How can I paint the whole form on a bitmap?

Question

I want to paint the whole form including its caption bar and frame on a TBitmap object.

GetFormImage is cool, but it has two problems:

Answer 1

Here is a little function that I've used that you might find useful.

Edit: Oops I didn't fully read the question. This probably doesn't work with a hidden window, but I'm not sure anything would unless the form could draw the frame itself, but it doesn't, the OS does.

function GetScreenShot(const aWndHandle:THandle; AeroAware:boolean=true):TBitmap;
var
  wWindow: HDC;
  wRect : TRect;
  wDesktop : THandle;
begin
  Result  := TBitmap.Create;
  try
    if AeroAware then
      wDesktop := GetDesktopWindow
    else
      wDesktop := aWndHandle;

    wWindow := GetDC(wDesktop);
    try
      Result.PixelFormat := pf32bit;
      GetWindowRect(aWndHandle, wRect);
      Result.Width := wRect.Right-wRect.Left;
      Result.Height := wRect.Bottom-wRect.Top;
      if AeroAware then
        BitBlt(Result.Canvas.Handle, 0, 0, Result.Width, Result.Height, wWindow, wRect.Left, wRect.Top, SRCCOPY)
      else
        BitBlt(Result.Canvas.Handle, 0, 0, Result.Width, Result.Height, wWindow, 0, 0, SRCCOPY);
      Result.Modified := True;
    finally
      ReleaseDC(wDesktop, wWindow);
    end;
  except
    Result.Free;
    Result := nil;
  end;
end;