Placing text along node shape

tikz-pgf

I'd like to place text along the shape of a node. The MWE below generates the following image. I'd like the text 'Classic First Program' to follow the circle of the node shape.

\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\draw (0,0) node [label=above:Classic First Program, align=center,circle,font=\huge,draw] {Hello\\ World!};
\end{tikzpicture}
\end{document}

Is there an automated way to do this without self-defining another path that matches the node shape? I'd like to be able to change the interior text (and hence the node shape) without also having to adjust the label text.

Best Answer

Maybe there is an easy way, but I could not find it.

\documentclass[tikz, border=1 cm]{standalone}
\usetikzlibrary{decorations.text}
\begin{document}
\begin{tikzpicture}
\node[
circle, 
draw,
align=center,
font=\huge,
decoration={text along path, text align=center, reverse path=true, text={Classic First Program}},
postaction={decorate}, 
rotate=-90,
]  {\rotatebox[origin=c]{90}{Hello}\,\rotatebox[origin=c]{90}{World!}};
\end{tikzpicture}
\end{document}

Edit: An alternative way:

\documentclass[tikz, border=1 cm]{standalone}
\usetikzlibrary{decorations.text}
\begin{document}
\begin{tikzpicture}
\node[
circle, 
draw,
align=center,
font=\huge,
text opacity=0,
decoration={text along path, text align=center, reverse path=true, text={Classic First Program}},
postaction={decorate}, 
rotate=-90,
label={[align=center, font=\huge]center:Hello\\World!},
]  {Hello\\World!};
\end{tikzpicture}
\end{document}

Edit: I did it :o)

\documentclass[tikz, border=1 cm]{standalone}
\usetikzlibrary{decorations.text}
\begin{document}
\begin{tikzpicture}
\node[
circle, 
draw,
align=center,
font=\huge,
decoration={text along path, text align=center, reverse path=true, text={Classic First Program}},
postaction={transform canvas={rotate=-90}, postaction={decorate}}, 
]  {Hello\\World!};
\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] Numerical conditional within tikz keys

I am definitely unfamiliar with both beamer and tikz (do not quite get what the \only are supposed to do) but perhaps this could go in the direction you want:

\documentclass{beamer}
\usepackage{tikz}
\usetikzlibrary{chains}
\newcounter{count}

% helper macro:
\long\def\GobToSemiColon #1;{}

\newcommand\myPicture{
\begin{tikzpicture}
  \begin{scope}[start chain = going below]
  \ifnum\value{count}<1 \expandafter\GobToSemiColon\fi
  \ifnum\value{count}>3 \expandafter\GobToSemiColon\fi
  \node[draw, rectangle, on chain] {display only when counter is between
    1 and 3};

  \ifnum\value{count}>-1 \expandafter\GobToSemiColon\fi
  \node[draw, rectangle, on chain] {display only when counter is
    negative}; 

  \ifnum\value{count}<100 \expandafter\GobToSemiColon\fi
  \ifnum\value{count}>200 \expandafter\GobToSemiColon\fi  
  \node[draw, rectangle, on chain] {display only if counter is between
    100 and 200};

  \ifnum\value{count}<3 \expandafter\GobToSemiColon\fi
  \ifnum\value{count}>20 \expandafter\GobToSemiColon\fi
  \node[draw, circle, on chain] {only when counter is in the range 3 to 20};
  \end{scope}
\end{tikzpicture}
}

\begin{document}
\begin{frame}
\only{\setcounter{count}{-3}\myPicture}
\only{\setcounter{count}{105}\myPicture}
\only{\setcounter{count}{39}\myPicture}
\only{\setcounter{count}{2}\myPicture}
\only{\setcounter{count}{5}\myPicture}
\end{frame}
\end{document}

beamer

Best Answer

Related Solutions

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

[Tex/LaTex] Numerical conditional within tikz keys

Related Question