Solution for \aemph{} command, avoiding \overline (and amsmath package)

[DomoViridi]

The manual for v1.2.1 has a note about the \aemph{} command (page 5, note 9, at end of introduction for section 3)

This macro makes use of the mathematical command \overline, which explains why arabxetex requires the amsmath package. I welcome any suggestion that would make it possible to circumvent this dependency by emulating \overline directly."

I had a similar problem with ancient Greek number codes, which require adding a horizontal line over one or more Greek characters. The math \overline was impractical, as switching to math mode interfered with the Greek font used.

To overcome this I wrote a command which draws a TeX "rule" over the characters, without using math mode.
The code is about 10 lines long. See the attached files (a zipped tex file, and a text file; the contents of these two is the same).
ruleover.tex.zip
ruleover.txt

The code defines a command \ruleover[<scale>]{<text>}. This takes a string of text as a parameter, shrinks that text down by a factor defined by the scale parameter (default 0.75) and draws a horizontal line (a "rule") over that text,
at a height of 1.3333 (1 and 1/3) times the height of the text string.

This code can easily be adapted into (a base for) the \aemph command, e.g. by defining
\newcommand{\aemph}[1]{\ruleover[1.0]{#1}}
to get a version with no shrinking.

Things that may need tweaking:

• Remove \makeatletter and \makeatother; not needed inside a package
• Rename ROver@ prefix to something else (e.g. ax@over@) to prevent future name clashes.
• The command was developed based on LTR text. Might need to be modified to work with RTL text. This needs testing. Edit: It does need modification. See later comment.
• Thickness of the rule is now 0.5333pt (for no scaling, 0.4pt for 0.75 scaling). Modify if desired.
• The rule is drawn at 1.3333 times the text height above the baseline. Modify if desired.

[DomoViridi]

It turns out that \scalebox is part of the graphics package. Requiring an extra package is undesirable.

As the command is not needed if we don't want to shrink the text, a modified version can made without it.
Here is a modified version:

\makeatletter
\newlength{\ax@over@width} % width of the string
\newlength{\ax@over@height} % height of the string
\newlength{\ax@over@thick} % thickness of the line
\newcommand{\lineover}[1]{%
\settoheight{\ax@over@height}{#1}% Get height of original text
\settowidth{\ax@over@width}{#1}% Get width of original text
\setlength{\ax@over@thick}{0.4pt}% Set pre-shrink thickness of rule
\makebox[0pt][r]{#1}% Print the text
\rule[1.3333\ax@over@height]{\ax@over@width}{\ax@over@thick}% Draw bar
}
\makeatother

%% Re-define Arab emphasis command using \ruleover{} (no scaling)
\renewcommand{\aemph}[1]{\lineover{#1}}

ax-over.txt

This does away with the scaling, and so avoids using the graphics package.

Note: To work with RTL text, the second optional parameter to the \makebox command needs to be set to r. In the original version, designed for LTR text, it was set to l. We could keep things simple and stipulate that \aemph should only be used in RTL text. Or a clever package programmer could try to detect if the output is in LTR or RTL mode and issue the appropropriate \makebox command. I have no experience constructing package commands, so hopefully someone else can implement this.

[DomoViridi]

Note: To work with RTL text, the second optional parameter to the \makebox command needs to be set to r. In the original version, designed for LTR text, it was set to l. We could keep things simple and stipulate that \aemph should only be used in RTL text. Or a clever package programmer could try to detect if the output is in LTR or RTL mode and issue the appropriate \makebox command. I have no experience constructing package commands, so hopefully someone else can implement this.

Bidi package to the rescue! :-)

\makeatletter
\newlength{\ax@over@width} % width of the string
\newlength{\ax@over@height} % height of the string
\newlength{\ax@over@thick} % thickness of the line
%
\newcommand{\lineover}[1]{%
\settoheight{\ax@over@height}{#1}% Get height of original text
\settowidth{\ax@over@width}{#1}% Get width of original text
\setlength{\ax@over@thick}{0.4pt}% Set pre-shrink thickness of rule
\if@RTL%
\makebox[0pt][r]{#1}% Print the text Right to Left
\else%
\makebox[0pt][l]{#1}% Print the text Left to Right
\fi%
\rule[1.3333\ax@over@height]{\ax@over@width}{\ax@over@thick}% Draw bar
}
\makeatother

The \if@RTL condition is defined in the bidi package, which is already required by the arabxetex package.

[fc7]

Thanks for this suggestion. Would you be willing to make a pull request for this improvement? I would happily incorporate this into a new release, with due credits to you of course.