GarbageCollectObjects

Document properties, Optimisation

Description

Performs a mark-sweep garbage collection immediately on the currently selected document to remove indirect objects that are no longer reachable from the complete trailer root graph, including private trailer extension keys.

Syntax

Delphi

Function TPDFlib.GarbageCollectObjects: Integer;

ActiveX

Function PDFlib::GarbageCollectObjects() As Long

DLL

int DLGarbageCollectObjects(int InstanceID);

Return values

Negative value	Error during garbage collection.
>= 0	The number of orphaned indirect PDF objects that were removed from the document.

Remarks

Reachable objects are decoded on demand, and a decode failure aborts the sweep without deleting a partially traversed graph. Full saves rebuild object-stream membership after collection. You can also configure automatic garbage collection during saving using SetGarbageCollect.

Example

PDF.LoadFromFile('edit.pdf', '');
PDF.DeletePages(5, 10); // delete some pages
PDF.GarbageCollectObjects; // free unreferenced objects immediately
PDF.SaveToFile('edit_cleaned.pdf');