Bitmap에다가 화면을 캡쳐하는 함수 입니당... ^^

procedure TForm1.ScreenShot(x : integer; y : integer; Width : integer; Height : integer; bm : TBitMap);
var
  dc: HDC;
  lpPal : PLOGPALETTE;
begin
  if ((Width = 0) OR (Height = 0)) then
     exit;

  bm.Width := Width;
  bm.Height := Height;

{get the screen dc}
  dc := GetDc(0);
  if (dc = 0) then
     exit;

{do we have a palette device?}
  if (GetDeviceCaps(dc, RASTERCAPS) AND RC_PALETTE = RC_PALETTE) then
  begin
  {allocate memory for a logical palette}
     GetMem(lpPal, sizeof(TLOGPALETTE) + (255 * sizeof(TPALETTEENTRY)));
  
  {zero it out to be neat}
     FillChar(lpPal^, sizeof(TLOGPALETTE) + (255 * sizeof(TPALETTEENTRY)), #0);
  
  {fill in the palette version}
     lpPal^.palVersion := $300;

  {grab the system palette entries}
     lpPal^.palNumEntries := GetSystemPaletteEntries(dc, 0, 256, lpPal^.palPalEntry);
  
     if (lpPal^.PalNumEntries <> 0) then
     begin
    {create the palette}
       bm.Palette := CreatePalette(lpPal^);
     end;

    FreeMem(lpPal, sizeof(TLOGPALETTE) + (255 * sizeof(TPALETTEENTRY)));
  end;

{copy from the screen to the bitmap}
  BitBlt(bm.Canvas.Handle, 0, 0, Width, Height, Dc, x, y, SRCCOPY);

{release the screen dc}
  ReleaseDc(0, dc);
end;