1 files changed, 224 insertions, 0 deletions
diff --git a/src/envmetrics.cpp b/src/envmetrics.cpp
new file mode 100644
index 00000000..a6988909
--- /dev/null
+++ b/src/envmetrics.cpp
@@ -0,0 +1,224 @@
+#include "envmetrics.h"
+#include "env.h"
+#include <Windows.h>
+#include <shellscalingapi.h>
+#include <log.h>
+#include <utility.h>
+
+namespace env
+{
+
+using namespace MOBase;
+
+class DisplayEnumerator
+{
+public:
+  DisplayEnumerator()
+    : m_GetDpiForMonitor(nullptr)
+  {
+    m_shcore.reset(LoadLibraryW(L"Shcore.dll"));
+
+    if (m_shcore) {
+      // windows 8.1+ only
+      m_GetDpiForMonitor = reinterpret_cast<GetDpiForMonitorFunction*>(
+        GetProcAddress(m_shcore.get(), "GetDpiForMonitor"));
+    }
+
+    // gets all monitors and the device they're running on
+    getDisplayDevices();
+  }
+
+  std::vector<Metrics::Display>&& displays() &&
+  {
+    return std::move(m_displays);
+  }
+
+  const std::vector<Metrics::Display>& displays() const &
+  {
+    return m_displays;
+  }
+
+private:
+  using GetDpiForMonitorFunction =
+    HRESULT WINAPI (HMONITOR, MONITOR_DPI_TYPE, UINT*, UINT*);
+
+  std::unique_ptr<HINSTANCE, LibraryFreer> m_shcore;
+  GetDpiForMonitorFunction* m_GetDpiForMonitor;
+  std::vector<Metrics::Display> m_displays;
+
+  void getDisplayDevices()
+  {
+    // don't bother if it goes over 100
+    for (int i=0; i<100; ++i) {
+      DISPLAY_DEVICEW device = {};
+      device.cb = sizeof(device);
+
+      if (!EnumDisplayDevicesW(nullptr, i, &device, 0)) {
+        // no more
+        break;
+      }
+
+      // EnumDisplayDevices() seems to be returning a lot of devices that are
+      // not actually monitors, but those don't have the
+      // DISPLAY_DEVICE_ATTACHED_TO_DESKTOP bit set
+      if ((device.StateFlags & DISPLAY_DEVICE_ATTACHED_TO_DESKTOP) == 0) {
+        continue;
+      }
+
+      m_displays.push_back(createDisplay(device));
+    }
+  }
+
+  Metrics::Display createDisplay(const DISPLAY_DEVICEW& device)
+  {
+    Metrics::Display d;
+
+    d.adapter = QString::fromWCharArray(device.DeviceString);
+    d.monitor = QString::fromWCharArray(device.DeviceName);
+    d.primary = (device.StateFlags & DISPLAY_DEVICE_PRIMARY_DEVICE);
+
+    getDisplaySettings(device.DeviceName, d);
+    getDpi(d);
+
+    return d;
+  }
+
+  void getDisplaySettings(const wchar_t* monitorName, Metrics::Display& d)
+  {
+    DEVMODEW dm = {};
+    dm.dmSize = sizeof(dm);
+
+    if (!EnumDisplaySettingsW(monitorName, ENUM_CURRENT_SETTINGS, &dm)) {
+      log::error("EnumDisplaySettings() failed for '{}'", d.monitor);
+      return;
+    }
+
+    // all these fields should be available
+
+    if (dm.dmFields & DM_DISPLAYFREQUENCY) {
+      d.refreshRate = dm.dmDisplayFrequency;
+    }
+
+    if (dm.dmFields & DM_PELSWIDTH) {
+      d.resX = dm.dmPelsWidth;
+    }
+
+    if (dm.dmFields & DM_PELSHEIGHT) {
+      d.resY = dm.dmPelsHeight;
+    }
+  }
+
+  void getDpi(Metrics::Display& d)
+  {
+    if (!m_GetDpiForMonitor) {
+      // this happens on windows 7, get the desktop dpi instead
+      getDesktopDpi(d);
+      return;
+    }
+
+    // there's no way to get an HMONITOR from a device name, so all monitors
+    // will have to be enumerated and their name checked
+    HMONITOR hm = findMonitor(d.monitor);
+    if (!hm) {
+      log::error("can't get dpi for monitor '{}', not found", d.monitor);
+      return;
+    }
+
+    UINT dpiX=0, dpiY=0;
+    const auto r = m_GetDpiForMonitor(hm, MDT_EFFECTIVE_DPI, &dpiX, &dpiY);
+
+    if (FAILED(r)) {
+      log::error(
+        "GetDpiForMonitor() failed for '{}', {}",
+        d.monitor, formatSystemMessageQ(r));
+
+      return;
+    }
+
+    // dpiX and dpiY are always identical, as per the documentation
+    d.dpi = dpiX;
+  }
+
+  void getDesktopDpi(Metrics::Display& d)
+  {
+    // desktop dc
+    HDC dc = GetDC(0);
+
+    if (!dc) {
+      const auto e = GetLastError();
+      log::error("can't get desktop DC, {}", formatSystemMessageQ(e));
+      return;
+    }
+
+    d.dpi = GetDeviceCaps(dc, LOGPIXELSX);
+
+    ReleaseDC(0, dc);
+  }
+
+  HMONITOR findMonitor(const QString& name)
+  {
+    // passed to the enumeration callback
+    struct Data
+    {
+      DisplayEnumerator* self;
+      QString name;
+      HMONITOR hm;
+    };
+
+    Data data = {this, name, 0};
+
+    // for each monitor
+    EnumDisplayMonitors(0, nullptr, [](HMONITOR hm, HDC, RECT*, LPARAM lp) {
+      auto& data = *reinterpret_cast<Data*>(lp);
+
+      MONITORINFOEX mi = {};
+      mi.cbSize = sizeof(mi);
+
+      // monitor info will include the name
+      if (!GetMonitorInfoW(hm, &mi)) {
+        const auto e = GetLastError();
+        log::error(
+          "GetMonitorInfo() failed for '{}', {}",
+          data.name, formatSystemMessageQ(e));
+
+        // error for this monitor, but continue
+        return TRUE;
+      }
+
+      if (QString::fromWCharArray(mi.szDevice) == data.name) {
+        // found, stop
+        data.hm = hm;
+        return FALSE;
+      }
+
+      // not found, continue to the next monitor
+      return TRUE;
+      }, reinterpret_cast<LPARAM>(&data));
+
+    return data.hm;
+  }
+};
+
+
+Metrics::Metrics()
+{
+  m_displays = DisplayEnumerator().displays();
+}
+
+const std::vector<Metrics::Display>& Metrics::displays() const
+{
+  return m_displays;
+}
+
+QString Metrics::Display::toString() const
+{
+  return QString("%1*%2 %3hz dpi=%4 on %5%6")
+    .arg(resX)
+    .arg(resY)
+    .arg(refreshRate)
+    .arg(dpi)
+    .arg(adapter)
+    .arg(primary ? " (primary)" : "");
+}
+
+} // namespace