From c0c6a4b826eb6e8639feafca5eb412fbd8a419ce Mon Sep 17 00:00:00 2001
From: Maarten Bent <MaartenBent@users.noreply.github.com>
Date: Sun, 22 Jul 2018 14:20:38 +0200
Subject: [PATCH] Add DPI Aware replacement of SystemParametersInfo

Use SystemParametersInfoForDpi when this function is available and the DPI is
known. Otherwise keep using SystemParametersInfo.
---
 include/wx/msw/private.h |  4 ++++
 src/msw/window.cpp       | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/include/wx/msw/private.h b/include/wx/msw/private.h
index 575c598558..a1bdd9d5f4 100644
--- a/include/wx/msw/private.h
+++ b/include/wx/msw/private.h
@@ -302,6 +302,10 @@ HCURSOR wxBitmapToHCURSOR(const wxBitmap& bmp, int hotSpotX, int hotSpotY);
 
 extern int wxGetSystemMetrics(int nIndex, const wxWindow* win);
 
+extern bool wxSystemParametersInfo(UINT uiAction, UINT uiParam,
+                                   PVOID pvParam, UINT fWinIni,
+                                   const wxWindow* win);
+
 #if wxUSE_OWNER_DRAWN
 
 // Draw the bitmap in specified state (this is used by owner drawn controls)
diff --git a/src/msw/window.cpp b/src/msw/window.cpp
index 021e161b70..b396437249 100644
--- a/src/msw/window.cpp
+++ b/src/msw/window.cpp
@@ -4761,6 +4761,41 @@ int wxGetSystemMetrics(int nIndex, const wxWindow* win)
     return ::GetSystemMetrics(nIndex);
 }
 
+/*extern*/
+bool wxSystemParametersInfo(UINT uiAction, UINT uiParam, PVOID pvParam, UINT fWinIni, const wxWindow* win)
+{
+#if wxUSE_DYNLIB_CLASS
+    const wxTopLevelWindow* tlw = wxGetWinTLW(win);
+
+    if ( tlw )
+    {
+        typedef int (WINAPI * SystemParametersInfoForDpi_t)(UINT uiAction, UINT uiParam, PVOID pvParam, UINT fWinIni, UINT dpi);
+        static SystemParametersInfoForDpi_t s_pfnSystemParametersInfoForDpi = NULL;
+        static bool s_initDone = false;
+
+        if ( !s_initDone )
+        {
+            wxLoadedDLL dllUser32("user32.dll");
+            wxDL_INIT_FUNC(s_pfn, SystemParametersInfoForDpi, dllUser32);
+            s_initDone = true;
+        }
+
+        if ( s_pfnSystemParametersInfoForDpi )
+        {
+            const int y = ::GetDeviceCaps(::GetDC(tlw->GetHWND()), LOGPIXELSY);
+            if ( s_pfnSystemParametersInfoForDpi(uiAction, uiParam, pvParam, fWinIni, y) == TRUE )
+            {
+                return true;
+            }
+        }
+    }
+#else
+    wxUnusedVar(win);
+#endif // wxUSE_DYNLIB_CLASS
+
+    return ::SystemParametersInfo(uiAction, uiParam, pvParam, fWinIni) == TRUE;
+}
+
 // ---------------------------------------------------------------------------
 // colours and palettes
 // ---------------------------------------------------------------------------