Delphi ActiveX Requires Chilkat v11.7.0+

Remove PDF Objects Nothing Refers To

See more PDF Optimization Examples

Demonstrates removeUnreferenced. When a page, an image or a whole section is replaced in an editor, the objects it used often stay in the file with nothing pointing at them any more. They are not old revisions -- they are in the current revision, simply unreachable -- so only a reachability walk from the document catalog finds them. In a publication assembled over several editing passes this is frequently the largest single saving. Delphi ActiveX

var
success: Integer;
pdf: TChilkatPdf;
json: TChilkatJsonObject;
jsonOut: TChilkatJsonObject;

begin
success := 0;

//  This example requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

//  The PDF used in this example is available at watersense_accomplishments.pdf

pdf := TChilkatPdf.Create(Self);
success := pdf.LoadFile('qa_data/pdf/watersense_accomplishments.pdf');
if (success = 0) then
  begin
    Memo1.Lines.Add(pdf.LastErrorText);
    Exit;
  end;

json := TChilkatJsonObject.Create(Self);
jsonOut := TChilkatJsonObject.Create(Self);
success := pdf.Optimize('audit',json.ControlInterface,jsonOut.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(pdf.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('fileSize: ' + IntToStr(jsonOut.IntOf('fileSize')));
Memo1.Lines.Add('removeUnreferenced would save: ' + IntToStr(jsonOut.IntOf('estimatedSavings.removeUnreferenced')));

//  Optimize with the defaults and see how many objects were actually dropped.
success := pdf.Optimize('optimize',json.ControlInterface,jsonOut.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(pdf.LastErrorText);
    Exit;
  end;

success := pdf.WriteFile('qa_output/watersense_optimized.pdf');
if (success = 0) then
  begin
    Memo1.Lines.Add(pdf.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('objects removed: ' + IntToStr(jsonOut.IntOf('actions.removeUnreferenced.count')));
Memo1.Lines.Add('bytes saved:     ' + IntToStr(jsonOut.IntOf('actions.removeUnreferenced.bytesSaved')));

//  Nothing a page needs is ever removed: the walk starts at the document catalog and follows every
//  reference, including the ones in annotations, the structure tree, named destinations and the
//  optional-content configuration.
Memo1.Lines.Add('pages after: ' + IntToStr(pdf.NumPages));