code: function moveHandler(evt) {
          if (IN_SCALE_MODE) {
              var result = 0;
              var node = zoomNode;
              var device = this.deviceEvents;
              if (device.hasTouch) {
                  if (evt.targetTouches.length === 2) {
                      node.style.webkitTransitionDuration = '0';
                      evt.preventDefault();
                      scaleImage(evt);
                      result = 2;
                  } else if (evt.targetTouches.length === 1 && currentScale > 1) {
                      node.style.webkitTransitionDuration = '0';
                      evt.preventDefault();
                      moveImage.call(this, evt);
                      result = 1;
                  }
                  gesture = result;
  
                  if (result > 0) {
                      return;
                  }
              }
          }
          moveHandlerOriginal.call(this, evt);
      }
docs: Move event handle
  @param {object} evt
  @returns {number}