Re: Interaction between applications and compositing managers

[Olivier Chapuis <olivier chapuis free fr>]

Soeren Sandmann a écrit :
> Hello
>
> To integrate a compositing manager well with the rest of the desktop,
> new hints and protocols between applications and compositing managers
> are needed. This message is intended to start that discussion.
>
>
> *** Window types
>
> A compositing manager deals with all windows that are visible on the
> screen, even override-redirect ones. This means new window types
> are needed so the compositing manager will know how to decorate the 
> override-redirect windows with translucency and shadows etc.
>
> Here are some typical override redirect windows:
>
> - DND windows (showing drag icons etc.)
>
> - Tooltips
>
> - Menus, drop-down menus and right click menus.
>
> - Combo box popups
>
> - Notifications ("you are are running out of battery" etc.)
>
> - Random little popups, such as the search boxes on trees and lists
>
> Also many applications pop up their own app-specific override-redirect
> windows for whatever reason.
>
> One possibility is to add a bunch of new possible window types to the
> _NET_WM_WINDOW_TYPE property:
>
>    _NET_WM_WINDOW_TYPE_DND_WINDOW
>    _NET_WM_WINDOW_TYPE_TOOLTIP
>    _NET_WM_WINDOW_TYPE_NOTIFICATION 
>    _NET_WM_WINDOW_TYPE_DROP_DOWN_MENU
>    _NET_WM_WINDOW_TYPE_POPUP_MENU
>    _NET_WM_WINDOW_TYPE_COMBO
>
> That will take care of most of the override redirect windows on a
> typical. CM's will still need to deal with unannotated
> override-redirect windows from old applications.
>
> Do we need any other types?

I do not know, GTK and QT developer can surely answer (I found the
notification type a bit out of topic).

But:

(1) It will be useful to know for which window the  override-redirect
window is for. Either we can add, in the spec, that the WM_TRANSIENT_FOR
hint should be set for override-redirect windows or add a new hint, say
"_NET_WM_UNMANAGED_FOR", similar to WM_TRANSIENT_FOR.
This can help a compositor which makes some persistent transformations
on windows (as Metisse or Looking Glass).

(2) I think that using a new property "_NET_WM_UNMANAGED_TYPE" (and then
NET_WM_UNMANAGED_TYPE_DND_WINDOW ...etc) will help to avoid confusion.

Regards, Olivier