\documentclass{article}
\def\version{1.5}
%% Copyright 2013 Steven B. Segletes
%
% This work may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either version 1.3
% of this license or (at your option) any later version.
% The latest version of this license is in
%   http://www.latex-project.org/lppl.txt
% and version 1.3c or later is part of all distributions of LaTeX
% version 2005/12/01 or later.
%
% This work has the LPPL maintenance status `maintained'.
%
% The Current Maintainer of this work is Steven B. Segletes.

% V1.01 Correct typos in documentation
% V1.1  Corrected usepackage dependencies; Significant doc rewrite.
% V1.11 Corrected typo in documentation
% V1.2  Added \scaleleftright and \stretchleftright; revised docs.
% V1.3  Corrected missing % in stretch routines, added \hstretch and
%       \vstretch commands; fixed version number in .sty file
% V1.4 -Auto-detect mathmode and style; use the proper math display
%       style; Allow \ignoremathstyle and \discernmathstyle to
%       revert to former approach in rare cases and return to new
%       approach.
%      -Added \Isnextbyte as a supplemental routine
%      -Added \scaleobj (like \scalebox, but defaults to math mode
%       using current display style).
% V1.5 -Eliminated mathstyle package because of incompatibilites with
%       many other packages.  Implemented \mathchoice approach instead.
\parskip 1em
\parindent 0em
\newcommand\rl{\rule{2em}{0in}}
\usepackage{scalerel}
\usepackage{verbatim}
\usepackage[only,llbracket,rrbracket,llparenthesis,rrparenthesis]{stmaryrd}
\usepackage{accsupp} % for ensuring the right Unicode codepoint upon pasting
\def\sr{\textsf{scalerel}}
\let\vb\verb
\reversemarginpar
\marginparwidth 1.6in
\newcommand\margtt[1]{\marginpar{\hfill\ttfamily#1}}
\newcommand\margcmd[1]{\marginpar{\hfill\ttfamily\char'134#1}}

\begin{document}
\begin{center}
\LARGE The \textsf{scalerel} Package\\
\rule{0em}{.7em}\small Routines for constrained scaling and stretching
of objects,\\relative to a reference object or in absolute terms\\
\rule{0em}{2.7em}\large Steven B. Segletes\\
steven.b.segletes.civ@mail.mil\\
\rule{0em}{1.7em}\today\\
v\version
\end{center}

\section{Commands and Description}
The \textsf{scalerel} package is used to scale and vertically stretch
objects, either relative to other objects, or in absolute terms.  Its
commands may be invoked in either math mode or text mode (if there is no
math in the objects to manipulate); however, the objects it manipulates
will, by default, be processed in math mode.  Nonetheless, one may
process the objects in text mode (assuming they do not contain
math-specific characters or commands) by specifying arguments as
\vb|{$object$}|, instead of the usual \vb|{object}|.

There are four basic commands with the \textsf{scalerel} package, two
of which have star variants:
\begin{verbatim}
  \scalerel[*][max_width]{object}{reference}
  \stretchrel[*][min_aspect]{object}{reference}
  \scaleto[max_width]{object}{height}
  \stretchto[min_aspect]{object}{height}
\end{verbatim} 
In addition, there are a number of added commands that have been
implemented as composites of the four basic commands, they are
\begin{verbatim}
  \scaleleftright[max_width]{left-obj.}{reference}{right-obj.}
  \stretchleftright[min_aspect]{left-obj.}{reference}{right-obj.}
  \hstretch{scale}{object}
  \vstretch{scale}{object}
  \scaleobj{scale}{object}
\end{verbatim}
There are also several auxiliary commands, supporting backward
compatibility, \textit{etc.}:
\begin{verbatim}
  \ignoremathstyle
  \discernmathstyle
  \ThisStyle{...\SavedStyle...}
  \Isnextbyte[[v] OR q]{test byte}{string}
\end{verbatim}

In all cases, \vb|object| is the object to be scaled or 
stretched.  It can be as simple as a symbol, like a summation sign
($\sum$), or it can be an object of complex description.  Likewise, in
cases of \textit{relative} scaling and stretching, \vb|reference| is
the reference object in relation to which the manipulated
\vb|object| is scaled or vertically stretched.  The \vb|reference|
may likewise be of complex description (such as a mathematical
expression).  When an \vb|object| is scaled or stretched
\textit{relative} to a \vb|reference| object, it is also vertically
shifted, if necessary, so that its vertical extent conforms to that of
the \vb|reference| object.

In cases of scaling or stretching \textit{to} a specified size,
\vb|height| will the final vertical height of \vb|object| following
a scale or stretch manipulation.  Since scaling or stretching to an
absolute size provides no \vb|reference| object, the baseline of
manipulated \vb|object| remains unchanged.

In cases of scaling (relative or absolute), the constraint
\vb|max_width| is optionally specified as the maximum width allowable
for the manipulated object.  If the manipulated width would otherwise
exceed this limit, the
\vb|object| width is scaled back to this limit.  If the \vb|object|
width is scaled back, its aspect ratio will change with respect to its
original shape.

By definition, vertical stretching will change the aspect ratio of an
object.  In the case of stretching (relative or absolute), the
constraint \vb|min_aspect| is the minimum aspect ratio allowed by the
stretch.  Its value is given in \%, such that a parameter value of
\texttt{100} indicates 100\% or an aspect ratio of 1.  If the stretch
would otherwise cause the manipulated \vb|object|'s aspect ratio to
fall below this value, the width of the manipulated \vb|object| is
increased to meet this minimum threshold.  The value of
\vb|min_aspect| must be an integer.

Because \textit{relative} scaling or stretching is done
\textit{relative} to a reference object, the \vb|\scalerel| and
\margcmd{scalerel}\margcmd{stretchrel}%
\vb|\stretchrel| commands will, by default, print out the
manipulated \vb|object| followed immediately by the \vb|reference|
object.  Because this may not always be desired, the star (*) version of
these commands suppresses the output of the \vb|reference| object, so
that only the \vb|object| that was manipulated is output.

The \vb|\scaleleftright| and \vb|\stretchleftright| commands
\margcmd{scaleleftright}\margcmd{stretchleftright}%
are intended to provide the functional capability of the \vb|\left| and
\vb|\right| commands in math mode, for delimiting symbols not
otherwise supported by those commands.

The \vb|\hstretch| and \vb|\vstretch commands| merely take the
\margcmd{hstretch}\margcmd{vstretch}%
second argument and either horizontally or vertically stretch it by a
scale factor given by the first argument.  The scale is not given in
percent, like some aforementioned commands.  Remember also, that these
commands are, by default processed in math mode.  In a like manner,
\margcmd{scaleobj}%
\vb|\scaleobj| performs a scale of the object.  It is like the
\vb|\scalebox| command of the \textsf{graphicx} package, except that
its argument (like others in this package) defaults to math mode, and is
displayed in the current math display style.

As of version 1.4, {\sr} commands will autodetect the current math
display style and process its arguments in the same mode.  However, this
improvement could ``break'' a prior (rare but) accepted usage of the
package in which the {\sr} \vb|object| is given in mixed mode
(containing \vb|$| characters in the middle of the \vb|object|.  In
order to maintain backward compatibility, the user may invoke
\margcmd{ignoremathstyle}%
\vb|\ignoremathstyle|.  Thereafter, {\sr} objects will be processed in
the prior (pre-version 1.4) manner, until the command
\margcmd{discernmathstyle}
\vb|\discernmathstyle| is later invoked to restore the more modern
package settings.

A useful auxiliary command \vb|\ThisStyle{}| has been introduced for
\margcmd{ThisStyle}%
remembering the current math style.  When invoked, this command will
remember the math style present at the time of its invocation and then
execute its argument.  Within the extent of its argument, an invocation
\margcmd{SavedStyle}%
of the macro \vb|\SavedStyle| will reinstate the math style that was
active upon invocation.  This command is very useful when \LaTeX{} boxes
are being set within the math environment, since the prevailing math
style does not carry into the box, without the use of
\vb|\SavedStyle|.

A service routine \vb|\Isnextbyte| was employed by this package.
\margcmd{Isnextbyte}%
Because of its more general utility, it is made accessible to the user.
It is an improved version of the command \vb|\isnextbyte| from the
\textsf{stringstrings} package.  It will determine if the first
byte from a passed string argument matches a specified
\textit{match}-character.  It produces a \vb|T| or \vb|F| result,
which is printed out by default.  With the use of the \vb|q| optional
argument, the output can be suppressed, with the result instead being
stored in a macro \vb|\theresult|.

\section{Usage Examples}

Now for a few examples.  Let us define
\begin{verbatim}
    \def\preblob{\displaystyle\sum_{i=0}^3}
    \def\blob{\displaystyle\frac{\displaystyle\frac{x^3}{z+r^3}}%
              {\displaystyle\frac{y}{x^2}}%
    }
\end{verbatim}
    \def\preblob{\displaystyle\sum_{i=0}^3}
    \def\blob{\displaystyle\frac{\displaystyle\frac{x^3}{z+r^3}}%
              {\displaystyle\frac{y}{x^2}}%
    }
Here are the raw definitions of \vb|$\preblob\blob$|, unscaled:

    \rl$\preblob\blob$

\subsection{The $\backslash$\texttt{scalerel} Command}

Now we employ \vb|$\scalerel{\preblob}{\blob}$|

    \rl$\scalerel{\preblob}{\blob}$

If we wish constrain the width of the summation to 3ex, we employ\\
\vb|$\scalerel[3ex]{\preblob}{\blob}$|

    \rl$\scalerel[3ex]{\preblob}{\blob}$

Of course, if the manipulated object contains text symbols, a width
constraint will change their aspect ratio, which may not be desirable.

Now let's say you wanted to introduce notation to bound mathematical
expressions by triangles. After defining
\vb|\blob| as before, you could use\\
\vb|$\scalerel[3ex]{\triangleleft}{\blob}|\\
\vb|\scalerel*[3ex]{\triangleright}{\blob}$|

\rl%
$\scalerel[3ex]{\triangleleft}{\blob}\scalerel*[3ex]{\triangleright}{\blob}$

Here, the second call to \vb|\scalerel| was with the star (\vb|*|)
option, indicating that \vb|\blob| should not be printed out following
the right-hand delimiter.  A less-tall expression would appear in those
same delimiters as

\rl%
$\scalerel[3ex]{\triangleleft}{Q}\scalerel*[3ex]{\triangleright}{Q}$

Because the width limit had not been reached, no horizontal compression
of the object was required.  Note: see the \vb|\scaleleftright| and
\vb|\stretchleftright| commands for a more direct way to employ these
sort of transformations.

\subsection{The $\backslash$\texttt{stretchrel} Command}

In its most simple application \vb|\stretchrel| can be used in the
fashion of a \vb|\left\{| in math mode.  While there is no reason to
replace that more efficient usage supplied by \LaTeX{}, it is
nonetheless instructional to see a comparison of 
\vb|$\left\{\blob\right.$| and \vb|$\stretchrel[400]{\{}{\blob}$|, to
see how the aspect-ratio limiting option can be employed to avoid an
overly stretched manipulation:

\rl$\left\{\blob\right.$  ~~~~~ $\stretchrel[400]{\{}{\blob}$

The expression on the right uses a standard \{ character, which has been
vertically stretched, but limited to an aspect ratio of 4.  To use
symbols for which the \vb|\left| nomenclature will not work,
\vb|\stretchrel| provides a viable alternative, as shown in this
stick-figure example:\\
\vb|3m $\stretchrel[500]{\updownarrow\,}|\\
\vb|{\fbox{\rule[-1.8em]{0ex}{4em}Work Table}}$|

\rl3m $\stretchrel[500]{\updownarrow\,}
  {\fbox{\rule[-1.8em]{0ex}{4em}Work Table}}$

or in this use, \vb|$\stretchrel[225]{\int}{\blob} dx$|, of the
stretched integral sign (aspect limited to 2.25):

\rl$\stretchrel[225]{\int}{\blob} dx$


\subsection{Baseline Shifts of \textit{Relative} Scales and Stretches}

It was mentioned that when \vb|\scalerel| and \vb|\stretchrel| are
employed, the manipulated object gets vertically shifted to match the
extent of the reference object.  To see how this works, we provide the
following example, that employs some inline math and scaling.  

\rl\underline{The baseline is the line that runs under this text}
\fbox{$\scalerel{i}{\blob}$}\underline{\scaleto{i}{43.32pt}}

The first case of the large letter ``i'' was generated with 
\vb|\scalerel|, and so the baseline of the ``i'', normally not a
descending letter, was dropped to conform to the descended reference
equation.  All of this was set in an \vb|\fbox| to show the extent of
the objects.  For comparison, an ``i'' of the samesize was then placed
using a \vb|\scaleto| command, which does not change the baseline of
the original object.

\subsection{The $\backslash$\texttt{scaleto} and
$\backslash$\texttt{stretchto} Commands}

The \vb|\scaleto| and \vb|\stretchto| commands are comparable to the
\vb|\scalerel| and \vb|\stretchrel| commands, except they do not
accept a reference object as their second mandatory argument.  Rather,
they take an absolute height (specified with units).  These commands use
the same optional arguments as \vb|\scalerel| and \vb|\stretchrel|
to constrain the width and/or the aspect ratio, respectively, of the
manipulated object.

As was mentioned in the prior section, a difference between these and
the \textit{relative} commands is that an object's baseline is not
altered with the use of \vb|\scaleto| and \vb|\stretchto|.  Because
there is no reference object employed with these commands, there is no
need for starred (\vb|*|) versions of these commands, which would
otherwise suppress the printing of the reference object.

Examples follow the established pattern established in prior sections.
First, we scale the equation blob used as an example in this
documentation to a vertical extent of 80pt, preserving the original
aspect ratio,

\rl\vb|$\scaleto{\blob}{80pt}$      | $\scaleto{\blob}{80pt}$

Then, we stretch the Greek letter, capital phi, to 60pt, but constrain
the aspect ratio to no less than 1.75.

\rl\vb|$\stretchto[175]{\Phi}{60pt}$      | $\stretchto[175]{\Phi}{80pt}$

\subsection{The $\backslash$\texttt{scaleleftright} and
 $\backslash$\texttt{stretchleftright}\\Commands}

These commands are composites of several \vb|\scalerel| and
\vb|\stretchrel| commands, intended to provide the functionality of
the \vb|\left ...\right| syntax of mathmode, for symbols for which
the \vb|\left ...\right| syntax does not work.  It uses the same
optional arguments as \vb|\scalerel| and \vb|\stretchrel| in order
to limit the width or aspect ratio of the respective manipulated
objects.  If one of the symbols on the left or right end of the enclosed
reference block is to be blank, these commands support the use of the
period argument \vb|{.}| as a blank placeholder, in a fashion
analogous to the \vb|\left ...\right| syntax of mathmode.

\rl\vb|$\scaleleftright[3ex]{\prod}{\blob}{\coprod}$  |
$\scaleleftright[3ex]{\prod}{\blob}{\coprod}$

\rl\vb|$\stretchleftright[450]{.}{\blob}{\in}$        |
$\stretchleftright[450]{.}{\blob}{\in}$

\subsection{The $\backslash$\texttt{hstretch},
 $\backslash$\texttt{vstretch}, and $\backslash$\texttt{scaleobj}
 Commands}

These commands simply perform horizontal or vertical stretching,
respectively.  They use a scale factor, rather than an absolute length.
If the stretch factor is greater than 1, the stretched length is larger
than the original.  If less than one, it is compressed with respect to
the original.

\rl\vb|$\otimes\hstretch{3}{\otimes}\hstretch{0.5}{\otimes}$ |
$\otimes\hstretch{3}{\otimes}\hstretch{0.5}{\otimes}$

\rl\vb|$\otimes\vstretch{3}{\otimes}\vstretch{0.5}{\otimes}$ |
$\otimes\vstretch{3}{\otimes}\vstretch{0.5}{\otimes}$

The \vb|\scaleobj| command performs scaling in the fashion of a
\vb|\scalebox| command, except that its argument is processed in math
mode of the current math display style, by default.  Thus, the
difference between the following two invocations:
\begin{verbatim}
  \(\scaleobj{2}{\sum_{i=0}^{n}}\)
  \[\scaleobj{2}{\sum_{i=0}^{n}}\]
\end{verbatim}
is given as
\(\scaleobj{2}{\sum_{i=0}^{n}}\) versus
\[\scaleobj{2}{\sum_{i=0}^{n}}\]

\section{Real World Application}

\subsection{White Curly Brackets}

Ref: http://tex.stackexchange.com/questions/100966/defining-
scalable-white- curly-brackets-and-and

\newcommand*{\llbrace}{%
  \BeginAccSupp{method=hex,unicode,ActualText=2983}%
    \textnormal{\usefont{OMS}{lmr}{m}{n}\char102}%
    \mathchoice{\mkern-4.05mu}{\mkern-4.05mu}{\mkern-4.3mu}{\mkern-4.8mu}%
    \textnormal{\usefont{OMS}{lmr}{m}{n}\char106}%
  \EndAccSupp{}%
}
\newcommand*{\rrbrace}{%
  \BeginAccSupp{method=hex,unicode,ActualText=2984}%
    \textnormal{\usefont{OMS}{lmr}{m}{n}\char106}%
    \mathchoice{\mkern-4.05mu}{\mkern-4.05mu}{\mkern-4.3mu}{\mkern-4.8mu}%
    \textnormal{\usefont{OMS}{lmr}{m}{n}\char103}%
  \EndAccSupp{}%
}

A user defined two new symbols made by combining the font glyphs of a
brace and a vertical strut, calling them \vb|\llbrace| and
\vb|\rrbrace|, to look as follows around an argument (in this case
$x$):

\def\wbrace{\scalebox{5}{$\llbrace x\rrbrace$}}
\rl\wbrace

But they found that when represented in reduced size fonts, the symbol
glyphs of the brace and the strut separated (note: \vb|\tiny| font has
been scaled up to match prior figure's height):

\def\tinywbrace{\scalebox{3}{\tiny$\llbrace x\rrbrace$}}
\rl$\scalerel*{\tinywbrace}{\wbrace}$

This happens because font designers don't merely scale their fonts when
shrunk down in size, but they do things (like thickening up lines and
changing aspect ratios) in an attempt to retain legibility.  In this
case, the font's auto-adjustment at smaller scale caused this composite
representation to change in unacceptable ways.

The \textsf{scalerel} solution was to use the image from the normal-size
representation and to shrink it down as needed.  So, in this case, a
normal-sized copy of the braces were stored in boxes called
\vb|\lXbrace| and \vb|\rXbrace|, resepctively.  Then the following
terms were defined:
\begin{verbatim}
\def\lxbrace{\scalerel*{\usebox{\lXbrace}}{\llbrace}}
\def\rxbrace{\scalerel*{\usebox{\rXbrace}}{\rrbrace}}
\end{verbatim} 
Now, in lieu of using \vb|\llbrace| directly, the use of
\vb|\lxbrace| would take a copy of the normal-sized \vb|\lXbrace|
and scale it down to the vertical height of the malformed tiny
\vb|\llbrace|, and substitute for it.  Here, we show the result at
both normal size and tiny size:

\newsavebox{\lXbrace}
\savebox{\lXbrace}{$\llbrace$}
\newsavebox{\rXbrace}
\savebox{\rXbrace}{$\rrbrace$}
\def\lxbrace{\scalerel*{\usebox{\lXbrace}}{\llbrace}}
\def\rxbrace{\scalerel*{\usebox{\rXbrace}}{\rrbrace}}
\rl$\scalerel*{\lxbrace x\rxbrace}{\wbrace}$
{\tiny$\scalerel*{\lxbrace x\rxbrace}{\wbrace}$}

Note that the brace is the properly formed scale of the normal-sized
brace in both cases, even as the $x$ adjusts to the fontsize reduction.

If one wanted the default braces narrower (to match the look of the
comparable symbols in the literature), one could use
\vb|\hstretch| in the definitions to achieve that quickly as
\begin{verbatim}
\def\lxbrace{%
   \hstretch{0.6}{\scalerel*{\usebox{\lXbrace}}{\llbrace}}}
\def\rxbrace{%
   \hstretch{0.6}{\scalerel*{\usebox{\rXbrace}}{\rrbrace}}}
\end{verbatim}

to give the following

\def\lxbrace{\hstretch{0.6}{\scalerel*{\usebox{\lXbrace}}{\llbrace}}}
\def\rxbrace{\hstretch{0.6}{\scalerel*{\usebox{\rXbrace}}{\rrbrace}}}
\rl$\scalerel*{\lxbrace x\rxbrace}{\wbrace}$
{\tiny$\scalerel*{\lxbrace x\rxbrace}{\wbrace}$}

Likewise, the \vb|\left| and \vb|\right| features of equation mode
cannot be used with the white braces, 

\rl \(\llbrace \left\llbracket\left\{\left[(a) \cdot
bc^{2^3}\right]^4\right\}^5\right\rrbracket \rrbrace\)

but \textsf{scalerel} can fix that, too:

\def\core{ \left\llbracket\left\{\left[(a) \cdot
bc^{2^3}\right]^4\right\}^5\right\rrbracket}%
\rl
\(\scaleleftright[1.5ex]{\lxbrace}{\core}{\rxbrace}\)

with 
\begin{verbatim}
  \(\scaleleftright[1.5ex]{\lxbrace}{\core}{\rxbrace}\)
\end{verbatim}
where \vb|\core| is the core inner equation to which the white braces
need to be scaled.  In this case, the scaled white braces were
width-limited to 1.5ex.

\subsection{Extra-Wide Oversymbols}

Refs:
http://tex.stackexchange.com/questions/86036/use-overarc-to-represent-an-arc/101539\#101539,
http://tex.stackexchange.com/questions/100574/really-wide-hat-symbol/101136\#101136

There are many oversymbols defined to stand over a single-letter
variable.  There are a smaller number of extra-wide oversymbols to
extend over small groups of symbols.  Occasionally, however, a need
arises for an oversymbol to stretch over a larger group of symbols.

With these definitions,
\begin{verbatim}
\newcommand\reallywidehat[1]{%
\begin{array}{c}%
\stretchto{%
  \scaleto{%
    \scalerel*[\widthof{#1}]{\bigwedge}%
    {\rule[-\textheight/2]{1ex}{\textheight}}% WIDTH-LIMITED
%                                              BIG WEDGE
  }{1.25\textheight}%  THIS STRETCHES THE WEDGE A LITTLE EXTRA
%                      WIDE
}{0.9ex}\\%            THIS SQUEEZES THE WEDGE TO 0.9ex HEIGHT
#1\\%                  THIS STACKS THE WEDGE ATOP THE ARGUMENT
\rule{0ex}{.01ex}%
\end{array}%
}


\newcommand\reallywideparen[1]{%
\begin{array}{c}%
\stretchto{%
  \scaleto{%
    \scalerel*[\widthof{#1}]{\frown}%
    {\rule[-\textheight/2]{1ex}{\textheight}}% WIDTH-LIMITED
%                                              BIG WEDGE
  }{1.25\textheight}%  THIS STRETCHES THE WEDGE A LITTLE EXTRA
%                      WIDE
}{0.6ex}\\%            THIS SQUEEZES THE WEDGE TO 0.6ex HEIGHT
#1\\%                  THIS STACKS THE WEDGE ATOP THE ARGUMENT
\rule{0ex}{.01ex}%
\end{array}%
}
\end{verbatim}
arbitrarily wide oversymbols may be constructed:

\newcommand\reallywidehat[1]{%
\begin{array}{c}%
\stretchto{%
  \scaleto{%
    \scalerel*[\widthof{#1}]{\bigwedge}%
    {\rule[-\textheight/2]{1ex}{\textheight}}% WIDTH-LIMITED BIG WEDGE
  }{1.25\textheight}%  THIS STRETCHES THE WEDGE A LITTLE EXTRA WIDE
}{0.9ex}\\%            THIS SQUEEZES THE WEDGE TO 0.9ex HEIGHT
#1\\%                  THIS STACKS THE WEDGE ATOP THE ARGUMENT
\rule{0ex}{.01ex}%
\end{array}%
}

\newcommand\reallywideparen[1]{%
\begin{array}{c}%
\stretchto{%
  \scaleto{%
    \scalerel*[\widthof{#1}]{\frown}%
    {\rule[-\textheight/2]{1ex}{\textheight}}% WIDTH-LIMITED BIG WEDGE
  }{1.25\textheight}%  THIS STRETCHES THE WEDGE A LITTLE EXTRA WIDE
}{0.6ex}\\%            THIS SQUEEZES THE WEDGE TO 0.6ex HEIGHT
#1\\%                  THIS STACKS THE WEDGE ATOP THE ARGUMENT
\rule{0ex}{.01ex}%
\end{array}%
}

\rl
$\reallywideparen{POQ}$ $+ \reallywidehat{QOR} + \reallywidehat{ROP}=
2\pi r$

\rl $\reallywidehat{zbcdefghijklm}$

\section{Future Development}

It would be relatively straightforward to extend this approach to
horizontal scaling problems.  However, it is not exactly clear to the
author what format is best suited for user needs.  If he gets feedback
in that regard, it will inform him how best to proceed.

\section{Code Listing}

\verbatiminput{scalerel.sty}

\end{document}
