get dpi of monitor and calculate actual size of it.

Plugins/uDesktopDuplication/uDesktopDuplication/Monitor.cpp

@@ -1,4 +1,5 @@
 #include <d3d11.h>
+#include <ShellScalingAPI.h>
 #include "Common.h"
 #include "Cursor.h"
 #include "MonitorManager.h"
@@ -18,6 +19,8 @@ HRESULT Monitor::Initialize(IDXGIOutput* output)
     monitorInfo_.cbSize = sizeof(MONITORINFOEX);
     GetMonitorInfo(outputDesc_.Monitor, &monitorInfo_);
 
+    GetDpiForMonitor(outputDesc_.Monitor, MDT_RAW_DPI, &dpiX_, &dpiY_);
+
     auto output1 = reinterpret_cast<IDXGIOutput1*>(output);
     const auto hr = output1->DuplicateOutput(GetDevice(), &deskDupl_);
 
@@ -196,6 +199,18 @@ int Monitor::GetRotation() const
 }
 
 
+int Monitor::GetDpiX() const
+{
+    return static_cast<int>(dpiX_);
+}
+
+
+int Monitor::GetDpiY() const
+{
+    return static_cast<int>(dpiY_);
+}
+
+
 int Monitor::GetWidth() const
 {
     const auto rect = monitorInfo_.rcMonitor;

Plugins/uDesktopDuplication/uDesktopDuplication/Monitor.h

@@ -41,11 +41,14 @@ public:
     int GetWidth() const;
     int GetHeight() const;
     int GetRotation() const;
+    int GetDpiX() const;
+    int GetDpiY() const;
     IDXGIOutputDuplication* GetDeskDupl();
     const std::unique_ptr<Cursor>& GetCursor();
 
 private:
     int id_ = -1;
+    UINT dpiX_ = -1, dpiY_ = -1;
     State state_ = State::NotSet;
     std::unique_ptr<Cursor> cursor_;
     IDXGIOutputDuplication* deskDupl_ = nullptr;

Plugins/uDesktopDuplication/uDesktopDuplication/main.cpp

@@ -15,6 +15,7 @@
 #include "MonitorManager.h"
 
 #pragma comment(lib, "dxgi.lib")
+#pragma comment(lib, "Shcore.lib")
 
 
 namespace
@@ -234,6 +235,26 @@ extern "C"
         return DXGI_MODE_ROTATION_UNSPECIFIED;
     }
 
+    UNITY_INTERFACE_EXPORT int UNITY_INTERFACE_API GetDpiX(int id)
+    {
+        if (!g_manager) return -1;
+        if (auto monitor = g_manager->GetMonitor(id))
+        {
+            return monitor->GetDpiX();
+        }
+        return -1;
+    }
+
+    UNITY_INTERFACE_EXPORT int UNITY_INTERFACE_API GetDpiY(int id)
+    {
+        if (!g_manager) return -1;
+        if (auto monitor = g_manager->GetMonitor(id))
+        {
+            return monitor->GetDpiY();
+        }
+        return -1;
+    }
+
     UNITY_INTERFACE_EXPORT bool UNITY_INTERFACE_API IsCursorVisible(int id)
     {
         if (!g_manager) return false;