Get the root of the layer display order tree.
getLayerOrderRoot([out, retval] LONG *orderHandle)
PDF files with layers contain a tree structure that specifies the way layers are intended to be displayed to the user. Each node in the tree has either a name or a layer. Named nodes are used to provide a hierarchical structure for the layers, with labels to help the user. Each node also optionally has a list of child nodes.

This function returns the root node of the layer order tree, which will be a named node with an empty name.

scanLayerOrder(pdf.getLayerOrderRoot()) ... Sub scanLayerOrder(order As Long) Dim name As String Dim layer As Long If pdf.getLayerOrderIsName(order) Then ' this node has a name name = pdf.getLayerOrderName(order) ... Else ' this node has a layer layer = pdf.getLayerOrderLayer(order) ... End If nChildren = pdf.getLayerOrderNumChildren(order) For i = 0 To nChildren - 1 scanLayerOrder(pdf.getLayerOrderChild(order, i)) Next i End Sub