screen_capture.mojom

// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Mojo interface for performing screen capture in ChromeOS at the request of
// Android. Android does not have access to the full desktop for capture (it has
// access only to its Windows), so via this IPC mechanism it can request
// permissions to capture the entire desktop and then also perform that capture.

// The original version of this file lives in the Chromium repository at:
// src/components/arc/mojom/screen_capture.mojom

// Next MinVersion: 2

module arc.mojom;

import "components/arc/mojom/gfx.mojom";
import "components/arc/mojom/video_common.mojom";

// Implemented by Chrome in order to allow requesting of permissions to perform
// desktop capture as well as creating a session for it.
interface ScreenCaptureHost {
  // This will also show the desktop picker in case of multiple displays and
  // will then link that desktop window to the granted permission.
  // display_name is the string that should be used in the UI
  // package_name is what should be used as the permission token
  // returns true if the user accepts, false otherwise
  RequestPermission@0(string display_name, string package_name) => (bool granted);

  // Requests that a corresponding active permission dialog from a prior call to
  // RequestPermission be accepted. This will only be allowed under test
  // conditions.
  // package_name should match what was passed into RequestPermission
  [MinVersion=1] TestModeAcceptPermission@2(string package_name);

  // Starts a new capture session, binding the session interface to the passed
  // in session request.
  // notifier interface passed in will be used to send messages back to Android
  //     for when updates are needed by the Chrome rendering engine
  // package_name should correspond to what was passed into the
  //     RequestPermission call
  // size should have the width/height of the buffers used
  // returns null interface in the case the permission was not granted, a valid
  //     interface pointer otherwise
  OpenSession@1(pending_remote<ScreenCaptureSessionNotifier> notifier,
                string package_name, Size size)
      => (pending_remote<ScreenCaptureSession>? session);
};

// Implemented by Chrome for handling a screen capture session.
interface ScreenCaptureSession {
  // Called to set the graphics buffer that the screen capture should be
  // rendered to. This call does not return until the rendering is complete to
  // the passed in buffer.
  // graphics_buffer should be a handle to the buffer which corresponds to the
  //     surface being rendered to
  // stride is the stride in pixels for each row of the buffer
  SetOutputBuffer@0(handle graphics_buffer, uint32 stride) => ();
};

// Implemented by Android.
interface ScreenCaptureInstance {
  // Establishes full-duplex communication with the host.
  Init@0(pending_remote<ScreenCaptureHost> host_remote) => ();
};

// Implemented by Android as a callback mechanism.
interface ScreenCaptureSessionNotifier {
  // This is called when Chrome detects a compositor update but Android is not
  // actively rendering. This will occur if the Android windows are minimized or
  // not animating but Chrome windows are since Android’s rendering stack does
  // not update if nothing in Android itself is changing.
  ForceUpdate@0();
};