Drawing diagrams related to laser optics

Question

I came across this collection of svg images for drawing diagrams related to laser optics. It is called "ComponentLibrary" and it is developed by Alexander Franzen.

I used it in the past by importing the various images into an svg editor. Then, by connecting lines between them and inserting text nodes, I got very nice results:

I was thinking of creating similar images in tikz, and create such figures and diagrams with tikz only.

But I would like to get some advice from the more experienced tikz users here about the dimensions and positions of such small images.

For example, I created this image of a sensor:

Its tikz code is

% file sensor.tikz
\begin{tikzpicture}
  \draw[line width=0.25] (0,0) rectangle (1,1);
  \draw[very thin] (1.3,0.45) rectangle (1.6,0.55);
  \draw[very thin, rotate around={25:(0.75,0.5)}] (1.6,0.55) rectangle (1.3,0.45);
  \draw[very thin, rotate around={-25:(0.75,0.5)}] (1.6,0.55) rectangle (1.3,0.45);
\end{tikzpicture}

I chose to create a rectangle with sides of length 1, with its corners at (0,0) and (1,1).

Now I want to add a wavy arrow to indicate some EM radiation hitting it:

So I plotted a wavy arrow from (4,0.5) to (2,0.5), which I think is not ideal. Better is to instruct tikz to plot an arrow from "a bit to the right of the sensor, until the sensor".

%\usetikzlibrary{decorations.pathmorphing}
\begin{tikzpicture}
  \input{sensor.tikz}
  \path[->, draw=red,decorate,decoration={snake,pre length=3pt,post length=7pt}] (4,0.5) -- node[above] {Radiation} (2,0.5);
\end{tikzpicture}

I would like to ask for your thoughts about writing a collection of .tikz files, mainly about what positions should I set to each optics component, and about pre defining nodes in each image.

Because once you have more than 3 or 4 images on your canvas, you have to be able to control their position and relation more systematically.

Answer 1

This version uses a savebox, however due to the way [remember picture] works, it can only be used once. You also need to run it twice.

\documentclass{standalone}% so I don't have to crop it
\usepackage{tikz}
\usetikzlibrary{decorations.pathmorphing}

\newsavebox{\sensor}
\savebox{\sensor}{\begin{tikzpicture}[remember picture]
  \draw[line width=0.25] (0,0) rectangle (1,1);
  \draw[very thin] (1.3,0.45) rectangle (1.6,0.55)
    ++(0.1,-0.05) coordinate[right] (sensor 2);
  \draw[very thin, rotate around={25:(0.75,0.5)}] (1.3,0.45) rectangle (1.6,0.55)
    ++(0.1,-0.05) coordinate[right] (sensor 1);
  \draw[very thin, rotate around={-25:(0.75,0.5)}] (1.3,0.45) rectangle (1.6,0.55)
    ++(0.1,-0.05) coordinate[right] (sensor 3);
\end{tikzpicture}}

\begin{document}

\begin{tikzpicture}[remember picture]
\node[inner sep=0pt] at (0,0) {\usebox\sensor};
\path[<-, draw=red,decorate,decoration={snake,pre length=3pt,post length=7pt}]
  (sensor 1) ++(25:0.1) -- node[above, sloped] {Radiation} ++(25:2);
\path[<-, draw=red,decorate,decoration={snake,pre length=3pt,post length=7pt}]
  (sensor 2) ++(0:0.1) -- node[above, sloped] {Radiation} ++(0:2);
\path[<-, draw=red,decorate,decoration={snake,pre length=3pt,post length=7pt}]
  (sensor 3) ++(-25:0.1) -- node[above, sloped] {Radiation} ++(-25:2);
\end{tikzpicture}
\end{document}

---

This version creates the shape sensor. It differs from a standand TikZ shape in that it does not expand to fit the text inside. Also, I located the center anchor at the point where the sensors radiate outwand, making it assymetrical.

It automatically draws the shape, as opposed to using [draw]. This also makes it difficult to change colors. See \pgfusepath for options.

\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{decorations.pathmorphing}

\makeatletter
\pgfdeclareshape{sensor}{% locate center at pivot point, not symmetrical
  \savedanchor{\southwest}{\pgfpoint{-0.75cm}{-0.5cm}}%
  \savedanchor{\northeast}{\pgfpoint{0.85cm}{0.5cm}}%
  \anchor{center}{\pgfpointorigin}%
  \anchorborder{\pgfpointborderrectangle{\southwest}{\northeast}}%
  \anchor{south west}{\southwest}%
  \anchor{south}{\southwest \pgf@x=0pt}%
  \anchor{west}{\southwest \pgf@y=0pt}%
  \anchor{south east}{\southwest \pgf@x=0.85cm}%
  \anchor{north east}{\northeast}%
  \anchor{north}{\northeast \pgf@x=0pt}%
  \anchor{east}{\northeast \pgf@y=0pt}%
  \anchor{north west}{\northeast \pgf@x=-0.75cm}%
  \anchor{text}{\pgfpointadd{\pgfpoint{-0.25cm}{0pt}}%
    {\pgfpoint{-.5\wd\pgfnodeparttextbox}{-.5\ht\pgfnodeparttextbox}}}%
  \anchor{sensor 1}{\pgfpointpolar{25}{0.95cm}}%
  \anchor{sensor 2}{\pgfpoint{0.95cm}{0pt}}%
  \anchor{sensor 3}{\pgfpointpolar{-25}{0.95cm}}%
\foregroundpath{\pgfsetlinewidth{0.25pt}%
  \pgfpathrectanglecorners{\southwest}{\pgfpoint{0.25cm}{0.5cm}}%
  \pgfpathrectanglecorners{\pgfpoint{0.55cm}{-0.05cm}}{\pgfpoint{0.85cm}{0.05cm}}%
  \pgfusepath{draw}%
  \begin{pgfscope}%
    \pgftransformrotate{25}%
    \pgfpathrectanglecorners{\pgfpoint{0.55cm}{-0.05cm}}{\pgfpoint{0.85cm}{0.05cm}}%
    \pgfusepath{draw}%
  \end{pgfscope}%
  \begin{pgfscope}%
    \pgftransformrotate{-25}%
    \pgfpathrectanglecorners{\pgfpoint{0.55cm}{-0.05cm}}{\pgfpoint{0.85cm}{0.05cm}}%
    \pgfusepath{draw}%
  \end{pgfscope}%
}}%
\makeatother

\begin{document}

\begin{tikzpicture}
\node[sensor] (A) at (0,0) {name};
\path[<-, draw=red,decorate,decoration={snake,pre length=3pt,post length=7pt}]
  (A.sensor 1) ++(25:0.1) -- node[above, sloped] {Radiation} ++(25:2);
\path[<-, draw=red,decorate,decoration={snake,pre length=3pt,post length=7pt}]
  (A.sensor 2) ++(0:0.1) -- node[above, sloped] {Radiation} ++(0:2);
\path[<-, draw=red,decorate,decoration={snake,pre length=3pt,post length=7pt}]
  (A.sensor 3) ++(-25:0.1) -- node[above, sloped] {Radiation} ++(-25:2);
\end{tikzpicture}
\end{document}