Circularity Analyzer

How to measure

1. Connect the controller and press any button so the page can see it.
2. Disconnect Coda or any other remapping tool first, unless you want to see its output: with one running, the browser reads the virtual controller after its processing, circular output and max zone included.
3. Start the left stick, push it all the way out and turn it slowly along its edge, two or three times round. The bar fills as the edge is covered.
4. When the whole edge is covered, let the stick go back to the middle — that finishes the stick. Then do the right one.

How to read the result

The gold outline is the furthest reading in each 5° sector. The grey circle is full deflection, 1.0 in every direction; the dashed square is what a stick reports when each axis is limited to 1.0 on its own, which puts the corners at 1.41.

• Average reach, shortest and furthest are measured over the covered sectors, with the direction of the extremes (0° is right, 90° is up).
• Diagonals ÷ axes compares the reach within 10° of the four diagonals with the reach within 10° of the four straight directions. 1.00 means they match.
• Off the circle is the average of |reach − 1|: how far the outline sits from a perfect circle of full deflection, inwards or outwards.

The shape names follow fixed rules:

• Square-ish — all four diagonals reach at least 8% further than the straight directions.
• Short diagonals — all four fall at least 5% short of them.
• Uneven — otherwise, if the shortest and furthest reach differ by more than 15% of the average: one part of the edge falls short, not the whole shape.
• Round — none of these.
• Not enough of the edge — less than 90% of the sectors were reached at 0.7 or more.

What it cannot tell you

• Whether a controller is calibrated correctly. A round gate, a square output and a range that stops short of 1.0 can each be a design choice; the browser shows the result of all of them together, and this page describes it without grading it.
• How a game will feel. Games process the stick again — their own deadzones, curves and limits — before it moves anything on screen.
• Precision finer than the controller reports. An 8-bit axis moves in steps of about 0.008, so differences smaller than that are noise, not shape.