Fix generic wxDVC::EnsureVisible() to show full row

Generic wxDataViewCtrl's EnsureVisible() previously only ensured that at
least some part of the item (even if just 1px of it) was visible,
instead of being fully shown.

src/generic/datavgen.cpp

@@ -756,6 +756,7 @@ class wxDataViewMainWindow: public wxWindow
     // the displaying number of the tree are changing along with the
     // expanding/collapsing of the tree nodes
     unsigned int GetLastVisibleRow();
+    unsigned int GetLastFullyVisibleRow();
     unsigned int GetRowCount() const;
 
     const wxSelectionStore& GetSelections() const { return m_selection; }
@@ -2872,6 +2873,19 @@ unsigned int wxDataViewMainWindow::GetLastVisibleRow()
     return wxMin( GetRowCount()-1, row );
 }
 
+unsigned int wxDataViewMainWindow::GetLastFullyVisibleRow()
+{
+    unsigned int row = GetLastVisibleRow();
+
+    int bottom = GetLineStart(row) + GetLineHeight(row);
+    m_owner->CalcScrolledPosition(-1, bottom, NULL, &bottom);
+
+    if ( bottom > GetClientSize().y )
+        return wxMax(0, row - 1);
+    else
+        return row;
+}
+
 unsigned int wxDataViewMainWindow::GetRowCount() const
 {
     if ( m_count == -1 )
@@ -5491,7 +5505,7 @@ void wxDataViewCtrl::EnsureVisibleRowCol( int row, int column )
         row = m_clientArea->GetRowCount();
 
     int first = m_clientArea->GetFirstVisibleRow();
-    int last = m_clientArea->GetLastVisibleRow();
+    int last = m_clientArea->GetLastFullyVisibleRow();
     if( row < first )
         m_clientArea->ScrollTo( row, column );
     else if( row > last )
@@ -6178,7 +6192,7 @@ wxAccStatus wxDataViewCtrlAccessible::GetState(int childId, long* state)
         if ( !dvWnd->IsSingleSel() )
             st |= wxACC_STATE_SYSTEM_MULTISELECTABLE | wxACC_STATE_SYSTEM_EXTSELECTABLE;
 
-        if ( rowNum < dvWnd->GetFirstVisibleRow() || rowNum > dvWnd->GetLastVisibleRow() )
+        if ( rowNum < dvWnd->GetFirstVisibleRow() || rowNum > dvWnd->GetLastFullyVisibleRow() )
             st |= wxACC_STATE_SYSTEM_OFFSCREEN;
         if ( dvWnd->GetCurrentRow() == rowNum )
             st |= wxACC_STATE_SYSTEM_FOCUSED;