1/*
2 *  Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
3 *
4 *  Use of this source code is governed by a BSD-style license
5 *  that can be found in the LICENSE file in the root of the source
6 *  tree. An additional intellectual property rights grant can be found
7 *  in the file PATENTS.  All contributing project authors may
8 *  be found in the AUTHORS file in the root of the source tree.
9 */
10
11#include "webrtc/modules/desktop_capture/win/screen_capture_utils.h"
12
13#include <assert.h>
14#include <windows.h>
15
16namespace webrtc {
17
18bool GetScreenList(ScreenCapturer::ScreenList* screens) {
19  assert(screens->size() == 0);
20
21  BOOL enum_result = TRUE;
22  for (int device_index = 0;; ++device_index) {
23    DISPLAY_DEVICE device;
24    device.cb = sizeof(device);
25    enum_result = EnumDisplayDevices(NULL, device_index, &device, 0);
26
27    // |enum_result| is 0 if we have enumerated all devices.
28    if (!enum_result)
29      break;
30
31    // We only care about active displays.
32    if (!(device.StateFlags & DISPLAY_DEVICE_ACTIVE))
33      continue;
34
35    ScreenCapturer::Screen screen;
36    screen.id = device_index;
37    screens->push_back(screen);
38  }
39  return true;
40}
41
42bool IsScreenValid(ScreenId screen, std::wstring* device_key) {
43  if (screen == kFullDesktopScreenId) {
44    *device_key = L"";
45    return true;
46  }
47
48  DISPLAY_DEVICE device;
49  device.cb = sizeof(device);
50  BOOL enum_result = EnumDisplayDevices(NULL, screen, &device, 0);
51  if (enum_result)
52    *device_key = device.DeviceKey;
53
54  return !!enum_result;
55}
56
57DesktopRect GetScreenRect(ScreenId screen, const std::wstring& device_key) {
58  if (screen == kFullDesktopScreenId) {
59    return DesktopRect::MakeXYWH(GetSystemMetrics(SM_XVIRTUALSCREEN),
60                                 GetSystemMetrics(SM_YVIRTUALSCREEN),
61                                 GetSystemMetrics(SM_CXVIRTUALSCREEN),
62                                 GetSystemMetrics(SM_CYVIRTUALSCREEN));
63  }
64
65  DISPLAY_DEVICE device;
66  device.cb = sizeof(device);
67  BOOL result = EnumDisplayDevices(NULL, screen, &device, 0);
68  if (!result)
69    return DesktopRect();
70
71  // Verifies the device index still maps to the same display device, to make
72  // sure we are capturing the same device when devices are added or removed.
73  // DeviceKey is documented as reserved, but it actually contains the registry
74  // key for the device and is unique for each monitor, while DeviceID is not.
75  if (device_key != device.DeviceKey)
76    return DesktopRect();
77
78  DEVMODE device_mode;
79  device_mode.dmSize = sizeof(device_mode);
80  device_mode.dmDriverExtra = 0;
81  result = EnumDisplaySettingsEx(
82      device.DeviceName, ENUM_CURRENT_SETTINGS, &device_mode, 0);
83  if (!result)
84    return DesktopRect();
85
86  return DesktopRect::MakeXYWH(device_mode.dmPosition.x,
87                               device_mode.dmPosition.y,
88                               device_mode.dmPelsWidth,
89                               device_mode.dmPelsHeight);
90}
91
92}  // namespace webrtc
93