[PATCH fullscreen-shell v5 01/18] Add a fullscreen shell protocol

Jason Ekstrand jason at jlekstrand.net
Mon Mar 17 17:35:20 PDT 2014

Signed-off-by: Jason Ekstrand <jason at jlekstrand.net>
 protocol/fullscreen-shell.xml | 206 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 206 insertions(+)
 create mode 100644 protocol/fullscreen-shell.xml

diff --git a/protocol/fullscreen-shell.xml b/protocol/fullscreen-shell.xml
new file mode 100644
index 0000000..8639ea3
--- /dev/null
+++ b/protocol/fullscreen-shell.xml
@@ -0,0 +1,206 @@
+<protocol name="fullscreen_shell">
+  <interface name="_wl_fullscreen_shell" version="1">
+    <description summary="Displays a single surface per output">
+      Displays a single surface per output.
+      This interface provides a mechanism for a single client to display
+      simple full-screen surfaces.  While there technically may be multiple
+      clients bound to this interface, only one of those clients should be
+      shown at a time.
+      To present a surface, the client uses either the present_surface or
+      present_surface_for_mode requests.  Presenting a surface takes effect
+      on the next wl_surface.commit.  See the individual requests for
+      details about scaling and mode switches.
+      The client can have at most one surface per output at any time.
+      Requesting a surface be presented on an output that already has a
+      surface replaces the previously presented surface.  Presenting a null
+      surface removes its content and effectively disables the output.
+      Exactly what happens when an output is "disabled" is
+      compositor-specific.  The same surface may be presented on multiple
+      outputs simultaneously.
+      Once a surface is presented on an output, it stays on that output
+      until either the client removes it or the compositor destroys the
+      output.  This way, the client can update the output's contents by
+      simply attaching a new buffer.
+    </description>
+    <request name="release" type="destructor">
+      <description summary="release the wl_fullscreen_shell interface">
+      	Release the binding from the wl_fullscreen_shell interface
+	This destroys the server-side object and frees this binding.  If
+	the client binds to wl_fullscreen_shell multiple times, it may wish
+	to free some of those bindings.
+      </description>
+    </request>
+    <enum name="capability">
+      <description summary="capabilities advertised by the compositor">
+	Various capabilities that can be advertised by the compositor.  They
+	are advertised one-at-a-time when the wl_fullscreen_shell interface is
+	bound.  See the wl_fullscreen_shell.capability event for more details.
+	This is a hint to the client that indicates that the compositor is
+	capable of setting practially any mode on its outputs.  If this
+	capability is provided, wl_fullscreen_shell.present_surface_for_mode
+	will almost never fail and clients should feel free to set whatever
+	mode they like.  If the compositor does not advertise this, it may
+	still suppot some modes that are not advertised through wl_global.mode
+	but it is less likely.
+	This is a hint to the client that indicates that the compositor can
+	handle a cursor surface from the client without actually compositing.
+	This may be because of a hardware cursor plane or some other mechanism.
+	If the compositor does not advertise this capability then setting
+	wl_pointer.cursor may degrade performance or be ignored entirely.  If
+	CURSOR_PLANE is not advertised, it is recommended that the client draw
+	its own cursor and set wl_pointer.cursor(NULL).
+      </description>
+      <entry name="arbitrary_modes" value="1" summary="compositor is capable of almost any output mode"/>
+      <entry name="cursor_plane" value="2" summary="compositor has a seperate cursor plane"/>
+    </enum>
+    <event name="capability">
+      <description summary="advertises a capability of the compositor">
+	Advertises a single capability of the compositor.
+	When the wl_fullscreen_shell interface is bound, this event is emitted
+	once for each capability advertised.  Valid capabilities are given by
+	the wl_fullscreen_shell.capability enum.  If clients want to take
+	advantage of any of these capabilities, they sould use a
+	wl_display.sync request immediatly after binding to ensure that they
+	recieve all the capability events.
+      </description>
+      <arg name="capabilty" type="uint"/>
+    </event>
+    <enum name="present_method">
+      <description summary="different method to set the surface fullscreen">
+	Hints to indicate to the compositor how to deal with a conflict
+	between the dimensions of the surface and the dimensions of the
+	output. The compositor is free to ignore this parameter.
+      </description>
+      <entry name="default" value="0" summary="no preference, apply default policy"/>
+      <entry name="center" value="1" summary="center the surface on the output"/>
+      <entry name="zoom" value="2" summary="scale the surface, preserving aspect ratio, to the largest size that will fit on the output" />
+      <entry name="zoom_crop" value="3" summary="scale the surface, preserving aspect ratio, to fully fill the output cropping if needed" />
+      <entry name="stretch" value="4" summary="scale the surface to the size of the output ignoring aspect ratio" />
+    </enum>
+    <request name="present_surface">
+      <description summary="present surface for display">
+	Present a surface on the given output.
+	If the output is null, the compositor will present the surface on
+	whatever display (or displays) it thinks best.  In particular, this
+	may replace any or all surfaces currently presented so it should
+	not be used in combination with placing surfaces on specific
+	outputs.
+	The method parameter is a hint to the compositor for how the surface
+	is to be presented.  In particular, it tells the compostior how to
+	handle a size mismatch between the presented surface and the
+	output.  The compositor is free to ignore this parameter.
+	The "zoom", "zoom_crop", and "stretch" methods imply a scaling
+	operation on the surface.  This will override any kind of output
+	scaling, so the buffer_scale property of the surface is effectively
+	ignored.
+      </description>
+      <arg name="surface" type="object" interface="wl_surface" allow-null="true"/>
+      <arg name="method" type="uint"/>
+      <arg name="output" type="object" interface="wl_output" allow-null="true"/>
+    </request>
+    <request name="present_surface_for_mode">
+      <description summary="present surface for display at a particular mode">
+	Presents a surface on the given output for a particular mode.
+	If the current size of the output differs from that of the surface,
+	the compositor will attempt to change the size of the output to
+	match the surface.  The result of the mode-switch operation will be
+	returned via the provided wl_fullscreen_shell_mode_feedback object.
+	If the current output mode matches the one requested or if the
+	compositor successfully switches the mode to match the surface,
+	then the mode_successful event will be sent and the output will
+	contain the contents of the given surface.  If the compositor
+	cannot match the output size to the surface size, the mode_failed
+	will be sent and the output will contain the contents of the
+	previously presented surface (if any).  If another surface is
+	presented on the given output before either of these has a chance
+	to happen, the present_cancelled event will be sent.
+	Due to race conditions and other issues unknown to the client, no
+	mode-switch operation is guaranteed to succeed.  However, if the
+	mode is one advertised by wl_output.mode or if the compositor
+	advertises the ARBITRARY_MODES capability, then the client should
+	expect that the mode-switch operation will usually succeed.
+	If the size of the presented surface changes, the resulting output
+	is undefined.  The compositor may attempt to change the output mode
+	to compensate.  However, there is no guarantee that a suitable mode
+	will be found and the client has no way to be notified of success
+	or failure.
+	The framerate parameter specifies the desired framerate for the
+	output in mHz.  The compositor is free to ignore this parameter.  A
+	value of 0 indicates that the client has no preference.
+	If the value of wl_output.scale differs from wl_surface.buffer_scale,
+	then the compositor may choose a mode that matches either the buffer
+	size or the surface size.  In either case, the surface will fill the
+	output.
+      </description>
+      <arg name="surface" type="object" interface="wl_surface"/>
+      <arg name="output" type="object" interface="wl_output"/>
+      <arg name="framerate" type="int"/>
+      <arg name="feedback" type="new_id" interface="_wl_fullscreen_shell_mode_feedback"/>
+    </request>
+    <enum name="error">
+      <description summary="wl_fullscreen_shell error values">
+	These errors can be emitted in response to wl_fullscreen_shell requests
+      </description>
+      <entry name="invalid_method" value="0" summary="present_method is not known"/>
+    </enum>
+  </interface>
+  <interface name="_wl_fullscreen_shell_mode_feedback" version="1">
+    <event name="mode_successful">
+      <description summary="mode switch succeeded">
+	This event indicates that the attempted mode switch operation was
+	successful.  A surface of the size requested in the mode switch
+	will fill the output without scaling.
+	Upon receiving this event, the client should destroy the
+	wl_fullscreen_shell_mode_feedback object.
+      </description>
+    </event>
+    <event name="mode_failed">
+      <description summary="mode switch failed">
+	This event indicates that the attempted mode switch operation
+	failed. This may be because the requested output mode is not
+	possible or it may mean that the compositor does not want to allow it.
+	Upon receiving this event, the client should destroy the
+	wl_fullscreen_shell_mode_feedback object.
+      </description>
+    </event>
+    <event name="present_cancelled">
+      <description summary="mode switch cancelled">
+	This event indicates that the attempted mode switch operation was
+	cancelled.  Most likely this is because the client requested a
+	second mode switch before the first one completed.
+	Upon receiving this event, the client should destroy the
+	wl_fullscreen_shell_mode_feedback object.
+      </description>
+    </event>
+  </interface>

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