# TikZ: how to fill area defined by intersections?

I would like to fill this triangle-like

The code is:

\documentclass[border=0.2cm]{standalone}
\usepackage{tikz}

\begin{document}
\begin{tikzpicture}
% \draw [help lines] (7,0) grid (11,4);
\draw [fill=red] (0,1.3) circle (1.3);
\draw [fill=blue] plot [smooth cycle,scale=0.4, xshift=18cm, yshift=1.5cm] coordinates
{(1,0) (0,2) (1.3,4) (3.6,2) (3.6+3.6-1.3,4) (2*3.6,2) (3.6+3.6-1,0) (3.6,1)};
\draw (8.55,0.98) -- ++ (0.1,-1.47) (8.7,0.99) -- (8.55+0.1,-0.49);

\end{tikzpicture}
\end{document}


I have looked up on Filling area between two lines and an arc but I could not find a solution. I think that first I should give the name to the blue object through name path=candy. Then, I should give the command

\path[name path=twolines] (0.98) -- ++ (0.1,-1.47) (8.7,0.99) -- (8.55+0.1,-0.49);


to find the intersections. After that, with the command fill, I should be able to fill that area. The problem is that I do not know how. Maybe with the aid of \clip, but again, how?

• If you can use one of the answers, then please mark it as accepted. – hpekristiansen Mar 7 '18 at 12:45

Two simple tricks can save you a tone of work. Draw that triangle and fill it as usual [fill=<color>] before drawing that moth shape, then shift the triangle upward a very small length to hide that tiny white space between the arc and the triangle side. Finally draw the curvy shape. It's a bit of an approximation but will save you much headache.

\documentclass[border=0.2cm]{standalone}
\usepackage{tikz}

\begin{document}

\begin{tikzpicture}
% \draw [help lines] (7,0) grid (11,4);
\draw [fill=red] (0,1.3) circle (1.3);
\draw [fill=red,yshift=1pt] (8.55,0.98) -- ++(0.1,-1.47) -- (8.7,0.99);
\draw [fill=blue] plot [smooth cycle,scale=0.4, xshift=18cm, yshift=1.5cm] coordinates
{(1,0) (0,2) (1.3,4) (3.6,2) (3.6+3.6-1.3,4) (2*3.6,2) (3.6+3.6-1,0) (3.6,1)};
\end{tikzpicture}

\end{document}


You can simply draw your triangle a little too large in the top - I use the shortenoption with a negative length. -and then place your bow on top of it for a perfect result like this:

\documentclass[border=0.2cm]{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\draw [fill=red, shorten <=-0.1cm, shorten >=-0.1cm] (8.55,0.98) -- (8.65,-0.49) -- (8.7,0.99);
\draw [fill=blue] plot [smooth cycle,scale=0.4, xshift=18cm, yshift=1.5cm] coordinates
{(1,0) (0,2) (1.3,4) (3.6,2) (3.6+3.6-1.3,4) (2*3.6,2) (3.6+3.6-1,0) (3.6,1)};
\end{tikzpicture}
\end{document}


If you for some reason need a perfect filled triangle in the foreground, then you can use the inverted clip from @Jake's answer with the bow: https://tex.stackexchange.com/a/12033/8650