code: function otfContours2ttfContours(otfContours) {
              if (!otfContours || !otfContours.length) {
                  return otfContours;
              }
              var contours = [];
              for (var i = 0, l = otfContours.length; i < l; i++) {
  
                  // 这里可能由于转换错误导致空轮廓，需要去除
                  if (otfContours[i][0]) {
                      contours.push(transformContour(otfContours[i]));
                  }
              }
  
              return contours;
          }
docs: otf轮廓转ttf轮廓
  
  @param  {Array} otfContours otf轮廓数组
  @return {Array} ttf轮廓