Merge pull request #1475 from aws-lumberyard-dev/nvsickle/ViewportInfoDpiScaling

Make IMGUI & viewport info scale with DPI

Code/Editor/RenderViewport.h

@@ -219,6 +219,7 @@ public:
     void SetFullScreenState(bool fullScreenState) override;
     bool CanToggleFullScreenState() const override;
     void ToggleFullScreenState() override;
+    float GetDpiScaleFactor() const override { return 1.0f; };
 
     void ConnectViewportInteractionRequestBus();
     void DisconnectViewportInteractionRequestBus();

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 many 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() {};
     };

Code/Framework/AzFramework/Platform/Windows/AzFramework/Windowing/NativeWindow_Windows.cpp

@@ -8,6 +8,7 @@
 #include <AzFramework/Input/Buses/Notifications/RawInputNotificationBus_Windows.h>
 #include <AzFramework/Windowing/NativeWindow.h>
 
+#include <AzCore/Module/DynamicModuleHandle.h>
 #include <AzCore/PlatformIncl.h>
 
 namespace AzFramework
@@ -17,7 +18,7 @@ namespace AzFramework
     {
     public:
         AZ_CLASS_ALLOCATOR(NativeWindowImpl_Win32, AZ::SystemAllocator, 0);
-        NativeWindowImpl_Win32() = default;
+        NativeWindowImpl_Win32();
         ~NativeWindowImpl_Win32() override;
 
         // NativeWindow::Implementation overrides...
@@ -33,6 +34,7 @@ namespace AzFramework
         bool GetFullScreenState() const override;
         void SetFullScreenState(bool fullScreenState) override;
         bool CanToggleFullScreenState() const override { return true; }
+        float GetDpiScaleFactor() const override;
 
     private:
         static DWORD ConvertToWin32WindowStyleMask(const WindowStyleMasks& styleMasks);
@@ -49,6 +51,9 @@ namespace AzFramework
         RECT m_windowRectToRestoreOnFullScreenExit; //!< The position and size of the window to restore when exiting full screen.
         UINT m_windowStyleToRestoreOnFullScreenExit; //!< The style(s) of the window to restore when exiting full screen.
         bool m_isInBorderlessWindowFullScreenState = false; //!< Was a borderless window used to enter full screen state?
+
+        using GetDpiForWindowType = UINT(HWND hwnd);
+        GetDpiForWindowType* m_getDpiFunction = nullptr;
     };
 
     const char* NativeWindowImpl_Win32::s_defaultClassName = "O3DEWin32Class";
@@ -58,6 +63,15 @@ namespace AzFramework
         return aznew NativeWindowImpl_Win32();
     }
 
+    NativeWindowImpl_Win32::NativeWindowImpl_Win32()
+    {
+        // Attempt to load GetDpiForWindow from user32 at runtime, available on Windows 10+ versions >= 1607
+        if (auto user32module = AZ::DynamicModuleHandle::Create("user32"); user32module->Load(false))
+        {
+            m_getDpiFunction = user32module->GetFunction<GetDpiForWindowType*>("GetDpiForWindow");
+        }
+    }
+
     NativeWindowImpl_Win32::~NativeWindowImpl_Win32()
     {
         DestroyWindow(m_win32Handle);
@@ -237,6 +251,12 @@ namespace AzFramework
             // Send all other WM_SYSKEYDOWN messages to the default WndProc.
             break;
         }
+        case WM_DPICHANGED:
+        {
+            const float newScaleFactor = nativeWindowImpl->GetDpiScaleFactor();
+            WindowNotificationBus::Event(nativeWindowImpl->GetWindowHandle(), &WindowNotificationBus::Events::OnDpiScaleFactorChanged, newScaleFactor);
+            break;
+        }
         default:
             return DefWindowProc(hWnd, message, wParam, lParam);
             break;
@@ -330,6 +350,17 @@ namespace AzFramework
         }
     }
 
+    float NativeWindowImpl_Win32::GetDpiScaleFactor() const
+    {
+        constexpr UINT defaultDotsPerInch = 96;
+        UINT dotsPerInch = defaultDotsPerInch;
+        if (m_getDpiFunction)
+        {
+            dotsPerInch = m_getDpiFunction(m_win32Handle);
+        }
+        return aznumeric_cast<float>(dotsPerInch) / aznumeric_cast<float>(defaultDotsPerInch);
+    }
+
     void NativeWindowImpl_Win32::EnterBorderlessWindowFullScreen()
     {
         if (m_isInBorderlessWindowFullScreenState)

Code/LauncherUnified/launcher_generator.cmake

@@ -122,6 +122,8 @@ foreach(project_name project_path IN ZIP_LISTS LY_PROJECTS_TARGET_NAME LY_PROJEC
             FOLDER ${project_name}
     )
 
+    # After ensuring that we correctly support DPI scaling, this should be switched to "PerMonitor"
+    set_property(TARGET ${project_name}.GameLauncher APPEND PROPERTY VS_DPI_AWARE "OFF")
     if(LY_DEFAULT_PROJECT_PATH)
         set_property(TARGET ${project_name}.GameLauncher APPEND PROPERTY VS_DEBUGGER_COMMAND_ARGUMENTS "--project-path=\"${LY_DEFAULT_PROJECT_PATH}\"")
     endif()