Function handleMouseWheel

InteractiveHtmlBom/web/render.js:973–996

(e, layerdict)

}

function handleMouseWheel(e, layerdict) {
  e.preventDefault();
  e.stopPropagation();
  var t = layerdict.transform;
  var wheeldelta = e.deltaY;
  if (e.deltaMode == 1) {
    // FF only, scroll by lines
    wheeldelta *= 30;
  } else if (e.deltaMode == 2) {
    wheeldelta *= 300;
  }
  var m = Math.pow(1.1, -wheeldelta / 40);
  // Limit amount of zoom per tick.
  if (m > 2) {
    m = 2;
  } else if (m < 0.5) {
    m = 0.5;
  }
  t.zoom *= m;
  var zoomd = (1 - m) / t.zoom;
  t.panx += devicePixelRatio * e.offsetX * zoomd;
  t.pany += devicePixelRatio * e.offsetY * zoomd;
  redrawCanvas(layerdict);
}

function addMouseHandlers(div, layerdict) {
  div.addEventListener("pointerdown", function(e) {