Add ellipsization support to wxDataViewCtrl.

Implemented ellipsization in the generic, GTK and both OS X Carbon and Cocoa
versions but it currently doesn't work well in GTK as it changes the item
alignment unconditionally, this will need to be fixed later.

The behaviour for the columns is currently inconsistent between ports too:
under MSW they (natively) use wxELLIPSIZE_END, under GTK -- wxELLIPSIZE_NONE
and under OS X the same ellipsization mode as the column contents, i.e.
wxELLIPSIZE_MIDDLE by default.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62433 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/dataview.h

@@ -411,7 +411,7 @@ public:
     wxDataViewRendererBase( const wxString &varianttype,
                             wxDataViewCellMode mode = wxDATAVIEW_CELL_INERT,
                             int alignment = wxDVR_DEFAULT_ALIGNMENT );
-    ~wxDataViewRendererBase();
+    virtual ~wxDataViewRendererBase();
 
     virtual bool Validate( wxVariant& WXUNUSED(value) )
         { return true; }
@@ -435,6 +435,14 @@ public:
     virtual void SetAlignment( int align ) = 0;
     virtual int GetAlignment() const = 0;
 
+    // enable or disable (if called with wxELLIPSIZE_NONE) replacing parts of
+    // the item text (hence this only makes sense for renderers showing
+    // text...) with ellipsis in order to make it fit the column width
+    virtual void EnableEllipsize(wxEllipsizeMode mode = wxELLIPSIZE_MIDDLE) = 0;
+    void DisableEllipsize() { EnableEllipsize(wxELLIPSIZE_NONE); }
+
+    virtual wxEllipsizeMode GetEllipsizeMode() const = 0;
+
     // in-place editing
     virtual bool HasEditorCtrl() const
         { return false; }