Function makeArcPath

Shapes/Arc.js:7–41

(x, y, startAngleArg, endAngleArg, radius, direction)

const CIRCLE = Math.PI * 2;

function makeArcPath(x, y, startAngleArg, endAngleArg, radius, direction) {
  let startAngle = startAngleArg;
  let endAngle = endAngleArg;
  if (endAngle - startAngle >= CIRCLE) {
    endAngle = CIRCLE + (endAngle % CIRCLE);
  } else {
    endAngle = endAngle % CIRCLE;
  }
  startAngle = startAngle % CIRCLE;
  const angle =
    startAngle > endAngle
      ? CIRCLE - startAngle + endAngle
      : endAngle - startAngle;

  if (angle >= CIRCLE) {
    return `M${x + radius} ${y}
            a${radius} ${radius} 0 0 1 0 ${radius * 2}
            a${radius} ${radius} 0 0 1 0 ${radius * -2}`;
  }

  const directionFactor = direction === 'counter-clockwise' ? -1 : 1;
  endAngle *= directionFactor;
  startAngle *= directionFactor;
  const startSine = Math.sin(startAngle);
  const startCosine = Math.cos(startAngle);
  const endSine = Math.sin(endAngle);
  const endCosine = Math.cos(endAngle);

  const arcFlag = angle > Math.PI ? 1 : 0;
  const reverseFlag = direction === 'counter-clockwise' ? 0 : 1;

  return `M${x + radius * (1 + startSine)} ${y + radius - radius * startCosine}
          A${radius} ${radius} 0 ${arcFlag} ${reverseFlag} ${x +
    radius * (1 + endSine)} ${y + radius - radius * endCosine}`;
}

export default class Arc extends Component {
  static propTypes = {