Re: GTK+, WM, desktops and CSD

[Olivier Fourdan <fourdan gmail com>]

Hi Emmanuele,

On 5 March 2015 at 20:04, Emmanuele Bassi <ebassi gmail com> wrote:
> > [...]
>
> That's not what I was saying. I'm saying that precisely because we
> don't have an homogeneous environment you cannot use the "it's
> inconsistent" argument.
>
> It will always be inconsistent, for one reason or for another.

Right, so we actually agree :)

> > As I wrote, the final word would remain the to apps, just like now,
> > all I'm proposing is to replace the decision made by GTK to use CSD
> > based on a compositor with a hint from the DE instead, nothing more.
>
> You've conveniently ignored all the issues I've raised, so I'll just
> reiterate them, in the hope you have an answer instead of general
> handwaving:

Sure

> > >  • How does that hint get specified? Is it an X11 property on the root window?

Yes,

> > >  • How does it get monitored?

Yes, it could.

> > > What happens if the user changes the
> > > setting at run time?

The same as of today when someone enables or disables the compositor
at run time, i.e. nothing. The apps that have been started with
decorations keep it, those without remain without. Just like today.

> > > Do we get a client message?

Yes.

> > >  • How are applications supposed to react when that setting is found,
> > > or when it changes?

When it's found it's an indication, apps may or may not follow it. If
not found it remains as of today, GTK checks if there's a compositor
running.

> > > Do they ship with two different UIs, one for CSD
> > > and one for SSD?

They could but it's not mandatory. Today, they don't AFAIK.

> > >  • What happens if the application does not have two UIs? Is the
> > > setting ignored, and the application stays with client-side
> > > decorations even if the window manager does not support the Motif WM
> > > hints?

Yes.

The use of Motif MWM hints for this is a anachronism IMHO, but that's
another story.

Ideally, GTK should be able to use CSD even without a compositor. The
only reason it requires a compositor is because it uses the shadows as
resize handles. Ideally, it should use a larger border width when
there is no compositor - But that would another set of patches as not
directly related to the hint proposed.

Just to clarify, I know this topic is usually controversial, but I
really don't mean to be controversial here. I am genuinely trying to
come up with something that could possibly please those who don't want
CSD - And before anyone asks, xfce 4.12 has pretty good support for
CSD windows with GTK, including support for GTK_FRAME_EXTENTS or
GTK_SHOW_WINDOW_MENU.

Cheers,
Olivier