Dart Requires Chilkat v11.7.0+

Replace PDF Text on Selected Pages Only

See more PDF Text Replacement Examples

Demonstrates the "pages" option, which limits the search for placeholders and labels to the given pages: "all" (the default), "first", "last", "odd", "even", or a list such as "1,3,5-9". The two-page order confirmation carries the same "Status:" label on both pages; the status is changed on page 2 only, then on both pages. 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 order_confirmation.pdf

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

  final json = CkJsonObject();
  final jsonOut = CkJsonObject();

  // Both pages have "Status:   Pending".  With pages "2", only page 2 is searched.
  json.updateString('pages', '2');
  json.updateString('labels[0].label', 'Status:');
  json.updateString('labels[0].value', 'Shipped');
  try {
    pdf.textReplace('check', json, jsonOut);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('pages 2: found on page(s) ${jsonOut.stringOf('replacements[0].pages')}');

  // With every page searched, the default occurrence ("first") still replaces one -- the first in reading order.
  json.updateString('pages', 'all');
  try {
    pdf.textReplace('check', json, jsonOut);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('pages all, first occurrence: found on page(s) ${jsonOut.stringOf('replacements[0].pages')}');

  // Every occurrence on every page.
  json.updateString('labels[0].occurrence', 'all');
  try {
    pdf.textReplace('apply', json, jsonOut);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('pages all, every occurrence: ${jsonOut.intOf('replacements[0].count')} replaced on page(s) ${jsonOut.stringOf('replacements[0].pages')}');

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

  // Sample output:

  // pages 2: found on page(s) 2
  // pages all, first occurrence: found on page(s) 1
  // pages all, every occurrence: 2 replaced on page(s) 1,2
}