\hrulefill with vertical alignment of the line as in dashes

Question

\hrulefill vertically aligns the line at the bottom of the text. There is also \xrfill in the package xhfill which raises the line, but it is raised too much for my esthetics.

What I'm looking for is a command working similarly to \hrulefill, but such that the filler line is like a stretched em-dash, so the vertical alignment is the same as for an em-dash.

EDIT

As a clarification: I don't want to have to guess the thickness nor the amount the line is raised over the baseline. I want a command which produces a stretched em-dashed, independently of the current font size etc.

Answer 1

You can try:

\def\myrulefillat{.65ex}
\def\myrulefill{\leaders \hrule height\myrulefillat 
                                depth-\dimexpr \myrulefillat-.3pt\relax \hfil}

test:

\hbox to3cm{a --\myrulefill -- b}

The height of this rule is given by \myrulefillat macro and the thickness is .3pt. You can set another values.

Answer 2

Since the rule is drawn in relation to the baseline, raising the baseline will raise the rule.

And since the command syntax is long and very low-level, storing all the technicality in a macro with a short name is useful and saves typing.

Using this answer (David Carlisle + a comment by flow), raising the baseline without using boxes or lua, Possible to vertically shift baseline without using a box?

gives:

\special in xelatex

MWE

\documentclass{article}
\newcommand\hrf{\special{pdf:literal 1 0 0 1 0 2 cm}\hrulefill\special{pdf:literal 1 0 0 1 0 -2 cm}}

\begin{document}
\textbackslash special with xelatex

no change x\hrulefill x

raised x\special{pdf:literal 1 0 0 1 0 2 cm}\hrulefill \special{pdf:literal 1 0 0 1 0 -2 cm}x

macro x\hrf x


\end{document}

or \pdfliteral in pdflatex

MWE

\documentclass{article}
\newcommand\hrfp{\pdfliteral{ 1 0  0 1 0 2 cm}\hrulefill\pdfliteral{ 1 0  0 1 0 -2 cm}}

\begin{document}
\textbackslash pdfliteral with pdflatex

no change x\hrulefill x

raised x\pdfliteral{ 1 0  0 1 0 2 cm}\hrulefill\pdfliteral{ 1 0  0 1 0 -2 cm}x

macro x\hrfp x


\end{document}