[PATCH wayland-protocols v6] unstable: add xdg-decoration protocol
Simon Ser
contact at emersion.fr
Sun May 20 10:39:39 UTC 2018
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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