Fill the area between two arcs and x-axis between two circles

tikz-pgftkz-euclide

I am trying the fill the area between the two circles below their point of contact as shown below:

What I want is something like:

You need not worry about other details in the sample, just to fill the colored part. I tried actually using ..controls (x1,y1) and (x2,y2).. but it is very painstaking and boring. I am looking for more efficient way to do this. I have defined their point of contact with the help of intersection. Here's my minimal WE:

\documentclass[border=3mm,tikz]{standalone}
\usepackage{tkz-euclide}
\usetikzlibrary{intersections,calc,angles}

\begin{document}

\begin{tikzpicture}[scale=0.9]
%frames
\draw[thick,->] (0,0) coordinate (origin) -- (23,0) coordinate (a1) node[right]{$x$}; % x-axis
\draw[thick,->] (origin) -- (0,20) coordinate (a2) node[above]{$y$}; % y-axis
\draw[name path=lline,thick] (origin) -- (60:22.25) coordinate (a3) node[anchor=south west]{$l$}; % l-line

%circle 1
\coordinate (CC1) at (1.7299,1){};
\coordinate[label={[red]below:$C_1$}] (C1) at (1.7299,0){};
\tkzDrawPoint[red,scale=2pt](CC1)
\tkzDrawCircle[name path=circle1,red](CC1,C1);
\draw[thick,red](C1)--(CC1) node[right,pos=.5]{1};
\draw[name intersections={of=lline and circle1}] (intersection-1) coordinate (A1);
\draw[thick,red](A1)--(CC1) node[above,pos=.5]{1};

%circle 2
\coordinate (CC2) at (5.19690701,3){};
\coordinate[label={[blue]below:$C_2$}] (C2) at (5.19690701,0){};
\tkzDrawPoint[blue,scale=2pt](CC2)
\tkzDrawCircle[name path=circle2,blue](CC2,C2);
\draw[thick,blue](C2)--(CC2) node[right,pos=.5]{3};
\draw[name intersections={of=lline and circle2}] (intersection-1) coordinate (A2);
\draw[thick,blue](A2)--(CC2) node[above,pos=.5]{3};

%% circle 1 and circle 2 point of contact
\draw[name intersections={of=circle1 and circle2}] (intersection-1) coordinate (A3);

%section color
%\fill[purple] (C1) ..controls (2.74,0.19) and (2.81,0.81)..  (A3) ..controls (5,0.10) and (3.5,0.81).. (C2) -- cycle;

%\fill[red] (5,0.10) circle (2pt) (3.5,0.81) circle (2pt);
\end{tikzpicture}

\end{document}

Best Answer

\documentclass[border=3mm,tikz]{standalone}
\usepackage{tkz-euclide}
\usetikzlibrary{intersections,calc,angles}

\begin{document}

\begin{tikzpicture}[scale=0.9]
%frames
\draw[thick,->] (0,0) coordinate (origin) -- (23,0) coordinate (a1) node[right]{$x$}; % x-axis
\draw[thick,->] (origin) -- (0,20) coordinate (a2) node[above]{$y$}; % y-axis
\draw[name path=lline,thick] (origin) -- (60:22.25) coordinate (a3) node[anchor=south west]{$l$}; % l-line

%circle 1
\coordinate (CC1) at (1.7299,1){};
\coordinate[label={[red]below:$C_1$}] (C1) at (1.7299,0){};
\tkzDrawPoint[red,scale=2pt](CC1)
\tkzDrawCircle[name path=circle1,red](CC1,C1);
\draw[thick,red](C1)--(CC1) node[right,pos=.5]{1};
\draw[name intersections={of=lline and circle1}] (intersection-1) coordinate (A1);
\draw[thick,red](A1)--(CC1) node[above,pos=.5]{1};

%circle 2
\coordinate (CC2) at (5.19690701,3){};
\coordinate[label={[blue]below:$C_2$}] (C2) at (5.19690701,0){};
\tkzDrawPoint[blue,scale=2pt](CC2)
\tkzDrawCircle[name path=circle2,blue](CC2,C2);
\draw[thick,blue](C2)--(CC2) node[right,pos=.5]{3};
\draw[name intersections={of=lline and circle2}] (intersection-1) coordinate (A2);
\draw[thick,blue](A2)--(CC2) node[above,pos=.5]{3};

%% circle 1 and circle 2 point of contact
\draw[name intersections={of=circle1 and circle2}] (intersection-1) coordinate (A3);

%fill
\begin{scope}
\clip (CC1) circle[radius=1] (CC1) -- (CC2) -- (C2) -- (C1);
\clip (CC2) circle[radius=3] (CC1) -- (CC2) -- (C2) -- (C1);
\fill[magenta] (CC1) -- (CC2) -- (C2) -- (C1);
\end{scope}

\end{tikzpicture}
\end{document}

Like this the filled area covers half of your lines. You need to rearrange to order, so that first the coordinates are defined, and then the fill is drawn and finally all the lines.

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[Tex/LaTex] Line up nested tikz enviroments or how to get rid of them

As is explained in How do I draw shapes inside a tikz node? pics can be used for defining new objects. My main problem using pics is how to place where you want because they aren't nodes and positioning them is not so easy.

Following code shows how to define EDFA block.

    EDFA/.pic={
        \begin{scope}[scale=.5]
        \draw (-1,0) coordinate (in) --  (-1,1) -- (1,0) coordinate (out) --  (-1,-1) -- cycle;
        \node[anchor=north,inner sep=2pt] at (0,-1) {$1$};
        \end{scope}

In this case, coordinate (-1,0) will act as west anchor and 1,0 as east. Both point will have an special name for further reference. Every pic is placed according its own origin (0,0). You can use Claudio's answer to Anchoring TiKZ pics for better positioning.

As your example was simple, I'd prefer to star with EDFA and place Source and Sink after it.

\documentclass[]{article}

% tikz
\usepackage{tikz}
\usetikzlibrary{positioning} %relative positioning

\begin{document}

\tikzset{%
    EDFA/.pic={
        \begin{scope}[scale=.5]
        \draw (-1,0) coordinate (in) --  (-1,1) -- (1,0) coordinate (out) --  (-1,-1) -- cycle;
        \node[anchor=north,inner sep=2pt] at (0,-1) {$1$};
        \end{scope}
    }
}

\begin{tikzpicture}[
block/.style={draw},
]

\draw pic (edfa) {EDFA};

\node[block, left=of edfain] (source) {Source};

\node[block, right= of edfaout] (sink) {Sink};

\draw[->] (source) -- (edfain);
\draw[->] (edfaout) -- (sink);

\end{tikzpicture}

\end{document}

I understand that your components are more complex than EDFA because for this particular case an isosceles triangle node with a label will do the work and it can be used as a node and not as a pic:

\documentclass[]{article}

% tikz
\usepackage{tikz}
\usetikzlibrary{positioning} %relative positioning
\usetikzlibrary{shapes.geometric}

\begin{document}

\begin{tikzpicture}[
    block/.style={draw},
    edfa/.style={isosceles triangle, minimum width=1cm, 
         draw, anchor=west, isosceles triangle stretches, 
         minimum height=1cm, label=-80:#1}
]

\node[block] (source) {Source};

\node[edfa=1, right=of source] (edfa) {};

\node[block, right= of edfa] (sink) {Sink};

\draw[->] (source) -- (edfa);
\draw[->] (edfa) -- (sink);

\end{tikzpicture}

\end{document}

Document header with tikz

\documentclass[tikz,border=2pt]{standalone}
\usetikzlibrary{chains, positioning, shapes.symbols}
\usepackage{xcolor}
\definecolor{darkblue}{RGB}{9,72,90}
\definecolor{lightblue}{RGB}{124,184,201}

\begin{document}
\begin{tikzpicture}[
    node distance = 2pt,
    start chain = going right,
    start/.style = {signal, 
                    draw=darkblue, 
                    fill=lightblue,
                    text width=2cm, 
                    minimum height=1cm, 
                    font=\scriptsize,
                    text=white,
                    signal pointer angle=120, on chain},
    cont/.style = {start, 
                    signal from=west}
    ]
    
    \node[start,](a) {\bfseries Construction de l'image};
    \node[above=0.6cm of a.west, anchor=south west,
            rectangle, 
            draw=darkblue, 
            fill=darkblue,
            minimum height=2cm,
            minimum width=13cm,
            text=white,
            inner sep=1pt]
            (titre){\large{La photographie numérique}};
    \node[cont] {\bfseries Métadonnées EXIF};
    \node[cont](b) {\bfseries Step3};
    \node[right=5.4cm of titre.north east, anchor=north east,
            rectangle,
            draw=darkblue,
            fill=darkblue,thick,
            rounded corners,
            minimum height=3cm,
            text width=5cm,
            text=white]
            (competences){Identifier les étapes de la construction de l'image finale};
\end{tikzpicture}
\end{document}

Best Answer

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[Tex/LaTex] Line up nested tikz enviroments or how to get rid of them

Document header with tikz

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