  begin
    l := Length(TPA);
    if (l > 0) then
    begin
      b := GetTPABounds(TPA);
      w := ((b.X2 - b.X1) + 1);
      h := ((b.Y2 - b.Y1) + 1);
      if (times > 0) then
      begin
        width := (w * times);
        height := (h * times);
      end else
      begin
        times := Abs(times);
        width := (w div times);
        height := (h div times);
      end;
      SetLength(m, w);
      for x := 0 to (w - 1) do
      begin
        SetLength(m[x], h);
        for y := 0 to (h - 1) do
          m[x][y] := False;
      end;
      for i := 0 to (l - 1) do
        m[(TPA[i].X - b.X1)][(TPA[i].Y - b.Y1)] := True;
      SetLength(TPA, 0);
      l := 0;
      for y := 0 to (height - 1) do
        for x := 0 to (width - 1) do
          if m[((x * w) div width)][((y * h) div height)] then
          begin
            SetLength(TPA, (l + 1));
            TPA[l] := Point((x + b.X1), (y + b.Y1));
            Inc(l);
          end;
    end;
  end;
end;

procedure SetPixels(bmp: Integer; TPA: TPointArray; color: Integer);
var
  a, b, w, h: Integer;
begin
  b := High(TPA);
  if (b > -1) then
  begin
    try
      GetBitmapSize(bmp, w, h);
    except
      Exit;
    end;
    for a := 0 to b do
      if ((TPA[a].X > -1) and (TPA[a].Y > -1) and (TPA[a].X < w) and (TPA[a].Y < h)) then
        FastSetPixel(bmp, TPA[a].X, TPA[a].Y, color);
  end;
end;

var
  zoomed, original: TPointArray;
  bmp: Integer;
  b: TBox;

const
  ZOOM = 3;

begin
  bmp := CreateBitmap(500, 500);
  original := [Point(211, 212), Point(213, 214), Point(215, 216), Point(217, 218)];
  zoomed := CopyTPA(original);
  ZoomTPA(zoomed, ZOOM);
  b := GetTPABounds(original);
  TPACentralize(zoomed, b);
  SetPixels(bmp, zoomed, 255);
  SetPixels(bmp, original, 16777215);
  DisplayDebugImgWindow(500, 500);
  DrawBitmapDebugImg(bmp);
end.