Gsyfuy

I'm searching for a math symbol that shows saturation. It looks like a slash with a horizontal line at each end.
I found a question about drawing it in a node: Saturation block

But I want to use it as a subscript in math mode.

I'm not sure if this is what you want, but you can design your own symbol without tikz. Use mathchoice to allow for use as a subscript or subsubscript.

Here is the code:

documentclass{article}

usepackage{calc} % needed to subtract from hght



newlength{wdth}

newlength{hght}

newlength{dpth}



newcommand{sat}{mathchoice%

{settowidth{wdth}{/}settoheight{hght}{/}settodepth{dpth}{/}%

    rule[-dpth]{.25em}{.09ex}hspace{-.13wdth}/%

    hspace{-.15wdth}rule[hght-.09ex]{.25em}{.09ex}}

{settowidth{wdth}{/}settoheight{hght}{/}settodepth{dpth}{/}%

    rule[-dpth]{.25em}{.09ex}hspace{-.15wdth}/%

    hspace{-.15wdth}rule[hght-.09ex]{.25em}{.09ex}}   

{settowidth{wdth}{$scriptstyle /$}settoheight{hght}{$scriptstyle /$}settodepth{dpth}{$scriptstyle /$}%

    rule[-dpth]{.2em}{.08ex}hspace{-.17wdth}scriptstyle /%

    hspace{-.17wdth}rule[hght-.08ex]{.2em}{.08ex}} 

{settowidth{wdth}{$scriptstyle /$}settoheight{hght}{$scriptscriptstyle /$}settodepth{dpth}{$scriptscriptstyle /$}%

    rule[-dpth]{.15em}{.07ex}hspace{-.19wdth}scriptscriptstyle /%

    hspace{-.19wdth}rule[hght-.07ex]{.15em}{.07ex}} 

}



begin{document}



$Asat B_{Asat B_{Asat B}}$



end{document}

If you want longer or shorter tails you can adjust the lengths in the rule parameters. The .25em (or .2em for subscript, .18em for subsubscript) controls the length.

First create a standalone version of your icon, here in saturation.tex:

documentclass[border=0mm]{standalone}

usepackage{tikz}



usetikzlibrary{positioning}



makeatletter



pgfdeclareshape{record}{

inheritsavedanchors[from={rectangle}]

inheritbackgroundpath[from={rectangle}]

inheritanchorborder[from={rectangle}]

foreach x in {center,north east,north west,north,south,south east,south west}{

inheritanchor[from={rectangle}]{x}

}

foregroundpath{

pgfpointdiff{northeast}{southwest}

pgf@xa=pgf@x pgf@ya=pgf@y

northeast

pgfpathmoveto{pgfpoint{0}{0.33pgf@ya}}

pgfpathlineto{pgfpoint{0}{-0.33pgf@ya}}

pgfpathmoveto{pgfpoint{0.33pgf@xa}{0}}

pgfpathlineto{pgfpoint{-0.33pgf@xa}{0}}

pgfpathmoveto{pgfpointadd{southwest}{pgfpoint{-0.33pgf@xa}{-0.6pgf@ya}}}

pgfpathlineto{pgfpointadd{southwest}{pgfpoint{-0.5pgf@xa}{-0.6pgf@ya}}}

pgfpathlineto{pgfpointadd{northeast}{pgfpoint{-0.5pgf@xa}{-0.6pgf@ya}}}

pgfpathlineto{pgfpointadd{northeast}{pgfpoint{-0.33pgf@xa}{-0.6pgf@ya}}}

}

}

makeatother



begin{document}

begin{tikzpicture}



node[record,minimum size=1cm,fill=blue!30,draw] (a) {};

end{tikzpicture} 

end{document}

Then, use this code to include it as the height of the local value of 1ex, with a little horizontal gap on each side. This code will adjust to the current font size (so no problem if you go Huge) as well as to the current math style (scriptstyle and scriptscriptstyle):

documentclass{article}

usepackage{scalerel,graphicx}

newcommandsat{ThisStyle{%

  kern.5LMptincludegraphics[height=1LMex]{saturation}kern.5LMpt}}

begin{document}

centering

Here is sat.

In math, $A_{sat}$

[

A_{sat_{sat}}

]

end{document}

Obviously, you can change the size by adjusting 1LMex to something different. You can adjust the gap by adjusting the .5LMpt to something different, and you can change the color and line thickness in the original tikz code.

For example, by changing the color at saturation.tex to gray!5 and adding a thick specification to the draw, one gets this:

That carries over directly into the main document, where I have changed the height specification to 1.3LMex, to arrive at:

SUPPLEMENT

To help the OP with a follow up request to eliminate the border and axes, replace saturation.tex with this:

documentclass[border=0mm]{standalone}

usepackage{tikz}

begin{document}

begin{tikzpicture}

coordinate (A) at (-.5,-.4);

coordinate (B) at (-.3,-.4);

coordinate (C) at (+.3,+.4);

coordinate (D) at (+.5,+.4);

draw [black, thick] (A)--(B)--(C)--(D);

end{tikzpicture} 

end{document}

Then, with the document code definition that

newcommandsat{ThisStyle{%

  kern.5LMptincludegraphics[height=1.3LMex]{saturation}kern.5LMpt}}

we arrive at

documentclass{article}

usepackage{scalerel,graphicx}

newcommandsat{ThisStyle{%

  kern.5LMptincludegraphics[height=1.3LMex]{saturation}kern.5LMpt}}

begin{document}

centering

Here is sat.

In math, $A_{sat}$

[

A_{sat_{sat}}

]

Huge

[

A_{sat_{sat}}

]

end{document}

With picture mode:

documentclass{article}

usepackage{amsmath}

usepackage{pict2e}



makeatletter

DeclareRobustCommand{saturation}{%

  mathrel{%

    mkern1munonscriptmkern-1mu

    mathpalettesatur@tionrelax

    mkern1munonscriptmkern-1mu

  }%

}



newcommand{satur@tion}[2]{%

  vcenter{hbox{%

    sboxz@{$m@th#1|$}%

    setlength{unitlength}{dimexprhtz@+dpz@}%

    saturation@linethickness{#1}%

    begin{picture}(0.6,1)

    roundcap

    polyline(0,0)(0.2,0)(0.4,1)(0.6,1)

    end{picture}%

  }}%

}

newcommand{saturation@linethickness}[1]{%

  linethickness{%

    1.25fontdimen8

      ifx#1displaystyletextfontelse

      ifx#1textstyletextfontelse

      ifx#1scriptstylescriptfontelse

      scriptscriptfontfififi 3

  }%

}



makeatother



begin{document}



$Asaturation B_{Asaturation B_{Asaturation B}}$



end{document}

The command saturation@linethickess is an old trick of mine, see https://tex.stackexchange.com/a/412159/4427

I chose to make the symbol the same vertical size as |; the width is 60% of the height and the three parts have equal width. Feel free to change the proportions. You can get it wider with

newcommand{satur@tion}[2]{%

  vcenter{hbox{%

    sboxz@{$m@th#1|$}%

    setlength{unitlength}{dimexprhtz@+dpz@}%

    saturation@linethickness{#1}%

    begin{picture}(0.8,1)

    roundcap

    polyline(0,0)(0.2,0)(0.6,1)(0.8,1)

    end{picture}%

  }}%

}