Dart Requires Chilkat v11.7.0+

QR Code with Non-English Text (UTF-8 and ECI)

See more QR Code Examples

Demonstrates text outside ASCII. QrCode always stores text as UTF-8 bytes, which is what phones expect. A QR code can also say so explicitly with an ECI header: setting encoding.eci to 26 declares the bytes to be UTF-8, for readers that would otherwise assume another character set. The header costs a little space, and a few older readers do not understand it, so it is off by default. 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 text is "Gruesse aus Muenchen" written with u-umlaut and sharp s.  It is given here with
  // JSON escapes only so that this source is plain ASCII.  Decode turns the escapes into characters.
  final sbText = CkStringBuilder();
  sbText.append('Gr\u00fc\u00dfe aus M\u00fcnchen');
  sbText.decode('json', 'utf-8');

  final json = CkJsonObject();
  json.updateSb('payload.text', sbText);
  json.updateString('output.path', 'qa_output/qr_utf8.png');
  json.updateBool('output.overwrite', true);
  json.updateString('output.return', 'none');

  final fmt = CkFormats();
  final jsonOut = CkJsonObject();
  try {
    fmt.qrCode('generate', json, jsonOut);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // 17 characters, three of which take two bytes in UTF-8.
  print('characters: ${sbText.length}');
  print('bytes encoded: ${jsonOut.intOf('symbols[0].payloadBytes')}');
  print('ECI header: ${jsonOut.hasMember('symbols[0].selectedEncoding.eci')}');

  // Without an ECI header (qa_output/qr_utf8.png):

  // 

  // The same text with an ECI header declaring UTF-8.
  json.updateInt('encoding.eci', 26);
  json.updateString('output.path', 'qa_output/qr_utf8_eci.png');
  try {
    fmt.qrCode('generate', json, jsonOut);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('with encoding.eci = 26, ECI header: ${jsonOut.hasMember('symbols[0].selectedEncoding.eci')}, value ${jsonOut.intOf('symbols[0].selectedEncoding.eci')}');

  // With the ECI header (qa_output/qr_utf8_eci.png).  Both scan as the same text:

  // 

  // Sample output:

  // characters: 17
  // bytes encoded: 20
  // ECI header: False
  // with encoding.eci = 26, ECI header: True, value 26
}