Jim's TrueType QR Code Font

This project, hosted by jimparis on GitHub, provides an experimental OpenType font capable of transforming specific text strings into functional QR code symbols.

🌐 Live Demo: https://qr.jim.sh/

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📦 Available Font Versions

Depending on the required data capacity, there are three distinct font files available for download:

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🛠️ How It Works

The font is designed to identify text wrapped in brackets and render that specific segment as a QR code, while leaving the surrounding text as standard, readable characters.

Example Input: abc[hello]ghi Result: The characters abc and ghi appear normally, but [hello] is rendered as a QR code symbol.

Technical Specifications

• Input Type: Printable ASCII.
• Encoding Mode: Byte mode.
• Masking: Uses a fixed mask pattern 0.
• Delimiters: [ and ] are used to trigger the QR generation.
• Creation Method: These fonts are hand-authored $\rightarrow$ programmatically generated.

The Generation Pipeline

The build process utilizes a script to create glyph outlines and GSUB (Glyph Substitution) feature logic.

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🏗️ Build Instructions

The project leverages uv for managing Python dependencies.

Installation & Compilation

To build the font, you can use the following methods:

• Standard Build: Run make
• Direct Python Execution: uv run tools/build_font.py

[!NOTE] By default, the generator looks for the base font at: /usr/share/fonts/truetype/liberation/LiberationSans-Regular.ttf

If you wish to use a different TrueType source, use the --base-font flag: uv run tools/build_font.py --base-font /path/to/BaseFont-Regular.ttf

Build Variants

Depending on your needs, you can choose between two build paths:

1. Full Parity: make full-parity
   • Detail: Generates thousands of contextual lookups.
   • Performance: Takes significantly longer to compile.
2. Fast Placeholder: make fast-placeholder
   • Detail: Uses placeholder zero parity for rapid layout testing.

Debugging

To analyze the shaped glyph stream, execute: uv run tools/shape_debug.py ' [a] ' ' [b] '

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📤 Project Outputs

Upon a successful build, the following files are generated in the dist/ and build/ directories:

• dist/qrfont-*.ttf: The actual font files (1-L, 2-L, 3-L).
• dist/index.html: An interactive web-based demonstration.
• build/qrfont-*.fea: The OpenType feature files.

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⚖️ Licensing & Requirements

The resulting fonts are considered a Modified Version of Liberation Sans Regular. Consequently, they are licensed under the SIL Open Font License, Version 1.1.

Critical Requirements:

• Shaping Engine: Because the font relies heavily on OpenType shaping, it must be used in an environment that supports GSUB features.
• Constraints: Input within the QR blocks is strictly limited to printable ASCII and the character limits defined in the version table above.