JavaScript Requires Chilkat v11.7.0+

PDF Object Streams: generate, preserve or disable

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Demonstrates the objectStreams option. An object stream packs many small objects (dictionaries, not stream data) into one compressed stream, which is usually a worthwhile saving in a document with many pages or tags. "generate" (the default) packs them and writes a cross-reference stream; "preserve" keeps the file as it is -- packed if it already was, not packed if it was not; "disable" writes every object on its own with a classic cross-reference table, which is what a PDF 1.4 reader needs. Object streams require PDF 1.5 and are skipped for PDF/A-1. JavaScript

var success = false;

//  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 grand_canyon_hiking_guide.pdf

var fac = new CkFileAccess();
var json = new CkJsonObject();
var jsonOut = new CkJsonObject();

//  generate: pack the objects (the default).
var pdf1 = new CkPdf();
success = pdf1.LoadFile("qa_data/pdf/grand_canyon_hiking_guide.pdf");
if (success == false) {
    console.log(pdf1.LastErrorText);
    return;
}

json.UpdateString("objectStreams","generate");
success = pdf1.Optimize("optimize",json,jsonOut);
if (success == false) {
    console.log(pdf1.LastErrorText);
    return;
}

success = pdf1.WriteFile("qa_output/grand_canyon_objstm_generate.pdf");
if (success == false) {
    console.log(pdf1.LastErrorText);
    return;
}

console.log("generate: " + fac.FileSize("qa_output/grand_canyon_objstm_generate.pdf") + " bytes, objects packed: " + jsonOut.IntOf("actions.objectStreams.count"));

//  disable: every object on its own, with a classic cross-reference table.
var pdf2 = new CkPdf();
success = pdf2.LoadFile("qa_data/pdf/grand_canyon_hiking_guide.pdf");
if (success == false) {
    console.log(pdf2.LastErrorText);
    return;
}

json.UpdateString("objectStreams","disable");
success = pdf2.Optimize("optimize",json,jsonOut);
if (success == false) {
    console.log(pdf2.LastErrorText);
    return;
}

success = pdf2.WriteFile("qa_output/grand_canyon_objstm_disable.pdf");
if (success == false) {
    console.log(pdf2.LastErrorText);
    return;
}

console.log("disable:  " + fac.FileSize("qa_output/grand_canyon_objstm_disable.pdf") + " bytes");

//  preserve: leave the file's own structure alone.  Use it when the output must stay readable by
//  whatever reads the input today.
var pdf3 = new CkPdf();
success = pdf3.LoadFile("qa_data/pdf/grand_canyon_hiking_guide.pdf");
if (success == false) {
    console.log(pdf3.LastErrorText);
    return;
}

json.UpdateString("objectStreams","preserve");
success = pdf3.Optimize("optimize",json,jsonOut);
if (success == false) {
    console.log(pdf3.LastErrorText);
    return;
}

success = pdf3.WriteFile("qa_output/grand_canyon_objstm_preserve.pdf");
if (success == false) {
    console.log(pdf3.LastErrorText);
    return;
}

console.log("preserve: " + fac.FileSize("qa_output/grand_canyon_objstm_preserve.pdf") + " bytes");