add the wxFont(const wxSize& pixelSize, ...) ctor to all ports; add some wxCHECK_MSGs to ensure that the wxSize objects contains non-negative arguments; document that passing zero for the width parameter is allowed; other minor doc fixes

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@59564 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/font.cpp

@@ -565,11 +565,16 @@ void wxNativeFontInfo::SetPointSize(int pointsize)
 
 void wxNativeFontInfo::SetPixelSize(const wxSize& pixelSize)
 {
+    // NOTE: although the MSW port allows for negative pixel size heights,
+    //       other ports don't and since it's a very useful feature assert
+    //       here if we get a negative height:
+    wxCHECK_RET( pixelSize.GetWidth() >= 0 && pixelSize.GetHeight() > 0,
+                 "Negative values for the pixel size or zero pixel height are not allowed" );
+    
     lf.lfHeight = pixelSize.GetHeight();
     lf.lfWidth = pixelSize.GetWidth();
 }
 
-
 void wxNativeFontInfo::SetStyle(wxFontStyle style)
 {
     switch ( style )