text: /**
   * calculate points for arc
   * @module shape-points/arc
   * @param {number} x
   * @param {number} y
   * @param {number} start angle (radians)
   * @param {number} end angle (radians)
   * @param {number} radius
   * @param {number} [pointsInArc=5]
   * @returns {array} [x1, y1, x2, y2, ... xn, yn]
   */
  export function arc(x, y, start, end, radius, pointsInArc)
  {
      pointsInArc = pointsInArc || 5
      const points = []
      let angle = start
      const interval = (end - start) / pointsInArc
      for (let count = 0; count < pointsInArc; count++)
      {
          points.push(x + radius * Math.cos(angle), y + radius * Math.sin(angle))
          angle += interval
      }
      return points
  }
  
  