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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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The point feature of i and j is suppressed in equations #253

Open Qhgu opened 1 year ago

Qhgu commented 1 year ago

As shown in the screenshot, when an arrow is added on the top of the characters, the point feature of i and j is suppressed. Really hope you can fix this issue.

Font version: STIX Two Math 2.13 b171, static_ttf Application: Microsoft Word 2021 x64

Snipaste_2023-06-01_19-51-54

tiroj commented 1 year ago

Hmm. Can you do a couple of things to help me diagnose this issue:

  1. Please test the same equation using Microsoft’s Cambria Math font and confirm whether this exhibits the same behaviour.

  2. Please try a similar equation in which the last character before the arrow is not i or j (but still with intermediate subscripted i and j).

This may be a math handler issue, rather than something specific to the font. Suppression of the dot on i and j in an OpenType math font is implemented via the OT Layout dtls feature, but it is the math handler that determines when to apply this feature in equation layout.

Qhgu commented 1 year ago

Hmm. Can you do a couple of things to help me diagnose this issue:

  1. Please test the same equation using Microsoft’s Cambria Math font and confirm whether this exhibits the same behaviour.
  2. Please try a similar equation in which the last character before the arrow is not i or j (but still with intermediate subscripted i and j).

This may be a math handler issue, rather than something specific to the font. Suppression of the dot on i and j in an OpenType math font is implemented via the OT Layout dtls feature, but it is the math handler that determines when to apply this feature in equation layout.

After testing, here are the results:

  1. This issue also exhibits with the default Microsoft’s Cambria Math font. Hence, I think you are right; this may be caused by a math handler issue of Microsoft Word.
  2. This issue persists no matter where i and j are located in the subscript.

I have also tested it on WPS office with the STIX Two Math font, and it works very well. I think the WPS office handles this math issue well. I searched this issue on Google and found that in 2018, a guy had reported it to Microsoft; however, 5 years later, they haven't fixed it yet.

Thank you very much.

tiroj commented 1 year ago

Thank you. That is very helpful. I wasn’t aware of this issue in MS Word, but will follow up on it.