Function pt

src/lib/angles.js:137–139

(r, a)

    // N.B. svg coordinates here, where y increases downward
    function pt(r, a) {
        return [r * Math.cos(a) + cx, cy - r * Math.sin(a)];
    }

    var largeArc = Math.abs(aEnd - aStart) <= PI ? 0 : 1;
    function arc(r, a, cw) {