wdisplays/protocol/wlr-screencopy-unstable-v1.xml

<?xml version="1.0" encoding="UTF-8"?>
<protocol name="wlr_screencopy_unstable_v1">
  <copyright>
    Copyright © 2018 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 copy part of the
    screen content to a client buffer.

    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="zwlr_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>

    <request name="capture_output">
      <description summary="capture an output">
        Capture the next frame of an entire output.
      </description>
      <arg name="frame" type="new_id" interface="zwlr_screencopy_frame_v1"/>
      <arg name="overlay_cursor" type="int"
        summary="composite cursor onto the frame"/>
      <arg name="output" type="object" interface="wl_output"/>
    </request>

    <request name="capture_output_region">
      <description summary="capture an output's region">
        Capture the next frame of an output's region.

        The region is given in output logical coordinates, see
        xdg_output.logical_size. The region will be clipped to the output's
        extents.
      </description>
      <arg name="frame" type="new_id" interface="zwlr_screencopy_frame_v1"/>
      <arg name="overlay_cursor" type="int"
        summary="composite cursor onto the frame"/>
      <arg name="output" type="object" interface="wl_output"/>
      <arg name="x" type="int"/>
      <arg name="y" type="int"/>
      <arg name="width" type="int"/>
      <arg name="height" type="int"/>
    </request>

    <request name="destroy" type="destructor">
      <description summary="destroy the manager">
        All objects created by the manager will still remain valid, until their
        appropriate destroy request has been called.
      </description>
    </request>
  </interface>

  <interface name="zwlr_screencopy_frame_v1" version="1">
    <description summary="a frame ready for copy">
      This object represents a single frame.

      When created, a "buffer" event will be sent. The client will then be able
      to send a "copy" request. If the capture is successful, the compositor
      will send a "flags" followed by a "ready" event.

      If the capture failed, the "failed" event is sent. This can happen anytime
      before the "ready" event.

      Once either a "ready" or a "failed" event is received, the client should
      destroy the frame.
    </description>

    <event name="buffer">
      <description summary="buffer information">
        Provides information about the frame's buffer. This event is sent once
        as soon as the frame is created.

        The client should then create a buffer with the provided attributes, and
        send a "copy" request.
      </description>
      <arg name="format" type="uint" summary="buffer format"/>
      <arg name="width" type="uint" summary="buffer width"/>
      <arg name="height" type="uint" summary="buffer height"/>
      <arg name="stride" type="uint" summary="buffer stride"/>
    </event>

    <request name="copy">
      <description summary="copy the frame">
        Copy the frame to the supplied buffer. The buffer must have a the
        correct size, see zwlr_screencopy_frame_v1.buffer. The buffer needs to
        have a supported format.

        If the frame is successfully copied, a "flags" and a "ready" events are
        sent. Otherwise, a "failed" event is sent.
      </description>
      <arg name="buffer" type="object" interface="wl_buffer"/>
    </request>

    <enum name="error">
      <entry name="already_used" value="0"
        summary="the object has already been used to copy a wl_buffer"/>
      <entry name="invalid_buffer" value="1"
        summary="buffer attributes are invalid"/>
    </enum>

    <enum name="flags" bitfield="true">
      <entry name="y_invert" value="1" summary="contents are y-inverted"/>
    </enum>

    <event name="flags">
      <description summary="frame flags">
        Provides flags about the frame. This event is sent once before the
        "ready" event.
      </description>
      <arg name="flags" type="uint" enum="flags" summary="frame flags"/>
    </event>

    <event name="ready">
      <description summary="indicates frame is available for reading">
        Called as soon as the frame is copied, indicating it is available
        for reading. This event includes the time at which presentation happened
        at.

        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]. The seconds part
        may have an arbitrary offset at start.

        After receiving this event, the client should destroy the object.
      </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="failed">
      <description summary="frame copy failed">
        This event indicates that the attempted frame copy has failed.

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

    <request name="destroy" type="destructor">
      <description summary="delete this object, used or not">
        Destroys the frame. This request can be sent at any time by the client.
      </description>
    </request>
  </interface>
</protocol>