procedure BeginIncrementalSave(AllowSignedDocument: Boolean = False);
| AllowSignedDocument | Boolean value that permits a session on a document that already carries signatures when set to True; the default False raises EPdfError for signed input |
Captures the current document as the baseline of an incremental save session. Each later CommitIncrementalSave compares the live document against that baseline and appends only the changed objects together with a new cross-reference section, leaving all earlier bytes intact
An encrypted source keeps its complete original bytes as the immutable prefix while the session compares decrypted semantic snapshots; appended strings and streams inherit the existing R5, R6, or R7 security parameters, exact /Encrypt reference and object generations, and a new PDF MAC is issued when the source uses authenticated encryption
Encrypted progressive input is accepted only after the complete original source is available. Signed documents are rejected unless AllowSignedDocument says otherwise, because appending a revision is exactly what a signature is meant to make visible
IncrementalSaveActive reports whether a session is open. Close it with EndIncrementalSave