# Random Double Arc Endpoint Angles

I am trying to add some randomness to a double arc using random steps. The top and bottom endpoints of the arc are not at the same angles as the same arc drawn normally.

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{decorations.pathmorphing}
\tikzset{rough/.style={decorate,decoration={random steps,segment length=6pt}}}
\begin{document}
\begin{tikzpicture}
\draw[double distance=1cm, double=yellow, rough, color=red] (0,0) arc (0:90:3);
\draw[line width=0.01cm] (0,0) arc (0:90:3) -- (-3,0) -- cycle;
\end{tikzpicture}
\end{document}

I want the following angles at the endpoints, with random steps in between:

How do I make the double arc's endpoints perfectly horizontal and vertical (preferably in a way that works with any amplitude and segment length)?

• Draw little extra and Use clip to crop it – nidhin Aug 12 '19 at 14:57

One way is to draw little extra double arc and crop it using clip. In order to draw little longer double arc, polar coordinates are used.

\draw[double distance=1cm, double=yellow, rough, color=red] (-10:3) arc (-10:100:3);

A rectanglar cropping is done using clip.

\clip (0,0) rectangle (4,4);

See MWE below.

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{decorations.pathmorphing}
\tikzset{rough/.style={decorate,decoration={random steps,segment length=6pt}}}
\begin{document}
\begin{tikzpicture}
\clip (0,0) rectangle (4,4); % <-added
\draw[double distance=1cm, double=yellow, rough, color=red] (-10:3) arc (-10:100:3);% <-changed
\end{scope}
\draw[line width=0.01cm] (0,0) arc (0:90:3) -- (-3,0) -- cycle;
\end{tikzpicture}
\end{document}

### EDIT

Triangular clipping can be used for clipping other angle ranges.

Example:

\clip (0:0) -- (10:6) -- (80:6)--cycle;

and

\clip (0:0) -- (30:6) -- (60:6)--cycle;

produces following output.

• Thank you for this solution! Is it possible to cleanly clip the arc in a way that works for other angle ranges (-30:30 degrees for example)? – anonymous_pigeon Aug 12 '19 at 16:02
• @anonymous_pigeon yes. In that case clipping path has to be changed from rectangle to required shape (double arc). – nidhin Aug 12 '19 at 16:07

Just for fun: a reminder that one can switch on and off decorations along a path.

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{decorations.pathmorphing}
\tikzset{rough/.style={decoration={random steps,segment length=6pt}}}
\begin{document}
\begin{tikzpicture}
\draw[red,fill=yellow, rough] (0.5,0) decorate {arc (0:90:3.5)}
-- ++(0,-1)
decorate {arc(90:0:2.5)} -- cycle ;
\draw[line width=0.01cm] (0,0) arc (0:90:3) -- (-3,0) -- cycle;
\end{tikzpicture}
\end{document}