--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.desktop/windows/native/common/awt/systemscale/systemScale.cpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,89 @@
+/*
+* Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+*
+* This code is free software; you can redistribute it and/or modify it
+* under the terms of the GNU General Public License version 2 only, as
+* published by the Free Software Foundation.
+*
+* This code is distributed in the hope that it will be useful, but WITHOUT
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+* version 2 for more details (a copy is included in the LICENSE file that
+* accompanied this code).
+*
+* You should have received a copy of the GNU General Public License version
+* 2 along with this work; if not, write to the Free Software Foundation,
+* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+*
+* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+* or visit www.oracle.com if you need additional information or have any
+* questions.
+*/
+#include "systemScale.h"
+#include <d2d1.h>
+#pragma comment(lib, "d2d1")
+#include <jdk_util.h>
+#ifndef MDT_EFFECTIVE_DPI
+#define MDT_EFFECTIVE_DPI 0
+#endif
+
+void GetScreenDpi(HMONITOR hmon, float *dpiX, float *dpiY)
+{
+    unsigned x = 0;
+    unsigned y = 0;
+
+    // for debug purposes
+    static float scale = -2.0f;
+    if (scale == -2) {
+        scale = -1;
+        char *uiScale = getenv("J2D_UISCALE");
+        if (uiScale != NULL) {
+            scale = (float)strtod(uiScale, NULL);
+            if (errno == ERANGE || scale <= 0) {
+                scale = -1;
+            }
+        }
+    }
+
+    if (scale > 0) {
+        *dpiX = *dpiY = scale;
+        return;
+    }
+
+    typedef HRESULT(WINAPI GetDpiForMonitorFunc)(HMONITOR, int, UINT*, UINT*);
+    static HMODULE hLibSHCoreDll = NULL;
+    static GetDpiForMonitorFunc *lpGetDpiForMonitor = NULL;
+
+    if (hLibSHCoreDll == NULL) {
+        hLibSHCoreDll = JDK_LoadSystemLibrary("shcore.dll");
+        if (hLibSHCoreDll != NULL) {
+            lpGetDpiForMonitor = (GetDpiForMonitorFunc*)GetProcAddress(
+                hLibSHCoreDll, "GetDpiForMonitor");
+        }
+    }
+
+    if (lpGetDpiForMonitor != NULL) {
+        HRESULT hResult = lpGetDpiForMonitor(hmon,
+                                             MDT_EFFECTIVE_DPI, &x, &y);
+        if (hResult == S_OK) {
+            *dpiX = static_cast<float>(x);
+            *dpiY = static_cast<float>(y);
+        }
+    } else {
+        ID2D1Factory* m_pDirect2dFactory;
+        HRESULT res = D2D1CreateFactory(D2D1_FACTORY_TYPE_SINGLE_THREADED,
+                                        &m_pDirect2dFactory);
+        if (res == S_OK) {
+            m_pDirect2dFactory->GetDesktopDpi(dpiX, dpiY);
+            m_pDirect2dFactory->Release();
+        }
+    }
+    return;
+}
+
+HMONITOR WINAPI getPrimaryMonitor()
+{
+    const POINT point = { 0, 0 };
+    return MonitorFromPoint(point, MONITOR_DEFAULTTOPRIMARY);
+}