Accessibility

Last updated October 8, 2026

Brocot aims to meet the Web Content Accessibility Guidelines 2.2 at level AA. This statement says what that means on a page whose two main objects are drawings, what is measured, and where the drawings still ask for eyes.

What is built in

• Every control is reachable and usable with a keyboard, in reading order, with a visible focus ring. A skip link jumps past the header.
• Every fraction on the tree that can be drawn is also a row in Brocot's Table, with its own button, so the tree can be used without a pointer. The Closest Trains table lists every train the search found, each with a button.
• Every control has a written label. Errors are written beside the field they belong to, and say what to change.
• Text meets a contrast of at least 4.5 to 1 against its background, and large text and controls at least 3 to 1.
• The marks on the tree differ in shape as well as colour (filled, struck through, dashed), and each is written out in words beside it.
• With reduced motion set in your system, the wheels start still and the path is drawn at once. The Turn the Wheels button starts and stops the wheels at any time.
• Text inputs use a 16-pixel size so phones do not zoom, and tap targets are at least 44 pixels tall.
• The tables sit in regions that scroll sideways on a narrow screen, and each region can be reached and scrolled with a keyboard.

The drawings, in words

The train is drawn in SVG with a written description that names every wheel, every pair and the ratio. The tree's path is described by its length, its runs and where it stops, and every fraction on it is written out as text beside its mark. The verdict, the error and the train are always given as text above the drawings.

What is still visual

Seeing how large a 118-tooth wheel is beside a 10-tooth pinion is a visual task, and so is reading the shape of the path. Pressing a fraction on the tree needs a pointer; Brocot's Table gives the same choice to a keyboard.

How it is checked

Each release is measured on the live page with automated checks for contrast, names, landmarks and keyboard reach at phone and desktop widths, and for tap-target size on three device sizes. Automated checks find part of what matters, not all of it.

Tell us

If something on Brocot does not work with the way you use the web, write to PaintedApp, LLC at support@painted.app. Say what you were trying to do and what you use, and we will answer.