导出pdf的公式字体太丑

[loowace]

Describe the bug
这个导出pdf的公式字体太丑了吧？

这才是正常的公式字体

To Reproduce
Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
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Desktop (please complete the following information):

• OS: [e.g. Windows 10]
• Version [e.g. 3.0.0]

Additional context
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