Dart 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. Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // 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

  final pdf = CkPdf();
  try {
    pdf.loadFile('qa_data/pdf/watersense_accomplishments.pdf');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  final json = CkJsonObject();
  final jsonOut = CkJsonObject();
  try {
    pdf.optimize('audit', json, jsonOut);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  final fileSize = jsonOut.intOf('fileSize');
  final estimated = jsonOut.intOf('estimatedSavings.total');
  print('fileSize:  $fileSize');
  print('estimated: $estimated');

  // Only bother when at least a tenth of the file would go.
  if (estimated > (fileSize ~/ 10)) {
    print('Worth optimizing.');
    try {
      pdf.optimize('optimize', json, jsonOut);
    } on ChilkatException catch (e) {
      print(e.lastErrorText);
      return;
    }

    try {
      pdf.writeFile('qa_output/watersense_optimized.pdf');
    } on ChilkatException catch (e) {
      print(e.lastErrorText);
      return;
    }

    print('bytesSaved: ${jsonOut.intOf('bytesSaved')}');
  } else {
    print('Already small enough; left as it is.');
  }
}