# ilustra.si

Turn a photo into a pen-and-ink illustration drawn stroke by stroke, then export plotter-ready SVG.

All rendering runs client-side in the browser in a Web Worker. Photos are not uploaded. There is no AI model, machine learning inference, or rendering service. The core is dependency-free TypeScript computational geometry.

Algorithms:
- Stipple: density-weighted Voronoi stippling with Lloyd relaxation and grid-accelerated nearest search.
- One line: spatial-grid nearest-neighbour travelling-salesman tour with budgeted 2-opt improvement.
- Hatch: tone-thresholded layered cross-hatching, clipped into runs with seeded wobble.
- Contour: gradient-perpendicular streamlines with Jobard-Lefer style spacing and seeding.
- Scribble: one continuous looping path with tone-dependent radius and traversal speed.

Experiment page: https://ilustra.si/flint-hills draws the Flint Hills series 1/(n^3 sin^2 n) for n up to 10^7 as a log-log skyline with the same pen engine, after the September 2026 result that the irrationality exponent of pi is 2 (openai/math family 017). Spike heights at the convergents p_k/q_k of pi follow (alpha_{k+1} + q_{k-1}/q_k)^2 / (pi^3 q_k).

https://ilustra.si/