code: function ttf2icon(ttfBuffer, options) {
  
              options = options || {};
  
              // 读取ttf二进制流
              if (ttfBuffer instanceof ArrayBuffer) {
                  var reader = new TTFReader();
                  var ttfObject = reader.read(ttfBuffer);
                  reader.dispose();
  
                  return ttfobject2icon(ttfObject, options);
              }
              // 读取ttfObject
              else if (ttfBuffer.version && ttfBuffer.glyf) {
  
                  return ttfobject2icon(ttfBuffer, options);
              }
  
              error.raise(10101);
          }
docs: ttf格式转换成icon
  
  @param {ArrayBuffer|ttfObject} ttfBuffer ttf缓冲数组或者ttfObject对象
  @param {Object} options 选项
  @param {Object} options.metadata 字体相关的信息
  
  @return {Object} icon object