Introduction

libqrcode is C++20 header-only library for generating QR/Micro QR Codes.

Features include:

• Header-only library
• Completely constexpr
• Code is (unit-)tested with static_asserts during compile-time
• Utilizes standard library only
• Uses C++20 Ranges
• No C++ exceptions (however)
• Supports Conan package manager

QR support

Supported:

• Versions: 1-40
• Error correction levels: L, M, Q, H
• Encodings: Numeric, alphanumeric, byte and kanji
• ECI mode (Enhanced channel interpretation)
• (Simple) Bit stream optimization

Not supported

• Structured append mode
• FNC1 mode

Micro QR support

Supported:

• Versions: M1-M4
• Error correction levels: L, M, Q (where possible)
• Encodings: Numeric, alphanumeric, byte and kanji encoding (where possible)

Usage

One can either use the conan recipe provided in this repository or directly integrate the library into your project. As this libary is header-only, it should be quite easy to setup. Add the libqrcode include directory to your project's header search path

In your project, just in include the header qrcode/qrcode.h. Micro QR api is located within namespace micro_qr. QR api is located within namespace qr.

Simple example

#include <qrcode/qrcode.h>

int main()
{
    using namespace qrcode;

    auto qr_symbol = qr::make_symbol("Foo!", qr::error_correction::level_H);
    auto micro_qr_symbol = micro_qr::make_symbol("Bar!", micro_qr::error_correction::level_L);
}

ECI example

#include <qrcode/qrcode.h>

int main()
{
    using namespace qrcode;
    using namespace std::literals;

    auto symbol = qr::make_symbol(
        eci::view{eci::assignment_number{9}, "\xC1\xC2\xC3\xC4\xC5"sv}, 
        qr::error_correction::level_H);
}

Accessing modules

#include <qrcode/qrcode.h>
#include <iostream>

int main()
{
    using namespace qrcode;
    using namespace std::literals;
    
    auto symbol = qr::make_symbol("Hello World!"sv, qr::error_correction::level_L).value();

    auto count = 0;
    for (auto i : views::horizontal(symbol))
    {
        std::cout << (i ? '#' : ' ');
        ++count;
        if (count % width(symbol) == 0)
            std::cout << '\n';
    }
}

Requirements

• C++20 compiler and standard library
• Supported:
  • gcc10 and libstdc++-10-dev or higher (see test/linux.Dockerfile)
  • msvc: Visual Studio 2019 16.10.0 (see test/win.Dockerfile)
• Not supported:
  • clang doesn't seem to support all featured of C++20 needed to make this work
  • macOS (due to lack of C++20 features), support will be added in the future

How to build

• Since the library is header-only, building is actually not necessary.
• Just put the include folder of this project into your header search path and it should just work.
• However, if you'd like to run the tests, please select the top-level of the project in order to run CMake.
• For more information, please have a look at the Dockerfile in the test folder and consider the remarks below.

How to run the tests

If you would like to run the tests, one has to add the following cmake flag: -DQRCODE_TESTS_ENABLED:BOOL=True

Debug builds using MSVC

Building with tests enabled in Debug configuration won't build due to an issue in Microsoft's STL implementation. Release configuration works though.

CI builds

CI builds usually consists of a test build and a conan demo build. If and only if both builds were successful, the CI state is green.

Tests

All tests are usually built and run in docker containers. See test/linux.Dockerfile for more info. You can also hit test/linux_run.sh which creates and runs the docker image for you.

Conan

The library supports Conan out of the box. The conan_demo/Dockerfile and conan_demo/run.sh are for demonstration purposes. It creates a small command-line tool which can create QR symbols from a given text message.

Please note: The Conan build is part of the CI checks. The tool has to be compiled successfully in order to clear this stage.