docs: private boolean isClick(MotionEvent upEvent, float xDown, float yDown, float xUp, float yUp) {
          if (upEvent == null) return false;
          long time = upEvent.getEventTime() - upEvent.getDownTime();
          float distance = PointF.length( //
                  xDown - xUp, //
                  yDown - yUp);
          return time < MAX_CLICK_TIME && distance < MAX_CLICK_DISTANCE;
      }