[Tex/LaTex] \left\langle bigger then \Biggl\langle

beamerdelimitersmath-modescaling

I am putting a graphics inside
\left\langle .. \right\rangle, as

\left\langle \vcenter{\hbox{\includegraphics[scale=0.05]{images/lhs.pdf}}}\right\rangle_{av}

The problem is, as it seems, for scale=0.05, it is using \[l/r]angle's biggest possible size, and if I try to make the graphics bigger, it is not expanding.

I have searched google and stackexchange's older posts, and got this thread, which suggested to use scalebox.

I tried that, as

\scalebox{2.0}{\left\langle} \vcenter{\hbox{\includegraphics[scale=0.105]{images/lhs.pdf}}}\scalebox{2.0}{\left\langle} {\right\rangle}_{av}

which ends up in a error:

l.113 \end{frame}

? 
! Extra }, or forgotten \right.
\Gscale@box ...scale@y {#2}\setbox \z@ \hbox {{#3}
                                                  }\setbox \tw@ \hbox {\Gsca...
l.113 \end{frame}

l.113 is the \end{frame} of my working frame. So, something is missing. Not Sure.

May I get some help?

EDIT
As for example, 

\Biggl\langle \vcenter{\hbox{\includegraphics[scale=0.105]{images/lhs.pdf}}}\Biggr\rangle_{av}

gives

This Picture

Best Answer

The scalerel package allows you to scale up glyphs to meet the size of an object. The \scaleleftright{}{}{} macro mimics what you might have expected from the \left(...\right) syntax (but didn't get). The optional argument to \scaleleftright is the maximum allowed width of the scaled delimiter, since scaling a glyph very large without limiting its width often looks too thick in its stroke. Here, I have limited the width of the scaled angle brackets to 3ex.

I initially show the view without any manipulation, which is what you observed. Below to the left was my initial fix. Finally, to the right is taking Heiko's suggestion of using \Biggl\langle etc. to minimize the necessary scaling, which will leave the final scaled object not so thick in its stroke.

\documentclass{beamer}
\usepackage{scalerel}
\usepackage{graphicx}
\parskip 1em
\begin{document}
\centering\( \left\langle \vcenter{\hbox{\includegraphics[width=1.5in]{hlCr3}}}\right\rangle_{av} \)

\( {\scaleleftright[3ex]{\langle}{\vcenter{\hbox{%
  \includegraphics[width=1.5in]{hlCr3}}}}{\rangle}}_{\textstyle av} \)
\( {\scaleleftright[3ex]{\Biggl\langle}{\vcenter{\hbox{%
\includegraphics[width=1.5in]{hlCr3}}}}{\Biggr\rangle}}_{\textstyle av} \)
\end{document}

enter image description here

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