Creating a Package for Engineering Symbols | Geometric Dimensioning & Tolerancing - TeX

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Top Answer

samcarter

### Preface:

Using Ti*k*Z to draw symbols is both rather slow[^1] and also adds a lots of dependencies to a document. I would only follow the approach for symbols which are not available in another way (I'm saying this as someone who wrote a couple packages using Ti*k*Z).

----

You're question is very broad, but maybe this short example could be a starting point. 

I'm defining one symbol which will scale with the surrounding font, but also allows the user to pass the common Ti*k*Z options to the macro. I also added an option to draw it with or without the surrounding square. 

```
\documentclass{article}

\usepackage{test}

\begin{document}

Test \mysymbol

\Huge \textcolor{red}{Test \mysymbol[noframe]}

Test \mysymbol[scale=2]

\end{document}
```


`test.sty`:

```
\ProvidesPackage{test}[2021/08/23 v0.1 test package]

\RequirePackage{tikz}

\newif\iftest@noframe

\tikzset{
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  %
  % Pass unknown keys on to tikz
  %
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  /test/.search also={/tikz,/pgf},
  /test/.cd,
  noframe/.code= \test@noframetrue,
}

\newcommand{\mysymbol}[1][]{%
    \begin{tikzpicture}%
      %
      \tikzset{/test/.cd,#1}%
      %
      % store scaling factor from https://topanswers.xyz/tex?q=819#a965
      \pgfgettransformentries{\tmpscaleA}{\tmpscaleB}{\tmpscaleC}{\tmpscaleD}{\tmp}{\tmp}%
      \pgfmathsetmacro{\test@scalingfactor}{sqrt(abs(\tmpscaleA*\tmpscaleD-\tmpscaleB*\tmpscaleC))*sqrt(abs((\pgf@xx/1cm)*(\pgf@yy/1cm)-(\pgf@xy/1cm)*(\pgf@yx/1cm)))}%
      %
      % 
      \iftest@noframe
        \path[line width=\test@scalingfactor*0.4pt] (0,0) rectangle ++ (1.5ex,1.5ex);
      \else  
        \draw[line width=\test@scalingfactor*0.4pt] (0,0) rectangle ++ (1.5ex,1.5ex);
      \fi  
      \draw[line width=\test@scalingfactor*0.4pt] (0.75ex,0.75ex) circle [radius=0.6ex];
      \draw[line width=\test@scalingfactor*0.4pt] (0.15ex,0.15ex) -- (1.35ex,1.35ex);
      \end{tikzpicture}%
}

\endinput
```

![Screenshot 2021-08-23 at 18.16.00.png](/image?hash=f64d0626545f3182bc9f2d925ab48dd505cc9f60e3053b25214f8a8a8c09ea98)

[^1]: Unless you have magic killer bunny skills and can write packages like [xistercian](https://ctan.org/pkg/xistercian)

> PS: I somewhere read that LuaTeX is considered to be a successor to the pdfTeX, is that true? It could be considered a successor, since it's younger, has a similar scope, and supports more modern technology (think fonts, UTF-8) out of the box. But I'd consider it more an alternative with more possibilities (that I seldom or never need....).

@joulev I understand and agree with what you are saying, but what bothered me was not the preference given to the pdfLaTeX engine, considering Lua/XeLaTeX as regional/language-specific engines sounded a bit problematic to me and that's it. Of course I can understand that a lot of places need old stuff for stability concerns and therefore developing something which can support older technology is always a good thing in my opinion too! @samcarter I think this also includes cases like arXive :smile: PS: I somewhere read that LuaTeX is considered to be a successor to the pdfTeX, is that true?

There is a reason web developers still worry about providing support for Internet Explorer, which is so outdated and lack of features that Microsoft is even scrapping it for good. Never in a thousand years would I use IE, yet, if I write a website, I still need to provide support for it.

For a user, I agree with what you say: it's best to just move to a newer, more feature-rich engine. But that does not hold for package writers, who *make software for others to use* rather than *use softwares*.

Agreed one can use `iftex`. And let me say that PDFLaTeX, old as it sounds like, is not *old* at all, period. It is still the default engine used in many places (at least places where people use the Latin script). So, in Japan for example, people don't use PDFLaTeX because Japanese is not writtten in the Latin script; however in Vietnam or (I think) basically every country using Latin script, PDFLaTeX is still the preferred engine. A random code block in a random question on any LaTeX site is still considered to be run by PDFLaTeX by default, unless explicitly specified otherwise. It will continue that way for at least a decade to the future in my opinion. Thus, I expect any packages to fully support PDFLaTeX, unless it is specifically for Unicode-related purposes (fonts, extension of character set for languages), or it essentially requires Lua programming. I do frequently use XeLaTeX, and I do know thousands of advantages such modern engines have over the good old PDFLaTeX. But that doesn't mean the whole world will scrap PDFLaTeX for good tomorrow.

I don't think LuaLaTeX and XeLaTeX are only supposed to be used for regional or language related packages. They are just modern engines. What is more important? Usability of the PDF or the package being useful with a really old engine which doesn't even give you any additional benefits? For me at least the answer is a more usable and modern PDF rather than just sticking to an old engine. Saying this, if the author is quite enthu and willing to support pdfLaTeX, there shall not be any problem with providing alternative approaches with packages like `iftex`. e.g. ``` \iftutex % Code with Unicode encoding \else % The TikZ code. \fi ```

Using fonts, such as Noto, includes the risk of the package not usable in pdf(La)TeX. Since this is meant to be a general package, i.e. not specific to any regions/languages, pdfLaTeX support is something I do expect in it. Of course, if one only wants to provide support for more modern engines, using fonts is fine.

@PARVESH, re: [your question](#question), I don't know whether all the symbols that you need are available with LaTeX or not, but let's assume for a moment that some of them aren't available in the standard LaTeX, still have you checked for Unicode compliant (and free and open source) fonts? e.g. I found the symbol for cylindricity `⌭` on Google. In my opinion creating a command, like, say, `\cylindricity` which outputs this Unicode character is a much better choice than defining the command with a TikZ diagram. You can enjoy all the benefits of Unicode i.e. copy-pasting ability, searchability and so on. Please try to find Unicode compliant fonts used in your field. If nothing else works, I am sure there will be some Noto variant for your particular Unicode block. Noto family is open source (SIL font license), so you can distribute it with the TeXLive too! There are chances that your Noto font already exists in the TeXLive. So just work on these things first to make better use of the technology. Best of luck! :)

For creating a LaTeX package file, well, there are tons of tutorials online, I think I need not reproduce them here. But I suggest getting fluent in drawing the symbols first before moving to making a new package, since drawing them and making a package for them are two different challenges.

Welcome to TopTeX. Many of these symbols are available in maths mode; please have a look at the [Comprehensive Symbol List](https://download.nus.edu.sg/mirror/ctan/info/symbols/comprehensive/symbols-a4.pdf). For more complicated ones, yes, TikZ is the right tool. Since you don't know how to use it yet, I suggest starting with the TikZ tutorial. In fact, since all of these symbols are still pretty simple, you should be able to draw all of them after reading the tutorial.

1 Answer