Breakable tcolorbox and centering environment error

Question

I believe I have a compatibility problem with center environment and the breakable tcolorbox package.

What I'm doing is:

\usepackage[breakable]{tcolorbox}
\tcbset{before=\begin{center}, after=\end{center}, width=0.8\linewidth, colback=blue!20!white, colframe=blue!70!white, boxrule=0.3mm, toptitle=1.5mm, bottomtitle=1.5mm}

The document is compiled but with some errors:

\begin{center} on input line 53 ended by \end{tcolorbox}. \end{tcolorbox}
\begin{tcolorbox} on input line 43 ended by \end{center}. \end{tcolorbox}
Missing } inserted. \end{tcolorbox}
Too many }'s. \end{tcolorbox}

Beforehand, I appreciate your help!

Answer 1

There is no need for etoolbox. tcolorbox has facilities for this.

When you say width=0.8\linewidth,, to make the box centered, you have to push it to right by 0.1\linewidth. This can be done by

,enlarge left by=0.1\linewidth,
%% enlarge right by=0.1\linewidth  %% if needed from right

So this code (template stolen from Christian Hupfer) works as intended.

\documentclass{article}
\usepackage{showframe}
\usepackage[breakable]{tcolorbox}

\newtcolorbox{brokenbox}[1][]{width=0.8\linewidth, colback=blue!20!white, colframe=blue!70!white, boxrule=0.3mm, toptitle=1.5mm, bottomtitle=1.5mm,breakable,enlarge left by=0.1\linewidth,#1}


\usepackage{blindtext}

\begin{document}

\begin{brokenbox}[colback=yellow]
  \blindtext[5]
\end{brokenbox}

\end{document}

Answer 2

The breaking mechanism uses individual tcolorbox enviroments and I assume that the verbatim way of tcolorbox provides wrong \end{tcolorbox} code for the last box -- the \end{center} is lost.

Using \BeforeBeginEnvironment and \AfterEndEnvironment from the etoolbox package this can be circumvented:

\documentclass{article}
\usepackage{etoolbox}
\usepackage[breakable]{tcolorbox}

\newtcolorbox{brokenbox}[1][]{width=0.8\linewidth, colback=blue!20!white, colframe=blue!70!white, boxrule=0.3mm, toptitle=1.5mm, bottomtitle=1.5mm,breakable,#1}


\usepackage{blindtext}


\BeforeBeginEnvironment{brokenbox}{%
\begin{center}
}

\AfterEndEnvironment{brokenbox}{%
\end{center}
}

\begin{document}

\begin{brokenbox}[colback=yellow]
  \blindtext[5]
\end{brokenbox}

\end{document}

Answer 3

As a complement to the two other answers which already solve the problem, here is third possibility. Instead of restricting the width of the box to 0.8\linewidth followed by some centering method, the left skip and right skip values could be set to 0.1\linewidth. Technically, this changes the bounding box and gives the same effect as the answer by Harish Kumar.

\documentclass{article}
\usepackage{showframe}
\usepackage[breakable]{tcolorbox}

\newtcolorbox{brokenbox}[1][]{
  % width=0.8\linewidth,          <---- removed
  leftright skip=0.1\linewidth,%  <---- added
  colback=blue!20!white,
  colframe=blue!70!white,
  boxrule=0.3mm,
  toptitle=1.5mm,
  bottomtitle=1.5mm,
  breakable,
  #1}

\usepackage{blindtext}

\begin{document}

\begin{brokenbox}[colback=yellow]
  \blindtext[5]
\end{brokenbox}

\end{document}