JavaScript Requires Chilkat v11.7.0+

Deflate Compression Level When Optimizing a PDF

See more PDF Optimization Examples

Demonstrates compressionLevel, which is the deflate level (1 to 9, 9 by default) used for every stream the optimizer re-encodes. Level 9 is the smallest and the slowest; level 1 is the quickest. The difference is usually a percent or two, so level 9 is the right default for a file that will be downloaded many times, and a lower level is worth considering only when a server optimizes PDFs on the fly. A value outside 1 to 9 is an error. 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 watersense_accomplishments.pdf

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

var pdf1 = new CkPdf();
success = pdf1.LoadFile("qa_data/pdf/watersense_accomplishments.pdf");
if (success == false) {
    console.log(pdf1.LastErrorText);
    return;
}

json.UpdateInt("compressionLevel",1);
success = pdf1.Optimize("optimize",json,jsonOut);
if (success == false) {
    console.log(pdf1.LastErrorText);
    return;
}

success = pdf1.WriteFile("qa_output/watersense_level1.pdf");
if (success == false) {
    console.log(pdf1.LastErrorText);
    return;
}

console.log("level 1: " + fac.FileSize("qa_output/watersense_level1.pdf"));

var pdf9 = new CkPdf();
success = pdf9.LoadFile("qa_data/pdf/watersense_accomplishments.pdf");
if (success == false) {
    console.log(pdf9.LastErrorText);
    return;
}

json.UpdateInt("compressionLevel",9);
success = pdf9.Optimize("optimize",json,jsonOut);
if (success == false) {
    console.log(pdf9.LastErrorText);
    return;
}

success = pdf9.WriteFile("qa_output/watersense_level9.pdf");
if (success == false) {
    console.log(pdf9.LastErrorText);
    return;
}

console.log("level 9: " + fac.FileSize("qa_output/watersense_level9.pdf"));

//  A level outside 1..9 fails, and LastErrorText says why.
var pdfBad = new CkPdf();
success = pdfBad.LoadFile("qa_data/pdf/watersense_accomplishments.pdf");
if (success == false) {
    console.log(pdfBad.LastErrorText);
    return;
}

json.UpdateInt("compressionLevel",12);
success = pdfBad.Optimize("optimize",json,jsonOut);
if (success == false) {
    console.log("compressionLevel 12 was refused, as it should be.");
}