1 /*
   2 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
   3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4 *
   5 * This code is free software; you can redistribute it and/or modify it
   6 * under the terms of the GNU General Public License version 2 only, as
   7 * published by the Free Software Foundation.
   8 *
   9 * This code is distributed in the hope that it will be useful, but WITHOUT
  10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12 * version 2 for more details (a copy is included in the LICENSE file that
  13 * accompanied this code).
  14 *
  15 * You should have received a copy of the GNU General Public License version
  16 * 2 along with this work; if not, write to the Free Software Foundation,
  17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18 *
  19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20 * or visit www.oracle.com if you need additional information or have any
  21 * questions.
  22 */
  23 #include "systemScale.h"
  24 #include <d2d1.h>
  25 #pragma comment(lib, "d2d1")
  26 #include <jdk_util.h>
  27 #ifndef MDT_EFFECTIVE_DPI
  28 #define MDT_EFFECTIVE_DPI 0
  29 #endif
  30 
  31 void GetScreenDpi(HMONITOR hmon, float *dpiX, float *dpiY)
  32 {
  33     unsigned x = 0;
  34     unsigned y = 0;
  35 
  36     // for debug purposes
  37     static float scale = -2.0f;
  38     if (scale == -2) {
  39         scale = -1;
  40         char *uiScale = getenv("J2D_UISCALE");
  41         if (uiScale != NULL) {
  42             scale = (float)strtod(uiScale, NULL);
  43             if (errno == ERANGE || scale <= 0) {
  44                 scale = -1;
  45             }
  46         }
  47     }
  48 
  49     if (scale > 0) {
  50         *dpiX = *dpiY = scale;
  51         return;
  52     }
  53 
  54     typedef HRESULT(WINAPI GetDpiForMonitorFunc)(HMONITOR, int, UINT*, UINT*);
  55     static HMODULE hLibSHCoreDll = NULL;
  56     static GetDpiForMonitorFunc *lpGetDpiForMonitor = NULL;
  57 
  58     if (hLibSHCoreDll == NULL) {
  59         hLibSHCoreDll = JDK_LoadSystemLibrary("shcore.dll");
  60         if (hLibSHCoreDll != NULL) {
  61             lpGetDpiForMonitor = (GetDpiForMonitorFunc*)GetProcAddress(
  62                 hLibSHCoreDll, "GetDpiForMonitor");
  63         }
  64     }
  65 
  66     if (lpGetDpiForMonitor != NULL) {
  67         HRESULT hResult = lpGetDpiForMonitor(hmon,
  68                                              MDT_EFFECTIVE_DPI, &x, &y);
  69         if (hResult == S_OK) {
  70             *dpiX = static_cast<float>(x);
  71             *dpiY = static_cast<float>(y);
  72         }
  73     } else {
  74         ID2D1Factory* m_pDirect2dFactory;
  75         HRESULT res = D2D1CreateFactory(D2D1_FACTORY_TYPE_SINGLE_THREADED,
  76                                         &m_pDirect2dFactory);
  77         if (res == S_OK) {
  78             m_pDirect2dFactory->GetDesktopDpi(dpiX, dpiY);
  79             m_pDirect2dFactory->Release();
  80         }
  81     }
  82     return;
  83 }
  84 
  85 HMONITOR WINAPI getPrimaryMonitor()
  86 {
  87         const POINT point = { 0, 0 };
  88         return MonitorFromPoint(point, MONITOR_DEFAULTTOPRIMARY);
  89 }