1 files changed, 89 insertions, 0 deletions
diff --git a/widget/windows/ScreenHelperWin.cpp b/widget/windows/ScreenHelperWin.cpp
new file mode 100644
index 0000000000..ff455b6c8c
--- /dev/null
+++ b/widget/windows/ScreenHelperWin.cpp
@@ -0,0 +1,89 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ScreenHelperWin.h"
+
+#include "mozilla/Logging.h"
+#include "nsTArray.h"
+#include "WinUtils.h"
+
+static mozilla::LazyLogModule sScreenLog("WidgetScreen");
+
+namespace mozilla {
+namespace widget {
+
+BOOL CALLBACK CollectMonitors(HMONITOR aMon, HDC, LPRECT, LPARAM ioParam) {
+  auto screens = reinterpret_cast<nsTArray<RefPtr<Screen>>*>(ioParam);
+  BOOL success = FALSE;
+  MONITORINFOEX info;
+  info.cbSize = sizeof(MONITORINFOEX);
+  success = ::GetMonitorInfoW(aMon, &info);
+  if (!success) {
+    MOZ_LOG(sScreenLog, LogLevel::Error, ("GetMonitorInfoW failed"));
+    return TRUE;  // continue the enumeration
+  }
+
+  double scale = WinUtils::LogToPhysFactor(aMon);
+  DesktopToLayoutDeviceScale contentsScaleFactor;
+  if (WinUtils::IsPerMonitorDPIAware()) {
+    contentsScaleFactor.scale = 1.0;
+  } else {
+    contentsScaleFactor.scale = scale;
+  }
+  CSSToLayoutDeviceScale defaultCssScaleFactor(scale);
+  LayoutDeviceIntRect rect(info.rcMonitor.left, info.rcMonitor.top,
+                           info.rcMonitor.right - info.rcMonitor.left,
+                           info.rcMonitor.bottom - info.rcMonitor.top);
+  LayoutDeviceIntRect availRect(info.rcWork.left, info.rcWork.top,
+                                info.rcWork.right - info.rcWork.left,
+                                info.rcWork.bottom - info.rcWork.top);
+
+  HDC hDC = CreateDC(nullptr, info.szDevice, nullptr, nullptr);
+  if (!hDC) {
+    MOZ_LOG(sScreenLog, LogLevel::Error, ("CollectMonitors CreateDC failed"));
+    return TRUE;
+  }
+  uint32_t pixelDepth = ::GetDeviceCaps(hDC, BITSPIXEL);
+  DeleteDC(hDC);
+  if (pixelDepth == 32) {
+    // If a device uses 32 bits per pixel, it's still only using 8 bits
+    // per color component, which is what our callers want to know.
+    // (Some devices report 32 and some devices report 24.)
+    pixelDepth = 24;
+  }
+
+  float dpi = WinUtils::MonitorDPI(aMon);
+  MOZ_LOG(sScreenLog, LogLevel::Debug,
+          ("New screen [%d %d %d %d (%d %d %d %d) %d %f %f %f]", rect.X(),
+           rect.Y(), rect.Width(), rect.Height(), availRect.X(), availRect.Y(),
+           availRect.Width(), availRect.Height(), pixelDepth,
+           contentsScaleFactor.scale, defaultCssScaleFactor.scale, dpi));
+  auto screen = new Screen(rect, availRect, pixelDepth, pixelDepth,
+                           contentsScaleFactor, defaultCssScaleFactor, dpi);
+  if (info.dwFlags & MONITORINFOF_PRIMARY) {
+    // The primary monitor must be the first element of the screen list.
+    screens->InsertElementAt(0, std::move(screen));
+  } else {
+    screens->AppendElement(std::move(screen));
+  }
+  return TRUE;
+}
+
+void ScreenHelperWin::RefreshScreens() {
+  MOZ_LOG(sScreenLog, LogLevel::Debug, ("Refreshing screens"));
+
+  AutoTArray<RefPtr<Screen>, 4> screens;
+  BOOL result = ::EnumDisplayMonitors(
+      nullptr, nullptr, (MONITORENUMPROC)CollectMonitors, (LPARAM)&screens);
+  if (!result) {
+    NS_WARNING("Unable to EnumDisplayMonitors");
+  }
+  ScreenManager& screenManager = ScreenManager::GetSingleton();
+  screenManager.Refresh(std::move(screens));
+}
+
+}  // namespace widget
+}  // namespace mozilla