Oneline

How Oneline works

Oneline turns a photo into a single continuous pen stroke in three steps, all in your browser.

1. Stipple. It reads the image's brightness and scatters dots so darker areas get more of them, then runs Lloyd relaxation (weighted Voronoi) to space the dots evenly within each tone. That is what makes the shading read cleanly instead of clumping.
2. Solve. It treats every dot as a stop and solves a traveling-salesman path through all of them: a greedy nearest-neighbour tour, tightened with a neighbour-list 2-opt. The result is one open path that never returns to its start, so a pen draws it without lifting.
3. Export. It writes the path as a single SVG <path> scaled to a real paper size in millimetres, ready to send to a pen plotter such as an AxiDraw.

The whole pipeline runs in a Web Worker, so the page stays responsive while thousands of points get stitched. Nothing is uploaded: your photo is decoded and drawn on your own device.

Using it

Drop a photo onto the sheet or click to choose one. Portraits and high-contrast subjects work best. Use the Dots slider to trade detail for plot time, and the Contrast slider to push the tones lighter or heavier. Pick a paper size and click Export SVG. No photo handy? The Bust, Spiral, and Cat samples run the full pipeline so you can watch the line draw itself.

FAQ