Add XdgOutput client support

XdgOutput is an extension of wl_output with the benefit of having the
logical size of a screen as an explicit parameter, instead of clients
inferring it from modeSize / scale. This is useful as it allows
compositors to implement fractional scaling whilst clients can still
fill the screen.

In the future XdgOutputV2 will support a more useful name and ID that
we can use.

[ChangeLog][QPA plugin] Added support for xdg-output-unstable-v1

Change-Id: I2e1e64ad6cb497a1cbb7b7b170f28ac92231c2c4
Reviewed-by: Pier Luigi Fiorini <pierluigi.fiorini@liri.io>
Reviewed-by: Johan Helsing <johan.helsing@qt.io>

2 files changed, 225 insertions, 0 deletions

diff --git a/src/3rdparty/protocol/qt_attribution.json b/src/3rdparty/protocol/qt_attribution.json
index d934622c9..6034508ba 100644
--- a/src/3rdparty/protocol/qt_attribution.json
+++ b/src/3rdparty/protocol/qt_attribution.json
@@ -37,6 +37,22 @@ Copyright (c) 2013 BMW Car IT GmbH"
     },
 
     {
+        "Id": "wayland-xdg-output-protocol",
+        "Name": "Wayland XDG Output Protocol",
+        "QDocModule": "qtwaylandcompositor",
+        "QtUsage": "Used in the Qt Wayland platform plugin.",
+        "Files": "xdg-output-unstable-v1.xml",
+        "Description": "The XDG Output protocol is an extended way to describe output regions under Wayland",
+        "Homepage": "https://wayland.freedesktop.org",
+        "Version": "unstable v1, version 2",
+        "DownloadLocation": "https://cgit.freedesktop.org/wayland/wayland-protocols/plain/unstable/xdg-output/xdg-output-unstable-v1.xml?h=1.16",
+        "LicenseId": "MIT",
+        "License": "MIT License",
+        "LicenseFile": "MIT_LICENSE.txt",
+        "Copyright": "Copyright © 2017 Red Hat Inc."
+    },
+
+    {
         "Id": "wayland-xdg-shell-protocol",
         "Name": "Wayland XDG Shell Protocol",
         "QDocModule": "qtwaylandcompositor",
diff --git a/src/3rdparty/protocol/xdg-output-unstable-v1.xml b/src/3rdparty/protocol/xdg-output-unstable-v1.xml
new file mode 100644
index 000000000..ccbfe1c9a
--- /dev/null
+++ b/src/3rdparty/protocol/xdg-output-unstable-v1.xml
@@ -0,0 +1,209 @@
+<?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="2">
+    <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_v1"/>
+      <arg name="output" type="object" interface="wl_output"/>
+    </request>
+  </interface>
+
+  <interface name="zxdg_output_v1" version="2">
+    <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.
+
+	For example, for a wl_output mode 1920×1080 and a 90 degree rotation,
+	the compositor will advertise a logical size of 1080x1920.
+
+	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>
+
+    <!-- Version 2 additions -->
+
+    <event name="name" since="2">
+      <description summary="name of this output">
+	Many compositors will assign names to their outputs, show them to the
+	user, allow them to be configured by name, etc. The client may wish to
+	know this name as well to offer the user similar behaviors.
+
+	The naming convention is compositor defined, but limited to
+	alphanumeric characters and dashes (-). Each name is unique among all
+	wl_output globals, but if a wl_output global is destroyed the same name
+	may be reused later. The names will also remain consistent across
+	sessions with the same hardware and software configuration.
+
+	Examples of names include 'HDMI-A-1', 'WL-1', 'X11-1', etc. However, do
+	not assume that the name is a reflection of an underlying DRM
+	connector, X11 connection, etc.
+
+	The name event is sent after creating an xdg_output (see
+	xdg_output_manager.get_xdg_output). This event is only sent once per
+	xdg_output, and the name does not change over the lifetime of the
+	wl_output global.
+      </description>
+      <arg name="name" type="string" summary="output name"/>
+    </event>
+
+    <event name="description" since="2">
+      <description summary="human-readable description of this output">
+	Many compositors can produce human-readable descriptions of their
+	outputs.  The client may wish to know this description as well, to
+	communicate the user for various purposes.
+
+	The description is a UTF-8 string with no convention defined for its
+	contents. Examples might include 'Foocorp 11" Display' or 'Virtual X11
+	output via :1'.
+
+	The description event is sent after creating an xdg_output (see
+	xdg_output_manager.get_xdg_output). This event is only sent once per
+	xdg_output, and the description does not change over the lifetime of
+	the wl_output global. The description is optional, and may not be sent
+	at all.
+      </description>
+      <arg name="description" type="string" summary="output description"/>
+    </event>
+
+  </interface>
+</protocol>