Font is italic for unicode text

[abnerlee]

MathJax v3

For math like $$数学$$, the Chinese characters are italic, its character is rendered as

<mjx-utext variant="italic" style="font-size: 84%; padding: 0.893em 0px 0.238em; font-family: MJXZERO, serif; font-style: italic;">学</mjx-utext>

but in v2, the character are not in italic.

So, is there a reason of this spec change, and is there any options to control this?

[GoBigorGoHome]

@abnerlee Just upgraded to the latest Typora and noticed the change. The italic Chinese characters in my math formulas looks really bad (actually italic font shapes are just not for Chinese characters at all). Is it possible to change the font by solely configuring Typora, for example, using CSS?

A workaround is to wrap Chinese characters in math into \text{...}. But that's too much work for existing math formulas. I wish there is a way to change the font as I often include Chinese characters in math formulas for expository purpose. It is tedious for me to have to write \text{...}.

[abnerlee]

@GoBigorGoHome If you don't need italic in math at all, then you can use css

[data-variant='italic'] {
    font-style: normal;
}

to force ignore italic texts, but that is just workaround with side effects.

---

still requires feedback from MathJax side.

[dpvc]

In versions prior to 3.2, MathJax would place all characters that it doesn't think of as "letters" into <mo> elements. In version 3.2, that decision was made more nuanced so that the unicode block in which such characters occur is now taken into account to determine what MathML node to use. Now <mo> is used for symbols, while <mi> is used for letters and most language-specific characters. This improves the semantics of the underlying MathML (since these characters are not operators, as <mo> would indicate).

Since an <mi> with a single character is in italics, that is why your characters are now in italics. The expected encoding for your expression would be $$\text{数学}$$, since these two characters form a single word, just as you would use $$\text{mathematics}$$ rather than $$mathematics$$ (which would be typeset in italics with incorrect inter-character spacing). While it does take extra work to include \text{..}, that does properly indicate your intent, while leaving it out does not.

As a work-around, you could change the MathML node associated with the Chinese ranges to be <mtext> rather than <mi>, which would give you upright letters, but each in its own <mtext> element, which is still not correct, but at least will display as you prefer. To do that merge

MathJax = {
  startup: {
    ready() {
      const {RANGES} = MathJax._.core.MmlTree.OperatorDictionary;
      RANGES[28][3] = RANGES[30][3] = RANGES[33][3] = RANGES[47][3] = 'mtext';
      MathJax.startup.defaultReady();
    }
  }
};

into your current MathJax configuration.

[jtzwuwu]

In versions prior to 3.2, MathJax would place all characters that it doesn't think of as "letters" into <mo> elements. In version 3.2, that decision was made more nuanced so that the unicode block in which such characters occur is now taken into account to determine what MathML node to use. Now <mo> is used for symbols, while <mi> is used for letters and most language-specific characters. This improves the semantics of the underlying MathML (since these characters are not operators, as <mo> would indicate).

Since an <mi> with a single character is in italics, that is why your characters are now in italics. The expected encoding for your expression would be $$\text{数学}$$, since these two characters form a single word, just as you would use$$\test{mathematics}$$ rather than $$mathematics$$ (which would be typeset in italics with incorrect inter-character spacing). While it does take extra work to include \text{..}, that does properly indicate your intent, while leaving it out does not.

As a work-around, you could change the MathML node associated with the Chinese ranges to be <mtext> rather than <mi>, which would give you upright letters, but each in its own <mtext> element, which is still not correct, but at least will display as you prefer. To do that merge

MathJax = {
  startup: {
    ready() {
      const {RANGES} = MathJax._.core.MmlTree.OperatorDictionary;
      RANGES[28][3] = RANGES[30][3] = RANGES[33][3] = RANGES[47][3] = 'mtext';
      MathJax.startup.defaultReady();
    }
  }
};

into your current MathJax configuration.

Frankly speaking, the biggest problem is that almost no one uses italicized Chinese characters.

[abnerlee]

I saw English letters and geek letters like α are also be put into <mi>, like $$aaa$$, but they are not italics as default

[dpvc]

I saw English letters and geek letters like α are also be put into <mi>, like $$aaa$$, but they are not italics as default

They should be, and they are for me. Can you provide a minimal example page where they are not italic?

[abnerlee]

I see, so their italic are just font change?