Add wxDataViewCtrl::GetTopItem() and GetCountPerPage()

Add methods doing the same thing for wxDataViewCtrl as the existing wxListBox
methods.

Closes #17498.

docs/changes.txt

@@ -113,6 +113,7 @@ All (GUI):
 - Make wxDataViewCtrl::Expand() expand ancestors in native ports too.
 - Add wxDataViewTextRenderer::EnableMarkup().
 - Add wxDataViewCtrl::SetHeaderAttr().
+- Add wxDataViewCtrl::GetTopItem() and GetCountPerPage() (Andreas Falkenhahn).
 - Add wxListCtrl::SetHeaderAttr().
 - Add support for using markup in wxDataViewCtrl text items.
 - Implement auto complete in generic wxSearchCtrl (Eric Jensen).

include/wx/dataview.h

@@ -699,6 +699,9 @@ public:
     wxDataViewItem GetCurrentItem() const;
     void SetCurrentItem(const wxDataViewItem& item);
 
+    virtual wxDataViewItem GetTopItem() const { return wxDataViewItem(0); }
+    virtual int GetCountPerPage() const { return wxNOT_FOUND; }
+
     // Currently focused column of the current item or NULL if no column has focus
     virtual wxDataViewColumn *GetCurrentColumn() const = 0;
 

include/wx/generic/dataview.h

@@ -226,6 +226,9 @@ public:
     virtual wxDataViewColumn *GetSortingColumn() const wxOVERRIDE;
     virtual wxVector<wxDataViewColumn *> GetSortingColumns() const wxOVERRIDE;
 
+    virtual wxDataViewItem GetTopItem() const wxOVERRIDE;
+    virtual int GetCountPerPage() const wxOVERRIDE;
+
     virtual int GetSelectedItemsCount() const wxOVERRIDE;
     virtual int GetSelections( wxDataViewItemArray & sel ) const wxOVERRIDE;
     virtual void SetSelections( const wxDataViewItemArray & sel ) wxOVERRIDE;

include/wx/gtk/dataview.h

@@ -169,6 +169,9 @@ public:
 
     virtual wxDataViewColumn *GetCurrentColumn() const wxOVERRIDE;
 
+    virtual wxDataViewItem GetTopItem() const wxOVERRIDE;
+    virtual int GetCountPerPage() const wxOVERRIDE;
+
     static wxVisualAttributes
     GetClassDefaultAttributes(wxWindowVariant variant = wxWINDOW_VARIANT_NORMAL);
 

include/wx/osx/cocoa/dataview.h

@@ -480,8 +480,10 @@ public:
     virtual void EnsureVisible(const wxDataViewItem& item,
                                wxDataViewColumn const* columnPtr);
     virtual unsigned int GetCount() const;
+    virtual int GetCountPerPage() const;
     virtual wxRect GetRectangle(const wxDataViewItem& item,
                                 wxDataViewColumn const* columnPtr);
+    virtual wxDataViewItem GetTopItem() const;
     virtual bool IsExpanded(const wxDataViewItem& item) const;
     virtual bool Reload();
     virtual bool Remove(const wxDataViewItem& parent,

include/wx/osx/core/dataview.h

@@ -63,7 +63,9 @@ public:
   virtual void         Collapse     (wxDataViewItem const& item)                                     = 0; // collapses the passed item in the native control
   virtual void         EnsureVisible(wxDataViewItem const& item, wxDataViewColumn const* columnPtr)  = 0; // ensures that the passed item's value in the passed column is visible (column pointer can be NULL)
   virtual unsigned int GetCount     (void) const                                                     = 0; // returns the number of items in the native control
+  virtual int          GetCountPerPage(void) const                                                   = 0; // get number of items that fit into a single page
   virtual wxRect       GetRectangle (wxDataViewItem const& item, wxDataViewColumn const* columnPtr)  = 0; // returns the rectangle that is used by the passed item and column in the native control
+  virtual wxDataViewItem GetTopItem (void) const                                                     = 0; // get top-most visible item
   virtual bool         IsExpanded   (wxDataViewItem const& item) const                               = 0; // checks if the passed item is expanded in the native control
   virtual bool         Reload       (void)                                                           = 0; // clears the native control and reloads all data
   virtual bool         Remove       (wxDataViewItem const& parent, wxDataViewItem const& item)       = 0; // removes an item from the native control

include/wx/osx/dataview.h

@@ -172,11 +172,14 @@ public:
   virtual bool IsExpanded(const wxDataViewItem & item) const wxOVERRIDE;
 
   virtual unsigned int GetCount() const;
+  virtual int GetCountPerPage() const wxOVERRIDE;
   virtual wxRect GetItemRect(const wxDataViewItem& item,
                              const wxDataViewColumn* columnPtr = NULL) const wxOVERRIDE;
   virtual int GetSelectedItemsCount() const wxOVERRIDE;
   virtual int GetSelections(wxDataViewItemArray& sel) const wxOVERRIDE;
 
+  virtual wxDataViewItem GetTopItem() const wxOVERRIDE;
+
   virtual void HitTest(const wxPoint& point, wxDataViewItem& item, wxDataViewColumn*& columnPtr) const wxOVERRIDE;
 
   virtual bool SetRowHeight(int rowHeight) wxOVERRIDE;

interface/wx/dataview.h

@@ -1647,6 +1647,28 @@ public:
         @since 3.1.0
     */
     virtual void ToggleSortByColumn(int column);
+
+    /**
+        Return the number of items that can fit vertically in the visible area of
+        the control.
+
+        Returns -1 if the number of items per page couldn't be determined. On
+        wxGTK this method can only determine the number of items per page if
+        there is at least one item in the control.
+
+        @since 3.1.1
+    */
+    int GetCountPerPage() const;
+
+    /**
+        Return the topmost visible item.
+
+        Returns an invalid item if there is no topmost visible item or if the method
+        is not implemented for the current platform.
+
+        @since 3.1.1
+    */
+    wxDataViewItem GetTopItem() const;
 };
 
 

src/generic/datavgen.cpp

@@ -751,6 +751,7 @@ public:
     int GetCountPerPage() const;
     int GetEndOfLastCol() const;
     unsigned int GetFirstVisibleRow() const;
+    wxDataViewItem GetTopItem() const;
 
     // I change this method to un const because in the tree view,
     // the displaying number of the tree are changing along with the
@@ -2842,6 +2843,27 @@ int wxDataViewMainWindow::GetCountPerPage() const
     return size.y / m_lineHeight;
 }
 
+wxDataViewItem wxDataViewMainWindow::GetTopItem() const
+{
+    unsigned int item = GetFirstVisibleRow();
+    wxDataViewTreeNode *node = NULL;
+    wxDataViewItem dataitem;
+
+    if ( !IsVirtualList() )
+    {
+        node = GetTreeNodeByRow(item);
+        if( node == NULL ) return wxDataViewItem(0);
+
+        dataitem = node->GetItem();
+    }
+    else
+    {
+        dataitem = wxDataViewItem( wxUIntToPtr(item+1) );
+    }
+
+    return dataitem;
+}
+
 int wxDataViewMainWindow::GetEndOfLastCol() const
 {
     int width = 0;
@@ -5386,6 +5408,16 @@ int wxDataViewCtrl::GetSelectedItemsCount() const
     return m_clientArea->GetSelections().GetSelectedCount();
 }
 
+wxDataViewItem wxDataViewCtrl::GetTopItem() const
+{
+    return m_clientArea->GetTopItem();
+}
+
+int wxDataViewCtrl::GetCountPerPage() const
+{
+    return m_clientArea->GetCountPerPage();
+}
+
 int wxDataViewCtrl::GetSelections( wxDataViewItemArray & sel ) const
 {
     sel.Empty();

src/gtk/dataview.cpp

@@ -4917,6 +4917,53 @@ void wxDataViewCtrl::DoSetCurrentItem(const wxDataViewItem& item)
     gtk_tree_view_set_cursor(GTK_TREE_VIEW(m_treeview), path, NULL, FALSE);
 }
 
+wxDataViewItem wxDataViewCtrl::GetTopItem() const
+{
+    wxGtkTreePath start;
+    if ( !gtk_tree_view_get_visible_range
+          (
+           GTK_TREE_VIEW(m_treeview),
+           start.ByRef(),
+           NULL
+          ) )
+    {
+        return wxDataViewItem();
+    }
+
+    return GTKPathToItem(start);
+}
+
+int wxDataViewCtrl::GetCountPerPage() const
+{
+    wxGtkTreePath path;
+    GtkTreeViewColumn *column;
+
+    if ( !gtk_tree_view_get_path_at_pos
+          (
+            GTK_TREE_VIEW(m_treeview),
+            0,
+            0,
+            path.ByRef(),
+            &column,
+            NULL,
+            NULL
+          ) )
+    {
+        return -1;
+    }
+
+    GdkRectangle rect;
+    gtk_tree_view_get_cell_area(GTK_TREE_VIEW(m_treeview), path, column, &rect);
+
+    if ( !rect.height )
+        return -1;
+
+    GdkRectangle vis;
+    gtk_tree_view_get_visible_rect(GTK_TREE_VIEW(m_treeview), &vis);
+
+    return vis.height / rect.height;
+}
+
 wxDataViewColumn *wxDataViewCtrl::GetCurrentColumn() const
 {
     // The tree doesn't have any current item if it hadn't been created yet but

src/osx/cocoa/dataview.mm

@@ -2313,6 +2313,27 @@ unsigned int wxCocoaDataViewControl::GetCount() const
     return [m_OutlineView numberOfRows];
 }
 
+int wxCocoaDataViewControl::GetCountPerPage() const
+{
+    NSScrollView *scrollView = [m_OutlineView enclosingScrollView];
+    NSTableHeaderView *headerView = [m_OutlineView headerView];
+    NSRect visibleRect = scrollView.contentView.visibleRect;
+    if ( headerView )
+        visibleRect.size.height -= headerView.visibleRect.size.height;
+    return (int) (visibleRect.size.height / [m_OutlineView rowHeight]);
+}
+
+wxDataViewItem wxCocoaDataViewControl::GetTopItem() const
+{
+    NSScrollView *scrollView = [m_OutlineView enclosingScrollView];
+    NSTableHeaderView *headerView = [m_OutlineView headerView];
+    NSRect visibleRect = scrollView.contentView.visibleRect;
+    if ( headerView )
+        visibleRect.origin.y += headerView.visibleRect.size.height;
+    NSRange range = [m_OutlineView rowsInRect:visibleRect];
+    return wxDataViewItem([[m_OutlineView itemAtRow:range.location] pointer]);
+}
+
 wxRect wxCocoaDataViewControl::GetRectangle(const wxDataViewItem& item, const wxDataViewColumn *columnPtr)
 {
     return wxFromNSRect([m_osxView superview],[m_OutlineView frameOfCellAtColumn:GetColumnPosition(columnPtr)

src/osx/dataview_osx.cpp

@@ -563,6 +563,16 @@ int wxDataViewCtrl::GetSelections(wxDataViewItemArray& sel) const
   return GetDataViewPeer()->GetSelections(sel);
 }
 
+wxDataViewItem wxDataViewCtrl::GetTopItem() const
+{
+    return GetDataViewPeer()->GetTopItem();
+}
+
+int wxDataViewCtrl::GetCountPerPage() const
+{
+    return GetDataViewPeer()->GetCountPerPage();
+}
+
 void wxDataViewCtrl::HitTest(wxPoint const& point, wxDataViewItem& item, wxDataViewColumn*& columnPtr) const
 {
   return GetDataViewPeer()->HitTest(point,item,columnPtr);