[profile/ivi/wayland.git] / protocol / wayland.xml

<?xml version="1.0" encoding="UTF-8"?>
<protocol name="wayland">

  <copyright>
    Copyright © 2008-2011 Kristian Høgsberg
    Copyright © 2010-2011 Intel Corporation

    Permission to use, copy, modify, distribute, and sell this
    software and its documentation for any purpose is hereby granted
    without fee, provided that the above copyright notice appear in
    all copies and that both that copyright notice and this permission
    notice appear in supporting documentation, and that the name of
    the copyright holders not be used in advertising or publicity
    pertaining to distribution of the software without specific,
    written prior permission.  The copyright holders make no
    representations about the suitability of this software for any
    purpose.  It is provided "as is" without express or implied
    warranty.

    THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
    SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
    FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
    SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
    WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
    AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
    ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
    THIS SOFTWARE.
  </copyright>

  <interface name="wl_display" version="1">
    <description summary="core global object">
      The core global object.  This is a special singleton object.  It
      is used for internal Wayland protocol features.
    </description>

    <request name="sync">
      <description summary="asynchronous roundtrip">
        The sync request asks the server to emit the 'done' event
        on the provided wl_callback object.  Since requests are
        handled in-order, this can be used as a barrier to ensure all
        previous requests have been handled.
      </description>
      <arg name="callback" type="new_id" interface="wl_callback"/>
    </request>

    <request name="get_registry">
      <description summary="get global registry object">
        This request creates a registry object that allows the client
        to list and bind the global objects available from the
        compositor.
      </description>
      <arg name="callback" type="new_id" interface="wl_registry"/>
    </request>

    <event name="error">
      <description summary="fatal error event">
        The error event is sent out when a fatal (non-recoverable)
        error has occurred.  The @object_id argument is the object
        where the error occurred, most often in response to a request
        to that object.  The @code identifies the error and is defined
        by the object interface.  As such, each interface defines its
        own set of error codes.  The @message is an brief description
        of the error, for (debugging) convenience.
      </description>
      <arg name="object_id" type="object"/>
      <arg name="code" type="uint"/>
      <arg name="message" type="string"/>
    </event>

    <enum name="error">
      <description summary="global error values">
        These errors are global and can be emitted in response to any
        server request.
      </description>
      <entry name="invalid_object" value="0"
             summary="server couldn't find object"/>
      <entry name="invalid_method" value="1"
             summary="method doesn't exist on the specified interface"/>
      <entry name="no_memory" value="2"
             summary="server is out of memory"/>
    </enum>

    <event name="delete_id">
      <description summary="acknowledge object id deletion">
        This event is used internally by the object ID management
        logic.  When a client deletes an object, the server will send
        this event to acknowledge that it has seen the delete request.
        When the client receive this event, it will know that it can
        safely reuse the object ID
      </description>
      <arg name="id" type="uint" />
    </event>
  </interface>

  <interface name="wl_registry" version="1">
    <description summary="global registry object">
      The global registry object.  The server has a number of global
      objects that are available to all clients.  These objects
      typically represent an actual object in the server (for example,
      an input device) or they are singleton objects that provides
      extension functionality.

      When a client creates a registry object, the registry object
      will emit a global event for each global currently in the
      regitry.  Globals come and go as a result of device hotplugs,
      reconfiguration or other events, and the registry will send out
      @global and @global_remove events to keep the client up to date
      with the changes.  To mark the end of the initial burst of
      events, the client can use the wl_display.sync request
      immediately after calling wl_display.get_registry.

      A client can 'bind' to a global object by using the bind
      request.  This creates a client side handle that lets the object
      emit events to the client and lets the client invoke requests on
      the object.
    </description>

    <request name="bind">
      <description summary="bind an object to the display">
        Binds a new, client-created object to the server using @name as
        the identifier.
      </description>
      <arg name="name" type="uint" summary="unique number id for object"/>
      <arg name="id" type="new_id"/>
    </request>

    <event name="global">
      <description summary="announce global object">
        Notify the client of global objects.  
      </description>
      <arg name="name" type="uint"/>
      <arg name="interface" type="string"/>
      <arg name="version" type="uint"/>
    </event>

    <event name="global_remove">
      <description summary="announce removal of global object">
        Notify the client of removed global objects.  This event
        notifies the client that the global identifies by @name is no
        longer available.  If the client bound to the global using the
        'bind' request, the client should now destroy that object.
        The object remains valid and requests to the object will be
        ignored until the client destroys it, to avoid races between
        the global going away and a client sending a request to it.
      </description>
      <arg name="name" type="uint"/>
    </event>
  </interface>

  <interface name="wl_callback" version="1">
    <event name="done">
      <arg name="serial" type="uint"/>
    </event>
  </interface>

  <interface name="wl_compositor" version="1">
    <description summary="the compositor singleton">
      A compositor.  This object is a singleton global.  The
      compositor is in charge of combining the contents of multiple
      surfaces into one displayable output.
    </description>

    <request name="create_surface">
      <description summary="create new surface">
        Ask the compositor to create a new surface.
      </description>
      <arg name="id" type="new_id" interface="wl_surface"/>
    </request>

    <request name="create_region">
      <description summary="create new region">
        Ask the compositor to create a new region.
      </description>
      <arg name="id" type="new_id" interface="wl_region"/>
    </request>
  </interface>

  <interface name="wl_shm_pool" version="1">
    <description summary="a shared memory pool">
      The wl_shm_pool object encapsulates a piece of memory shared
      between the compositor and client.  Through the wl_shm_pool
      object, the client can allocate shared memory wl_buffer objects.
      The objects will share the same underlying mapped memory.
      Reusing the mapped memory avoids the setup/teardown overhead and
      is useful when interactively resizing a surface or for many
      small buffers.
    </description>

    <request name="create_buffer">
      <description summary="create wl_buffer from pool">
        Create a wl_buffer from the pool.  The buffer is created a
        offset bytes into the pool and has width and height as
        specified.  The stride arguments specifies the number of bytes
        from beginning of one row to the beginning of the next.  The
        format is the pixel format of the buffer and must be one of
        those advertised through the wl_shm.format event.

        A buffer will keep a reference to the pool it was created from
        so it is valid to destroy the pool immediately after creating
        a buffer from it.
      </description>

      <arg name="id" type="new_id" interface="wl_buffer"/>
      <arg name="offset" type="int"/>
      <arg name="width" type="int"/>
      <arg name="height" type="int"/>
      <arg name="stride" type="int"/>
      <arg name="format" type="uint"/>
    </request>

    <request name="destroy" type="destructor">
      <description summary="destroy the pool">
        Destroy the pool.
      </description>
    </request>

    <request name="resize">
      <description summary="change the size of the pool mapping">
        This request will cause the server to remap the backing memory
        for the pool from the fd passed when the pool was creating but
        using the new size.
      </description>

      <arg name="size" type="int"/>
    </request>
  </interface>

  <interface name="wl_shm" version="1">
    <description summary="shared memory support">
      Support for shared memory buffers.
    </description>

    <enum name="error">
      <entry name="invalid_format" value="0"/>
      <entry name="invalid_stride" value="1"/>
      <entry name="invalid_fd" value="2"/>
    </enum>

    <enum name="format">
      <entry name="argb8888" value="0"/>
      <entry name="xrgb8888" value="1"/>
    </enum>

    <request name="create_pool">
      <description summary="create a shm pool">
        This creates wl_shm_pool object, which can be used to create
        shared memory based wl_buffer objects.  The server will mmap
        size bytes of the passed fd, to use as backing memory for then
        pool.
      </description>

      <arg name="id" type="new_id" interface="wl_shm_pool"/>
      <arg name="fd" type="fd"/>
      <arg name="size" type="int"/>
    </request>

    <event name="format">
      <arg name="format" type="uint"/>
    </event>
  </interface>

  <interface name="wl_buffer" version="1">
    <description summary="content for a wl_surface">
      A buffer provides the content for a wl_surface. Buffers are
      created through factory interfaces such as wl_drm, wl_shm or
      similar. It has a width and a height and can be attached to a
      wl_surface, but the mechanism by which a client provides and
      updates the contents is defined by the buffer factory interface.
    </description>

    <request name="destroy" type="destructor">
      <description summary="destroy a buffer">
        Destroy a buffer. If and how you need to release the backing
        storage is defined by the buffer factory interface.

        For possible side-effects to a surface, see wl_surface.attach.
      </description>
    </request>

    <event name="release">
      <description summary="compositor releases buffer">
        Sent when this wl_buffer is no longer used by the compositor.
        The client is now free to re-use or destroy this buffer and its
        backing storage.

        If a client receives a release event before the frame callback
        requested in the same wl_surface.commit that attaches this
        wl_buffer to a surface, then the client is immediately free to
        re-use the buffer and its backing storage, and does not need a
        second buffer for the next surface content update. Typically
        this is possible, when the compositor maintains a copy of the
        wl_surface contents, e.g. as a GL texture. This is an important
        optimization for GL(ES) compositors with wl_shm clients.
      </description>
    </event>
  </interface>


  <interface name="wl_data_offer" version="1">
    <description summary="offer to transfer data">
      A wl_data_offer represents a piece of data offered for transfer
      by another client (the source client).  It is used by the
      copy-and-paste and drag-and-drop mechanisms.  The offer
      describes the different mime types that the data can be
      converted to and provides the mechanism for transferring the
      data directly from the source client.
    </description>

    <request name="accept">
      <description summary="accept one of the offered mime-types">
        Indicate that the client can accept the given mime-type, or
        NULL for not accepted.  Use for feedback during drag and drop.
      </description>

      <arg name="serial" type="uint"/>
      <arg name="type" type="string" allow-null="true"/>
    </request>

    <request name="receive">
      <description summary="request that the data is transferred">
        To transfer the offered data, the client issues this request
        and indicates the mime-type it wants to receive.  The transfer
        happens through the passed fd (typically a pipe(7) file
        descriptor).  The source client writes the data in the
        mime-type representation requested and then closes the fd.
        The receiving client reads from the read end of the pipe until
        EOF and the closes its end, at which point the transfer is
        complete.
      </description>
      <arg name="mime_type" type="string"/>
      <arg name="fd" type="fd"/>
    </request>

    <request name="destroy" type="destructor"/>

    <event name="offer">
      <description summary="advertise offered mime-type">
        Sent immediately after creating the wl_data_offer object.  One
        event per offered mime type.
      </description>

      <arg name="type" type="string"/>
    </event>
  </interface>

  <interface name="wl_data_source" version="1">
    <description summary="offer to transfer data">
      The wl_data_source object is the source side of a wl_data_offer.
      It is created by the source client in a data transfer and
      provides a way to describe the offered data and a way to respond
      to requests to transfer the data.
    </description>

    <request name="offer">
      <description summary="add an offered mime type">
        This request adds a mime-type to the set of mime-types
        advertised to targets.  Can be called several times to offer
        multiple types.
      </description>
      <arg name="type" type="string"/>
    </request>

    <request name="destroy" type="destructor">
      <description summary="destroy the data source">
        Destroy the data source.
      </description>
    </request>

    <event name="target">
      <description summary="a target accepts an offered mime-type">
        Sent when a target accepts pointer_focus or motion events.  If
        a target does not accept any of the offered types, type is NULL.
      </description>

      <arg name="mime_type" type="string" allow-null="true"/>
    </event>

    <event name="send">
      <description summary="send the data">
        Request for data from another client.  Send the data as the
        specified mime-type over the passed fd, then close the fd.
      </description>

      <arg name="mime_type" type="string"/>
      <arg name="fd" type="fd"/>
    </event>

    <event name="cancelled">
      <description summary="selection was cancelled">
        This data source has been replaced by another data source.
        The client should clean up and destroy this data source.
      </description>
    </event>

  </interface>

  <interface name="wl_data_device" version="1">
    <request name="start_drag">
      <description summary="start drag and drop operation">
        This request asks the compositor to start a drag and drop
        operation on behalf of the client.

        The source argument is the data source that provides the data
        for the eventual data transfer. If source is NULL, enter, leave
        and motion events are sent only to the client that initiated the
        drag and the client is expected to handle the data passing
        internally.

        The origin surface is the surface where the drag originates and
        the client must have an active implicit grab that matches the
        serial.

        The icon surface is an optional (can be nil) surface that
        provides an icon to be moved around with the cursor.  Initially,
        the top-left corner of the icon surface is placed at the cursor
        hotspot, but subsequent wl_surface.attach request can move the
        relative position. Attach requests must be confirmed with
        wl_surface.commit as usual.

        The current and pending input regions of the icon wl_surface are
        cleared, and wl_surface.set_input_region is ignored until the
        wl_surface is no longer used as the icon surface. When the use
        as an icon ends, the the current and pending input regions
        become undefined, and the wl_surface is unmapped.
      </description>
      <arg name="source" type="object" interface="wl_data_source" allow-null="true"/>
      <arg name="origin" type="object" interface="wl_surface"/>
      <arg name="icon" type="object" interface="wl_surface" allow-null="true"/>
      <arg name="serial" type="uint"/>
    </request>

    <request name="set_selection">
      <arg name="source" type="object" interface="wl_data_source" allow-null="true"/>
      <arg name="serial" type="uint"/>
    </request>

    <event name="data_offer">
      <description summary="introduce a new wl_data_offer">
        The data_offer event introduces a new wl_data_offer object,
        which will subsequently be used in either the
        data_device.enter event (for drag and drop) or the
        data_device.selection event (for selections).  Immediately
        following the data_device_data_offer event, the new data_offer
        object will send out data_offer.offer events to describe the
        mime-types it offers.
      </description>

      <arg name="id" type="new_id" interface="wl_data_offer"/>
    </event>

    <event name="enter">
      <description summary="initiate drag and drop session">
        This event is sent when an active drag-and-drop pointer enters
        a surface owned by the client.  The position of the pointer at
        enter time is provided by the @x an @y arguments, in surface
        local coordinates.
      </description>

      <arg name="serial" type="uint"/>
      <arg name="surface" type="object" interface="wl_surface"/>
      <arg name="x" type="fixed"/>
      <arg name="y" type="fixed"/>
      <arg name="id" type="object" interface="wl_data_offer" allow-null="true"/>
    </event>

    <event name="leave">
      <description summary="end drag and drop session">
        This event is sent when the drag-and-drop pointer leaves the
        surface and the session ends.  The client must destroy the
        wl_data_offer introduced at enter time at this point.
      </description>
    </event>

    <event name="motion">
      <description summary="drag and drop session motion">
        This event is sent when the drag-and-drop pointer moves within
        the currently focused surface. The new position of the pointer
        is provided by the @x an @y arguments, in surface local
        coordinates.
      </description>
      <arg name="time" type="uint"/>
      <arg name="x" type="fixed"/>
      <arg name="y" type="fixed"/>
    </event>

    <event name="drop"/>

    <event name="selection">
      <description summary="advertise new selection">
        The selection event is sent out to notify the client of a new
        wl_data_offer for the selection for this device.  The
        data_device.data_offer and the data_offer.offer events are
        sent out immediately before this event to introduce the data
        offer object.  The selection event is sent to a client
        immediately before receiving keyboard focus and when a new
        selection is set while the client has keyboard focus.  The
        data_offer is valid until a new data_offer or NULL is received
        or until the client loses keyboard focus.
      </description>
      <arg name="id" type="object" interface="wl_data_offer" allow-null="true"/>
    </event>
  </interface>

  <interface name="wl_data_device_manager" version="1">
    <description summary="data transfer interface">
      The wl_data_device_manager is a a singleton global object that
      provides access to inter-client data transfer mechanisms such as
      copy and paste and drag and drop.  These mechanisms are tied to
      a wl_seat and this interface lets a client get a wl_data_device
      corresponding to a wl_seat.
    </description>

    <request name="create_data_source">
      <arg name="id" type="new_id" interface="wl_data_source"/>
    </request>

    <request name="get_data_device">
      <arg name="id" type="new_id" interface="wl_data_device"/>
      <arg name="seat" type="object" interface="wl_seat"/>
    </request>
  </interface>

  <interface name="wl_shell" version="1">
    <request name="get_shell_surface">
      <arg name="id" type="new_id" interface="wl_shell_surface"/>
      <arg name="surface" type="object" interface="wl_surface"/>
    </request>
  </interface>

  <interface name="wl_shell_surface" version="1">

    <description summary="desktop style meta data interface">
      An interface implemented by a wl_surface.  On server side the
      object is automatically destroyed when the related wl_surface is
      destroyed.  On client side, wl_shell_surface_destroy() must be
      called before destroying the wl_surface object.
    </description>

    <request name="pong">
      <description summary="respond to a ping event">
        A client must respond to a ping event with a pong request or
        the client may be deemed unresponsive.
      </description>
      <arg name="serial" type="uint"/>
    </request>

    <request name="move">
      <arg name="seat" type="object" interface="wl_seat"/>
      <arg name="serial" type="uint"/>
    </request>

    <enum name="resize">
      <entry name="none" value="0"/>
      <entry name="top" value="1"/>
      <entry name="bottom" value="2"/>
      <entry name="left" value="4"/>
      <entry name="top_left" value="5"/>
      <entry name="bottom_left" value="6"/>
      <entry name="right" value="8"/>
      <entry name="top_right" value="9"/>
      <entry name="bottom_right" value="10"/>
    </enum>

    <request name="resize">
      <arg name="seat" type="object" interface="wl_seat"/>
      <arg name="serial" type="uint"/>
      <arg name="edges" type="uint"/>
    </request>

    <request name="set_toplevel">
      <description summary="make the surface a top level surface">
        Make the surface a toplevel window.
      </description>
    </request>

    <enum name="transient">
      <entry name="inactive" value="0x1" summary="do not set keyboard focus"/>
    </enum>

    <request name="set_transient">
      <description summary="make the surface a transient surface">
        Map the surface relative to an existing surface. The x and y
        arguments specify the locations of the upper left corner of
        the surface relative to the upper left corner of the parent
        surface.  The flags argument controls overflow/clipping
        behaviour when the surface would intersect a screen edge,
        panel or such.  And possibly whether the offset only
        determines the initial position or if the surface is locked to
        that relative position during moves.
      </description>

      <arg name="parent" type="object" interface="wl_surface"/>
      <arg name="x" type="int"/>
      <arg name="y" type="int"/>
      <arg name="flags" type="uint"/>
    </request>

    <request name="set_fullscreen">
      <description summary="make the surface a fullscreen surface">
        Map the surface as a fullscreen surface. If an output parameter is
        given then the surface will be made fullscreen on that output. If the
        client does not specify the output then the compositor will apply its
        policy - usually choosing the output on which the surface has the
        biggest surface area.

        The client may specify a method to resolve a size conflict between the
        output size and the surface size - this is provided through the
        fullscreen_method parameter.

        The framerate parameter is used only when the fullscreen_method is set
        to "driver", to indicate the preferred framerate. framerate=0 indicates
        that the app does not care about framerate.  The framerate is
        specified in mHz, that is framerate of 60000 is 60Hz.

        The compositor must reply to this request with a configure event with
        the dimensions for the output on which the surface will be made fullscreen.
      </description>
      <arg name="method" type="uint"/>
      <arg name="framerate" type="uint"/>
      <arg name="output" type="object" interface="wl_output" allow-null="true"/>
    </request>

    <enum name="fullscreen_method">
      <description summary="different method to set the surface fullscreen">
        Hints to indicate compositor how to deal with a conflict between the
        dimensions for the surface and the dimensions of the output. As a hint
        the compositor is free to ignore this parameter.

        "default" The client has no preference on fullscreen behavior,
        policies are determined by compositor.

        "scale" The client prefers scaling by the compositor. Scaling would
        always preserve surface's aspect ratio with surface centered on the
        output

        "driver" The client wants to switch video mode to the smallest mode
        that can fit the client buffer. If the sizes do not match the
        compositor must add black borders.

        "fill" The surface is centered on the output on the screen with no
        scaling. If the surface is of insufficient size the compositor must
        add black borders.
      </description>
      <entry name="default" value="0"/>
      <entry name="scale" value="1"/>
      <entry name="driver" value="2"/>
      <entry name="fill" value="3"/>
    </enum>

    <request name="set_popup">
      <description summary="make the surface a popup surface">
        Popup surfaces.  Will switch an implicit grab into
        owner-events mode, and grab will continue after the implicit
        grab ends (button released).  Once the implicit grab is over,
        the popup grab continues until the window is destroyed or a
        mouse button is pressed in any other clients window.  A click
        in any of the clients surfaces is reported as normal, however,
        clicks in other clients surfaces will be discarded and trigger
        the callback.

        TODO: Grab keyboard too, maybe just terminate on any click
        inside or outside the surface?
      </description>

      <arg name="seat" type="object" interface="wl_seat"/>
      <arg name="serial" type="uint"/>
      <arg name="parent" type="object" interface="wl_surface"/>
      <arg name="x" type="int"/>
      <arg name="y" type="int"/>
      <arg name="flags" type="uint"/>
    </request>

    <request name="set_maximized">
      <description summary="make the surface a maximized surface">
        A request from the client to notify the compositor the maximized
        operation. The compositor will reply with a configure event telling
        the expected new surface size. The operation is completed on the
        next buffer attach to this surface.
        A maximized client will fill the fullscreen of the output it is bound
        to, except the panel area. This is the main difference between
        a maximized shell surface and a fullscreen shell surface.
      </description>
      <arg name="output" type="object" interface="wl_output" allow-null="true"/>
    </request>

    <request name="set_title">
      <description summary="set surface title">
      </description>
      <arg name="title" type="string"/>
    </request>

    <request name="set_class">
      <description summary="set surface class">
        The surface class identifies the general class of applications
        to which the surface belongs.  The class is the file name of
        the applications .desktop file (absolute path if non-standard
        location). 
      </description>
      <arg name="class_" type="string"/>
    </request>

    <event name="ping">
      <description summary="ping client">
        Ping a client to check if it is receiving events and sending
        requests. A client is expected to reply with a pong request.
      </description>
      <arg name="serial" type="uint"/>
    </event>

    <event name="configure">
      <description summary="suggest resize">
        The configure event asks the client to resize its surface.
        The size is a hint, in the sense that the client is free to
        ignore it if it doesn't resize, pick a smaller size (to
        satisfy aspect ratio or resize in steps of NxM pixels).  The
        client is free to dismiss all but the last configure event it
        received.
      </description>

      <arg name="edges" type="uint"/>
      <arg name="width" type="int"/>
      <arg name="height" type="int"/>
    </event>

    <event name="popup_done">
      <description summary="popup interaction is done">
        The popup_done event is sent out when a popup grab is broken,
        that is, when the users clicks a surface that doesn't belong
        to the client owning the popup surface.
      </description>
    </event>
  </interface>

  <interface name="wl_surface" version="1">
    <description summary="an onscreen surface">
      A surface.  This is an image that is displayed on the screen.
      It has a location, size and pixel contents.
    </description>

    <request name="destroy" type="destructor">
      <description summary="delete surface">
        Deletes the surface and invalidates its object id.
      </description>
    </request>

    <request name="attach">
      <description summary="set the surface contents">
        Set the contents of a buffer into this surface. The x and y
        arguments specify the location of the new pending buffer's upper
        left corner, relative to the current buffer's upper left corner. In
        other words, the x and y, and the width and height of the wl_buffer
        together define in which directions the surface's size changes.

        Surface contents are double-buffered state, see wl_surface.commit.

        The initial surface contents are void; there is no content.
        wl_surface.attach assigns the given wl_buffer as the pending wl_buffer.
        wl_surface.commit applies the pending wl_buffer as the new
        surface contents, and the size of the surface becomes the size of
        the wl_buffer. The wl_buffer is also kept as pending, until
        changed by wl_surface.attach or the wl_buffer is destroyed.

        Committing a pending wl_buffer allows the compositor to read the
        pixels in the wl_buffer. The compositor may access the pixels at any
        time after the wl_surface.commit request. When the compositor will
        not access the pixels anymore, it will send the wl_buffer.release
        event. Only after receiving wl_buffer.release, the client may re-use
        the wl_buffer. A wl_buffer, that has been attached and then replaced
        by another attach instead of committed, will not receive a release
        event, and is not used by the compositor.

        Destroying the wl_buffer after wl_buffer.release does not change the
        surface contents, even if the wl_buffer is still pending for the
        next commit. In such case, the next commit does not change the
        surface contents. However, if the client destroys the wl_buffer
        before receiving wl_buffer.release, the surface contents become
        undefined immediately.

        Only if wl_surface.attach is sent with a nil wl_buffer, the
        following wl_surface.commit will remove the surface content.
      </description>

      <arg name="buffer" type="object" interface="wl_buffer" allow-null="true"/>
      <arg name="x" type="int"/>
      <arg name="y" type="int"/>
    </request>

    <request name="damage">
      <description summary="mark part of the surface damaged">
        This request is used to describe the regions where the pending
        buffer (or if pending buffer is none, the current buffer as updated
        in-place) on the next wl_surface.commit will be different from the
        current buffer, and needs to be repainted. The pending buffer can be
        set by wl_surface.attach. The compositor ignores the parts of the
        damage that fall outside of the surface.

        Damage is double-buffered state, see wl_surface.commit.

        The initial value for pending damage is empty: no damage.
        wl_surface.damage adds pending damage: the new pending damage is the
        union of old pending damage and the given rectangle.
        wl_surface.commit assigns pending damage as the current damage, and
        clears pending damage. The server will clear the current damage as
        it repaints the surface.
      </description>

      <arg name="x" type="int"/>
      <arg name="y" type="int"/>
      <arg name="width" type="int"/>
      <arg name="height" type="int"/>
    </request>

    <request name="frame">
      <description summary="request repaint feedback">
        Request notification when the next frame is displayed. Useful
        for throttling redrawing operations, and driving animations.
        The frame request will take effect on the next wl_surface.commit.
        The notification will only be posted for one frame unless
        requested again.

        A server should avoid signalling the frame callbacks if the
        surface is not visible in any way, e.g. the surface is off-screen,
        or completely obscured by other opaque surfaces.

        A client can request a frame callback even without an attach,
        damage, or any other state changes. wl_surface.commit triggers a
        display update, so the callback event will arrive after the next
        output refresh where the surface is visible.
      </description>

      <arg name="callback" type="new_id" interface="wl_callback"/>
    </request>

    <request name="set_opaque_region">
      <description summary="set opaque region">
        This request sets the region of the surface that contains
        opaque content.  The opaque region is an optimization hint for
        the compositor that lets it optimize out redrawing of content
        behind opaque regions.  Setting an opaque region is not
        required for correct behaviour, but marking transparent
        content as opaque will result in repaint artifacts.
        The compositor ignores the parts of the opaque region that fall
        outside of the surface.

        Opaque region is double-buffered state, see wl_surface.commit.

        wl_surface.set_opaque_region changes the pending opaque region.
        wl_surface.commit copies the pending region to the current region.
        Otherwise the pending and current regions are never changed.

        The initial value for opaque region is empty. Setting the pending
        opaque region has copy semantics, and the wl_region object can be
        destroyed immediately. A nil wl_region causes the pending opaque
        region to be set to empty.
      </description>

      <arg name="region" type="object" interface="wl_region" allow-null="true"/>
    </request>

    <request name="set_input_region">
      <description summary="set input region">
        This request sets the region of the surface that can receive
        pointer and touch events. Input events happening outside of
        this region will try the next surface in the server surface
        stack. The compositor ignores the parts of the input region that
        fall outside of the surface.

        Input region is double-buffered state, see wl_surface.commit.

        wl_surface.set_input_region changes the pending input region.
        wl_surface.commit copies the pending region to the current region.
        Otherwise the pending and current regions are never changed,
        except cursor and icon surfaces are special cases, see
        wl_pointer.set_cursor and wl_data_device.start_drag.

        The initial value for input region is infinite. That means the whole
        surface will accept input. Setting the pending input region has copy
        semantics, and the wl_region object can be destroyed immediately. A
        nil wl_region causes the input region to be set to infinite.
      </description>

      <arg name="region" type="object" interface="wl_region" allow-null="true"/>
    </request>

    <request name="commit">
      <description summary="commit pending surface state">
        Surface state (input, opaque, and damage regions, attached buffers,
        etc.) is double-buffered. Protocol requests modify the pending
        state, as opposed to current state in use by the compositor. Commit
        request atomically applies all pending state, replacing the current
        state. After commit, the new pending state is as documented for each
        related request.

        On commit, a pending wl_buffer is applied first, all other state
        second. This means that all coordinates in double-buffered state are
        relative to the new wl_buffer coming into use, except for
        wl_surface.attach itself. If the pending wl_buffer is none, the
        coordinates are relative to the current surface contents.

        All requests that need a commit to become effective are documented
        to affect double-buffered state.

        Other interfaces may add further double-buffered surface state.
      </description>
    </request>

    <event name="enter">
      <description summary="surface enters an output">
        This is emitted whenever a surface's creation, movement, or resizing
        results in some part of it being within the scanout region of an
        output.
      </description>
      <arg name="output" type="object" interface="wl_output"/>
    </event>

    <event name="leave">
      <description summary="surface leaves an output">
        This is emitted whenever a surface's creation, movement, or resizing
        results in it no longer having any part of it within the scanout region
        of an output.
      </description>
      <arg name="output" type="object" interface="wl_output"/>
    </event>
  </interface>

  <interface name="wl_seat" version="1">
    <description summary="seat">
      A group of keyboards, pointer (mice, for example) and touch
      devices . This object is published as a global during start up,
      or when such a device is hot plugged.  A seat typically has a
      pointer and maintains a keyboard_focus and a pointer_focus.
    </description>

    <enum name="capability">
      <description summary="seat capability bitmask">
        This is a bitmask of capabilities this seat has; if a member is
        set, then it is present on the seat.
      </description>
      <entry name="pointer" value="1" summary="wl_pointer"/>
      <entry name="keyboard" value="2" summary="wl_keyboard"/>
      <entry name="touch" value="4" summary="wl_touch"/>
    </enum>


    <event name="capabilities">
      <description summary="seat capabilities changed">
        This is emitted whenever a seat gains or loses the pointer,
        keyboard or touch capabilities.  The argument is a wl_seat_caps_mask
        enum containing the complete set of capabilities this seat has.
      </description>
      <arg name="capabilities" type="uint"/>
    </event>

    <request name="get_pointer">
      <description summary="return pointer object">
        The ID provided will be initialized to the wl_pointer interface
        for this seat.
      </description>
      <arg name="id" type="new_id" interface="wl_pointer"/>
    </request>

    <request name="get_keyboard">
      <description summary="return pointer object">
        The ID provided will be initialized to the wl_keyboard interface
        for this seat.
      </description>
      <arg name="id" type="new_id" interface="wl_keyboard"/>
    </request>

    <request name="get_touch">
      <description summary="return pointer object">
        The ID provided will be initialized to the wl_touch interface
        for this seat.
      </description>
      <arg name="id" type="new_id" interface="wl_touch"/>
    </request>
  </interface>

  <interface name="wl_pointer" version="1">
    <request name="set_cursor">
      <description summary="set the pointer surface">
        Set the pointer surface, i.e., the surface that contains the
        pointer image (cursor). This request only takes effect if the pointer
        focus for this device is one of the requesting client's surfaces
        or the surface parameter is the current pointer surface. If
        there was a previous surface set with this request it is
        replaced. If surface is NULL, the pointer image is hidden.

        The parameters hotspot_x and hotspot_y define the position of
        the pointer surface relative to the pointer location. Its
        top-left corner is always at (x, y) - (hotspot_x, hotspot_y),
        where (x, y) are the coordinates of the pointer location.

        On surface.attach requests to the pointer surface, hotspot_x
        and hotspot_y are decremented by the x and y parameters
        passed to the request. Attach must be confirmed by
        wl_surface.commit as usual.

        The hotspot can also be updated by passing the currently set
        pointer surface to this request with new values for hotspot_x
        and hotspot_y.

        The current and pending input regions of the wl_surface are
        cleared, and wl_surface.set_input_region is ignored until the
        wl_surface is no longer used as the cursor. When the use as a
        cursor ends, the current and pending input regions become
        undefined, and the wl_surface is unmapped.
      </description>

      <arg name="serial" type="uint"/>
      <arg name="surface" type="object" interface="wl_surface" allow-null="true"/>
      <arg name="hotspot_x" type="int"/>
      <arg name="hotspot_y" type="int"/>
    </request>

    <event name="enter">
      <description summary="enter event">
        Notification that this seat's pointer is focused on a certain
        surface. When an seat's focus enters a surface, the pointer image
        is undefined and a client should respond to this event by setting
        an appropriate pointer image.
      </description>

      <arg name="serial" type="uint"/>
      <arg name="surface" type="object" interface="wl_surface"/>
      <arg name="surface_x" type="fixed"/>
      <arg name="surface_y" type="fixed"/>
    </event>

    <event name="leave">
      <description summary="leave event">
      </description>
      <arg name="serial" type="uint"/>
      <arg name="surface" type="object" interface="wl_surface"/>
    </event>

    <event name="motion">
      <description summary="pointer motion event">
        Notification of pointer location change. The arguments surface_[xy]
        are the location relative to the focused surface.
      </description>

      <arg name="time" type="uint"/>
      <arg name="surface_x" type="fixed"/>
      <arg name="surface_y" type="fixed"/>
    </event>

    <enum name="button_state">
      <description summary="physical button state">
        Describes the physical state of a button which provoked the button
        event.
      </description>
      <entry name="released" value="0" summary="button is not pressed"/>
      <entry name="pressed" value="1" summary="button is pressed"/>
    </enum>

    <event name="button">
      <description summary="pointer button event">
        Mouse button click and release notifications.  The location
        of the click is given by the last motion or pointer_focus event.
      </description>

      <arg name="serial" type="uint"/>
      <arg name="time" type="uint"/>
      <arg name="button" type="uint"/>
      <arg name="state" type="uint"/>
    </event>

    <enum name="axis">
      <description summary="axis types"/>
      <entry name="vertical_scroll" value="0"/>
      <entry name="horizontal_scroll" value="1"/>
    </enum>

    <event name="axis">
      <description summary="axis event">
        Scroll and other axis notifications.

        For scroll events (vertical and horizontal scroll axes), the
        value parameter is the length of a vector along the specified
        axis in a coordinate space identical to those of motion events,
        representing a relative movement along the specified axis.

        For devices that support movements non-parallel to axes multiple
        axis events will be emitted.

        When applicable, for example for touch pads, the server can
        choose to emit scroll events where the motion vector is
        equivalent to a motion event vector.

        When applicable, clients can transform its view relative to the
        scroll distance.
      </description>

      <arg name="time" type="uint"/>
      <arg name="axis" type="uint"/>
      <arg name="value" type="fixed"/>
    </event>
  </interface>

  <interface name="wl_keyboard" version="1">
    <description summary="keyboard input device">
    </description>

    <enum name="keymap_format">
      <description summary="keyboard mapping format">
        This enum specifies the format of the keymap provided to the client
        with the wl_keyboard::keymap event.
      </description>
      <entry name="xkb_v1" value="1" description="libxkbcommon compatible"/>
    </enum>

    <event name="keymap">
      <description summary="keyboard mapping">
        This event provides a file descriptor to the client which can be
        memory-mapped to provide a keyboard mapping description.
      </description>
      <arg name="format" type="uint"/>
      <arg name="fd" type="fd"/>
      <arg name="size" type="uint"/>
    </event>

    <event name="enter">
      <arg name="serial" type="uint"/>
      <arg name="surface" type="object" interface="wl_surface"/>
      <arg name="keys" type="array"/>
    </event>

    <event name="leave">
      <arg name="serial" type="uint"/>
      <arg name="surface" type="object" interface="wl_surface"/>
    </event>

    <enum name="key_state">
      <description summary="physical key state">
        Describes the physical state of a key which provoked the key event.
      </description>
      <entry name="released" value="0" summary="key is not pressed"/>
      <entry name="pressed" value="1" summary="key is pressed"/>
    </enum>

    <event name="key">
      <description summary="key event">
        A key was pressed or released.
      </description>

      <arg name="serial" type="uint"/>
      <arg name="time" type="uint"/>
      <arg name="key" type="uint"/>
      <arg name="state" type="uint"/>
    </event>

    <event name="modifiers">
      <description summary="modifier and group state">
        Notifies clients that the modifier and/or group state has
        changed, and it should update its local state.
      </description>

      <arg name="serial" type="uint"/>
      <arg name="mods_depressed" type="uint"/>
      <arg name="mods_latched" type="uint"/>
      <arg name="mods_locked" type="uint"/>
      <arg name="group" type="uint"/>
    </event>
  </interface>

  <interface name="wl_touch" version="1">
    <description summary="touch screen input device">
    </description>

    <event name="down">
      <arg name="serial" type="uint"/>
      <arg name="time" type="uint"/>
      <arg name="surface" type="object" interface="wl_surface"/>
      <arg name="id" type="int" />
      <arg name="x" type="fixed" />
      <arg name="y" type="fixed" />
    </event>

    <event name="up">
      <arg name="serial" type="uint"/>
      <arg name="time" type="uint"/>
      <arg name="id" type="int" />
    </event>

    <event name="motion">
      <arg name="time" type="uint"/>
      <arg name="id" type="int" />
      <arg name="x" type="fixed" />
      <arg name="y" type="fixed" />
    </event>

    <event name="frame">
      <description summary="end of touch frame event">
        Indicates the end of a contact point list.
      </description>
    </event>

    <event name="cancel">
      <description summary="touch session cancelled">
        Sent if the compositor decides the touch stream is a global
        gesture. No further events are sent to the clients from that
        particular gesture.
      </description>
    </event>
  </interface>


  <interface name="wl_output" version="1">
    <description summary="compositor output region">
      An output describes part of the compositor geometry.  The
      compositor work in the 'compositor coordinate system' and an
      output corresponds to rectangular area in that space that is
      actually visible.  This typically corresponds to a monitor that
      displays part of the compositor space.  This object is published
      as global during start up, or when a screen is hot plugged.
    </description>

    <enum name="subpixel">
      <entry name="unknown" value="0"/>
      <entry name="none" value="1"/>
      <entry name="horizontal_rgb" value="2"/>
      <entry name="horizontal_bgr" value="3"/>
      <entry name="vertical_rgb" value="4"/>
      <entry name="vertical_bgr" value="5"/>
    </enum>

    <enum name="transform">
      <description summary="transform from framebuffer to output">
        This describes the transform that a compositor will apply to a
        surface to compensate for the rotation or mirroring of an
        output device.

        The flipped values correspond to an initial flip around a
        vertical axis followed by rotation.

        The purpose is mainly to allow clients render accordingly and
        tell the compositor, so that for fullscreen surfaces, the
        compositor will still be able to scan out directly from client
        surfaces.
      </description>

      <entry name="normal" value="0"/>
      <entry name="90" value="1"/>
      <entry name="180" value="2"/>
      <entry name="270" value="3"/>
      <entry name="flipped" value="4"/>
      <entry name="flipped_90" value="5"/>
      <entry name="flipped_180" value="6"/>
      <entry name="flipped_270" value="7"/>
    </enum>

    <event name="geometry">
      <description summary="properties of the output"/>
      <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"/>
      <arg name="physical_width" type="int"
           summary="width in millimeters of the output"/>
      <arg name="physical_height" type="int"
           summary="height in millimeters of the output"/>
      <arg name="subpixel" type="int"
           summary="subpixel orientation of the output"/>
      <arg name="make" type="string"
           summary="textual description of the manufacturer"/>
      <arg name="model" type="string"
           summary="textual description of the model"/>
      <arg name="transform" type="int"
           summary="transform that maps framebuffer to output"/>
    </event>

    <enum name="mode">
      <description summary="values for the flags bitfield in the mode event"/>
      <entry name="current" value="0x1"
             summary="indicates this is the current mode"/>
      <entry name="preferred" value="0x2"
             summary="indicates this is the preferred mode"/>
    </enum>
      
    <event name="mode">
      <description summary="advertise available modes for the output">
        The mode event describes an available mode for the output.
        The event is sent when binding to the output object and there
        will always be one mode, the current mode.  The event is sent
        again if an output changes mode, for the mode that is now
        current.  In other words, the current mode is always the last
        mode that was received with the current flag set.
      </description>
      <arg name="flags" type="uint" summary="mask of wl_output_mode flags"/>
      <arg name="width" type="int" summary="width of the mode in pixels"/>
      <arg name="height" type="int" summary="height of the mode in pixels"/>
      <arg name="refresh" type="int" summary="vertical refresh rate in mHz"/>
    </event>
  </interface>

  <interface name="wl_region" version="1">
    <description summary="region interface">
      Region.
    </description>

    <request name="destroy" type="destructor">
      <description summary="destroy region">
        Destroy the region.  This will invalidate the object id.
      </description>
    </request>

    <request name="add">
      <description summary="add rectangle to region">
        Add the specified rectangle to the region
      </description>

      <arg name="x" type="int"/>
      <arg name="y" type="int"/>
      <arg name="width" type="int"/>
      <arg name="height" type="int"/>
    </request>

    <request name="subtract">
      <description summary="subtract rectangle from region">
        Subtract the specified rectangle from the region
      </description>

      <arg name="x" type="int"/>
      <arg name="y" type="int"/>
      <arg name="width" type="int"/>
      <arg name="height" type="int"/>
    </request>

  </interface>

</protocol>