PDF: math glyphs going out of bounds from table rows (works in HTML and Word)

[ronaldtse]

The font being used is "STIX Two Math" or "Cambria Math" -- both will cause the same out of bounds issue.

Word (works):

HTML (works):

PDF (out of bounds):

Please see this ticket for details:

• https://github.com/metanorma/pdfa-iso-32000-2/pull/31

[Intelligent2013]

Source document from https://github.com/metanorma/pdfa-iso-32000-2/pull/31

1. HTML doesn't work ok for:
   
   

2. DOC doesn't work ok too, for instance:
   

Word doesn't render overflowed glyph, just cuts it.

If manually set 5pt font size, then renders fully:

3. The table row height in the XSL-FO/PDF is 5mm vs. 6.5mm for DOC.
   The table cell vertical alignment in the PDF is 'top' vs. 'bottom' DOC (I didn't find how Word sets/calculate this property).
   I've tried to set row height and vertical alignment manually in XSL-FO similar to DOC - PDF renders OK:
   
   
   

But in any case, 'braceleftmid' and 'bracerightmid' don't fit properly, and need to decrease the font-size:

Apache FOP can't increase the table row height automatically, just it doesn't catch the max glyph height (Word too, for braceleftmid and bracerightmid).

[ronaldtse]

@Intelligent2013 I looked into this carefully, and you are absolutely right...

Because these particular glyphs are designed to go out of glyph bounds! I've checked "STIX Two Math" below. Originally it looks like it worked for HTML but it's just because HTML row has extra padding on top/bottom (see the first image to view actual bounding box)

HTML:

Word:

In BirdFont (free font glyph viewer), you can see that they extend out of the glyph area:

So... maybe the only way is to shrink their height? Sad but true...

We only have two choices:

• only use [css font-family:STIX Two Math;font-size: Npt]
• create new syntax that allows [custom-charset: math] with font-size...