helpers.js

export function sv2sl(s, v) {
  var l = ((2 - s) * v) / 2
  if (l !== 0) {
    if (l === 1) {
      s = 0
    } else if (l < 0.5) {
      s = (s * v) / (l * 2)
    } else {
      s = (s * v) / (2 - l * 2)
    }
  }
  return [s, l]
}

export function xy2deg(x, y) {
  const deltaX = 0.5 - x
  const deltaY = y - 0.5
  const rad = Math.atan2(deltaY, deltaX)
  const deg = rad * (180 / Math.PI)
  const correctedDeg = (270 + deg) % 360
  const errorMargin = 5
  const errorMarginFrom45 = correctedDeg % 45
  const errorCorrectedDeg =
    errorMarginFrom45 > 45 - errorMargin
      ? correctedDeg + 45 - errorMarginFrom45
      : errorMarginFrom45 < errorMargin
        ? correctedDeg - errorMarginFrom45
        : correctedDeg
  return errorCorrectedDeg
}

export function angle2rad(angle) {
  return angle * (Math.PI / 180)
}