source: node_modules/d3-selection/src/pointer.js@ e4c61dd

import sourceEvent from "./sourceEvent.js";

export default function(event, node) {
  event = sourceEvent(event);
  if (node === undefined) node = event.currentTarget;
  if (node) {
    var svg = node.ownerSVGElement || node;
    if (svg.createSVGPoint) {
      var point = svg.createSVGPoint();
      point.x = event.clientX, point.y = event.clientY;
      point = point.matrixTransform(node.getScreenCTM().inverse());
      return [point.x, point.y];
    }
    if (node.getBoundingClientRect) {
      var rect = node.getBoundingClientRect();
      return [event.clientX - rect.left - node.clientLeft, event.clientY - rect.top - node.clientTop];
    }
  }
  return [event.pageX, event.pageY];
}