Store fractional point size in wxMSW wxNativeFontInfo

We can't losslessly recover the fractional point size from LOGFONT, so
store it in parallel.

include/wx/fontutil.h

@@ -118,9 +118,14 @@ public:
     // set the XFLD
     void SetXFontName(const wxString& xFontName);
 #elif defined(__WXMSW__)
-    wxNativeFontInfo(const LOGFONT& lf_) : lf(lf_) { }
+    wxNativeFontInfo(const LOGFONT& lf_) : lf(lf_), pointSize(0.0f) { }
 
     LOGFONT      lf;
+
+    // MSW only has limited support for fractional point sizes and we need to
+    // store the fractional point size separately if it was initially specified
+    // as we can't losslessly recover it from LOGFONT later.
+    float        pointSize;
 #elif defined(__WXOSX__)
 public:
     wxNativeFontInfo(const wxNativeFontInfo& info) { Init(info); }

src/msw/font.cpp

@@ -440,10 +440,15 @@ void wxNativeFontInfo::Init()
     lf.lfQuality = wxSystemOptions::GetOptionInt("msw.font.no-proof-quality")
                     ? DEFAULT_QUALITY
                     : PROOF_QUALITY;
+
+    pointSize = 0.0f;
 }
 
 float wxNativeFontInfo::GetFractionalPointSize() const
 {
+    if ( pointSize != 0.0f )
+        return pointSize;
+
     // FIXME: using the screen here results in incorrect font size calculation
     //        for printing!
     const int ppInch = ::GetDeviceCaps(ScreenHDC(), LOGPIXELSY);
@@ -531,6 +536,10 @@ wxFontEncoding wxNativeFontInfo::GetEncoding() const
 
 void wxNativeFontInfo::SetFractionalPointSize(float pointsize)
 {
+    // Store it to be able to return it from GetFractionalPointSize() later
+    // exactly.
+    pointSize = pointsize;
+
     // FIXME: using the screen here results in incorrect font size calculation
     //        for printing!
     const int ppInch = ::GetDeviceCaps(ScreenHDC(), LOGPIXELSY);