property Document;
Native PDFium FPDF_DOCUMENT handle for direct low-level access.
Use only when calling FPdfApi / FPdfEdit functions that PDFiumVCL does not wrap.
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.Document;