TikZ-PGF – How to Draw an Elliptical Arc with Given Radii in TikZ

tikz-pgf

I am new to TikZ and reading its manual now.
For the sake of exercises, I want to draw Batman's logo as follows:

enter image description here

Using TikZ, how to draw an elliptical arc starting from point A to point B with the origin as its center?

\documentclass{article}
\usepackage{tikz}


\usepackage[active,tightpage]{preview}
\PreviewEnvironment{tikzpicture}
\PreviewBorder=12pt


\begin{document}
\begin{tikzpicture}

    \filldraw[fill opacity=0.5,fill=yellow] (0,0) ellipse (7.0 and 4.3);
    \draw[line width=5mm] (0,0) ellipse (6.5 and 3.8);
    \draw[line width=2pt,dashed,white] (0,0) ellipse (6.0 and 3.3);

    \draw[line width=2pt]   
                            (0,2.7) -- (0.5,2.7) -- (1,3.25) 
                            .. controls (1.2,1.3) and (1.3,1.0) .. 
                            (2.0,1.0) 
                            .. controls (3.0,1.0) and (3.0,2.2) .. 
                            (2,3.1);

    %How to draw an elliptical arc from (2,3.1) to (3.2,-2.8)?
    %\draw ()   arc ();

    \draw[line width=2pt] 
            (3.2,-2.8) 
            .. controls (4,-2) and (4,0) ..
            (2.2,-1.8)
            .. controls (1.5,-1) and (1,-1) ..
            (0,-3.2);
\end{tikzpicture}
\end{document}

Note: Horizontal and vertical radii are given.

Bonus question: Instead of drawing the left part by using the same method as I did for the right part, how to use reflection technique to get a complete Batman's logo?

Best Answer

I would use a slightly lower level PGF (Portable Graphics Format) command \pgfpatharcto for this ~~and I have guessed the 11cm by eyeballing~~. For the bonus I created a scope where I defined the x unit vector to be (-1,0) so whatever is drawn inside, the horizontal coordinate will be reversed. Hence, I can literally copy the right part code into left part except the arc command which accepts absolute coordinates (unless there is any coordinate transformation is going on).

\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
    \filldraw[fill opacity=0.5,fill=yellow] (0,0) ellipse (7.0 and 4.3);
    \draw[line width=5mm] (0,0) ellipse (6.5 and 3.8);
    \draw[line width=2pt,dashed,white] (0,0) ellipse (6.0 and 3.3);

    \draw[line width=2pt]   (0,2.7) -- (0.5,2.7) -- (1,3.25) 
                            .. controls (1.2,1.3) and (1.3,1.0) .. 
                            (2.0,1.0) .. controls (3.0,1.0) and (3.0,2.2) .. (2,3.1);
    \draw[line width=2pt] 
            (3.2,-2.8) .. controls (4,-2) and (4,0) .. (2.2,-1.8)
            .. controls (1.5,-1) and (1,-1) ..(0,-3.2);

    \pgfsetlinewidth{2pt}
    \pgfmoveto{\pgfpoint{2cm}{3.1cm}}
    \pgfpatharcto{6cm}{3.3cm}{0}{0}{0}{\pgfpoint{3.2cm}{-2.8cm}}\pgfusepath{stroke};

\begin{scope}[x=-1cm]
    \draw[line width=2pt]   (0,2.7) -- (0.5,2.7) -- (1,3.25) 
                            .. controls (1.2,1.3) and (1.3,1.0) .. 
                            (2.0,1.0) .. controls (3.0,1.0) and (3.0,2.2) .. (2,3.1);
    \draw[line width=2pt] 
            (3.2,-2.8) .. controls (4,-2) and (4,0) .. (2.2,-1.8)
            .. controls (1.5,-1) and (1,-1) ..(0,-3.2);
\end{scope}
    \pgfsetlinewidth{2pt}
    \pgfmoveto{\pgfpoint{-2cm}{3.1cm}}
    \pgfpatharcto{6cm}{3.3cm}{0}{0}{1}{\pgfpoint{-3.2cm}{-2.8cm}}\pgfusepath{stroke};
\end{tikzpicture}
\end{document}

enter image description here

EDIT2 : Filling the curve was much difficult with the code above so making a continuous path seemed easier since Damien already provided the necessary coordinates. There is simply no complication other than renaming the commands. The \pgfpathcurveto is equivalent to \draw (coord1) ..controls (support1) and (support2) .. (coord2) except that you have to move to (coord1) first. After the coordinate transformation, it is again a matter of copy-paste.

\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}

    \filldraw[fill opacity=0.5,fill=yellow] (0,0) ellipse (7.0 and 4.3);
    \draw[line width=5mm] (0,0) ellipse (6.5 and 3.8);
    \draw[line width=2pt,dashed,white] (0,0) ellipse (6.0 and 3.3);

\pgfsetlinewidth{2pt}
\pgfpathmoveto{\pgfpoint{0}{2.7cm}}
\pgfpathlineto{\pgfpoint{0.5cm}{2.7cm}}
\pgfpathlineto{\pgfpoint{1cm}{3.25cm}}
\pgfpathcurveto{\pgfpoint{1.2cm}{1.3cm}}{\pgfpoint{1.3cm}{1cm}}{\pgfpoint{2cm}{1cm}}
\pgfpathcurveto{\pgfpoint{3cm}{1cm}}{\pgfpoint{3cm}{2.2cm}}{\pgfpoint{2cm}{3.1cm}}
\pgfpatharcto{6cm}{3.3cm}{0}{0}{0}{\pgfpoint{3.2cm}{-2.8cm}}
\pgfpathcurveto{\pgfpoint{4cm}{-2cm}}{\pgfpoint{4cm}{0}}{\pgfpoint{2.2cm}{-1.8cm}}
\pgfpathcurveto{\pgfpoint{1.5cm}{-1cm}}{\pgfpoint{1cm}{-1cm}}{\pgfpoint{0cm}{-3.2cm}}
\pgftransformcm{-1}{0}{0}{1}{\pgfpointorigin} % This is the coordinate change from x to -x
\pgfpathcurveto{\pgfpoint{1cm}{-1cm}}{\pgfpoint{1.5cm}{-1cm}}{\pgfpoint{2.2cm}{-1.8cm}}
\pgfpathcurveto{\pgfpoint{4cm}{0cm}}{\pgfpoint{4cm}{-2cm}}{\pgfpoint{3.2cm}{-2.8cm}}
\pgfpatharcto{6cm}{3.3cm}{0}{0}{1}{\pgfpoint{2cm}{3.1cm}}
\pgfpathcurveto{\pgfpoint{3cm}{2.2cm}}{\pgfpoint{3cm}{1cm}}{\pgfpoint{2cm}{1cm}}
\pgfpathcurveto{\pgfpoint{1.3cm}{1cm}}{\pgfpoint{1.2cm}{1.3cm}}{\pgfpoint{1cm}{3.25cm}}
\pgfpathlineto{\pgfpoint{0.5cm}{2.7cm}}
\pgfpathclose
\pgfusepath{fill,stroke}   


\end{tikzpicture}
\end{document}

EDIT3 Alfred, join this curve nicely will ya? So we draw one half and carry on backwards for a proper line join at the tail and fill.

enter image description here

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] How to draw an arc with varying line thickness

Here you have a TikZ version, although it's "cheated": it doesnt draw arcs, but overlays a white ellipse on top of a red one:

\documentclass[parskip]{scrartcl}
\usepackage[margin=15mm]{geometry}
\usepackage{tikz}
\usepackage{kurier}

\begin{document}
\begin{tikzpicture}[scale=0.5, every node/.style={font=\fontsize{70}{70}\selectfont}];
\fill[red] (0,0) circle (10cm and 5cm);
\fill[white] (0.5,0.5) circle (9.5cm and 4.75cm);
\node[blue] at (0,1.3) {infineon};
\fill[white] (-8.1,2.8) circle (0.7cm);
\fill[blue] (-8.1,2.8) circle (0.5cm);
\end{tikzpicture}
\end{document}

enter image description here

Edit 1: I tweaked it a little: a better font, and I used your colors:

\documentclass[parskip]{scrartcl}
\usepackage[margin=15mm]{geometry}
\usepackage{tikz}
%\usepackage[condensed,math]{iwona}
\usepackage{iwona}
\usepackage[T1]{fontenc}

\begin{document}
\begin{tikzpicture}[scale=0.5, every node/.style={font=\fontsize{70}{70}\selectfont}];
\definecolor{infblue}{HTML}{0066b3}
\definecolor{infred}{HTML}{ec1840}

\fill[infred] (0,0) circle (10cm and 5cm);
\fill[white] (0.5,0.5) circle (9.5cm and 4.75cm);
\node[infblue] at (-0.20,0.8) {\textbf{Infineon}};
\fill[white] (-8,2.9) circle (0.7cm);
\fill[infblue] (-8,2.9) circle (0.5cm);
\end{tikzpicture}
\end{document}

enter image description here

Edit 2: As I wasn't happy with the ellipses, I changed that to come closer to the original:

\documentclass[parskip]{scrartcl}
\usepackage[margin=15mm]{geometry}
\usepackage{tikz}
%\usepackage[condensed,math]{iwona}
\usepackage{iwona}
\usepackage[T1]{fontenc}

\begin{document}
\begin{tikzpicture}[scale=0.5, every node/.style={font=\fontsize{70}{70}\selectfont}];
\definecolor{infblue}{HTML}{0066b3}
\definecolor{infred}{HTML}{ec1840}

\fill[infred] (0,0) circle (10cm and 5cm);
\fill[white] (0.5,0.25) circle (9.8cm and 4.75cm);
\node[infblue] at (-0.20,0.4) {\textbf{Infineon}};
\fill[white] (-8,2.9) circle (0.7cm);
\fill[infblue] (-8,2.9) circle (0.5cm);
\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] How to draw an arc with varying line thickness

Related Question