Make wxRescaleCoord() private functions

They're probably not that useful in application code, which should just
use wxDPIChangedEvent::Scale() instead, so move them to a private
header instead of making them part of the public API.

include/wx/event.h

@@ -3142,8 +3142,8 @@ public:
 
     // Scale the value by the ratio between new and old DPIs carried by this
     // event.
-    int ScaleX(int x) const { return wxRescaleCoord(x, m_newDPI.x, m_oldDPI.x); }
-    int ScaleY(int y) const { return wxRescaleCoord(y, m_newDPI.y, m_oldDPI.y); }
+    int ScaleX(int x) const;
+    int ScaleY(int y) const;
 
     wxSize Scale(wxSize sz) const { return wxSize(ScaleX(sz.x), ScaleY(sz.y)); }
 

include/wx/gdicmn.h

@@ -1104,23 +1104,5 @@ extern wxRect WXDLLIMPEXP_CORE wxGetClientDisplayRect();
 // set global cursor
 extern void WXDLLIMPEXP_CORE wxSetCursor(const wxCursor& cursor);
 
-// Scale the given value by the ratio between 2 other values, with rounding.
-// Do not scale the value if it's -1, just return it unchanged in this case.
-extern int WXDLLIMPEXP_CORE wxRescaleCoord(int n, int newScale, int oldScale);
-
-inline wxPoint
-wxRescaleCoord(wxPoint pt, wxSize newScale, wxSize oldScale)
-{
-    return wxPoint(wxRescaleCoord(pt.x, newScale.x, oldScale.x),
-                   wxRescaleCoord(pt.y, newScale.y, oldScale.y));
-}
-
-inline wxSize
-wxRescaleCoord(wxSize sz, wxSize newScale, wxSize oldScale)
-{
-    return wxSize(wxRescaleCoord(sz.x, newScale.x, oldScale.x),
-                  wxRescaleCoord(sz.y, newScale.y, oldScale.y));
-}
-
 #endif
     // _WX_GDICMNH__

include/wx/private/rescale.h

@@ -0,0 +1,43 @@
+///////////////////////////////////////////////////////////////////////////////
+// Name:        wx/private/rescale.h
+// Purpose:     Helpers for rescaling coordinates
+// Author:      Vadim Zeitlin
+// Created:     2021-07-13
+// Copyright:   (c) 2021 Vadim Zeitlin <vadim@wxwidgets.org>
+// Licence:     wxWindows licence
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef _WX_PRIVATE_RESCALE_H_
+#define _WX_PRIVATE_RESCALE_H_
+
+#include "wx/gdicmn.h"
+#include "wx/math.h"
+
+#ifdef __WINDOWS__
+    // Required in order to use wxMulDivInt32().
+    #include "wx/msw/wrapwin.h"
+#endif
+
+
+// Scale the given value by the ratio between 2 other values, with rounding.
+// Do not scale the value if it's -1, just return it unchanged in this case.
+inline int wxRescaleCoord(int n, int newScale, int oldScale)
+{
+    return n == -1 ? -1 : wxMulDivInt32(n, newScale, oldScale);
+}
+
+inline wxPoint
+wxRescaleCoord(wxPoint pt, wxSize newScale, wxSize oldScale)
+{
+    return wxPoint(wxRescaleCoord(pt.x, newScale.x, oldScale.x),
+                   wxRescaleCoord(pt.y, newScale.y, oldScale.y));
+}
+
+inline wxSize
+wxRescaleCoord(wxSize sz, wxSize newScale, wxSize oldScale)
+{
+    return wxSize(wxRescaleCoord(sz.x, newScale.x, oldScale.x),
+                  wxRescaleCoord(sz.y, newScale.y, oldScale.y));
+}
+
+#endif // _WX_PRIVATE_RESCALE_H_

interface/wx/event.h

@@ -3450,7 +3450,8 @@ public:
 
         This is a convenience function to use in wxEVT_DPI_CHANGED event
         handlers, as they often need to update some sizes to the new DPI.
-        It simply calls wxRescaleCoord() with GetNewDPI() and GetOldDPI().
+        It simply calls wxMulDivInt32() with new and old DPI values, but
+        is more readable and less error-prone.
 
         For example, the returned value will be twice bigger than the original
         one when switching from normal (96) DPI to high (2x, 192) DPI.

interface/wx/gdicmn.h

@@ -1344,21 +1344,3 @@ void wxDisplaySizeMM(int* width, int* height);
 */
 wxSize wxGetDisplaySizeMM();
 //@}
-
-/**
-    Scale the given value by the ratio between 2 other values, with rounding.
-
-    Do not scale the value if it's -1, just return it unchanged in this case.
-
-    This simply calls wxMulDivInt32() with the provided arguments, but provides
-    a more clear name for this operation.
-
-    @since 3.1.6
- */
-int wxRescaleCoord(int n, int newScale, int oldScale);
-
-/// @overload
-wxPoint wxRescaleCoord(wxPoint pt, wxSize newScale, wxSize oldScale);
-
-/// @overload
-wxSize wxRescaleCoord(wxSize sz, wxSize newScale, wxSize oldScale);

src/common/event.cpp

@@ -51,6 +51,10 @@
     wxDEFINE_SCOPED_PTR(wxEvent, wxEventPtr)
 #endif // wxUSE_BASE
 
+#if wxUSE_GUI
+    #include "wx/private/rescale.h"
+#endif
+
 // ----------------------------------------------------------------------------
 // wxWin macros
 // ----------------------------------------------------------------------------
@@ -933,6 +937,20 @@ wxHelpEvent::Origin wxHelpEvent::GuessOrigin(Origin origin)
     return origin;
 }
 
+// ----------------------------------------------------------------------------
+// wxDPIChangedEvent
+// ----------------------------------------------------------------------------
+
+int wxDPIChangedEvent::ScaleX(int x) const
+{
+    return wxRescaleCoord(x, m_newDPI.x, m_oldDPI.x);
+}
+
+int wxDPIChangedEvent::ScaleY(int y) const
+{
+    return wxRescaleCoord(y, m_newDPI.y, m_oldDPI.y);
+}
+
 #endif // wxUSE_GUI
 
 

src/common/gdicmn.cpp

@@ -16,7 +16,6 @@
 
 #include "wx/display.h"
 #include "wx/gdiobj.h"
-#include "wx/math.h"
 
 #ifndef WX_PRECOMP
     #include "wx/log.h"
@@ -33,10 +32,6 @@
     #include "wx/math.h"
 #endif
 
-#ifdef __WINDOWS__
-    // Required in order to use wxMulDivInt32().
-    #include "wx/msw/wrapwin.h"
-#endif
 
 wxIMPLEMENT_ABSTRACT_CLASS(wxGDIObject, wxObject);
 
@@ -926,8 +921,3 @@ wxResourceCache::~wxResourceCache ()
         node = node->GetNext ();
     }
 }
-
-int wxRescaleCoord(int n, int newScale, int oldScale)
-{
-    return n == -1 ? -1 : wxMulDivInt32(n, newScale, oldScale);
-}

src/common/wincmn.cpp

@@ -74,12 +74,9 @@
 #include "wx/display.h"
 #include "wx/platinfo.h"
 #include "wx/recguard.h"
+#include "wx/private/rescale.h"
 #include "wx/private/window.h"
 
-#ifdef __WINDOWS__
-    #include "wx/msw/wrapwin.h"
-#endif
-
 // Windows List
 WXDLLIMPEXP_DATA_CORE(wxWindowList) wxTopLevelWindows;
 

src/msw/button.cpp

@@ -42,6 +42,7 @@
 #include "wx/stockitem.h"
 #include "wx/msw/private/button.h"
 #include "wx/msw/private/dc.h"
+#include "wx/private/rescale.h"
 #include "wx/private/window.h"
 
 #if wxUSE_MARKUP