Re: make-pointer-invisible on Windows

[Eli Zaretskii <eliz@gnu.org>]

> Date: Tue, 30 Jun 2015 08:01:53 +0200
> From: martin rudalics <rudalics@gmx.at>
> CC: emacs-devel@gnu.org
> 
>  > Maybe I'm missing something, but this:
>  >
>  >      case WM_ERASEBKGND:
>  >        f = x_window_to_frame (dpyinfo, hwnd);
>  >        if (f)
>  > 	{
>  >            HDC hdc = get_frame_dc (f);
>  > 	  GetUpdateRect (hwnd, &wmsg.rect, FALSE);
>  > 	  w32_clear_rect (f, hdc, &wmsg.rect); <<<<<<<<<<<<<<<<<<<<
>  >            release_frame_dc (f, hdc);
>  >
>  > looks to me like us erasing the rectangle.
> 
> Then if we didn't erase here there would be no gaps.  Would it be a
> silly idea to pass the erase call to the main thread?

We've been through this: it's not silly, but implementing that will
have to be able to compact several such redraw pairs into one, because
by the time the main thread wakes up, we could have received several
different expose events, and handling them one by one will cause
flickering.

And after all that, we are still left with the use case of resizing
the frame.