[PATCH wayland-protocols v6] unstable: add xdg-decoration protocol

Simon Ser contact at emersion.fr
Mon Jun 4 08:11:34 UTC 2018


Hi Jonas,

Did you have the chance to have a look at this version?

Thanks,
---
Simon Ser
https://emersion.fr

On May 28, 2018 8:04 AM, Simon Ser <contact at emersion.fr> wrote:
> Hi Jonas,
>
> What do you think of this new proposal?
>
> Thanks,
> ---
> Simon Ser
> https://emersion.fr
>
> On May 20, 2018 11:39 AM, Simon Ser <contact at emersion.fr> wrote:
> > This adds a new protocol to negotiate server-side rendering of window
> > decorations for xdg-toplevels. This allows compositors that want to draw
> > decorations themselves to send their preference to clients, and clients that
> > prefer server-side decorations to request them.
> >
> > This is inspired by a protocol from KDE [1] which has been implemented in
> > KDE and Sway and was submitted for consideration in 2017 [2]. This patch
> > provides an updated protocol with those concerns taken into account.
> >
> > Signed-off-by: Simon Ser <contact at emersion.fr>
> >
> > [1] https://github.com/KDE/kwayland/blob/master/src/client/protocols/server-decoration.xml
> > [2] https://lists.freedesktop.org/archives/wayland-devel/2017-October/035564.html
> > ---
> >
> > This was iterated on privately between representatives of Sway and wlroots
> > (Simon Ser, Drew DeVault and Tony Crisci), KDE and Qt (David Edmundson), and
> > Mir (Alan Griffiths).
> >
> > A proof-of-concept of a client and server implementation is available at [1].
> >
> > Changes from v5 to v6:
> > - Add back the set_mode request, add a new unset_mode request
> >
> > This version fixes the race condition Jonas pointed out in his v4 review.
> >
> > I believe there were two client use-cases for the set_mode request in v4:
> > - Request a specific preferred mode, and ignore the compositor preference. This
> >   is still possible since the set_mode request is back.
> > - Use the compositor's preference, as the client doesn't have one. In v4 this
> >   was achieved by sending a set_mode request with the mode received in the
> >   preferred_mode event. In this version this is achieved by not unsetting the
> >   mode (either by not sending any set_mode request, or by sending an unset_mode
> >   request).
> >
> > The race condition could happen in v4 if the compositor sent a preferred_mode
> > event and couldn't decide if the client would want to keep its current mode or
> > change it (ie. should the compositor wait for a set_mode request or not?). This
> > new design doesn't let the client know the compositor's preferred mode. When the
> > compositor changes its preferred mode, it already knows if the client prefers to
> > use it or to use its own - and thus can directly send a configure event if
> > necessary.
> >
> > I believe this lso simplifies the protocol and makes it easier to understand. I
> > don't think there are any regressions due to the fact that the client doesn't
> > know anymore the compositor's preferred mode.
> >
> > [1] https://github.com/swaywm/wlroots/pull/638
> >
> >  Makefile.am                                   |   1 +
> >  unstable/xdg-decoration/README                |   4 +
> >  .../xdg-decoration-unstable-v1.xml            | 145 ++++++++++++++++++
> >  3 files changed, 150 insertions(+)
> >  create mode 100644 unstable/xdg-decoration/README
> >  create mode 100644 unstable/xdg-decoration/xdg-decoration-unstable-v1.xml
> >
> > diff --git a/Makefile.am b/Makefile.am
> > index 4b9a901..71909d8 100644
> > --- a/Makefile.am
> > +++ b/Makefile.am
> > @@ -17,6 +17,7 @@ unstable_protocols =								\
> >  	unstable/keyboard-shortcuts-inhibit/keyboard-shortcuts-inhibit-unstable-v1.xml \
> >  	unstable/xdg-output/xdg-output-unstable-v1.xml				\
> >  	unstable/input-timestamps/input-timestamps-unstable-v1.xml	\
> > +	unstable/xdg-decoration/xdg-decoration-unstable-v1.xml	\
> >  	$(NULL)
> >
> >  stable_protocols =								\
> > diff --git a/unstable/xdg-decoration/README b/unstable/xdg-decoration/README
> > new file mode 100644
> > index 0000000..73f0c52
> > --- /dev/null
> > +++ b/unstable/xdg-decoration/README
> > @@ -0,0 +1,4 @@
> > +xdg_decoration protocol
> > +
> > +Maintainers:
> > +Simon Ser <contact at emersion.fr>
> > diff --git a/unstable/xdg-decoration/xdg-decoration-unstable-v1.xml b/unstable/xdg-decoration/xdg-decoration-unstable-v1.xml
> > new file mode 100644
> > index 0000000..cf8cbdb
> > --- /dev/null
> > +++ b/unstable/xdg-decoration/xdg-decoration-unstable-v1.xml
> > @@ -0,0 +1,145 @@
> > +<?xml version="1.0" encoding="UTF-8"?>
> > +<protocol name="xdg_decoration_unstable_v1">
> > +  <copyright>
> > +    Copyright © 2018 Simon Ser
> > +
> > +    Permission is hereby granted, free of charge, to any person obtaining a
> > +    copy of this software and associated documentation files (the "Software"),
> > +    to deal in the Software without restriction, including without limitation
> > +    the rights to use, copy, modify, merge, publish, distribute, sublicense,
> > +    and/or sell copies of the Software, and to permit persons to whom the
> > +    Software is furnished to do so, subject to the following conditions:
> > +
> > +    The above copyright notice and this permission notice (including the next
> > +    paragraph) shall be included in all copies or substantial portions of the
> > +    Software.
> > +
> > +    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> > +    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> > +    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> > +    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> > +    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> > +    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> > +    DEALINGS IN THE SOFTWARE.
> > +  </copyright>
> > +
> > +  <interface name="zxdg_decoration_manager_v1" version="1">
> > +    <description summary="window decoration manager">
> > +      This interface allows a compositor to announce support for server-side
> > +      decorations.
> > +
> > +      A window decoration is a set of window controls as deemed appropriate by
> > +      the party managing them, such as user interface components used to move,
> > +      resize and change a window's state.
> > +
> > +      A client can use this protocol to request being decorated by a supporting
> > +      compositor.
> > +
> > +      If compositor and client do not negotiate the use of a server-side
> > +      decoration using this protocol, clients continue to self-decorate as they
> > +      see fit.
> > +
> > +      Warning! The protocol described in this file is experimental and
> > +      backward incompatible changes may be made. Backward compatible changes
> > +      may be added together with the corresponding interface version bump.
> > +      Backward incompatible changes are done by bumping the version number in
> > +      the protocol and interface names and resetting the interface version.
> > +      Once the protocol is to be declared stable, the 'z' prefix and the
> > +      version number in the protocol and interface names are removed and the
> > +      interface version number is reset.
> > +    </description>
> > +
> > +    <enum name="error">
> > +      <entry name="unconfigured_buffer" value="1"/>
> > +      <entry name="already_constructed" value="2"/>
> > +    </enum>
> > +
> > +    <request name="destroy" type="destructor">
> > +      <description summary="destroy the decoration manager object">
> > +        Destroy the decoration manager.
> > +      </description>
> > +    </request>
> > +
> > +    <request name="get_toplevel_decoration">
> > +      <description summary="create a new toplevel decoration object">
> > +        Create a new decoration object associated with the given toplevel.
> > +
> > +        Creating an xdg_toplevel_decoration from an xdg_toplevel which has a
> > +        buffer attached or committed is a client error, and any attempts by a
> > +        client to attach or manipulate a buffer prior to the first
> > +        xdg_toplevel_decoration.configure call must also be treated as
> > +        errors.
> > +      </description>
> > +      <arg name="id" type="new_id" interface="zxdg_toplevel_decoration_v1"/>
> > +      <arg name="toplevel" type="object" interface="xdg_toplevel"/>
> > +    </request>
> > +  </interface>
> > +
> > +  <interface name="zxdg_toplevel_decoration_v1" version="1">
> > +    <description summary="decoration object for a toplevel surface">
> > +      The decoration object allows the compositor to toggle server-side window
> > +      decorations for a toplevel surface. The client can request to switch to
> > +      another mode.
> > +
> > +      The xdg_toplevel_decoration object must be destroyed before its
> > +      xdg_toplevel.
> > +    </description>
> > +
> > +    <request name="destroy" type="destructor">
> > +      <description summary="destroy the decoration object">
> > +        Switch back to a mode without any server-side decorations at the next
> > +        commit.
> > +      </description>
> > +    </request>
> > +
> > +    <enum name="mode">
> > +      <description summary="window decoration modes">
> > +        These values describe window decoration modes.
> > +      </description>
> > +      <entry name="client_side" value="1" summary="no server-side window decoration"/>
> > +      <entry name="server_side" value="2" summary="server-side window decoration"/>
> > +    </enum>
> > +
> > +    <request name="set_mode">
> > +      <description summary="set the decoration mode">
> > +        Set the toplevel surface decoration mode. This informs the compositor
> > +        that the client prefers the provided decoration mode.
> > +
> > +        After requesting a decoration mode, the compositor will respond by
> > +        emitting a xdg_surface.configure event. The client should then update
> > +        its content, drawing it without decorations if the received mode is
> > +        server-side decorations. The client must also acknowledge the configure
> > +        when committing the new content (see xdg_surface.ack_configure).
> > +
> > +        The compositor can ignore this request.
> > +      </description>
> > +      <arg name="mode" type="uint" enum="mode" summary="the decoration mode"/>
> > +    </request>
> > +
> > +    <request name="unset_mode">
> > +      <description summary="unset the decoration mode">
> > +        Unset the toplevel surface decoration mode. This informs the compositor
> > +        that the client doesn't prefer a particular decoration mode.
> > +
> > +        After unsetting a decoration mode, the compositor will respond by
> > +        emitting a xdg_surface.configure event. The client should then update
> > +        its content, drawing it without decorations if the received mode is
> > +        server-side decorations. The client must also acknowledge the configure
> > +        when committing the new content (see xdg_surface.ack_configure).
> > +      </description>
> > +    </request>
> > +
> > +    <event name="configure">
> > +      <description summary="suggest a surface change">
> > +        The configure event asks the client to change its decoration mode. The
> > +        configured state should not be applied immediately. Clients must send an
> > +        ack_configure in response to this event. See xdg_surface.configure and
> > +        xdg_surface.ack_configure for details.
> > +
> > +        A configure event can be sent at any time. The specified mode must be
> > +        obeyed by the client.
> > +      </description>
> > +      <arg name="mode" type="uint" enum="mode" summary="the decoration mode"/>
> > +    </event>
> > +  </interface>
> > +</protocol>
> > --
> > 2.17.0
> >
> >
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