[PATCH wayland-protocols v6] unstable: add xdg-decoration protocol
Simon Ser
contact at emersion.fr
Mon May 28 07:04:54 UTC 2018
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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