# [XeTeX] Several apostrophe-related problems (kerning, mapping)

John Was john.was at ntlworld.com
Sun Oct 31 16:32:13 CET 2010

Hello

I can't help with the marginal kering (which I don't use), but here is what
I do in a font that also had overtight kerning associated with apostrophes:

\catcode"2019=\active
\def’{\leavevmode \kern 1sp \hbox{'}}
\catcode"201D=\active
\def”{\leavevmode \kern 1sp \hbox{''}}

Note that the characters in the \hboxes are the ordinary straight apostrophe
(since I also use TeX mapping in my font calls.)

As it stands, this would involve you actually using the correct Unicode
characters 2019 and 201D for closing single and double apostrophes in your
document, in spite of your tex-mapping - and I guess you could achieve this
by global search-and-replace in your file.  But you  may be able to do much
the same thing by making 0027 active instead (I haven't tried that - I can
see a potential danger of a loop if you are using 0027 to define itself).

I'm sure there are more elegant solutions - and I use plain TeX so there may
be LaTeX issues that I don't know about.

(Of course, if my request for custom kerning could be met, we would all be
able to refine the kerning of any font at will.  Unfortunately, someone in
another thread explained that that is very difficult in XeTeX because of the
way it looks up font information (LuaTeX can do it because it has another
method of accessing the font's tables).  I was rather hoping that someone
would see that as an opportunity to show off hrs computing prowess by
performing the miracle - but this hasn't happened yet.)

John

----- Original Message -----
From: "Pierre Morel" <pier.morel at gmail.com>
To: "Unicode-based TeX for Mac OS X and other platforms" <xetex at tug.org>
Sent: 31 October 2010 15:02
Subject: [XeTeX] Several apostrophe-related problems (kerning, mapping)

Hello,

My thesis is finished soon, but I have an annoying apostrophe problem.

In French we have a lot of apostrophes uses like this : L'œil,
l'incertitude, etc.
In theory, these apostrophes should be the unicode character U+2019 (right
single quotation mark) instead of a straight apostrophe (U+0027). This
replacement is automatically made by this command :
\defaultfontfeatures{Mapping=tex-text}

First there is a problem with the kerning of this U+2019 character, it is
possibly a bug in the font I'm using (Adobe Caslon Pro), but I'd like to
solve it anyway.
Here is an example (The word L'œil, on the top right) :
http://dl.dropbox.com/u/1205127/Images/xetex.jpg
The apostrophe is completely kerned above the "œ" (the same problem is
present for any small character), which thus touches the "L".
So my first question is: is there a way to override the default kerning of
this U+2019 character so that it behaves in a more correct way (with a
slight space between the apostrophe and the next letter) ?

Now there is a second problem (which solved the first one but in a bad way).
When activating margin kerning, xetex behaves as if the line
\defaultfontfeatures{Mapping=tex-text} was not present : U+0027 apostrophes
stay straight (which curiously solves the kerning problem, see the example
on the top left of the image), and  and '' are not converted appropriately
(more annoying).
Here is what I use for the margin kerning (when I comment these line, the
mapping problem is corrected) :

\newcount\countA
\ifx\XeTeXprotrudechars\undefined
\pdfprotrudechars=2
\else
\let\pdftexversion=\countA
\pdftexversion = 140
\XeTeXprotrudechars=2%\fi
\input protcode-native
\font\f="Adobe Caslon Pro" at 11pt \f
\setprotcode\f
\pretolerance=-1
\tolerance=9999
\emergencystretch=2em

With the file protcode-native file being

\def\setprotcode#1{
\rpcode#1 U"0021    55
\rpcode#1 U"002C    194
\rpcode#1 U"002D    233
\rpcode#1 U"002E    194
\rpcode#1 U"003B    138
\rpcode#1 U"003A    138
\rpcode#1 U"003F    94
\lpcode#1 U"2018    194
\rpcode#1 U"2019    194
\rpcode#1 U"0027    194
\lpcode#1 U"201C    250
\rpcode#1 U"201D    250
\rpcode#1 U"2013    150
\rpcode#1 U"2014    200
}

So, in short, I want to use margin kerning while maintaining the tex-text
mapping AND having a correct kerning with the U+2019 apostrophe.

PS: (this last problem also appears on my sans serif font (Myriad pro), an
example is visible in the linked image.

Thank you,

Pierre

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