[PATCH v4] Add xdg-output protocol

Olivier Fourdan ofourdan at redhat.com
Wed Jul 19 08:51:41 UTC 2017


This protocol aims at describing outputs in way which is more in line
with the concept of an output on desktop oriented systems.

Some information are more specific to the concept of an output for a
desktop oriented system and may not make sense in other applications,
such as IVI systems for example.

The goal is to gradually move the desktop specific concepts out of the
core wl_output protocol.

For now it just features the position and logical size which describe
the output position and size in the global compositor space.

Signed-off-by: Olivier Fourdan <ofourdan at redhat.com>
Reviewed-by: Jonas Ådahl <jadahl at gmail.com>
Acked-by: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
---
 v2: use "destroy" instead of "release" for destructor
 v3: adopt a more conventional global factory interface with a
     get_xdg_output() method, add some clarification and example.
 v4: Rebase on current master
     Add major version in interface name as per Pekka's review
     Add that objects already created are not affected by the manager
     destroy method.
     Remove the word "mode" from argument summary for logical_size as
     per Pekka's review
     Add A-b Pekka and R-b Jonas following their respective feedback.

 Makefile.am                                    |   1 +
 unstable/xdg-output/README                     |   4 +
 unstable/xdg-output/xdg-output-unstable-v1.xml | 162 +++++++++++++++++++++++++
 3 files changed, 167 insertions(+)
 create mode 100644 unstable/xdg-output/README
 create mode 100644 unstable/xdg-output/xdg-output-unstable-v1.xml

diff --git a/Makefile.am b/Makefile.am
index d100c13..5b5ae96 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -14,6 +14,7 @@ unstable_protocols =								\
 	unstable/idle-inhibit/idle-inhibit-unstable-v1.xml			\
 	unstable/xwayland-keyboard-grab/xwayland-keyboard-grab-unstable-v1.xml	\
 	unstable/keyboard-shortcuts-inhibit/keyboard-shortcuts-inhibit-unstable-v1.xml \
+	unstable/xdg-output/xdg-output-unstable-v1.xml				\
 	$(NULL)
 
 stable_protocols =								\
diff --git a/unstable/xdg-output/README b/unstable/xdg-output/README
new file mode 100644
index 0000000..e42b711
--- /dev/null
+++ b/unstable/xdg-output/README
@@ -0,0 +1,4 @@
+xdg_output protocol
+
+Maintainers:
+Olivier Fourdan <ofourdan at redhat.com>
diff --git a/unstable/xdg-output/xdg-output-unstable-v1.xml b/unstable/xdg-output/xdg-output-unstable-v1.xml
new file mode 100644
index 0000000..8a403a5
--- /dev/null
+++ b/unstable/xdg-output/xdg-output-unstable-v1.xml
@@ -0,0 +1,162 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<protocol name="xdg_output_unstable_v1">
+
+  <copyright>
+    Copyright © 2017 Red Hat Inc.
+
+    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>
+
+  <description summary="Protocol to describe output regions">
+    This protocol aims at describing outputs in a way which is more in line
+    with the concept of an output on desktop oriented systems.
+
+    Some information are more specific to the concept of an output for
+    a desktop oriented system and may not make sense in other applications,
+    such as IVI systems for example.
+
+    Typically, the global compositor space on a desktop system is made of
+    a contiguous or overlapping set of rectangular regions.
+
+    Some of the information provided in this protocol might be identical
+    to their counterparts already available from wl_output, in which case
+    the information provided by this protocol should be preferred to their
+    equivalent in wl_output. The goal is to move the desktop specific
+    concepts (such as output location within the global compositor space,
+    the connector name and types, etc.) out of the core wl_output protocol.
+
+    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>
+
+  <interface name="zxdg_output_manager_v1" version="1">
+    <description summary="manage xdg_output objects">
+      A global factory interface for xdg_output objects.
+    </description>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy the xdg_output_manager object">
+	Using this request a client can tell the server that it is not
+	going to use the xdg_output_manager object anymore.
+
+	Any objects already created through this instance are not affected.
+      </description>
+    </request>
+
+    <request name="get_xdg_output">
+      <description summary="create an xdg output from a wl_output">
+	This creates a new xdg_output object for the given wl_output.
+      </description>
+      <arg name="id" type="new_id" interface="zxdg_output"/>
+      <arg name="output" type="object" interface="wl_output"/>
+    </request>
+  </interface>
+
+  <interface name="zxdg_output_v1" version="1">
+    <description summary="compositor logical output region">
+      An xdg_output describes part of the compositor geometry.
+
+      This typically corresponds to a monitor that displays part of the
+      compositor space.
+    </description>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy the xdg_output object">
+	Using this request a client can tell the server that it is not
+	going to use the xdg_output object anymore.
+      </description>
+    </request>
+
+    <event name="logical_position">
+      <description summary="position of the output within the global compositor space">
+	The position event describes the location of the wl_output within
+	the global compositor space.
+
+	The logical_position event is sent after creating an xdg_output
+	(see xdg_output_manager.get_xdg_output) and whenever the location
+	of the output changes within the global compositor space.
+      </description>
+      <arg name="x" type="int"
+	   summary="x position within the global compositor space"/>
+      <arg name="y" type="int"
+	   summary="y position within the global compositor space"/>
+    </event>
+
+    <event name="logical_size">
+      <description summary="size of the output in the global compositor space">
+	The logical_size event describes the size of the output in the
+	global compositor space.
+
+	For example, a surface without any buffer scale, transformation
+	nor rotation set, with the size matching the logical_size will
+	have the same size as the corresponding output when displayed.
+
+	Most regular Wayland clients should not pay attention to the
+	logical size and would rather rely on xdg_shell interfaces.
+
+	Some clients such as Xwayland, however, need this to configure
+	their surfaces in the global compositor space as the compositor
+	may apply a different scale from what is advertised by the output
+	scaling property (to achieve fractional scaling, for example).
+
+	For example, for a wl_output mode 3840×2160 and a scale factor 2:
+
+	- A compositor not scaling the surface buffers will advertise a
+	  logical size of 3840×2160,
+
+	- A compositor automatically scaling the surface buffers will
+	  advertise a logical size of 1920×1080,
+
+	- A compositor using a fractional scale of 1.5 will advertise a
+	  logical size to 2560×1620.
+
+	The logical_size event is sent after creating an xdg_output
+	(see xdg_output_manager.get_xdg_output) and whenever the logical
+	size of the output changes, either as a result of a change in the
+	applied scale or because of a change in the corresponding output
+	mode(see wl_output.mode) or transform (see wl_output.transform).
+      </description>
+      <arg name="width" type="int"
+	   summary="width in global compositor space"/>
+      <arg name="height" type="int"
+	   summary="height in global compositor space"/>
+    </event>
+
+    <event name="done">
+      <description summary="all information about the output have been sent">
+	This event is sent after all other properties of an xdg_output
+	have been sent.
+
+	This allows changes to the xdg_output properties to be seen as
+	atomic, even if they happen via multiple events.
+      </description>
+    </event>
+
+  </interface>
+</protocol>
+
-- 
2.9.4



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