Command-line QR Code generator

Features: Model 2 byte/num/alpha modes, as specified in ISO/IEC 18004:2024. There are no dependencies, generator can be built from code on any platform. Outputs inline (stdout), bitmap, or vectors (svg).

Available generation and capacity (codewords):

Version	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40
Low	17	32	53	78	106	134	154	192	230	271	321	367	425	458	520	586	644	718	792	858	929	1003	1091	1171	1273	1367	1465	1528	1628	1732	1840	1952	2068	2188	2303	2431	2563	2699	2809	2953
Medium	14	26	42	62	84	106	122	152	180	213	251	287	331	362	412	450	504	560	624	666	711	779	857	911	997	1059	1125	1190	1264	1370	1452	1538	1628	1722	1809	1911	1989	2099	2213	2331
Quartile	11	20	32	46	60	74	86	108	130	151	177	203	241	258	292	322	364	394	442	482	509	565	611	661	715	751	805	868	908	982	1030	1112	1168	1228	1283	1351	1423	1499	1579	1663
High	7	14	24	34	44	58	64	84	98	119	137	155	177	194	220	250	280	310	338	382	403	439	461	511	535	593	625	658	698	742	790	842	898	958	983	1051	1093	1139	1219	1273

Note

Generator will auto-select lowest Version possible. Unless option -V is specified.
Each codeword refers to a full byte (8 bits).
Numeric encoding uses up to 10-bits for 3 digits (~58% reduction).
Alphanumeric encoding uses up to 11-bits for each pair of characters (~31% reduction).

Pre-generated lookup tables:

1. Reed-Solomon error correction generator polynomials.
2. Galois field of 256 (285 primitive) log and anti-log table.
3. Placement index of each module onto the encoding region.
4. QR Code Format and Version information tables.
5. QR Code Group/Block information table.

Usage

Options available:

Usage: qrcode [OPTIONS] <data to encode>
OPTIONS:
  -h, --help     show this help message
  --nolimit      ignore inline Version limit (for larger terminals)
  --optimize     reduce data size, encode numeric, alphanumeric, byte
                   segments separately (if any)
  --raw          print generated code with chars 1, 0 (no box-chars)
  -v, --version  show generator's version and build information
  -g <uint>      level of on-screen information <0-3>
  -l <char>      use a specific error correction level (l, m, q, or h)
  -m <uint>      force use of mask <0-7>, regardless of penalty
  -s <uint>      scale image output <1-30> times
  -V <uint>      force use of version <1-40> code (or lower, if
                   used with --optimize)
  -B <string>    create bitmap file with generated code
  -K <string>    create scalable vector image, disregards -s

Building and binaries

Latest (stable) release can be found at this repo's Releases. To build this project, use make. Otherwise, as long as your system has Clang and Python, you may run Makefile's build commands manually.

Caution

Beware 1: This repo's master branch may or may not contain uncompilable, unstable code. It's recommended that you select the latest tag release, unless you wish to collaborate with code.

Beware 2: Whilst building, scripts will generate +2MB of pre-calculated lookup tables. That process should take less than 10s.

Beware 3: If using LUT script in debug, make sure matplotlib is properly installed. If needed, activate a virtual envionment before executing make. With MinGW, make sure to use pacman instead of pip.

Build tools used for binaries:

Tool
GNU Make	4.3	4.4.1	4.4.1*	4.4.1*	4.4.1*
Clang	14.0.0	21.1.8	19.1.7	17.0.0	20.1.7
Python	3.10.12	3.14.3	3.11.13	3.14.3	3.13.3
status	🟩	🟩	🟩	🟩	🟩

* Use gmake instead of system-provided make.

Examples

1. Inline printing

Command-line:

qrcode oagoulart.github.io/rambles/keep-thyself-credible

Output:

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

Tip

Using a line-height of 1em (i.e. line height is equal to font size) will remove the unintended vertical spacing seen in the output above. Some fonts may require a slight different value between 1 +/- .25. You can also try value normal.

2. Bitmap generation

Command-line:

qrcode -s 6 -B gen.bmp oagoulart.github.io/rambles/keep-thyself-credible

Output:

3. Vector graphics generation

Command-line:

qrcode -K gen.svg oagoulart.github.io/rambles/keep-thyself-credible

Output:

Module path visualizer

If you wish to visualize how modules are placed onto the encoding region, you can use the generator script at scripts/indexes.py in debug mode. An usage example with MinGW is:

pacman -S mingw-w64-x86_64-python-matplotlib
python -m venv .venv --system-site-packages
source .venv/bin/activate
python scripts/indexes.py 2 debug

Where 2 is the bar code Version and debug is the debug mode.

Roadmap

Nothing planned at the moment.

Things that can be added, but are not planned at the moment:

• Kanji encoding support (due to lack of testing);
• Other image formats such as PNG (not a priority);
• Concurrency support with workers pool (this one is more likely in the near future).

Disclaimer

QR Code, iQR Code SQRC and FrameQR are registered trademarks of DENSO WAVE INCORPORATED in Japan and in other countries.

ISO/IEC 18004:2024 - Information technology — Automatic identification and data capture techniques — QR Code bar code symbology specification is © ISO/IEC 2024 – All rights reserved.

Further reading

1. ISO/IEC 18004:2024 documentation (purchase)
2. Denso's QR Code FAQ
3. BMP file format
4. Scalable Vector Graphics (SVG) 1.1 (Second Edition)