js/circle-mode.js

// *********** HERE STARTS circle-mode.js *************

circleMode = false;

function initCircleMode() {
  document.querySelector("#circle-mode").addEventListener('click', function() {
    if(circleMode) {
      circleMode = false;
      document.querySelector("#circle-mode i").innerText = "trip_origin";

      s.graph.nodes().forEach(function(n) {
        n.x = n.originalX;
        n.y = n.originalY;
        n.size = 10;
      });

      s.refresh();
    } else {
      circleMode = true;
      document.querySelector("#circle-mode i").innerText = "scatter_plot";

      s.graph.nodes().forEach(function(n) {
        n.x = n.circleX;
        n.y = n.circleY;
      });

      s.refresh();
    }
  });
}

function isInRect(x, y, rect) {
  if (x < -10000 || x > 10000) return true;
  if (y < -10000 || y > 10000) return true;

  var ans = true;
  var c = crossProd (rect[0], rect[1], x, y);

  for(var i = 1; i < 4; i++) {
    var temp = crossProd (rect[i], rect[(i+1)%4], x, y);
    if (c*temp < 0) ans = false;
  }
  return ans;
}

function crossProd(r1, r2, x, y) {
  return r1[0]*r2[1] + r2[0]*y + x*r1[1] - r1[0]*y - r2[0]*r1[1] - x*r2[1];
}