jitter 0.2.0

Add natural handwriting-like variation to digital text
jitter-0.2.0 is not a library.

jitter

Add natural handwriting-like variation to digital text.

Why

Digital fonts produce identical glyphs every time the same character appears. Real handwriting never does — each letter has subtle differences in size, angle, position, and weight. jitter brings that organic variation back to digital text.

Modes

render

Takes text and a font file, applies per-character random transformations (rotation, anisotropic scale, shear, position drift, subtle stroke-weight variation, and per-point shake), and outputs an SVG or PNG (auto-detected from the --output extension).

jitter render "Hello, world!" --font my-font.ttf --output hello.svg
jitter render "Hello, world!" --font my-font.ttf --output hello.png
jitter render "手書き風" --font noto-sans-jp.otf --output tegaki.svg --intensity 0.8 --size 64
jitter render "reproducible" --font my-font.ttf --seed 42

bake

Takes a TTF or OTF font and generates N variant glyphs per character, embedding them as an OpenType calt feature (contextual alternates). Text rendered with the output font in renderers that honor calt can cycle through alternates for consecutive identical glyphs, which makes browser and app support broader than rand-only GSUB.

jitter bake my-font.ttf --alternates 4 --intensity 0.6
jitter bake my-font.otf --output my-font-jittered.ttf

Bake mode details:

  • Input: TTF or OTF/CFF
  • Output: Always TTF (glyf format)
  • OTF/CFF inputs are converted to quadratic outlines to fit the TTF glyf table
  • GSUB uses calt, not rand, so repeated identical glyphs can rotate through alternates in browsers too

Installation

cargo install jitter

Usage

jitter render <TEXT> --font <FONT> [--output <FILE>] [--intensity <0.0-1.0>] [--size <PX>] [--seed <N>]
jitter bake <INPUT> [--output <FILE>] [--alternates <N>] [--intensity <0.0-1.0>]

Options

  • --font, -f: Path to a .ttf or .otf font file
  • --output, -o: Output file path (default: output.svg). Format is auto-detected from the extension (.svg or .png, render mode only).
  • --intensity, -i: How much variation to apply, from 0.0 (none) to 1.0 (maximum)
  • --size, -s: Font size in pixels (render mode only, default: 48)
  • --seed: Random seed (u64) for reproducible output. When omitted, output is non-deterministic (render mode only)
  • --alternates, -a: Number of variant glyphs per character (bake mode only, default: 3)

Output formats

  • SVG: Vector output, scalable, editable.
  • PNG: Rasterized output with transparent background (8-bit RGBA). Chosen automatically when the --output path ends in .png.

Roadmap

  1. render mode (text + font -> SVG with per-character variation) ✓
  2. stroke-weight variation for render mode ✓
  3. bake mode phase A (TTF + rand feature) ✓
  4. bake mode phase B (calt-based fallback for wider renderer support) ✓
  5. bake mode phase C (OTF/CFF support) ✓
  6. line-ending extension / pen-lift exaggeration (future)
  7. my-font-craft integration (use jitter as a post-processing step)

License

MIT