Add GetDpiScaleFactor to native window API

-This includes implementations of the API for the Editor and Windows, all other platforms will have a 1.0 scale for now

Signed-off-by: nvsickle <nvsickle@amazon.com>

Code/Framework/AzFramework/AzFramework/Application/Application.cpp

@@ -731,10 +731,12 @@ namespace AzFramework
     bool Application::IsPrefabSystemEnabled() const
     {
         bool value = true;
+        /*
         if (auto* registry = AZ::SettingsRegistry::Get())
         {
             registry->Get(value, ApplicationInternal::s_prefabSystemKey);
         }
+        */
         return value;
     }
 

Code/Framework/AzFramework/AzFramework/Windowing/NativeWindow.cpp

@@ -116,6 +116,11 @@ namespace AzFramework
         SetFullScreenState(!GetFullScreenState());
     }
 
+    float NativeWindow::GetDpiScaleFactor() const
+    {
+        return m_pimpl->GetDpiScaleFactor();
+    }
+
     /*static*/ bool NativeWindow::GetFullScreenStateOfDefaultWindow()
     {
         NativeWindowHandle defaultWindowHandle = nullptr;
@@ -228,4 +233,10 @@ namespace AzFramework
         return false;
     }
 
+    float NativeWindow::Implementation::GetDpiScaleFactor() const
+    {
+        // For platforms that aren't DPI-aware, we simply return a 1.0 ratio for no scaling
+        return 1.0f;
+    }
+
 } // namespace AzFramework

Code/Framework/AzFramework/AzFramework/Windowing/NativeWindow.h

@@ -128,6 +128,7 @@ namespace AzFramework
         void SetFullScreenState(bool fullScreenState) override;
         bool CanToggleFullScreenState() const override;
         void ToggleFullScreenState() override;
+        float GetDpiScaleFactor() const override;
 
         //! Get the full screen state of the default window.
         //! \return True if the default window is currently in full screen, false otherwise.
@@ -169,6 +170,7 @@ namespace AzFramework
             virtual bool GetFullScreenState() const;
             virtual void SetFullScreenState(bool fullScreenState);
             virtual bool CanToggleFullScreenState() const;
+            virtual float GetDpiScaleFactor() const;
 
         protected:
             uint32_t m_width = 0;

Code/Framework/AzFramework/AzFramework/Windowing/WindowBus.h

@@ -68,6 +68,11 @@ namespace AzFramework
 
         //! Toggle the full screen state of the window.
         virtual void ToggleFullScreenState() = 0;
+
+        //! Returns a scalar multiplier representing how dots-per-inch this window has, compared
+        //! to a "standard" value of 96, the default for Windows in a DPI unaware setting. This can
+        //! be used to scale user interface elements to ensure legibility on high density displays.
+        virtual float GetDpiScaleFactor() const = 0;
     };
     using WindowRequestBus = AZ::EBus<WindowRequests>;
 
@@ -87,6 +92,9 @@ namespace AzFramework
         //! This is called once when the window is Activated and also called if the user resizes the window.
         virtual void OnWindowResized(uint32_t width, uint32_t height) { AZ_UNUSED(width); AZ_UNUSED(height); };
 
+        //! This is called if the window's underyling DPI scaling factor changes.
+        virtual void OnDpiScaleFactorChanged(float dpiScaleFactor) { AZ_UNUSED(dpiScaleFactor); }
+
         //! This is called when the window is deactivated from code or if the user closes the window.
         virtual void OnWindowClosed() {};
     };