From: David De La Harpe Golden <david@harpegolden.net>
To: Luka Novsak <lnovsak@gmail.com>
Cc: 9181@debbugs.gnu.org
Subject: bug#9181: 24.0.50; Alpha transparency no longer works
Date: Fri, 29 Jul 2011 00:07:47 +0100 [thread overview]
Message-ID: <4E31EBC3.8050303@harpegolden.net> (raw)
In-Reply-To: <CAE6FkMKhMtzh3QaDf1P_HzxxyQMHqoAxvh5PJoE6fhFYVqn90Q@mail.gmail.com>
On 28/07/11 19:16, Luka Novsak wrote:
> Yes, I'm running xcompmgr; alpha transparency is working fine in other
> applications.
>
> I've noticed a peculiar detail--this problem does not occur when
> running X without a window manager, say if I only run xcompmgr and
> emacs in my X session. I've tried this with multiple window managers,
> so it doesn't seem to be the fault of either one.
Oh yeah... xcompmgr only looks for _NET_WM_WINDOW_OPACITY on truly
toplevel (i.e. direct children of root window) windows. It's working
when there's no window manager, because then emacs' window is a direct
child of the root window. But in a typical window manager case, emacs'
window is of course reparented under the window manager's frame window,
so emacs setting the property on its own window (with the other _NET_WM
properties) doesn't work for xcompmgr. It may be working for your other
apps depending on how you or they set their opacity (using "transset"
will set the property on the window manager frame, for example).
However, note that the current code _does_ work when using now-typical
combined compositing window managers rather than xcompmgr (hence my
works-for-me), because they, as a matter of current practice, _do_ look
for the property on the application windows they're managing, which
makes sense really, reasonable place for it with all the other similar
properties.
*** So why _was_ it working? emacs used to special-case in
xterm.c/x_set_frame_alpha() that set the property on the parent window
of the emacs window rather than the emacs window itself [1], it got
removed in trunk rev 104095 to fix bug #8608 (Jan cc'd)
I for one am not at all sure restoring it is the right thing to do, it
seems problematic. Emacs doesn't notionally "own" the window manager
frame around it, and some reparenting window managers could actually use
more than one level of window between the root and the app window too
anyway. (I don't think reparenting window managers actually do
typically copy the property up in practice as suggested under #8608,
either, I'm afraid. That would be rather unique handling of the property
AFAIK)
So maybe setting the property in both places (either optionally or
always) is the best we can do, at least if we want to support xcompmgr.
next prev parent reply other threads:[~2011-07-28 23:07 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-25 20:41 bug#9181: 24.0.50; Alpha transparency no longer works Luka Novsak
2011-07-28 12:10 ` David De La Harpe Golden
[not found] ` <CAE6FkMJNzKxmfpx+tCE4PaACMJQL3ih4RiOrWXGGHMjcrJuaqA@mail.gmail.com>
2011-07-28 18:16 ` Luka Novsak
2011-07-28 23:07 ` David De La Harpe Golden [this message]
2011-07-29 9:34 ` Jan Djärv
[not found] ` <CAE6FkM+TJPFJ9ETwYM+1fg9f6LE54YeC=2t8yN8xLx_KqwBRCw@mail.gmail.com>
2011-07-29 17:46 ` Luka Novsak
2011-07-30 7:04 ` Jan Djärv
2011-08-02 20:23 ` Luka Novsak
2011-08-02 20:28 ` Lars Magne Ingebrigtsen
2011-08-02 20:49 ` Luka Novsak
2011-08-03 8:13 ` Jan Djärv
2011-08-03 8:22 ` David De La Harpe Golden
2011-08-03 11:50 ` Jan Djärv
2011-08-03 15:12 ` David De La Harpe Golden
2011-08-03 17:29 ` Luka Novsak
2011-08-03 19:01 ` David De La Harpe Golden
2011-08-04 11:14 ` Jan Djärv
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