[bug #62923] [gropdf] glyph aliases in in font description files not parsed correctly

[Deri James]

Follow-up Comment #13, bug #62923 (project groff):

Yes, that's what I meant, \[sqrtex] is hard coded. :-)

When you install XITSMR repeat your test with .special XITSMR, then you can
see the problem. With .special S everything looks normal.

In XITSMR sr is an alias for sqrt and radicalex is an alias for sqrtex (this
one was added manually by Nikita, not by afmtodit). Without it groff complains
about missing glyph radicalex. One unusual aspect of the font is that it was
processed with text.enc and marked as "special" so it inherits a lot of
kernpairs which sort of makes sense because it contains general text glyphs as
well as maths symbols.


     .char \[radicalex] \h'-\w'\[sr]'u'\[radicalex]\h'\w'\[sr]'u'
    .fchar \[sqrtex] \[radicalex]


Good catch, you are Gunga Dinn! But this is crazy, my reading of this is it
assumes an radicalex follows an sr step back the width of the sr stroke the
radicalex and then step forward the width of the sr! I don't understand why it
steps back the width of sr before stroking the glyph.

If you .rchar the char radicalex so you are using the naked glyph you get some
interesting results which lead to an inescapeable, and surprising,
conclusion!

Run the attached s.trf (no need for eqn) to be totally surprised. (If the
excitement is too much, just look at s.pdf).

I'm not sure what the long term fix will be, for now Nikita can .rchar
\[radicalex]. The proper fix may be in eqn to adjust depending on the italic
correction of the sqrtex glyph to detect if it is an overscore following
character or overscore itself type.

As further confirmation I checked the S font in fontforge and the radicalex
glyph is shown with a red question mark and if you go into a screen called
Math Kerning you can see a filled box (the line outside the bounding box.



(file #53603, file #53604)

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Additional Item Attachment:

File name: s.trf                          Size:1 KB
    <https://file.savannah.gnu.org/file/s.trf?file_id=53603>

File name: s.pdf                          Size:12 KB
    <https://file.savannah.gnu.org/file/s.pdf?file_id=53604>



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