Is it possible to set the title for an mdframed newmdenv without specifying the frametitle key

Question

I want to be able to invoke a mdframed box and specify a title without using the frametitle=Title syntax:

I want to write

\begin{mdframedbox}[Title]
    ...content here...
\end{mdframedbox}

instead of

\begin{mdframedbox}[frametitle=Title]
    ...content here...
\end{mdframedbox}

Here is a tex document that compiles without contains how I am currently using the mdframed package to create a box.

\documentclass{article}

\usepackage[framemethod=TikZ]{mdframed}%boxes
\usepackage{xcolor}%boxes
\usepackage{lipsum}

%% Generic use box with grey background
\newmdenv[%
    backgroundcolor=gray!15,
    linecolor=black,
    outerlinewidth=1pt,
    roundcorner=1mm,
    skipabove=\baselineskip,
    skipbelow=\baselineskip,
    font=\small,
    nobreak=true,
]{graybox}

\begin{document}

\begin{graybox}[frametitle=Gray Box Title]
\lipsum[1]
\end{graybox}

\end{document}

Edit:

I have looked through the documentation for mdframed and didn't see anything that stood out. My first guess is that it's not possible as mdframed is written and I'll need to write a wrapper environment around it to get the desired behavior, however I wanted to make sure that I didn't miss something that already existed before trying to write said wrapper

Answer 1

What I've done is just modify very slightly the way \begin{graybox} works so that it new requires one argument which is the title. I then pass that to the frametitle key. I did this by modify the \graybox command which is implicitly called when you have \begin{graybox}. The little bit of magic that does this is:

\let\orig@graybox=\graybox
\def\graybox#1{
  \orig@graybox[frametitle={#1}]
}

The first line save the original \graybox definition in \orig@graybox. The second and third lines overwrite the \graybox definition so that it calls the original graybox and passes its the first argument (denoted by #1) to the frametitle key.

The \makeatletter and \makeatother below allows the @ symbol to be used in definitions so that \orig@graybox can't be accidentally used in the code.

\documentclass{article}

\usepackage[framemethod=TikZ]{mdframed}%boxes
\usepackage{xcolor}%boxes
\usepackage{lipsum}

%% Generic use box with grey background
\newmdenv[%
    backgroundcolor=gray!15,
    linecolor=black,
    outerlinewidth=1pt,
    roundcorner=1mm,
    skipabove=\baselineskip,
    skipbelow=\baselineskip,
    font=\small,
    nobreak=true,
]{graybox}

\makeatletter
\let\orig@graybox=\graybox
\def\graybox#1{
  \orig@graybox[frametitle={#1}]
}
\makeatother

\begin{document}

\begin{graybox}{Gray Box Title}
\lipsum[1]
\end{graybox}

\end{document}

Addendum

If you want to have the possibility of not displaying a title, the easiest option is to leave the argument blank as the mdframed package will take an blank frametitle as indicating no title.

Otherwise, an alternative would be to give it an optional argument which is conventionally surrounded by [].

% ...
\makeatletter
\let\orig@graybox=\graybox
\def\graybox{
  \@ifnextchar[{\graybox@opt}{\orig@graybox}
}
\def\graybox@opt[#1]{
  \orig@graybox[frametitle={#1}]
}
\makeatother

\begin{document}

\begin{graybox}[Gray Box Title]
\lipsum[1]
\end{graybox}

\begin{graybox}
\lipsum[1]
\end{graybox}

\end{document}