wayvnc/protocols/ext-screencopy-v1.xml

<?xml version="1.0" encoding="UTF-8"?>
<protocol name="ext_screencopy_v1">
  <copyright>
    Copyright © 2021-2023 Andri Yngvason
    Copyright © 2024 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>

  <description summary="screen content capturing on client buffers">
    This protocol allows clients to ask the compositor to capture screen
    contents to user submitted buffers.

    Warning! The protocol described in this file is currently in the testing
    phase. Backward compatible changes may be added together with the
    corresponding interface version bump. Backward incompatible changes can
    only be done by creating a new major version of the extension.
  </description>

  <interface name="ext_screencopy_manager_v1" version="1">
    <description summary="manager to inform clients and begin capturing">
      This object is a manager which offers requests to start capturing from a
      source.
    </description>

    <enum name="error">
      <entry name="invalid_option" value="1" summary="invalid option flag"/>
    </enum>

    <enum name="options" bitfield="true">
      <entry name="paint_cursors" value="1" summary="paint cursors onto captured frames"/>
    </enum>

    <request name="create_session">
      <description summary="capture an image source">
        Create a capturing session for an image source.

        If the paint_cursors option is set, cursors shall be composited onto
        the captured frame. The cursor shall not be composited onto the frame
        if this flag is not set.
      </description>
      <arg name="session" type="new_id" interface="ext_screencopy_session_v1"/>
      <arg name="source" type="object" interface="ext_image_source_v1"/>
      <arg name="options" type="uint" enum="options"/>
    </request>

    <request name="create_pointer_cursor_session">
      <description summary="capture the pointer cursor of an image source">
        Create a cursor capturing session for the pointer of an image source.

        The options argument has no effect and must be set to 0. This is
        intended for any future flags that might be added.
      </description>
      <arg name="session" type="new_id" interface="ext_screencopy_cursor_session_v1"/>
      <arg name="source" type="object" interface="ext_image_source_v1"/>
      <arg name="pointer" type="object" interface="wl_pointer"/>
      <arg name="options" type="uint"/>
    </request>

    <request name="destroy" type="destructor">
      <description summary="destroy the manager">
        Destroy the manager object.

        Other objects created via this interface are unaffected.
      </description>
    </request>
  </interface>

  <interface name="ext_screencopy_session_v1" version="1">
    <description summary="screen capture session">
      This object represents an active screencopy session.

      After a screencopy session is created, buffer constraint events will be
      emitted from the compositor to tell the client which buffer types and
      formats are supported for reading from the session. The compositor may
      re-send buffer constraint events whenever they change.

      The advertise buffer constraints, the compositor must send in no
      particular order: zero or more shm_format and dmabuf_format events, zero
      or one dmabuf_device event, and exactly one buffer_size event. Then the
      compositor must send a done event.

      When the client has received all the buffer constraints, it can create a
      buffer accordingly, attach it to the screencopy session using the
      attach_buffer request, set the buffer damage using the damage_buffer
      request and then send the capture request.
    </description>

    <event name="buffer_size">
      <description summary="image source dimensions">
        Provides the dimensions of the source image in buffer pixel coordinates.

        The client must attach buffers that match this size.
      </description>
      <arg name="width" type="uint" summary="buffer width"/>
      <arg name="height" type="uint" summary="buffer height"/>
    </event>

    <event name="shm_format">
      <description summary="shm buffer format">
        Provides the format that must be used for shared-memory buffers.

        This event may be emitted multiple times, in which case the client may
        choose any given format.
      </description>
      <arg name="format" type="uint" enum="wl_shm.format" summary="shm format"/>
    </event>

    <event name="dmabuf_device">
      <description summary="dma-buf device">
        This event advertises the device buffers must be allocated on for
        dma-buf buffers.

        In general the device is a DRM node. The DRM node type (primary vs.
        render) is unspecified. Clients must not rely on the compositor sending
        a particular node type. Clients cannot check two devices for equality
        by comparing the dev_t value.
      </description>
      <arg name="device" type="array" summary="device dev_t value"/>
    </event>

    <event name="dmabuf_format">
      <description summary="dma-buf format">
        Provides the format that must be used for dma-buf buffers.

        The client may choose any of the modifiers advertised in the array of
        64-bit unsigned integers.

        This event may be emitted multiple times, in which case the client may
        choose any given format.
      </description>
      <arg name="format" type="uint" summary="drm format code"/>
      <arg name="modifiers" type="array" summary="drm format modifiers"/>
    </event>

    <event name="done">
      <description summary="all constraints have been sent">
        This event is sent once when all buffer constraint events have been
        sent.

        The compositor must always end a batch of buffer constraint events with
        this event, regardless of whether it sends the initial constraints or
        an update.
      </description>
    </event>

    <event name="stopped">
      <description summary="session is no longer available">
        This event indicates that the capture session has stopped and is no
        longer available. This can happen in a number of cases, e.g. when the
        underlying source is destroyed, if the user decides to end the screen
        capture, or if an unrecoverable runtime error has occurred.

        The client should destroy the session after receiving this event.
      </description>
    </event>

    <request name="create_frame">
      <description summary="create a frame">
        Create a capture frame for this session.
      </description>
      <arg name="frame" type="new_id" interface="ext_screencopy_frame_v1"/>
    </request>

    <request name="destroy" type="destructor">
      <description summary="delete this object">
        Destroys the session. This request can be sent at any time by the
        client.

        This request doesn't affect ext_screencopy_frame_v1 objects created by
        this object.
      </description>
    </request>
  </interface>

  <interface name="ext_screencopy_frame_v1" version="1">
    <description summary="screen capture frame">
      This object represents a screen capture frame.

      The client should attach a buffer, damage the buffer, and then send a
      capture request.

      If the screen capture is successful, the compositor will send the frame
      metadata (transform, damage, presentation_time in any order) followed by
      the ready event.

      If the screen capture fails, the compositor will send the failed event.
    </description>

    <enum name="error">
      <entry name="no_buffer" value="1" summary="capture sent without attach_buffer"/>
      <entry name="invalid_buffer_damage" value="2" summary="invalid buffer damage"/>
      <entry name="already_captured" value="3" summary="capture request has been sent"/>
    </enum>

    <request name="destroy" type="destructor">
      <description summary="destroy this object">
        Destroys the session. This request can be sent at any time by the
        client.
      </description>
    </request>

    <request name="attach_buffer">
      <description summary="attach buffer to session">
        Attach a buffer to the session.

        The wl_buffer.release request is unused.

        This request must not be sent after capture, or else the
        already_captured protocol error is raised.
      </description>
      <arg name="buffer" type="object" interface="wl_buffer"/>
    </request>

    <request name="damage_buffer">
      <description summary="damage buffer">
        Apply damage to the buffer which is to be captured next. This request
        may be sent multiple times to describe a region.

        The client indicates the accumulated damage since this wl_buffer was
        last captured. During capture, the compositor will update the buffer
        with at least the union of the region passed by the client and the
        region advertised by ext_screencopy_frame_v1.damage.

        When a wl_buffer is captured for the first time, or when the client
        doesn't track damage, the client must damage the whole buffer.

        This is for optimisation purposes. The compositor may use this
        information to reduce copying.

        These coordinates originate from the upper left corner of the buffer.

        If x or y are strictly negative, or if width or height are negative or
        zero, the invalid_buffer_damage protocol error is raised.

        This request must not be sent after capture, or else the
        already_captured protocol error is raised.
      </description>
      <arg name="x" type="int" summary="region x coordinate"/>
      <arg name="y" type="int" summary="region y coordinate"/>
      <arg name="width" type="int" summary="region width"/>
      <arg name="height" type="int" summary="region height"/>
    </request>

    <request name="capture">
      <description summary="capture a frame">
        Capture a frame.

        Unless this is the first successful captured frame performed in this
        session, the compositor may wait an indefinite amount of time for the
        source content to change before performing the copy.

        This request may only be sent once, or else the already_captured
        protocol error is raised. A buffer must be attached before this request
        is sent, or else the no_buffer protocol error is raised.
      </description>
    </request>

    <event name="transform">
      <description summary="buffer transform">
        This event is sent before the ready event and holds the transform of
        the source buffer.
      </description>
      <arg name="transform" type="uint" enum="wl_output.transform"/>
    </event>

    <event name="damage">
      <description summary="buffer damaged region">
        This event is sent before the ready event. It may be generated multiple
        times to describe a region.

        The first captured frame in a session will always carry full damage.
        Subsequent frames' damaged regions describe which parts of the buffer
        have changed since the last ready event.

        These coordinates originate in the upper left corner of the buffer.
      </description>
      <arg name="x" type="int" summary="damage x coordinate"/>
      <arg name="y" type="int" summary="damage y coordinate"/>
      <arg name="width" type="int" summary="damage width"/>
      <arg name="height" type="int" summary="damage height"/>
    </event>

    <event name="presentation_time">
      <description summary="presentation time of the frame">
        This event indicates the time at which the frame is presented to the
        output in system monotonic time. This event is sent before the ready
        event.

        The timestamp is expressed as tv_sec_hi, tv_sec_lo, tv_nsec triples,
        each component being an unsigned 32-bit value. Whole seconds are in
        tv_sec which is a 64-bit value combined from tv_sec_hi and tv_sec_lo,
        and the additional fractional part in tv_nsec as nanoseconds. Hence,
        for valid timestamps tv_nsec must be in [0, 999999999].
      </description>
      <arg name="tv_sec_hi" type="uint"
           summary="high 32 bits of the seconds part of the timestamp"/>
      <arg name="tv_sec_lo" type="uint"
           summary="low 32 bits of the seconds part of the timestamp"/>
      <arg name="tv_nsec" type="uint"
           summary="nanoseconds part of the timestamp"/>
    </event>

    <event name="ready">
      <description summary="frame is available for reading">
        Called as soon as the frame is copied, indicating it is available
        for reading.

        The buffer may be re-used by the client after this event.

        After receiving this event, the client must destroy the object.
      </description>
    </event>

    <enum name="failure_reason">
      <entry name="unknown" value="0">
        <description summary="unknown runtime error">
          An unspecified runtime error has occurred. The client may retry.
        </description>
      </entry>
      <entry name="buffer_constraints" value="1">
        <description summary="buffer constraints mismatch">
          The buffer submitted by the client doesn't match the latest session
          constraints. The client should re-allocate its buffers and retry.
        </description>
      </entry>
      <entry name="stopped" value="2">
        <description summary="session is no longer available">
          The session has stopped. See ext_screencopy_session_v1.stopped.
        </description>
      </entry>
    </enum>

    <event name="failed">
      <description summary="capture failed">
        This event indicates that the attempted frame copy has failed.

        After receiving this event, the client must destroy the object.
      </description>
      <arg name="reason" type="uint" enum="failure_reason"/>
    </event>
  </interface>

  <interface name="ext_screencopy_cursor_session_v1" version="1">
    <description summary="cursor capture session">
      This object represents a cursor capture session. It extends the base
      capture session with cursor-specific metadata.
    </description>

    <enum name="error">
      <entry name="duplicate_session" value="1" summary="get_screencopy_session sent twice"/>
    </enum>

    <request name="destroy" type="destructor">
      <description summary="delete this object">
        Destroys the session. This request can be sent at any time by the
        client.

        This request doesn't affect ext_screencopy_frame_v1 objects created by
        this object.
      </description>
    </request>

    <request name="get_screencopy_session">
      <description summary="get screencopy session">
        Gets the screencopy session for this cursor session.

        The session will produce frames of the cursor image. The compositor may
        pause the session when the cursor leaves the captured area.

        This request must not be sent more than once, or else the
        duplicate_session protocol error is raised.
      </description>
      <arg name="session" type="new_id" interface="ext_screencopy_session_v1"/>
    </request>

    <event name="enter">
      <description summary="cursor entered captured area">
        Sent when a cursor enters the captured area. It shall be generated
        before the "position" and "hotspot" events when and only when a cursor
        enters the area.

        The cursor enters the captured area when the cursor image intersects
        with the captured area. Note, this is different from e.g.
        wl_pointer.enter.
      </description>
    </event>

    <event name="leave">
      <description summary="cursor left captured area">
        Sent when a cursor leaves the captured area. No "position" or "hotspot"
        event is generated for the cursor until the cursor enters the captured
        area again.
      </description>
    </event>

    <event name="position">
      <description summary="position changed">
        Cursors outside the image source do not get captured and no event will
        be generated for them.

        The given position is the position of the cursor's hotspot and it is
        relative to the main buffer's top left corner in transformed buffer
        pixel coordinates.

        The position coordinates are relative to the main buffer's upper left
        corner. The coordinates may be negative or greater than the main buffer
        size.
      </description>
      <arg name="x" type="int" summary="position x coordinates"/>
      <arg name="y" type="int" summary="position y coordinates"/>
    </event>

    <event name="hotspot">
      <description summary="hotspot changed">
        The hotspot describes the offset between the cursor image and the
        position of the input device.

        The given coordinates are the hotspot's offset from the origin in
        buffer coordinates.

        Clients should not apply the hotspot immediately: the hotspot becomes
        effective when the next ext_screencopy_frame_v1.ready event is received.
      </description>
      <arg name="x" type="int" summary="hotspot x coordinates"/>
      <arg name="y" type="int" summary="hotspot y coordinates"/>
    </event>
  </interface>
</protocol>