When a pen stroke becomes a shape, does it stay the same?
Baking means turning overlapping ink into one closed outline. Arc Bake Lab compares the earlier cubic-curve pipeline with a circular-arc pipeline, using the same input stroke.
The engineering question
The drawing engine needs more than a picture of ink: it needs a closed outline that can be stored, cut, moved and enlarged. Cubic curves look smooth, but their thick edges must be approximated. Circular arcs have exact circular offsets. This lab helped compare the two representations using the same stroke.
What the lab makes visible
Instead of fitting a thick edge around a cubic curve, a circular arc can use another circle with a slightly different radius. This makes some geometry simpler, but the result still has to close correctly at crossings. The lab makes the tradeoff visible: orange raw ink becomes green fill, with a thin red boundary to expose gaps or unwanted edges.
Try it
- Choose tight wiggle or self-crossing, or draw on the canvas.
- Toggle the raw stroke and baked fill, and inspect the red perimeter.
- Change the centerline tolerance and see how many arcs are needed.
- Use “time both, best of three” to compare the arc and cubic pipelines in this browser.
What it showed
On the strokes I had captured, the arc version baked three to four times faster than the cubic version and closed every outline without gaps. That result is why bound.less switched to circular arcs throughout: the pen, the baked outline and the eraser all use them now.
An earlier experiment from bound.less
I used AI to build focused tools for comparing engineering choices in bound.less. These pages make an abstract choice visible and measurable, so I could inspect the result and decide what to build next.
This version comes from the project’s revision of August 26, 2026. The lab pages were later removed from the main app, which has kept evolving; the geometry code here is from that same revision.
How to read the results
The accuracy panel measures how far the arc version moves from the curve the app drew at the time. It compares canvas images, so it doesn’t prove the current bound.less renderer is correct. Start with the small presets: the dense scribbles can make the page pause, and timings depend on your device and browser.