Function handlePointerMove

InteractiveHtmlBom/web/render.js:923–971

(e, layerdict)

}

function handlePointerMove(e, layerdict) {
  if (!layerdict.pointerStates.hasOwnProperty(e.pointerId)) {
    return;
  }
  e.preventDefault();
  e.stopPropagation();

  if (!e.hasOwnProperty("offsetX")) {
    // The polyfill doesn't set this properly
    e.offsetX = e.pageX - e.currentTarget.offsetLeft;
    e.offsetY = e.pageY - e.currentTarget.offsetTop;
  }

  var thisPtr = layerdict.pointerStates[e.pointerId];

  var dx = e.offsetX - thisPtr.lastX;
  var dy = e.offsetY - thisPtr.lastY;

  // If this number is low on pointer up, we count the action as a click
  thisPtr.distanceTravelled += Math.abs(dx) + Math.abs(dy);

  if (Object.keys(layerdict.pointerStates).length == 1) {
    // This is a simple drag
    layerdict.transform.panx += devicePixelRatio * dx / layerdict.transform.zoom;
    layerdict.transform.pany += devicePixelRatio * dy / layerdict.transform.zoom;
  } else if (Object.keys(layerdict.pointerStates).length == 2) {
    var otherPtr = Object.values(layerdict.pointerStates).filter((ptr) => ptr != thisPtr)[0];

    var oldDist = Math.sqrt(Math.pow(thisPtr.lastX - otherPtr.lastX, 2) + Math.pow(thisPtr.lastY - otherPtr.lastY, 2));
    var newDist = Math.sqrt(Math.pow(e.offsetX - otherPtr.lastX, 2) + Math.pow(e.offsetY - otherPtr.lastY, 2));

    var scaleFactor = newDist / oldDist;

    if (scaleFactor != NaN) {
      layerdict.transform.zoom *= scaleFactor;

      var zoomd = (1 - scaleFactor) / layerdict.transform.zoom;
      layerdict.transform.panx += devicePixelRatio * otherPtr.lastX * zoomd;
      layerdict.transform.pany += devicePixelRatio * otherPtr.lastY * zoomd;
    }
  }

  thisPtr.lastX = e.offsetX;
  thisPtr.lastY = e.offsetY;

  if (settings.redrawOnDrag) {
    redrawCanvas(layerdict);
  }
}

function handleMouseWheel(e, layerdict) {
  e.preventDefault();