// Position of our element; object provided.
const canvasPos = this.canvasEl.getBoundingClientRect()

// Position of the mouse-event relative to 'canvasPos'
const evtPos = {
  x: clientX - canvasPos.left,
  y: clientY - canvasPos.top
}

// e is the effective distance from the center; some pythag involved probs.
const e = (evtPos.x - (canvasX / 2)) * (evtPos.x - (canvasX / 2)) + (evtPos.y - (canvasY / 2)) * (evtPos.y - (canvasY / 2))