[Tex/LaTex] How to flip the direction of curly braces in TikZ

tikz-pgf

I am using TikZ with the following code to draw a picture. How can I turn the curly bracket next to $P_2$ to the right?

\documentclass{article}

\usepackage{tikz}
\usetikzlibrary{decorations.pathreplacing}

\begin{document}

\begin{tikzpicture}[scale=1]
\draw[thick] (-1,0) rectangle +(6,7.5);
\filldraw[thick, top color=white,bottom color=red!50!] (0.5,0) rectangle node{$N_S$} +(1.3,0.5);
\filldraw[thick, top color=white,bottom color=red!50!] (2.2,0) rectangle node{$N_L$} +(1.3,0.65);
\filldraw[top color=white,bottom color=blue!50!] (0.5,0.5) rectangle node{$P_{1}$} +(1.3,0.5);
\filldraw[top color=white,bottom color=blue!50!] (2.2,0.65) rectangle node{$P_{2}$} +(1.3,1.0);
\filldraw[top color=white,bottom color=blue!50!] (0.5,1.0) rectangle node{$P_{3}$} +(1.3,1.5);
\filldraw[top color=white,bottom color=blue!50!] (2.2,1.65) rectangle node{$P_{4}$} +(1.3,2.0);
\filldraw[top color=white,bottom color=blue!50!] (0.5,2.5) rectangle node{$P_{5}$} +(1.3,2.5);
\filldraw[top color=white,bottom color=blue!50!] (2.2,3.65) rectangle node{$P_{6}$} +(1.3,3.0);
\draw [decorate,decoration={brace,amplitude=10pt},xshift=-4pt,yshift=0pt]
(0.5,0.5) -- (0.5,5.0) node [black,midway,xshift=-0.6cm] 
{\footnotesize $P_1$};
\draw [decorate,decoration={brace,amplitude=10pt},xshift=-4pt,yshift=0pt]
(3.5,0.65) -- (3.5,6.5)node [black,midway,xshift=9pt] {\footnotesize
$P_2$};
\end{tikzpicture}
\end{document}

enter image description here

Best Answer

There's a mirror option for the decorations which in essence turns the direction of the path around:

\documentclass{article}

\usepackage{tikz}
\usetikzlibrary{decorations.pathreplacing}

\begin{document}
\begin{tikzpicture}[scale=1]
\draw[thick] (-1,0) rectangle +(6,7.5);
\filldraw[thick, top color=white,bottom color=red!50!] (0.5,0) rectangle node{$N_S$} +(1.3,0.5);
\filldraw[thick, top color=white,bottom color=red!50!] (2.2,0) rectangle node{$N_L$} +(1.3,0.65);
\filldraw[top color=white,bottom color=blue!50!] (0.5,0.5) rectangle node{$P_{1}$} +(1.3,0.5);
\filldraw[top color=white,bottom color=blue!50!] (2.2,0.65) rectangle node{$P_{2}$} +(1.3,1.0);
\filldraw[top color=white,bottom color=blue!50!] (0.5,1.0) rectangle node{$P_{3}$} +(1.3,1.5);
\filldraw[top color=white,bottom color=blue!50!] (2.2,1.65) rectangle node{$P_{4}$} +(1.3,2.0);
\filldraw[top color=white,bottom color=blue!50!] (0.5,2.5) rectangle node{$P_{5}$} +(1.3,2.5);
\filldraw[top color=white,bottom color=blue!50!] (2.2,3.65) rectangle node{$P_{6}$} +(1.3,3.0);
\draw [decorate,decoration={brace,amplitude=10pt},xshift=-4pt,yshift=0pt]
(0.5,0.5) -- (0.5,5.0) node [black,midway,xshift=-0.6cm] 
{\footnotesize $P_1$};
\draw [decorate,decoration={brace,amplitude=10pt,mirror,raise=4pt},yshift=0pt]
(3.5,0.65) -- (3.5,6.5) node [black,midway,xshift=0.8cm] {\footnotesize
$P_2$};
\end{tikzpicture}
\end{document}

Related Solutions

[Tex/LaTex] Rotate a node but not its content: the case of the ellipse decoration

The source of the difficulty is that ellipses are constructed in a particular way in TikZ. They are paths that start from the x-axis and proceed counter-clockwise around their centre. The vast majority of the time, the exact parametrisation doesn't matter. You appear to have found the one situation where it does!

In the actual question, you only want to be able to mirror the ellipse, and so draw it starting from the negative x-axis (the title of the question suggests a more flexible approach). That's actually not too hard since we can exploit the symmetry of the ellipse. The key is to provide it with a negative x-radius, since then it will start from the negative x-axis (and proceed clockwise, but we could correct for that by negating the y-radius as well). To do this, we interrupt the call from the node shape to the drawing command and flip the sign of the x-radius. The simplest way to do this is to redefine the \pgfpathellipse macro to do the negation and then call the original macro. The following code does this.

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{decorations,shapes,decorations.markings}
\makeatletter
\let\origpgfpathellipse=\pgfpathellipse
\def\revpgfpathellipse#1#2#3{%
  #2%
  \pgf@xa=-\pgf@x
  \origpgfpathellipse{#1}{\pgfqpoint{\pgf@xa}{0pt}}{#3}}
\makeatother

\tikzset{
  reversed ellipse/.style={
    ellipse,
    reverse the ellipse%
  },
  reverse the ellipse/.code={
    \let\pgfpathellipse=\revpgfpathellipse
  }
}
\begin{document}
\begin{tikzpicture}
\node[ellipse,
  draw,
  postaction={
    decorate,
    decoration={
      markings,
      mark=at position 1 with {
        \arrow[line width=5pt,blue]{>}
      }
    }
  }
] at (0,0) {hello world};

\node[reversed ellipse,
  draw,
  postaction={
    decorate,
    decoration={
      markings,
      mark=at position 1 with {
        \arrow[line width=5pt,blue]{>}
      }
    }
  }
] at (0,-2) {hello world};
\end{tikzpicture}

\end{document}

Here's the result:

rotated ellipse

(the arrow got clipped, but you can see where it lies)

[Tex/LaTex] short curly braces with tikz

Here is a primitive meta-decoration, but it is not as general as the standard brace such as raise,mirror etc. won't work. However, the brace amplitude and other local brace options are passed and would be available as I tried to show below. The new raise amount is controlled with meta-amplitude key.

\documentclass[tikz]{standalone}
\usetikzlibrary{decorations.pathreplacing}

\pgfdeclaremetadecoration{raisedbrace}{initial}{%
\state{initial}[width=\pgfmetadecoratedpathlength]{%
  \decoration{brace}%
  \pgfsetdecorationsegmenttransformation{%
      \pgftransformyshift{\pgfmetadecorationsegmentamplitude}%
  }
  \beforedecoration{
    \pgfpathmoveto{\pgfpointmetadecoratedpathfirst}
    \pgfpathlineto{\pgfpointadd{%
      \pgfpointmetadecoratedpathfirst%
      }{%
      \pgfpointpolar{\pgfdecoratedangle+90}{\pgfmetadecorationsegmentamplitude}%
      }%
    }%
  }%
  \afterdecoration{%
    \pgfpathlineto{\pgfpointmetadecoratedpathlast}%
    \pgfusepath{stroke}
  }
}
}
\begin{document}
\begin{tikzpicture}
\draw[style=help lines] (-1,-1) grid[step=1cm] (3,3);
\draw[decorate,decoration={raisedbrace,amplitude=2mm,meta-amplitude=4mm}]  (0,1) -- (2,2);  
\draw[decorate,decoration={raisedbrace,amplitude=4mm,meta-amplitude=1cm}]  (0,-1) -- (2,-0.5);
\draw[decorate,decoration={raisedbrace,amplitude=1cm,meta-amplitude=5mm}]  (2,3) -- (2,-0.5);
\end{tikzpicture}
\end{document}

enter image description here

Best Answer

Related Solutions

[Tex/LaTex] Rotate a node but not its content: the case of the ellipse decoration

[Tex/LaTex] short curly braces with tikz

Related Question