Chinese character incorrectly encoded when copied from generated PDF using 'Adobe Source Han' serif/sans font | 内置PDF导出含思源宋/黑字体时有特定字符无法正确复制

[klizet]

• Searched existing issues to avoid creating duplicates.

• Confirmed that it can be reproduced in built-in themes without customized css.

• Searched http://support.typora.io/

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Describe the bug
Some Chinese characters eg. '一'、'二' incorrectly encoded when copied from generated PDF using 'Adobe Source Han' serif/sans font.

To Reproduce
Steps to reproduce the behavior:

1. Modify some 3rd typora theme to specify the font to 'Adobe Source Han serif'/思源宋体 or 'Adobe Source Han sans'/思源黑体.
2. Simply type in '一二三四五六七八九十'.
3. Export as a pdf file.
4. Copy the text in the pdf file, but the characters will change to '⼀⼆三四五六七⼋九⼗'. Note the characters '⼀⼆⼋⼗' are different from original inputs even they look similar.

Expected behavior
Characters copied from the pdf should be exactly consistent with the original input.

Screenshots / Screencasts
Omitted.

Sample Markdown File
Omitted.

Desktop (please complete the following information):

• OS: Windows 11 64bit

Typora Version
1.8.10 in release channel.

Additional context

The issue is also discussed here but related to itext library or html2pdf program.
https://www.v2ex.com/t/965813 (in Chinese)
https://juejin.cn/post/6844903729439703053 (in Chinese)

This bug may be related to the upstream libraries of typora program. But, until this bug gets officially fixed, there are many ways to do a quick fix, for people who bothered.

• How to fix the pdf. It could be processed by the 'Pitstop Pro' plugin of Adobe Acrobat. Check 'Global Changes'->'Remap Font'.
• How to fix the copied characters. Personally, I prefer to the 'Unicode Normalizer' extension of VS Code. https://marketplace.visualstudio.com/items?itemName=espresso3389.unicode-normalizer

[abnerlee]

Typora uses Chromium's built-in PDF generation method, so, if you export the md to html, open it in Chrome and print as PDF, does the same bug occur?

[klizet]

Sure, you are correct. This bug is reproduced by the edge browser. At the same time, the built-in 'Save as pdf' function of firefox, and the virtual pdf printer of windows 'Print as PDF' works well without any issue.

After checking the chromium issue tracker, I found it's related to the bug 41469265 but marked as fixed. I will re-issue this to the chromium maintainers some days later.

[klizet]

It can be traced into the skia library, a very low level infra of chromium here. Perhaps it WONT BE FIX in a short time. Sad.