[texhax] checking if a piece of text stays on one line or more than one line

[Heiko Oberdiek]

On Tue, Oct 11, 2011 at 03:56:57PM +1100, Vafa Khalighi wrote:

> Can you please send a minimal example showing how this works because all my
> attempts with your package so far failed.

\documentclass{article}
\usepackage{color}
\usepackage{zref-savepos}
\makeatletter
\newcounter{mytextbf at count}
\newcommand*{\mytextbf at label}[1]{%
  mytextbf@#1@\the\value{mytextbf at count}%
}
\newif\ifmytextbf at oneline
\newcommand*{\mytextbf}[1]{%
  \leavevmode
  \stepcounter{mytextbf at count}%
  \zsavepos{\mytextbf at label{beg}}%
  \mytextbf at onelinefalse
  \ifnum\zposy{\mytextbf at label{beg}}=\zposy{\mytextbf at label{end}} %
    \ifnum\zposx{\mytextbf at label{end}}<\zposx{\mytextbf at label{beg}} %
    \else
      \mytextbf at onelinetrue
    \fi
  \fi
  \nobreak\hspace{0pt}% allow hyphenation
  \zref at ifrefundefined{\mytextbf at label{beg}}{%
    \textbf{#1}%
  }{%
    \ifmytextbf at oneline
      \textcolor{blue}{\textbf{#1}}%
    \else
      \textcolor{red}{\textbf{#1}}%
    \fi
  }%
  \zsavepos{\mytextbf at label{end}}%
}
\begin{document}

foo \mytextbf{include enabled primitives} bar bla bla bla
\mytextbf{include enabled primitives} bla
\mytextbf{include enabled primitives} end

\end{document}


And an extended version that completes the position by the absolute
page number and uses \newcount to avoid too much trouble with \include.


\documentclass{article}
\usepackage{color}
\usepackage{zref-savepos,zref-abspos}
\makeatletter
\newcount\mytextbf at count
\mytextbf at count=\z@
\newcommand*{\mytextbf at beg}{%
  mytextbf-\the\mytextbf at count
}
\newcommand*{\mytextbf at end}{%
  mytextbf+\the\mytextbf at count
}
\newif\ifmytextbf at oneline
\newcommand*{\mytextbf}[1]{%
  \leavevmode
  \global\advance\mytextbf at count\@ne
  \zref at savepos
  \zref at labelbyprops{\mytextbf at beg}{abspage,posx,posy}%
  \zref at refused{\mytextbf at beg}%
  \zref at refused{\mytextbf at end}%
  \mytextbf at onelinefalse
  \ifnum\zref at extract{mytextbf at beg}{abspage}=%
        \zref at extract{mytextbf at end}{abspage} %
    \ifnum\zposy{\mytextbf at beg}=%
          \zposy{\mytextbf at end} %
      \ifnum\zposx{\mytextbf at end}<%
            \zposx{\mytextbf at beg} %
      \else
        \mytextbf at onelinetrue
      \fi
    \fi
  \fi
  \nobreak\hspace\z@
  \zref at ifrefundefined{\mytextbf at beg}{%
    \textbf{#1}%
  }{%
    \ifmytextbf at oneline
      \textcolor{blue}{\textbf{#1}}%
    \else
      \textcolor{red}{\textbf{#1}}%
    \fi
  }%
  \zref at savepos
  \zref at labelbyprops{\mytextbf at end}{abspage,posx,posy}%
}
\begin{document}

foo \mytextbf{include enabled primitives} bar bla bla bla
\mytextbf{include enabled primitives} bla
\mytextbf{include enabled primitives} end

\end{document}


Adding support for right-to-left-writing is left as exercise for you.

Yours sincerely
  Heiko Oberdiek