public static void CenterNode(TreeNodeAdv node, int visibleLines)
{
// This function will only work properly if:
// 1) All TreeNodes have a fixed vertical height
// 2) The tree is fully collapsed except the ancestors
// of this node.
// 3) visibleLines is the actual number of nodes that can be
// displayed in the window vertically.
int paddingabove = (visibleLines - 1) / 2;
int paddingbelow = visibleLines - 1 - paddingabove;
TreeViewAdv tree = node.Tree;
TreeNodeAdv viewtop = node;
while (paddingabove > 0)
{
if (viewtop.PreviousNode != null)
{
viewtop = viewtop.PreviousNode;
}
else if (viewtop.Parent != null)
{
viewtop = viewtop.Parent;
}
else
{
break;
}
paddingabove--;
}
tree.EnsureVisible(viewtop);
TreeNodeAdv viewbottom = node;
node.Tree.EnsureVisible(node);
while (paddingbelow > 0)
{
if (viewbottom.NextNode != null)
{
viewbottom = viewbottom.NextNode;
}
else if ((viewbottom.Parent != null) && (viewbottom.Parent.NextNode != null))
{
viewbottom = viewbottom.Parent.NextNode;
}
else
{
break;
}
paddingbelow--;
}
tree.EnsureVisible(viewbottom);
tree.EnsureVisible(node);
}
