aboutsummaryrefslogtreecommitdiff
path: root/modules/desktop_capture/win/screen_capture_utils.cc
blob: 53b6dd399c758f7faca108a9341cdf3b9f405bee (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
/*
 *  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.
 */

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

#include <windows.h>

#include <string>
#include <vector>

#include "modules/desktop_capture/desktop_capturer.h"
#include "modules/desktop_capture/desktop_geometry.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
#include "rtc_base/string_utils.h"
#include "rtc_base/win32.h"

namespace webrtc {

bool GetScreenList(DesktopCapturer::SourceList* screens,
                   std::vector<std::string>* device_names /* = nullptr */) {
  RTC_DCHECK_EQ(screens->size(), 0U);
  if (device_names) {
    RTC_DCHECK_EQ(device_names->size(), 0U);
  }

  BOOL enum_result = TRUE;
  for (int device_index = 0;; ++device_index) {
    DISPLAY_DEVICEW device;
    device.cb = sizeof(device);
    enum_result = EnumDisplayDevicesW(NULL, device_index, &device, 0);

    // |enum_result| is 0 if we have enumerated all devices.
    if (!enum_result) {
      break;
    }

    // We only care about active displays.
    if (!(device.StateFlags & DISPLAY_DEVICE_ACTIVE)) {
      continue;
    }

    screens->push_back({device_index, std::string()});
    if (device_names) {
      device_names->push_back(rtc::ToUtf8(device.DeviceName));
    }
  }
  return true;
}

bool GetHmonitorFromDeviceIndex(const DesktopCapturer::SourceId device_index,
                                HMONITOR* hmonitor) {
  // A device index of |kFullDesktopScreenId| or -1 represents all screens, an
  // HMONITOR of 0 indicates the same.
  if (device_index == kFullDesktopScreenId) {
    *hmonitor = 0;
    return true;
  }

  std::wstring device_key;
  if (!IsScreenValid(device_index, &device_key)) {
    return false;
  }

  DesktopRect screen_rect = GetScreenRect(device_index, device_key);
  if (screen_rect.is_empty()) {
    return false;
  }

  RECT rect = {screen_rect.left(), screen_rect.top(), screen_rect.right(),
               screen_rect.bottom()};

  HMONITOR monitor = MonitorFromRect(&rect, MONITOR_DEFAULTTONULL);
  if (monitor == NULL) {
    RTC_LOG(LS_WARNING) << "No HMONITOR found for supplied device index.";
    return false;
  }

  *hmonitor = monitor;
  return true;
}

bool IsMonitorValid(const HMONITOR monitor) {
  // An HMONITOR of 0 refers to a virtual monitor that spans all physical
  // monitors.
  if (monitor == 0) {
    return true;
  }

  MONITORINFO monitor_info;
  monitor_info.cbSize = sizeof(MONITORINFO);
  return GetMonitorInfoA(monitor, &monitor_info);
}

DesktopRect GetMonitorRect(const HMONITOR monitor) {
  MONITORINFO monitor_info;
  monitor_info.cbSize = sizeof(MONITORINFO);
  if (!GetMonitorInfoA(monitor, &monitor_info)) {
    return DesktopRect();
  }

  return DesktopRect::MakeLTRB(
      monitor_info.rcMonitor.left, monitor_info.rcMonitor.top,
      monitor_info.rcMonitor.right, monitor_info.rcMonitor.bottom);
}

bool IsScreenValid(const DesktopCapturer::SourceId screen,
                   std::wstring* device_key) {
  if (screen == kFullDesktopScreenId) {
    *device_key = L"";
    return true;
  }

  DISPLAY_DEVICEW device;
  device.cb = sizeof(device);
  BOOL enum_result = EnumDisplayDevicesW(NULL, screen, &device, 0);
  if (enum_result) {
    *device_key = device.DeviceKey;
  }

  return !!enum_result;
}

DesktopRect GetFullscreenRect() {
  return DesktopRect::MakeXYWH(GetSystemMetrics(SM_XVIRTUALSCREEN),
                               GetSystemMetrics(SM_YVIRTUALSCREEN),
                               GetSystemMetrics(SM_CXVIRTUALSCREEN),
                               GetSystemMetrics(SM_CYVIRTUALSCREEN));
}

DesktopRect GetScreenRect(const DesktopCapturer::SourceId screen,
                          const std::wstring& device_key) {
  if (screen == kFullDesktopScreenId) {
    return GetFullscreenRect();
  }

  DISPLAY_DEVICEW device;
  device.cb = sizeof(device);
  BOOL result = EnumDisplayDevicesW(NULL, screen, &device, 0);
  if (!result) {
    return DesktopRect();
  }

  // Verifies the device index still maps to the same display device, to make
  // sure we are capturing the same device when devices are added or removed.
  // DeviceKey is documented as reserved, but it actually contains the registry
  // key for the device and is unique for each monitor, while DeviceID is not.
  if (device_key != device.DeviceKey) {
    return DesktopRect();
  }

  DEVMODEW device_mode;
  device_mode.dmSize = sizeof(device_mode);
  device_mode.dmDriverExtra = 0;
  result = EnumDisplaySettingsExW(device.DeviceName, ENUM_CURRENT_SETTINGS,
                                  &device_mode, 0);
  if (!result) {
    return DesktopRect();
  }

  return DesktopRect::MakeXYWH(
      device_mode.dmPosition.x, device_mode.dmPosition.y,
      device_mode.dmPelsWidth, device_mode.dmPelsHeight);
}

}  // namespace webrtc