bug#5721: Feature request: Function that returns absolute coordinates

[YAMAMOTO Mitsuharu]

>>>>> On Fri, 16 Jul 2010 14:19:21 +0200, Jan Djärv <jan.h.d@swipnet.se> said:

>>> That depends on your window manager.  If I do the same command, I
>>> get 'top equal to 124, as the title bar is 24 pixels high and the
>>> window manager (Compiz) puts the top of the title bar at 100.
>>> Other window managers may choose to put the Emacs window at 100
>>> and the title bar above that.  It isn't defined what a window
>>> manager should do.
>> 
>> I also checked that CDE's window manager behaves like Mac OS X's,
>> i.e., left/top frame parameters points to the title bar.
>> 
>> You mean one can specify the position of the top-left corner of the
>> title bar with the geometry specification, but that cannot reliably
>> be done with left/top frame parameters?

> When there is a window manager present, no move or resize can be
> done reliably.  The window manager is free to modify them.  Some
> don't allow move partly offscreen, some do.  Some don't allow move
> over the gnome-panel, some do.

In that case, Emacs is supposed to adjust left/top frame parameters
according to the title-bar top-left corner position that the window
manager modified, in response to some notification events.

Even with Compiz, left/top frame parameters point to the title bar if
we turn off visual effects.  I tested it with Ubuntu 10.04.

I suspect x_real_positions fails to get the window for decoration for
Compiz if visual effects are turned on.  Maybe Compiz does not assign
X11 windows for window decorations.

                                     YAMAMOTO Mitsuharu
                                mituharu@math.s.chiba-u.ac.jp