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stipub / stixfonts

OpenType Unicode fonts for Scientific, Technical, and Mathematical texts
SIL Open Font License 1.1
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Big (N-nary) operators are at the wrong vertical alignment #268

Open ronkok opened 2 weeks ago

ronkok commented 2 weeks ago

For big (N-nary) operators, STIX TWO, like other math fonts, has both a standard and an alternate glyph. The alternate glyph is used in what TeX calls displaystyle and what MathML calls display="block".

Some of the alternate glyphs in STIX TWO are at the wrong vertical alignment. They are placed entirely above the baseline. They should instead have a substantial depth (descender) below the baseline. The image below shows the glyphs for Unicode points U+22C2 and U+22C3.

STIX Issue

Latin Modern gets it right. STIX TWO gets it wrong. The results are appearing in production. The Temml library has an open issue that is the direct result of this misalignment.

tiroj commented 2 weeks ago

Noted for fix.

ronkok commented 2 weeks ago

I've done some more investigation. Below is a list of characters that all have this problem.

LaTeX function Character Code Point
\bigwedge ⋀ U+22C0
\bigvee ⋁ U+22C1
\bigcap ⋂ U+22C2
\bigcup ⋃ U+22C3
\bigodot ⨀ U+2A00
\bigoplus ⨁ U+2A01
\bigotimes ⨂ U+2A02
\bigcupdot ⨃ U+2A03
\bigcupplus ⨄ U+2A04
\bigsqcap ⨅ U+2A05
\bigsqcup ⨆ U+2A06
\bigdoublevee ⨇ U+2A07
\bigdoublewedge ⨈ U+2A08
\bigtimes ⨉ U+2A09

The integration symbols and the summation symbol all look good.