# mdframed with tikz-framework: roundcorner-keyword seem not to work completely

I got a similar problem to How to draw frame with rounded corners around box

I try to make round boxex for a poster presentation, I could nearly succeed using mdframed-package with tikz-option. But the innerline is almost not rounded and I can't see the reason why. Some small example-code:

\documentclass{beamer}
\usepackage[orientation=portrait,size=a0,scale=1.4,debug]{beamerposter}

\usepackage[absolute,overlay]{textpos}
\usepackage[framemethod=tikz]{mdframed}

\tikzset{contour/.style = {rounded corners = 2ex}}

\definecolor{posterbackground}{RGB}{255,245,225}    %beige
%\definecolor{blockborder}{RGB}{0,128,0}    %green
%\definecolor{blockborder}{RGB}{0,0,0}      %black
\definecolor{blockborder}{RGB}{235,235,235} %light grey

\mdfdefinestyle{frameborderstyle}%
{innerlinewidth=0.1em, innerlinecolor=black, middlelinewidth=1.0em, middlelinecolor=blockborder, outerlinewidth=0.1em, outerlinecolor=black, frametitlerule=false, innertopmargin=\topskip, backgroundcolor=posterbackground, roundcorner=0.5em}
%{outerlinecolor=blockborder, outerlinewidth=10pt, innerlinewidth=5pt, backgroundcolor=posterbackground, roundcorner=50pt}
\newenvironment{textframe}[4][]%
{\colorlet{currentcolor}{.} \fboxrule0.2em\fboxsep1.0em \begin{textblock*}{#2}(#3,#4) \begin{mdframed}[style=frameborderstyle, frametitle=#1]}
{\end{mdframed} \end{textblock*} \vspace{2.0ex}}

\begin{document}
\begin{frame}{blabla}
\begin{textframe}{1500pt}{50pt}{670pt}
this is written in a textpos-frame this is written in a textpos-frame this is written in a textpos-frame this is written in a textpos-frame this is written in a textpos-frame this is written in a textpos-frame this is written in a textpos-frame this is written in a textpos-frame this is written in a textpos-frame this is written in a textpos-frame this is written in a textpos-frame this is written in a textpos-frame this is written in a textpos-frame this is written in a textpos-frame
\end{textframe}
\end{frame}
\end{document}


What am I doing wrong?

You have to understand the calculation of the arc by TikZ. This is important because mdframed has no extra modification for the inner arc. Of course I can implement it.

Let's take the following mwe:

\documentclass{article}

\usepackage{tikz}

\begin{document}
\begin{tikzpicture}
\draw[line width=2ex,rounded corners = 1ex] (0,0) rectangle (7,4);
\end{tikzpicture}
\end{document}


The line width is 2ex and the arc is 1ex. The result is:

As you can see the inner arc isn't there. If you you increase rounded corners greater than 2ex you will get:

\documentclass{article}
\usepackage{tikz}

\begin{document}
\begin{tikzpicture}
\draw[line width=2ex,rounded corners = 3ex] (0,0) rectangle (7,4);
\end{tikzpicture}
\end{document}


Related to your example: Your are using innerlinewidth=0.1em, middlelinewidth=1.0em and outerlinewidth=0.1em which leads to the width 1.2em. On the other hand you are specifying roundcorner=0.5em. As explained 0.5em is too small.

So you can either use a greater dimension for roundcorner or you redefine some internal commands to specify an inner arc.

• ah how complex, thanks for the explanation :-) – Alice Jun 26 '13 at 8:35