img2irc/utils/README.md

This tool converts an image containing Unicode glyphs into Rust-compatible bitmap arrays for use in the img2irc project.

Workflow Overview

1. Create input files:

   • An image file with glyphs rendered horizontally, without gaps. Essentially a cropped screenshot of the rendered characters with no spaces in between.
   • A text file listing the same glyphs separated by spaces.

2. Generate JSON bitmap data (mkbitmap.py).

3. Convert JSON to Rust source (mkrust.py).

4. Replace src/chars.rs in img2irc with the generated Rust file and recompile.

---

mkbitmap.py

Slices an image into bitmaps and outputs JSON.

Arguments:

Argument	Description
chars_file	Text file containing glyphs separated by spaces.
image_file	Horizontal image of glyphs (no gaps).
--icw	Input character width (pixels).
--ich	Input character height (pixels).
--threshold	Black/white pixel threshold (0–255).
--obw	Output bitmap width.
--obh	Output bitmap height.
--output	Output JSON filename.

Example:

./mkbitmap.py chars.txt chars.png --icw 20 --ich 40 --threshold 128 --obw 10 --obh 20 --output chars.json

---

mkrust.py

Converts JSON bitmap data to Rust source code.

Arguments:

Argument	Description
input_json	JSON file from mkbitmap.py.
output_rs	Output Rust source file.

Example:

./mkrust.py chars.json chars.rs

Replace the resulting chars.rs in your img2irc project and recompile.

You can use the included chars.txt and chars.png as an example.