code: function ( startX, startY, endX, endY ) {
          var gapH = Math.max( startX, endX ) - Math.min( startX, endX ),
              gapV = Math.max( startY, endY ) - Math.min( startY, endY );
  
          if ( gapH > gapV ) {
              return 'horizontal';
          } else if ( gapH < gapV ) {
              return 'vertical';
          } else {
              return 'none';
          }
      }
docs: 제스츄어 방향축 반환 (vertical, horizontal)