Underbrace change font style

Question

I tried to underbrace a text with size 13 in ttfamily style. But as soon as I apply the underbrace, it changes the style. I also changed the color but that works somehow. I didn't find any options to set the font size or family, can this be done?

Here is the code I tried to achieve my target:

\fontsize{13}{13}{
  \ttfamily{
    $\underbrace{\textcolor{blue}{Title}}_{Title of the Project}$
  }
}

I don't care too much about the font, size and color below the braces but the one above is important. Would be great if that could be adjusted as well though.

Answer 1

You could use

$\underbrace{\texttt{\textcolor{blue}{Title}}}_{\texttt{Title}}$

but with some more work you can obtain a fairly general command where you can set text properties independently.

\documentclass{article}
\usepackage{amsmath}
\usepackage{xcolor}

\ExplSyntaxOn

\NewDocumentCommand{\textunderbrace}{ O{} m m }
  {
    \group_begin:
    \invalid_tub:NNnnn \underbrace \sb { #1 } { #2 } { #3 }
    \group_end:
  }
\NewDocumentCommand{\textoverbrace}{ O{} m m }
  {
    \group_begin:
    \invalid_tub:NNnnn \overbrace \sp { #1 } { #2 } { #3 }
    \group_end:
  }

\keys_define:nn { invalid/tub }
  {
    font .tl_set:N = \l__invalid_tub_font_tl,
    font-main .tl_set:N = \l__invalid_tub_fontmain_tl,
    font-sub .tl_set:N = \l__invalid_tub_fontsub_tl,
    color .tl_set:N = \l__invalid_tub_color_tl,
    color-main .tl_set:N = \l__invalid_tub_colormain_tl,
    color-sub .tl_set:N = \l__invalid_tub_colorsub_tl,
    font .initial:n = \text,
    color .initial:n = .,
  }

\cs_new_protected:Nn \invalid_tub:NNnnn
  {
    \keys_set:nn { invalid/tub } { #3 }
    \tl_if_empty:NT \l__invalid_tub_fontmain_tl
      {
        \tl_set_eq:NN \l__invalid_tub_fontmain_tl \l__invalid_tub_font_tl
      }
    \tl_if_empty:NT \l__invalid_tub_fontsub_tl
      {
        \tl_set_eq:NN \l__invalid_tub_fontsub_tl \l__invalid_tub_font_tl
      }
    \tl_if_empty:NT \l__invalid_tub_colormain_tl
      {
        \tl_set_eq:NN \l__invalid_tub_colormain_tl \l__invalid_tub_color_tl
      }
    \tl_if_empty:NT \l__invalid_tub_colorsub_tl
      {
        \tl_set_eq:NN \l__invalid_tub_colorsub_tl \l__invalid_tub_color_tl
      }
    \ensuremath
      {
        #1 % \underbrace or \overbrace
         {
          \l__invalid_tub_fontmain_tl { \color{\l__invalid_tub_colormain_tl} #4 }
         }
        #2 % \sb or \sp
         {
          \l__invalid_tub_fontsub_tl { \color{\l__invalid_tub_colorsub_tl} #5 }
         }
      }
  }

\ExplSyntaxOff

\begin{document}

$\underbrace{\texttt{\textcolor{blue}{Title}}}_{\texttt{Title of the Project}}$
\textunderbrace[font=\texttt,color-main=blue]{Title}{Title of the Project}

\bigskip

\textunderbrace{Title}{Title of the project}

\bigskip

\textoverbrace[
  font-main=\texttt,
  font-sub=\textit,
  color-main=blue,
  color-sub=red,
]{Title}{Title of the Project}

\end{document}

If you use font=<command>, it will affect both parts; but you can set separately font-main and font-sub; similarly for color, color-main and color-sub.

Fewer braces mean fewer occasions to count them wrong.