Circular Pattern

Here is an example of a circular pattern, separated into two functions: one for the positions and the other for the pattern sketch.

export function generateCircularPatternPositionStructs(radius: number, nrCopies: number, {
  startAngle = 0, endAngle = 2 * Math.PI, referenceAngle = 0, addLast = false } = {}) {
  const positionStructs: { position: SKYMATH.Vector2D, angle: number }[] = []
  const NC = addLast ? nrCopies + 1 : nrCopies
  const angleRange = endAngle - startAngle

  for (let i = 0; i < NC; i++) {
    const angle = angleRange * i / nrCopies + startAngle + referenceAngle
    const position = new SKYMATH.Vector2D(radius * Math.cos(angle), radius * Math.sin(angle))
    positionStructs.push({ position, angle }) // the angle is pushed here so the sketch can be rotated accordingly later
  }
  return positionStructs
}

export function generateCircularPatternSketch(sketchToUseInPattern: SKYSKETCH.Sketch, radius: number, nrCopies: number, {
  startAngle = 0, endAngle = 2 * Math.PI, referenceAngle = 0, addLast = false } = {}) {
  const positionStructs = generateCircularPatternPositionStructs(radius, nrCopies, { startAngle, endAngle, referenceAngle, addLast })
  const circularPatternSketch = new SKYSKETCH.Sketch()

  positionStructs.forEach(struct => {
    const { position, angle } = struct
    const patternSketch = sketchToUseInPattern.clone()
    patternSketch.scale(radius / 30) // scale sketch according to radius
    patternSketch.rotate(angle) // point inwards
    patternSketch.translate(position.x, position.y)
    circularPatternSketch.mergeSketch(patternSketch)
  })

  return circularPatternSketch
}