added wxHeaderCtrlSimple::GetBestFittingWidth() for even more automatic column resizing

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@57187 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/headerctrl.h

@@ -224,7 +224,17 @@ public:
     void RemoveSortIndicator();
 
 protected:
+    // implement/override base class methods
     virtual wxHeaderColumnBase& GetColumn(unsigned int idx);
+    virtual bool UpdateColumnWidthToFit(unsigned int idx, int widthTitle);
+
+    // and define another one to be overridden in the derived classes: it
+    // should return the best width for the given column contents or -1 if not
+    // implemented, we use it to implement UpdateColumnWidthToFit()
+    virtual int GetBestFittingWidth(unsigned int WXUNUSED(idx)) const
+    {
+        return -1;
+    }
 
 private:
     // functions implementing our public API

interface/wx/headerctrl.h

@@ -356,6 +356,22 @@ public:
             The column to remove sort indicator for.
      */
     void RemoveSortIndicator(unsigned int idx);
+
+protected:
+    /**
+        This function can be overridden in the classes deriving from this
+        control instead of overriding UpdateColumnWidthToFit().
+
+        To implement automatic column resizing to fit its contents width when
+        the column divider is double clicked, you need to simply return the
+        fitting width for the given column @a idx from this method, the control
+        will automatically use the biggest value between the one returned from
+        here and the one needed for the display of the column title itself.
+
+        The base class version returns -1 indicating that this function is not
+        implemented.
+     */
+    virtual int GetBestFittingWidth(unsigned int idx) const;
 };
 
 /**

src/common/headerctrlcmn.cpp

@@ -149,6 +149,19 @@ void wxHeaderCtrlSimple::RemoveSortIndicator()
     }
 }
 
+bool
+wxHeaderCtrlSimple::UpdateColumnWidthToFit(unsigned int idx, int widthTitle)
+{
+    const int widthContents = GetBestFittingWidth(idx);
+    if ( widthContents == -1 )
+        return false;
+
+    m_cols[idx].SetWidth(wxMax(widthContents, widthTitle));
+    UpdateColumn(idx);
+
+    return true;
+}
+
 // ============================================================================
 // wxHeaderCtrlEvent implementation
 // ============================================================================