我试图从RTF文件创建一个属性字符串对象，如下所示：
NSMutableAttributedString *rtfString = [[NSMutableAttributedString alloc] initWithURL:url options:@{} documentAttributes:NULL error:&error];
问题在于对于带有嵌入图像的RTF文件（参见下面的示例），在阅读过程中忽略了与图像相关的控制字和数据（据我所知），因此它们不作为属性或附件出现在属性字符串。
我的问题：如何使用RTF文件中的自定义/非标准属性填充NSAttributedString对象的属性？具体来说，我希望能够检索有关嵌入图像的信息，包括其相关的十六进制数据和字符串中的位置。获得此信息后，应该很容易将每个图像添加为属性字符串的附件。
注意：我知道NSAttributedString可以使用RTFD格式处理图像和附件，但是不能将RTF转换为RTFD，因为我无法控制输入文件。
带有图像的RTF文件示例：
{\rtf1
some text before \line
{\pict\jpegblip
FFD8FFE000104A46494600010101004800480000FFDB004300191113161310191614161C1B191E253E29252222254C373A2D3E5A505F5E595057566470907A64
6A886C56577DAA7E889499A1A2A16178B0BDAF9CBB909EA19AFFDB0043011B1C1C252125492929499A6757679A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A
9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9A9AFFC0001108004D006403011100021101031101FFC400190000020301000000000000
000000000000010200030405FFC4002E100002010203060601050100000000000001020003111221310413415152912261627181A132234243C1D1E1FFC40018
01010101010100000000000000000000000001020304FFC4002511010100020202030000070000000000000001021103211231415171041322324261D1FFDA00
0C03010002110311003F007C0BD23B4E8D0E05E91DA412C9D23B428597A07685D54183A476841C2BD23B42A605E91DA0428BD23B4214A2F48ED014AAF48ED2A0
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F4FDC281ADE9FB8086AFA7EE023D456521D030E46118F1056200384682F335AC6765C77CCF192B78DF923367A48B6BFFD9
}
\line some text after
}