/*

* 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);

}