Is there a way to measure the remaining space of a line of text?

Question

I'd like to write the following:

Some long paragraph of text \measureremainder{\whatsleft}\begin{mimipage}{\whatsleft}
    stuff
\end{minipage}

so that the minipage takes up exactly the remaining \hsize minus \widthof{Some long paragraph of text}. I tried the following, based on code in TeX by Topic:

\newbox\linebox
\newbox\snapbox
\def\restofline#1{%
  \hfill\par\setbox\linebox\lastbox% Fill the line, then pop it off
  \ifvoid\linebox%
  \else%
  \unskip\unpenalty%
  \setbox\snapbox\hbox{\unhcopy\linebox}% and reset the line without expanding flexible spaces
  \setlength{#1}{\wd\linebox}% Then retrieve the difference between the two settings
  \addtolength{#1}{-\wd\snapbox}%
  \usebox\snapbox% and replace the line with the tightly-set one
  \fi%
}

And that kinda works, in raw paragraphs: it will duplicate the initial \parindent, though, if the paragraph is only one line long. But it totally breaks if I try it inside, e.g., an itemize environment:

\begin{itemize}
  \item Some text \measurerest{\whatsleft}\showthe\whatsleft
\end{itemize}

Because \lastbox doesn't work in vertical mode.

Two approaches that didn't work: I tried \begin{minipage}{\textwidth plus -1fill}, but minipages take a length, not a dimen, so the stretch factors are ignored. I also tried \hfill\setlength\whatsleft\lastskip, but that returns 0.0pt plus 1.0fill instead of SomeNumberOfpt

Is there a way around the \lastbox-in-vertical mode restrictions? Or a more robust way to force TeX to set glue so it can be measured?

Answer 1

You could use TikZ for this by placing an empty TikZ picture in \measureremainder which then measures the distance of its position to the right border of the text area. This requires at least two compiler runs to work. It reuses some code from my answer to How to define a figure size so that it consumes the rest of a page?. Some of that code might be published as part of the TeX.SX-TikZ bundle.

\documentclass{article}

\usepackage{tikz}
\usetikzlibrary{calc}

\newcommand{\currentsidemargin}{%
  \ifodd\value{page}%
    \oddsidemargin%
  \else%
    \evensidemargin%
  \fi%
}

\newlength{\whatsleft}

\newcommand{\measureremainder}[1]{%
\begin{tikzpicture}[overlay,remember picture]
    % Helper nodes
    \path (current page.north west) ++(\hoffset, -\voffset)
        node[anchor=north west, shape=rectangle, inner sep=0, minimum width=\paperwidth, minimum height=\paperheight]
        (pagearea) {};


    \path (pagearea.north west) ++(1in+\currentsidemargin,-1in-\topmargin-\headheight-\headsep)
        node[anchor=north west, shape=rectangle, inner sep=0, minimum width=\textwidth, minimum height=\textheight]
        (textarea) {};

    % Measure distance to right text border
    \path let \p0 = (0,0), \p1 = (textarea.east) in
        [/utils/exec={\pgfmathsetlength#1{\x1-\x0}\global#1=#1}];

\end{tikzpicture}%
}


\begin{document}
\section{test}

Some long paragraph of text \measureremainder{\whatsleft}\begin{minipage}[t]{\whatsleft}
    \hrulefill
\end{minipage}

Some short text \measureremainder{\whatsleft}\begin{minipage}[t]{\whatsleft}
    \hrulefill
\end{minipage}

Some long long long long long long long long long long long long long
long long long long long long long long long long long text \measureremainder{\whatsleft}\begin{minipage}[t]{\whatsleft}
    \hrulefill
\end{minipage}

\end{document}

Result:

(The horizontal lines represent the width of the minipage.)

Update 2011/09/15:

I just uploaded the new package tikzpagenodes to CTAN, which simplifies the above code as follows:

\usepackage{tikzpagenodes}
\usetikzlibrary{calc}

\newcommand{\measureremainder}[1]{%
\begin{tikzpicture}[overlay,remember picture]
    % Measure distance to right text border
    \path let \p0 = (0,0), \p1 = (current page text area.east) in
        [/utils/exec={\pgfmathsetlength#1{\x1-\x0}\global#1=#1}];
\end{tikzpicture}%
}

Answer 2

The zref, zref-savepos package has the option to save the position of a marker. In normal text it works quite well. Inside lists it is a different story. On c.t.t. it was explained as: \item doesn't actually print anything, nor does it start a new line. It saves the box containing the bullet, and arranges for \everypar to print it whenever the next paragraph starts, which is after you have have marked the current position (which is then just above the coming new line and at the left margin.

The problem is illustrated by using the linegoal package (it uses zref internaly)

\documentclass{article}
\usepackage{linegoal}
\begin{document}
This is a test \rlap{\rule[.5ex]{\linegoal}{0.5pt}}{}of line goal and all
kinds of everything else here and here again all kinds of everything else
here and here again
\begin{itemize}
  \item This is a test \rlap{\rule[.5ex]{\linegoal}{0.5pt}}{}of line goal
      and all kinds of everything else here and here again all kinds of
      everything else here and here again
\end{itemize}
\end{document}

Answer 3

You can try the linegoal package.