tikz-pgf
Below is one solution (by @Stefan) for circled numbers with the help of tikz. What can I do to make it such that I can in-place customize its draw color, fill color, text color, etc.?
\documentclass[tikz,border=7pt]{standalone}
\newcommand*\circled[1]{\tikz[baseline=(char.base)]{
\node[shape=circle,draw,inner sep=2pt] (char) {#1};}}
\begin{document}
\circled{1}
\end{document}
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:
(the arrow got clipped, but you can see where it lies)
The node’s border is a path, you can use the same options for a \path, e.g. ultra thin, thick, very thick, and so on:
\node[circle, draw=blue!80, thick, inner sep=0pt, minimum size=12pt] (1) at (0,0) {1};
The line width key works as well:
\node[circle,draw=blue!80, line width=1mm, inner sep=0pt,minimum size=12pt] (1) at(0,0) {1};
All predefined line widths are
\tikzset{
ultra thin/.style= {line width=0.1pt},
very thin/.style= {line width=0.2pt},
thin/.style= {line width=0.4pt},% thin is the default
semithick/.style= {line width=0.6pt},
thick/.style= {line width=0.8pt},
very thick/.style= {line width=1.2pt},
ultra thick/.style={line width=1.6pt}
}
\documentclass[tikz]{standalone}
\begin{document}
\begin{tikzpicture}[
every node/.append style={circle, draw=blue!80, inner sep=0pt, minimum size=12pt}]
\node (1) at (0,0) {1};
\node[thick] (2) at (1,0) {2};
\node[line width=1mm] (3) at (2,0) {3};
\end{tikzpicture}
\end{document}
Best Answer
I would recommend using
tikzmarkhere because this amazing library detects which mode (text vs. math mode, if math mode, which) you are in, so you won't have to care about this. And I would like to argue that one should specify the line width in relative units such that it scales with the font size. Of course, you have all the possibilities to color stuff and so on. (The best part is that you can connect the nodes in paths and so on.)