1 files changed, 206 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/desktop_capture/win/screen_capture_utils.cc b/third_party/libwebrtc/modules/desktop_capture/win/screen_capture_utils.cc
new file mode 100644
index 0000000000..f68cfb94c1
--- /dev/null
+++ b/third_party/libwebrtc/modules/desktop_capture/win/screen_capture_utils.cc
@@ -0,0 +1,206 @@
+/*
+ *  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 <shellscalingapi.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 HasActiveDisplay() {
+  DesktopCapturer::SourceList screens;
+
+  return GetScreenList(&screens) && !screens.empty();
+}
+
+bool GetScreenList(DesktopCapturer::SourceList* screens,
+                   std::vector<std::string>* device_names /* = nullptr */) {
+  RTC_DCHECK(screens->empty());
+  RTC_DCHECK(!device_names || device_names->empty());
+
+  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, 0, 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) {
+    // There is a bug in a Windows OS API that causes a crash when capturing if
+    // there are no active displays. We must ensure there is an active display
+    // before returning true.
+    if (!HasActiveDisplay())
+      return false;
+
+    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));
+}
+
+DesktopVector GetDpiForMonitor(HMONITOR monitor) {
+  UINT dpi_x, dpi_y;
+  // MDT_EFFECTIVE_DPI includes the scale factor as well as the system DPI.
+  HRESULT hr = ::GetDpiForMonitor(monitor, MDT_EFFECTIVE_DPI, &dpi_x, &dpi_y);
+  if (SUCCEEDED(hr)) {
+    return {static_cast<INT>(dpi_x), static_cast<INT>(dpi_y)};
+  }
+  RTC_LOG_GLE_EX(LS_WARNING, hr) << "GetDpiForMonitor() failed";
+
+  // If we can't get the per-monitor DPI, then return the system DPI.
+  HDC hdc = GetDC(nullptr);
+  if (hdc) {
+    DesktopVector dpi{GetDeviceCaps(hdc, LOGPIXELSX),
+                      GetDeviceCaps(hdc, LOGPIXELSY)};
+    ReleaseDC(nullptr, hdc);
+    return dpi;
+  }
+
+  // If everything fails, then return the default DPI for Windows.
+  return {96, 96};
+}
+
+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