function DestinationByName;
Looks up a /Names destination by string name and returns its target page / fit-type / coordinates.
Returns Page = -1 when the name is not in the /Dests tree.
Wraps the corresponding PDFium API and exposes it as a TPdf instance member so consumers do not have to manage FPDF_DOCUMENT handles directly.
Pdf1.Active before calling page-scoped operations; methods that require an open document raise EPdfError otherwise.SaveToFile to persist.
if Pdf1.Active then
Pdf1.DestinationByName;