A solution which allows to draw intersection segments
of any two intersections is available as tikz library fillbetween
.
This library works as general purpose tikz
library, but it is shipped with pgfplots
and you need to load pgfplots
in order to make it work:
\documentclass{standalone}
\usepackage{tikz}
\usepackage{pgfplots}
\usetikzlibrary{fillbetween}
\begin{document}
\begin{tikzpicture}
\draw [name path=red,red] (120:1.06) circle (1.9);
%\draw [name path=yellow,yellow] (0:1.06) circle (2.12);
\draw [name path=green,green!50!black] (0:0.77) circle (2.41);
\draw [name path=blue,blue] (0:0) circle (1.06);
% substitute this temp path by `\path` to make it invisible:
\draw[name path=temp1, intersection segments={of=red and blue,sequence=L1}];
\draw[red,-stealth,ultra thick, intersection segments={of=temp1 and green,sequence=L3}];
\end{tikzpicture}
\end{document}
The key intersection segments
is described in all detail in the pgfplots
reference manual section "5.6.6 Intersection Segment Recombination"; the key idea in this case is to
create a temporary path temp1
which is the first intersection segment of red and blue
, more precisely, it is the first intersection segment in the L
eft argument in red and blue
: red
. This path is drawn as thin black path. Substitute its \draw
statement by \path
to make it invisible.
Compute the desired intersection segment
by intersecting temp1
and green
and use the correct intersection segment. By trial and error I figured that it is the third segment of path temp1
which is written as L3
(L
= left argument in temp1 and green
and 3
means third segment of that path).
The argument involves some trial and error because fillbetween
is unaware of the fact that end and startpoint are connected -- and we as end users do not see start and end point.
Note that you can connect these path segments with other paths. If such an intersection segment
should be the continuation of another path, use --
as before the first argument in sequence. This allows to fill paths segments:
\documentclass{standalone}
\usepackage{tikz}
\usepackage{pgfplots}
\usetikzlibrary{fillbetween}
\begin{document}
\begin{tikzpicture}
\draw [name path=red,red] (120:1.06) circle (1.9);
%\draw [name path=yellow,yellow] (0:1.06) circle (2.12);
\draw [name path=green,green!50!black] (0:0.77) circle (2.41);
\draw [name path=blue,blue] (0:0) circle (1.06);
% substitute this temp path by `\path` to make it invisible:
\draw[name path=temp1, intersection segments={of=red and blue,sequence=L1}];
\draw[red,fill=blue,-stealth,ultra thick, intersection segments={of=temp1 and green,sequence=L3}]
[intersection segments={of=temp1 and green, sequence={--R2}}]
;
\end{tikzpicture}
\end{document}
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}
Best Answer
You can use the
intersections
library for this, as Dylan suggested.First, you'll need to name the paths you want to find the intersections for, using
name path=<name>
. Then you can find the intersections within adraw
command usingname intersections={of=<first path> and <second path>}
. By default, they'll be namedintersection-<number>
.