JavaScript Requires Chilkat v11.7.0+

Audit a PDF First, Optimize Only If It Is Worth It

See more PDF Optimization Examples

Demonstrates deciding whether to rewrite a PDF at all. "audit" costs a fraction of a second and changes nothing, so a batch job can audit every file and optimize only those where enough would be saved. Here the threshold is a tenth of the file; a file already as small as it can be is left alone. 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 pdf = new CkPdf();
success = pdf.LoadFile("qa_data/pdf/watersense_accomplishments.pdf");
if (success == false) {
    console.log(pdf.LastErrorText);
    return;
}

var json = new CkJsonObject();
var jsonOut = new CkJsonObject();
success = pdf.Optimize("audit",json,jsonOut);
if (success == false) {
    console.log(pdf.LastErrorText);
    return;
}

var fileSize = jsonOut.IntOf("fileSize");
var estimated = jsonOut.IntOf("estimatedSavings.total");
console.log("fileSize:  " + fileSize);
console.log("estimated: " + estimated);

//  Only bother when at least a tenth of the file would go.
if (estimated > (fileSize / 10)) {
    console.log("Worth optimizing.");
    success = pdf.Optimize("optimize",json,jsonOut);
    if (success == false) {
        console.log(pdf.LastErrorText);
        return;
    }

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

    console.log("bytesSaved: " + jsonOut.IntOf("bytesSaved"));
}
else {
    console.log("Already small enough; left as it is.");
}