ascii_qr

Generate QR codes as ASCII art in your terminal.

This package creates scannable QR codes using Unicode block characters, making them work well in monospace terminal fonts while maintaining proper proportions.

Installation

Add this package to your Dart project with:

dart pub add ascii_qr

Or add it to your pubspec.yaml manually:

dependencies:
  ascii_qr: ^1.0.1

Usage

The package provides a simple interface through the AsciiQrGenerator class:

import 'package:ascii_qr/ascii_qr.dart';

void main() {
  print(AsciiQrGenerator.generate(
    'https://cypherstack.com/',
    errorCorrectLevel: QrErrorCorrectLevel.H,
  ));
}

This produces a scannable QR code in your terminal:

███████████████████████████████
█ ▄▄▄▄▄ █▄▀▀ ▀  █▀▄ █ █ ▄▄▄▄▄ █
█ █   █ █▄█ ▀▄▄█▀ ▀▄▀▄█ █   █ █
█ █▄▄▄█ █▄█▀  ▄ ▀▀ ▄▄ █ █▄▄▄█ █
█▄▄▄▄▄▄▄█ ▀▄█▄█ █ █▄█▄█▄▄▄▄▄▄▄█
█▀▀███▄▄▀▀██   ▀  █  ██▄▀ █ ▀▄█
█▄▀▄█▄▀▄█ ██ ▄█▄▀ ▄█▀ ▄ ▄▀▀▄███
█▀ ▄▄▄▄▄█ ▀▀▀▀▄ ▄ ██▀▀▄ █▀▀█ ▀█
█  ▄▄ ▄▄ ██▀▄▄  ▀   ▀  ▄▄▀▀▀▀▀█
█▀█▄█ ▄▄▄█ ▄█▄ ▄ ▄ █▀▀▄▀▀▀▄▄█▀█
█ ▄▄█  ▄ █▄▄▄▀█  ▀▄▄ █▀▀█ ▀██▄█
█▄████▄▄▄ ▄ █  ▀▀ ▀▀█ ▄▄▄   ▄▄█
█ ▄▄▄▄▄ █▀▄▀▄█▀▀█ ▀█  █▄█ ▀████
█ █   █ ██▄  ▀▄▀▀▄ ▄  ▄▄ ▄▀█ ██
█ █▄▄▄█ ██   ▄▄▀▄▀  ▄▄ ▄▄ ▀▀▄▀█
█▄▄▄▄▄▄▄██▄▄▄▄██▄██▄▄█▄▄█▄█▄███
███████████████████████████████

Configuration Options

The generate method accepts several parameters to customize the output:

String generate(
  String data, {
  int errorCorrectLevel = QrErrorCorrectLevel.L,
  int horizontalScale = 1,
  int verticalScale = 1,
})

errorCorrectLevel determines the QR code's error correction capability:

• QrErrorCorrectLevel.L: Recovers 7% of data
• QrErrorCorrectLevel.M: Recovers 15% of data
• QrErrorCorrectLevel.Q: Recovers 25% of data
• QrErrorCorrectLevel.H: Recovers 30% of data

horizontalScale and verticalScale let you adjust the QR code's aspect ratio to match your terminal's font metrics. Some terminals may need a horizontalScale of 2 to create properly square QR codes.

How it works

The generator creates QR codes using Unicode block characters to represent pairs of modules vertically:

• Full block (█) for light modules
• Space ( ) for dark modules
• Upper half-block (▀) and lower half-block (▄) for mixed pairs

This approach creates compact, scannable QR codes that maintain proper proportions in most terminal fonts.

License

MIT License. See LICENSE file for details.