Add wxDataViewValueAdjuster

Add wxDataViewRenderer:: SetValueAdjuster() and a
wxDataViewValueAdjuster class. This can be used to customize rendering
of values depending on whether they are highlighted (selection) or not,
without having to implement an entire new custom renderer.

include/wx/dvrenderers.h

@@ -96,6 +96,16 @@ enum wxDataViewCellRenderState
     wxDATAVIEW_CELL_FOCUSED     = 8
 };
 
+// helper for fine-tuning rendering of values depending on row's state
+class WXDLLIMPEXP_ADV wxDataViewValueAdjuster
+{
+public:
+    virtual ~wxDataViewValueAdjuster() {}
+
+    // changes the value to have appearance suitable for highlighted rows
+    virtual wxVariant MakeHighlighted(const wxVariant& value) const { return value; }
+};
+
 class WXDLLIMPEXP_ADV wxDataViewRendererBase: public wxObject
 {
 public:
@@ -190,6 +200,10 @@ public:
     // Send wxEVT_DATAVIEW_ITEM_EDITING_STARTED event.
     void NotifyEditingStarted(const wxDataViewItem& item);
 
+    // Sets the transformer for fine-tuning rendering of values depending on row's state
+    void SetValueAdjuster(wxDataViewValueAdjuster *transformer)
+        { delete m_valueAdjuster; m_valueAdjuster = transformer; }
+
 protected:
     // These methods are called from PrepareForItem() and should do whatever is
     // needed for the current platform to ensure that the item is rendered
@@ -197,6 +211,10 @@ protected:
     virtual void SetAttr(const wxDataViewItemAttr& attr) = 0;
     virtual void SetEnabled(bool enabled) = 0;
 
+    // Return whether the currently rendered item is on a highlighted row
+    // (typically selection with dark background). For internal use only.
+    virtual bool IsHighlighted() const = 0;
+
     // Called from {Cancel,Finish}Editing() to cleanup m_editorCtrl
     void DestroyEditControl();
 
@@ -211,6 +229,8 @@ protected:
     wxWeakRef<wxWindow>     m_editorCtrl;
     wxDataViewItem          m_item; // Item being currently edited, if valid.
 
+    wxDataViewValueAdjuster *m_valueAdjuster;
+
     // internal utility, may be used anywhere the window associated with the
     // renderer is required
     wxDataViewCtrl* GetView() const;

include/wx/generic/dvrenderer.h

@@ -52,6 +52,12 @@ public:
                                 const wxMouseEvent* WXUNUSED(mouseEvent))
         { return false; }
 
+    void SetState(int state) { m_state = state; }
+
+protected:
+    virtual bool IsHighlighted() const wxOVERRIDE
+        { return m_state & wxDATAVIEW_CELL_SELECTED; }
+
 private:
     int                          m_align;
     wxDataViewCellMode           m_mode;
@@ -60,6 +66,8 @@ private:
 
     wxDC *m_dc;
 
+    int m_state;
+
     wxDECLARE_DYNAMIC_CLASS_NO_COPY(wxDataViewRenderer);
 };
 

include/wx/gtk/dvrenderer.h

@@ -64,6 +64,8 @@ public:
     // different from the editor control widget for the custom renderers
     virtual GtkWidget* GtkGetEditorWidget() const;
 
+    void GtkSetCurrentItem(const wxDataViewItem& item) { m_itemBeingRendered = item; }
+
 private:
     // Change the mode at GTK level without touching m_mode, this is useful for
     // temporarily making the renderer insensitive but does mean that GetMode()
@@ -74,6 +76,8 @@ protected:
     virtual void SetAttr(const wxDataViewItemAttr& attr) wxOVERRIDE;
     virtual void SetEnabled(bool enabled) wxOVERRIDE;
 
+    virtual bool IsHighlighted() const wxOVERRIDE;
+
     virtual void GtkOnCellChanged(const wxVariant& value,
                                   const wxDataViewItem& item,
                                   unsigned col);
@@ -93,6 +97,9 @@ protected:
     // doing this
     bool m_usingDefaultAttrs;
 
+    // the item currently being rendered
+    wxDataViewItem m_itemBeingRendered;
+
 protected:
     wxDECLARE_DYNAMIC_CLASS_NO_COPY(wxDataViewRenderer);
 };

include/wx/osx/dvrenderer.h

@@ -93,6 +93,8 @@ protected:
     void SetEnabled(bool WXUNUSED(enabled)) wxOVERRIDE { };
 #endif
 
+    virtual bool IsHighlighted() const wxOVERRIDE;
+
 private:
     // contains the alignment flags
     int m_alignment;