Re: A GTK-only problem when making frames invisible

[martin rudalics <rudalics@gmx.at>]

 > However, frame-visible-p still returns t (not
 > `icon').

So we have at least two different behaviors though I'm unsure how yours
may happen.  Here I trapped it as follows: Making the frame invisible
via x_make_frame_invisible does

   /* We can't distinguish this from iconification
      just by the event that we get from the server.
      So we can't win using the usual strategy of letting
      FRAME_SAMPLE_VISIBILITY set this.  So do it by hand,
      and synchronize with the server to make sure we agree.  */
   SET_FRAME_VISIBLE (f, 0);
   SET_FRAME_ICONIFIED (f, false);

   x_sync (f);

so f->visible is zero from now on and f->iconified is false.  Next I get
an Expose event (which is a mystery to me because why should making a
frame invisible expose it) causing the execution of

           if (!FRAME_VISIBLE_P (f))
             {
               block_input ();
               SET_FRAME_VISIBLE (f, 1);
               SET_FRAME_ICONIFIED (f, false);

because "expose events must be treated like map events" as ISTR having
read somewhere.  Hence, f->visible is one from now on and f->iconified
still false.  Finally, I get the UnmapNotify event which does

	  bool visible = FRAME_VISIBLE_P (f);
           /* While a frame is unmapped, display generation is
              disabled; you don't want to spend time updating a
              display that won't ever be seen.  */
           SET_FRAME_VISIBLE (f, 0);
           /* We can't distinguish, from the event, whether the window
              has become iconified or invisible.  So assume, if it
              was previously visible, than now it is iconified.
              But x_make_frame_invisible clears both
              the visible flag and the iconified flag;
              and that way, we know the window is not iconified now.  */
           if (visible || FRAME_ICONIFIED_P (f))
             {
               SET_FRAME_ICONIFIED (f, true);
               inev.ie.kind = ICONIFY_EVENT;
               XSETFRAME (inev.ie.frame_or_window, f);

so while f->visible is zero ,`visible' is true and SET_FRAME_ICONIFIED
will succeed in setting f->iconified to true.

 > I don't have an earlier build from master than from 2017-01-25, which
 > behaves the same.  However, with my build from emacs-25 from 2016-11-16,
 > frame-visible-p returns nil.

Same here.

 >>                                        And is there any difference if, as
 >> a second step, you do (iconify-frame frame) instead?
 >
 > This does minimize the frame to the taskbar, and frame-visible-p returns
 > `icon' instead of t.

As expected.

Thank your very much for testing.  Anyone else's experiences with this
would be highly interesting.  Something is fishy here.

martin