Function calcMaxHalfSize

src/traces/pie/plot.js:836–839

(a, halfAngle, r, ring)

}

function calcMaxHalfSize(a, halfAngle, r, ring) {
    var q = a + 1 / (2 * Math.tan(halfAngle));
    return r * Math.min(1 / (Math.sqrt(q * q + 0.5) + q), ring / (Math.sqrt(a * a + ring / 2) + a));
}

function getInscribedRadiusFraction(pt, cd0) {
    if (pt.v === cd0.vTotal && !cd0.trace.hole) return 1; // special case of 100% with no hole