Help for writing an app (running zones using Karvonnen method)

You can just use the library to draw an arc like this:

g.clear();
const GU = require("graphics_utils");
let centreX = 0.5 * g.getWidth();
let centreY = 0.5 * g.getWidth();
let startAngle = GU.degreesToRadians(20);
let endAngle = GU.degreesToRadians(135);
let minRadius = 0.3 * g.getWidth();
let maxRadius = 0.45 * g.getWidth();
GU.fillArc(g, centreX, centreY, minRadius, maxRadius, startAngle, endAngle);

Gordons code does very similar things by constructing a polygon that approximates the arc.

1 Attachment