CompressPage

Page properties

Description

Compresses the content stream of the currently selected page using Flate (zlib). The behaviour is identical to CompressContent but limited to a single page. Looping through every page with SelectPage and CompressPage produces the same result as one call to CompressContent, with the advantage that the application can report per-page progress in the UI.

Syntax

Delphi

function TPDFlib.CompressPage: Integer;

ActiveX

Function PDFlib::CompressPage As Long

DLL

int DLCompressPage(int InstanceID);

Return values

0	Failed — no document is open or no page is selected.
1	The page's content stream was compressed (or was already compressed and left as-is).

Remarks

Already-compressed streams are skipped, so calling CompressPage twice on the same page is harmless. The Win64 build uses the bundled zlib-ng SIMD object set; the Win32 build uses the generic zlib-ng object set in zlib-compatible mode.

Example

// Compress every page individually so the UI can report progress
var
  I, N: Integer;
begin
  N := PDF.GetPageCount;
  for I := 1 to N do
  begin
    PDF.SelectPage(I);
    PDF.CompressPage;
    ProgressBar1.Position := (I * 100) div N;
    Application.ProcessMessages;
  end;
  PDF.SaveToFile('compressed.pdf');
end;