code: function adjustQuadrant(quadrant, point, opposite) {
  		if ((opposite.x == point.x) || (opposite.y == point.y)) return quadrant;
  		var flipHorizontally = [4, 3, 2, 1]
  		var flipVertically = [2, 1, 4, 3]
  		var oppositeQuadrant = (opposite.y < point.y) ?
  							((opposite.x < point.x) ? 2 : 1) :
  							((opposite.x < point.x) ? 3 : 4);
  		// if an opposite relation end is in the same quadrant as a label, we need to flip the label
  		if (oppositeQuadrant === quadrant) {
  			if (config.direction === 'LR') return flipHorizontally[quadrant-1];
  			if (config.direction === 'TD') return flipVertically[quadrant-1];
  		}
  		return quadrant; 	
  	}
docs: Flip basic label quadrant if needed, to avoid crossing a bent relationship line