\input pdfToolbox
\input measurebox

\setlayout{horizontal margin=2cm, vertical margin=2cm}
\parindent=0pt
\parskip=3pt plus 2pt minus 2pt

\loadsyntax{TeX}
\setsyntax{TeX}
\everylisting={\lstlinenum=\z@}

\def\mb{{\bf MeasureBox}}
\def\macro#1{{\setfont{tt}\string#1}}
\def\displaymacro#1{\quitvmode\kern-1cm\macro#1}
\def\@setupverb{\setupverb\catcode`\ =10\relax}
\def\inlinecode#1{
    \bgroup%
    \@setupverb%
    \catcode`#1=2%
    \tt%
}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\centerline{\mbscalebox{5}{\mb}}
\bigskip
\centerline{Version \measureboxversion}
\centerline{\measureboxauthor\ ---\ \measureboxemail}
\bigskip

\bgroup
\leftskip=3cm plus 1fil \rightskip=\leftskip
\hrule
\medskip
\mb{} is a package designed for measuring material.
Its only dependency is the \url{https://ctan.org/pkg/pdftoolbox?lang=en}{\pdftoolbox} toolkit.\par
\medskip
\hrule
\egroup
\bigskip

It provides four main macros:
\blist
    \item \macro\mbscalebox;
    \item \macro\measurebox;
    \item \macro\measureh;
    \item \macro\measurew.
\elist

\displaymacro\mbscalebox{} is the simplest.
It takes two inputs: a scale factor and material to scale, and then scales the material by the given factor.
For example

\blisting
\mbscalebox{5}{Hello!}
\elisting

Will produce

\centerline{\mbscalebox{5}{Hello!}}
\bigskip

\displaymacro\measurebox{} is the main player.
It takes two arguments: the first is the material to measure, and the second is a list of \macro\measureh{}
and \macro\measurew{} commands to add measurements.
\macro\measurebox{} will draw a box around the material with a stroke width governed by \macro\mbstrokewd{}
(non-dimension), with a dash pattern of \macro\mbdashwd{} (dimension), and a color determined by the color
{\tt mbcolor}.
It will then scale this box by a factor of \macro\mbscale.

After boxing the material, \macro\measurebox{} sets \macro\mbwd, \macro\mbht, and \macro\mbdp{} to the width,
height, and depth of the box respectively.
These can then be used by the measurement commands.

\displaymacro\measureh{} measures vertical dimensions.
It accepts a single input, which is a list of key-value pairs.
These keys are:
\blist
    \item {\tt b} (default: \inlinecode|-\the\mbdp|): the height at which to begin the measurement;
    \item {\tt e} (required): the height at which to end the measurement;
    \item {\tt x} (default: \inlinecode|.5\mbwd|): the x-position to place the line connecting the beginning
    and end measurement;
    \item {\tt stroke} (default: .01): the stroke weight of the measurement;
    \item {\tt label}: the label of the measurement;
    \item {\tt color} (default: {\tt black}): the color to draw the measurement;
    \item {\tt dash}: the dash length to stroke the measurement with, if provided;
    \item {\tt legend} (valueless): add to add this measurement to the legend;
    \item {\tt noprint} (valueless): add to not print the label on the measurement.
\elist

\displaymacro\measurew{} measures horizontal dimensions.
It accepts a single input, which is a list of key-value pairs.
These keys are the same as \macro\measureh, except {\tt x} is swapped with {\tt y}, and the meanings of
{\tt b}, {\tt e}, {\tt x} are the dual of their meanings for \macro\measureh{} (i.e. {\tt b} is the {\it width}
at which to begin the measurement).

The font scale at which the labels are printed (before magnification) is determined by \macro\mblblscale.

For example

\blisting
\def\mbscale{7}
\def\mbstrokewd{.01}
\def\mblblscale{1pt}
\measurebox{\mbnodp{$\prod$}}{%
    \measureh{b=.5\mbht, e=10pt, stroke=.01, color=blue, dash=.1, label=(top stroke top), noprint, legend}%
    \measureh{b=.5\mbht, e=9.6pt, stroke=.01, color=blue, dash=.1, label=(top stroke bot), noprint, legend}%
    \measurew{b=1.59pt, e=2.56pt, stroke=.01, color=red, dash=.1, label=(left stroke), noprint, legend}%
    \measurew{b=\mbwd-2.574pt, e=\mbwd, stroke=.01, color=red, dash=.1, label=(right stroke left),
    noprint, legend, y=.5\mbht-1pt}%
    \measurew{e=\mbwd, b=\mbwd-1.604pt, stroke=.01, color=red, dash=.1, label=(right stroke right),
    noprint, legend, y=.5\mbht-1pt}%
    \measurew{e=\mbwd, stroke=.01, color=green, y=2pt, label=(width), legend}%
}
\elisting

will produce

\bigskip
\def\mbscale{7}
\def\mbstrokewd{.01}
\def\mblblscale{1pt}
\centerline{\measurebox{\mbnodp{$\prod$}}{%
    \measureh{b=.5\mbht, e=10pt, stroke=.01, color=blue, dash=.1, label=(top stroke top), noprint, legend}%
    \measureh{b=.5\mbht, e=9.6pt, stroke=.01, color=blue, dash=.1, label=(top stroke bot), noprint, legend}%
    \measurew{b=1.59pt, e=2.56pt, stroke=.01, color=red, dash=.1, label=(left stroke), noprint, legend}%
    \measurew{b=\mbwd-2.574pt, e=\mbwd, stroke=.01, color=red, dash=.1, label=(right stroke left),
    noprint, legend, y=.5\mbht-1pt}%
    \measurew{e=\mbwd, b=\mbwd-1.604pt, stroke=.01, color=red, dash=.1, label=(right stroke right),
    noprint, legend, y=.5\mbht-1pt}%
    \measurew{e=\mbwd, stroke=.01, color=green, y=2pt, label=(width), legend}%
}}

\bye