superposition of text styles in wxTextCtrl now works as expected (and as documented)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@12709 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/textctrl.h

@@ -45,6 +45,7 @@
 #endif
 
 class WXDLLEXPORT wxTextCtrl;
+class WXDLLEXPORT wxTextCtrlBase;
 
 // ----------------------------------------------------------------------------
 // constants
@@ -123,6 +124,13 @@ public:
         return !HasTextColour() && !HasBackgroundColour() && !HasFont();
     }
 
+    // return the attribute having the valid font and colours: it uses the
+    // attributes set in attr and falls back first to attrDefault and then to
+    // the text control font/colours for those attributes which are not set
+    static wxTextAttr Combine(const wxTextAttr& attr,
+                              const wxTextAttr& attrDef,
+                              const wxTextCtrlBase *text);
+
 private:
     wxColour m_colText,
              m_colBack;