Function getCanvasPosition

src/helpers/helpers.dom.ts:73–96

* @param e * @param canvas * @returns Canvas position

(
  e: Event | TouchEvent | MouseEvent,
  canvas: HTMLCanvasElement
)

 * @returns Canvas position
 */
function getCanvasPosition(
  e: Event | TouchEvent | MouseEvent,
  canvas: HTMLCanvasElement
): {
    x: number;
    y: number;
    box: boolean;
  } {
  const touches = (e as TouchEvent).touches;
  const source = (touches && touches.length ? touches[0] : e) as MouseEvent;
  const {offsetX, offsetY} = source as MouseEvent;
  let box = false;
  let x, y;
  if (useOffsetPos(offsetX, offsetY, e.target)) {
    x = offsetX;
    y = offsetY;
  } else {
    const rect = canvas.getBoundingClientRect();
    x = source.clientX - rect.left;
    y = source.clientY - rect.top;
    box = true;
  }
  return {x, y, box};
}

/**
 * Gets an event's x, y coordinates, relative to the chart area