get dpi of monitor and calculate actual size of it.

Assets/uDesktopDuplication/Examples/Scripts/MultipleMonitorCreator.cs

@@ -4,7 +4,7 @@ using System.Collections.Generic;
 public class MultipleMonitorCreator : MonoBehaviour
 {
     [SerializeField] GameObject monitorPrefab;
-    [SerializeField] float width = 0.3f;
+    [SerializeField] float scale = 1f;
     [SerializeField] float margin = 1f;
 
     private List<GameObject> monitors_ = new List<GameObject>();
@@ -49,19 +49,17 @@ public class MultipleMonitorCreator : MonoBehaviour
             // Assign monitor
             var texture = go.GetComponent<uDesktopDuplication.Texture>();
             texture.monitorId = i;
+            var monitor = texture.monitor;
 
             // Set width / height
-            var isHorizontal = texture.monitor.isHorizontal;
+            go.transform.localScale = new Vector3(monitor.widthMeter, go.transform.localScale.y, monitor.heightMeter);
-            var w = isHorizontal ? width : (width * texture.monitor.aspect);
-            var h = isHorizontal ? width / texture.monitor.aspect : width;
-            go.transform.localScale = new Vector3(w, go.transform.localScale.y, h);
 
             // Set parent as this object
             go.transform.SetParent(transform);
 
             // Calc actual size considering mesh size
             var scaleX = go.GetComponent<MeshFilter>().sharedMesh.bounds.extents.x * 2f;
-            totalWidth_ += w * scaleX;
+            totalWidth_ += monitor.widthMeter * scaleX;
         }
     }
 
@@ -71,10 +69,10 @@ public class MultipleMonitorCreator : MonoBehaviour
         totalWidth_ += margin * (monitors_.Count - 1);
         var x = -totalWidth_ / 2;
         foreach (var go in monitors_) {
-            var texture = go.GetComponent<uDesktopDuplication.Texture>();
+            var monitor = go.GetComponent<uDesktopDuplication.Texture>().monitor;
             var halfScaleX = go.GetComponent<MeshFilter>().sharedMesh.bounds.extents.x;
-            var w = texture.monitor.isHorizontal ? width : (width * texture.monitor.aspect);
+            var width = monitor.widthMeter;
-            var halfWidth = w * halfScaleX;
+            var halfWidth = width * halfScaleX;
             x += halfWidth;
             go.transform.localPosition = new Vector3(x, 0f, 0f);
             x += halfWidth + margin;

Assets/uDesktopDuplication/Scripts/Lib.cs

@@ -80,6 +80,10 @@ public static class Lib
     [DllImport("uDesktopDuplication")]
     public static extern int GetHeight(int id);
     [DllImport("uDesktopDuplication")]
+    public static extern int GetDpiX(int id);
+    [DllImport("uDesktopDuplication")]
+    public static extern int GetDpiY(int id);
+    [DllImport("uDesktopDuplication")]
     public static extern MonitorRotation GetRotation(int id);
     [DllImport("uDesktopDuplication")]
     public static extern bool IsPrimary(int id);

Assets/uDesktopDuplication/Scripts/Monitor.cs

@@ -92,6 +92,26 @@ public class Monitor
         get { return Lib.GetHeight(id); }
     }
 
+    public int dpiX
+    { 
+        get { return Lib.GetDpiX(id); }
+    }
+
+    public int dpiY
+    { 
+        get { return Lib.GetDpiY(id); }
+    }
+
+    public float widthMeter
+    { 
+        get { return width / dpiX * 0.0254f; }
+    }
+
+    public float heightMeter
+    { 
+        get { return height / dpiY * 0.0254f; }
+    }
+
     public MonitorRotation rotation
     { 
         get { return Lib.GetRotation(id); }

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;