screen_capturer_win_magnifier.h

Enable keyboard shortcuts

/*

 *  Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.

 *  Use of this source code is governed by a BSD-style license

 *  that can be found in the LICENSE file in the root of the source

 *  tree. An additional intellectual property rights grant can be found

 *  in the file PATENTS.  All contributing project authors may

 *  be found in the AUTHORS file in the root of the source tree.

*/

#ifndef MODULES_DESKTOP_CAPTURE_WIN_SCREEN_CAPTURER_WIN_MAGNIFIER_H_

#define MODULES_DESKTOP_CAPTURE_WIN_SCREEN_CAPTURER_WIN_MAGNIFIER_H_

#include <magnification.h>

#include <wincodec.h>

#include <windows.h>

#include <memory>

#include "modules/desktop_capture/desktop_capturer.h"

#include "modules/desktop_capture/screen_capture_frame_queue.h"

#include "modules/desktop_capture/screen_capturer_helper.h"

#include "modules/desktop_capture/shared_desktop_frame.h"

#include "modules/desktop_capture/win/scoped_thread_desktop.h"

namespace webrtc {

class DesktopFrame;

class DesktopRect;

// Captures the screen using the Magnification API to support window exclusion.

// Each capturer must run on a dedicated thread because it uses thread local

// storage for redirecting the library callback. Also the thread must have a UI

// message loop to handle the window messages for the magnifier window.

//

// This class does not detect DesktopFrame::updated_region(), the field is

// always set to the entire frame rectangle. ScreenCapturerDifferWrapper should

// be used if that functionality is necessary.

class ScreenCapturerWinMagnifier : public DesktopCapturer {

 public:

  ScreenCapturerWinMagnifier();

  ~ScreenCapturerWinMagnifier() override;

  ScreenCapturerWinMagnifier(const ScreenCapturerWinMagnifier&) = delete;

  ScreenCapturerWinMagnifier& operator=(const ScreenCapturerWinMagnifier&) =

      delete;

  // Overridden from ScreenCapturer:

  void Start(Callback* callback) override;

  void SetSharedMemoryFactory(

      std::unique_ptr<SharedMemoryFactory> shared_memory_factory) override;

  void CaptureFrame() override;

  bool GetSourceList(SourceList* screens) override;

  bool SelectSource(SourceId id) override;

  void SetExcludedWindow(WindowId window) override;

 private:

  typedef BOOL(WINAPI* MagImageScalingCallback)(HWND hwnd,

                                                void* srcdata,

                                                MAGIMAGEHEADER srcheader,

                                                void* destdata,

                                                MAGIMAGEHEADER destheader,

                                                RECT unclipped,

                                                RECT clipped,

                                                HRGN dirty);

  typedef BOOL(WINAPI* MagInitializeFunc)(void);

  typedef BOOL(WINAPI* MagUninitializeFunc)(void);

  typedef BOOL(WINAPI* MagSetWindowSourceFunc)(HWND hwnd, RECT rect);

  typedef BOOL(WINAPI* MagSetWindowFilterListFunc)(HWND hwnd,

                                                   DWORD dwFilterMode,

                                                   int count,

                                                   HWND* pHWND);

  typedef BOOL(WINAPI* MagSetImageScalingCallbackFunc)(

      HWND hwnd,

      MagImageScalingCallback callback);

  static BOOL WINAPI OnMagImageScalingCallback(HWND hwnd,

                                               void* srcdata,

                                               MAGIMAGEHEADER srcheader,

                                               void* destdata,

                                               MAGIMAGEHEADER destheader,

                                               RECT unclipped,

                                               RECT clipped,

                                               HRGN dirty);

  // Captures the screen within `rect` in the desktop coordinates. Returns true

  // if succeeded.

  // It can only capture the primary screen for now. The magnification library

  // crashes under some screen configurations (e.g. secondary screen on top of

  // primary screen) if it tries to capture a non-primary screen. The caller

  // must make sure not calling it on non-primary screens.

  bool CaptureImage(const DesktopRect& rect);

  // Helper method for setting up the magnifier control. Returns true if

  // succeeded.

  bool InitializeMagnifier();

  // Called by OnMagImageScalingCallback to output captured data.

  void OnCaptured(void* data, const MAGIMAGEHEADER& header);

  // Makes sure the current frame exists and matches `size`.

  void CreateCurrentFrameIfNecessary(const DesktopSize& size);

  Callback* callback_ = nullptr;

  std::unique_ptr<SharedMemoryFactory> shared_memory_factory_;

  ScreenId current_screen_id_ = kFullDesktopScreenId;

  std::wstring current_device_key_;

  HWND excluded_window_ = NULL;

  // Queue of the frames buffers.

  ScreenCaptureFrameQueue<SharedDesktopFrame> queue_;

  ScopedThreadDesktop desktop_;

  // Used for getting the screen dpi.

  HDC desktop_dc_ = NULL;

  HMODULE mag_lib_handle_ = NULL;

  MagInitializeFunc mag_initialize_func_ = nullptr;

  MagUninitializeFunc mag_uninitialize_func_ = nullptr;

  MagSetWindowSourceFunc set_window_source_func_ = nullptr;

  MagSetWindowFilterListFunc set_window_filter_list_func_ = nullptr;

  MagSetImageScalingCallbackFunc set_image_scaling_callback_func_ = nullptr;

  // The hidden window hosting the magnifier control.

  HWND host_window_ = NULL;

  // The magnifier control that captures the screen.

  HWND magnifier_window_ = NULL;

  // True if the magnifier control has been successfully initialized.

  bool magnifier_initialized_ = false;

  // True if the last OnMagImageScalingCallback was called and handled

  // successfully. Reset at the beginning of each CaptureImage call.

  bool magnifier_capture_succeeded_ = true;

};

}  // namespace webrtc

#endif  // MODULES_DESKTOP_CAPTURE_WIN_SCREEN_CAPTURER_WIN_MAGNIFIER_H_