Function drag

external/.d3.js:2721–2890

()

}

function drag() {
  var filter = defaultFilter$2,
      container = defaultContainer,
      subject = defaultSubject,
      touchable = defaultTouchable$2,
      gestures = {},
      listeners = dispatch("start", "drag", "end"),
      active = 0,
      mousedownx,
      mousedowny,
      mousemoving,
      touchending,
      clickDistance2 = 0;

  function drag(selection) {
    selection
        .on("mousedown.drag", mousedowned)
      .filter(touchable)
        .on("touchstart.drag", touchstarted)
        .on("touchmove.drag", touchmoved, nonpassive)
        .on("touchend.drag touchcancel.drag", touchended)
        .style("touch-action", "none")
        .style("-webkit-tap-highlight-color", "rgba(0,0,0,0)");
  }

  function mousedowned(event, d) {
    if (touchending || !filter.call(this, event, d)) return;
    var gesture = beforestart(this, container.call(this, event, d), event, d, "mouse");
    if (!gesture) return;
    select(event.view)
      .on("mousemove.drag", mousemoved, nonpassivecapture)
      .on("mouseup.drag", mouseupped, nonpassivecapture);
    dragDisable(event.view);
    nopropagation$2(event);
    mousemoving = false;
    mousedownx = event.clientX;
    mousedowny = event.clientY;
    gesture("start", event);
  }

  function mousemoved(event) {
    noevent$2(event);
    if (!mousemoving) {
      var dx = event.clientX - mousedownx, dy = event.clientY - mousedowny;
      mousemoving = dx * dx + dy * dy > clickDistance2;
    }
    gestures.mouse("drag", event);
  }

  function mouseupped(event) {
    select(event.view).on("mousemove.drag mouseup.drag", null);
    yesdrag(event.view, mousemoving);
    noevent$2(event);
    gestures.mouse("end", event);
  }

  function touchstarted(event, d) {
    if (!filter.call(this, event, d)) return;