From 9fac39c5e09cc6157fe77dca8810b329ad8e43f2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Blissing?= <bjorn.blissing@vti.se>
Date: Thu, 30 Nov 2017 13:00:54 +0100
Subject: [PATCH] Applications declared DPI-aware in the Windows environment

Applications that run on a Windows computer with desktop scaling enabled
gets scaled incorrectly since windows assumes that applications are
DPI-unaware unless declared otherwise.

This change declares the application DPI-aware, thus not automatically
scaled by the operating system.

The corresponding library call requires Windows 8.1 or later.
---
 src/osgViewer/GraphicsWindowWin32.cpp | 35 +++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/src/osgViewer/GraphicsWindowWin32.cpp b/src/osgViewer/GraphicsWindowWin32.cpp
index b1cb6ce9d..6905a8856 100644
--- a/src/osgViewer/GraphicsWindowWin32.cpp
+++ b/src/osgViewer/GraphicsWindowWin32.cpp
@@ -144,6 +144,26 @@ static CloseTouchInputHandleFunc *closeTouchInputHandleFunc = NULL;
 static GetTouchInputInfoFunc *getTouchInputInfoFunc = NULL;
 static GetPointerTypeFunc *getPointerTypeFunc = NULL;
 
+// DPI Awareness
+#if(WINVER >= 0x0603)
+
+#ifndef DPI_ENUMS_DECLARED
+
+typedef enum PROCESS_DPI_AWARENESS {
+	PROCESS_DPI_UNAWARE = 0,
+	PROCESS_SYSTEM_DPI_AWARE = 1,
+	PROCESS_PER_MONITOR_DPI_AWARE = 2
+} PROCESS_DPI_AWARENESS;
+
+#endif // DPI_ENUMS_DECLARED
+
+typedef
+BOOL
+(WINAPI	SetProcessDpiAwarenessFunc(
+	PROCESS_DPI_AWARENESS dpi_awareness));
+
+static SetProcessDpiAwarenessFunc *setProcessDpiAwareness = NULL;
+#endif
 
 
 
@@ -765,6 +785,21 @@ Win32WindowingSystem::Win32WindowingSystem()
             FreeLibrary( hModule);
         }
     }
+
+
+#if(WINVER >= 0x0603)
+	// For Windows 8.1 and higher 
+	//
+	// Per monitor DPI aware.This app checks for the DPI when it is created and adjusts the scale factor 
+	// whenever the DPI changes.These applications are not automatically scaled by the system.
+	HMODULE hModuleShore = LoadLibrary("Shcore");
+	if (hModuleShore) {
+		setProcessDpiAwareness = (SetProcessDpiAwarenessFunc *) GetProcAddress(hModuleShore, "SetProcessDpiAwareness");
+		if (setProcessDpiAwareness) {
+			(*setProcessDpiAwareness)(PROCESS_DPI_AWARENESS::PROCESS_PER_MONITOR_DPI_AWARE);
+		}
+	}
+#endif
 }
 
 Win32WindowingSystem::~Win32WindowingSystem()