THPDFHeadlessDocument.SaveAnnotationsFDFToFile method

function SaveAnnotationsFDFToFile(const FileName: string;
  const Bytes: SysUtils.TBytes; const Options: THPDFFDFOptions): Integer;

Imports binary FDF annotations into a prepared incremental revision and atomically publishes it to FileName

Returns the number of changed annotations, with zero for a semantically unchanged import; matching nonempty annotation names are scoped to their page and identify replacements

Resource graphs, appearance states, string bytes and local action destinations are prepared before publication, with budgets and cancellation from THPDFFDFOptions

Actual changes require annotation permission and authenticated signature-policy admission; malformed data, ambiguous identities, failed allocation and cancellation leave the destination and loaded document unchanged

A successful save also leaves the loaded document unchanged; reload the published PDF to adopt its revision

Annotation-only import rejects nonempty Fields and embedded document Differences; it does not execute actions or apply redactions

See native annotation FDF exchange for the supported profile and callback transaction behaviour