Re: [EWMH] _NET_WM_WINDOW_TYPE_AUXILIARY

[Nathaniel Smith <njs pobox com>]

On Sat, Oct 13, 2007 at 03:52:13PM -0700, Mark Tiefenbruck wrote:
> I agree with you entirely, though some points have been made (or
> almost made, at least) that should not be ignored. The window manager
> should not be concerned with override-redirect windows at all, and
> these composite manager features really have no business in the
> wm-spec. Composite managers should have their own spec.

Actually, I disagree with you on this (though my previous probably
should have been more careful with throwing around the word "WM").  I
think there should be one spec that describes the interface between
"managers" (i.e., things that impose policy on how disparate
apps interact to create a single UI) and "clients" (i.e., things that
policy is imposed on, and that provide the hints needed to make that
policy smart).

EWMH is already a spec for WMs, pagers, taskbars, alt-tab-style
task-switchers, icon boxes, etc.  Historically there's been major flux
in the extent to which these different UI elements are managed within
a single process or not.

> For that matter, why are window managers being made with composite
> managers built in, anyway? The world would be a much better place if
> people could choose composite effects independently from the window
> manager (you wouldn't believe how often I get asked "can I use fluxbox
> in beryl/compiz?"). With that goal in mind, what information is the
> composite manager relying on that it can't get from EWMH? Making this
> information available should be our primary focus, IMO.

The problem is... which composite effects are you talking about?
Wobbly windows, so WMs should start exposing "estimated velocity of
window movement" via EWMH-hints?  (It'd be an awesome task-switching
storm too :-/.) Windows on the face of a see-through cube, so we need
to start exposing "3d geometry of virtual desktop layout" through
EWMH, I guess as some kind of triangle-mesh?

I don't think it makes sense to draw a bright line and say WMs and CMs
are different, and always shall be.  (And more to the point, I don't
think it's a spec like EWMH's job to draw that line.)  Compositing is
really just another primitive in our display model; if the WM is the
best place to use that primitive to achieve certain effects, then so
be it.

-- Nathaniel

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