How may I augment or diminish the size of a symbol?

Question

We may change the font size used in a document, but what may I do to obtain a glyph as \circ, but larger, and smaller than \bigcirc? Is there, in general, a way to regulate the size of symbols?

circ and bigcirc are two separate characters like a and A so there is no general way to constrict a character in between, but you can use something like \scalebox{1.4}{$\circ$} if you must. but this will scale the stroke thickness and make it look bold as well as larger — David Carlisle, Sep 12 '21 at 14:35
Thanks, I discovered that there are special ways, as \medcirc under txfonts. — Frode Alfson Bjørdal, Sep 12 '21 at 14:51
You have Donald Arseneau's relsize package, which includes a \mathlarger{…} command. — Bernard, Sep 12 '21 at 14:56
\medcirc is not a special way of scaling though, it is simply another character in the font. So it has matching stroke widths but a different diamater, but to tex the relationship between circ, medcirc and bigcirc is the same as the relationship between a b and c. — David Carlisle, Sep 12 '21 at 15:03

score 3 · Accepted Answer · answered Sep 12 '21 at 15:33

If possible it would be better to choose a symbol from the font rather than scale a symbol, the font designer will have generated circles of different diameters but with compatible stroke widths.

Unicode has a range of circles of various sizes that are available via the unicode-math package (although not all sizes are available in all fonts) This shows the circles in the Stix Two math fonts with \circ and \bigcirc shown on the second line.

\documentclass{article}
\usepackage{unicode-math}
\setmathfont{Stix Two Math}
\begin{document}
[
[\vysmwhtcircle]
[\smwhtcircle]
[\mdsmwhtcircle]
[\mdwhtcircle]
[\mdlgwhtcircle]
[\lgwhtcircle]
]
[
[\circ]
[\bigcirc]
]
\end{document}

unicode-math requires luatex or xetex, but the commands are available for pdftex if you use the stix2 package or other packages using compatble set of symbol names.

Puck · Answer 2 · 2021-09-12T15:09:12.313

1

First Edit: Thank you David P. Carlisle for your comment.

Try firstly with these functions:

\newcommand*{\Scale}[2][4]{\scalebox{#1}{$#2$}}%
\newcommand*{\Resize}[2]{\resizebox{#1}{!}{$#2$}}

The \Scale enlarge the math operator The \Resize scale down the math operator You can consider the Resize as a Scale[0<#1<1].

\newcommand{\MathOp}[5]{\mathop{\Scale[#1]{#2}}_{#3}^{#4}#5}

where #1 is a number (generally greater then 1) that specify how enlarge the mathoperator; #2 is the mathoperator (in your case \circ); #3 is the pedex; #4 is the the apex; #5 is the argument of \bigcirc (generally functions):

You'd have this for example

\MathOp{1.5}{\circ}{i=1}{n}{f_i}

Best regards

edited Sep 12 '21 at 15:09

answered Sep 12 '21 at 14:46

Puck

1,208

1

There is another function, very complicated. Would you like to have it, or my previous answer is enough? If so I'll add a new answer – Puck Sep 12 '21 at 14:52
I would like to see it. – Frode Alfson Bjørdal Sep 12 '21 at 14:59
1

where is \Scale defined? also why \mathop both \circ and \bigcirc are \mathbin. – David Carlisle Sep 12 '21 at 14:59
1

why use a 5 argument form rather than use just two argument for the scale and and symbol use \Matop{1.5}{\circ}+{i=1}^n if you want limits? – David Carlisle Sep 12 '21 at 15:13
Because I prefer so, for me \MathOp{}{}{}{}{} is easier – Puck Sep 12 '21 at 15:15
it's harder for anyone else reading the source though, having to remember the argument order also its not possible to omit the limits (_{} is not the same as having no subscript) – David Carlisle Sep 12 '21 at 15:34
Something like this, https://tex.stackexchange.com/questions/389238/is-there-a-black-dot-symbol-that-i-can-use/389240#389240, done for a filled dot, could be adapted to \circ. – Steven B. Segletes Sep 12 '21 at 15:49
@DavidCarlisle I didn’t know you had a P in your name. – Gaussler Sep 12 '21 at 17:47
@Gaussler look at (more or less) any latex log file for DPC :-) – David Carlisle Sep 12 '21 at 17:49
@DavidCarlisle Well, as you pointed out yourself in the past, to me, it’ll have to be David \letter[script=latin,unicode=0050] Carlisle. ;-) – Gaussler Sep 12 '21 at 17:51

score 0 · Answer 3 · answered Sep 12 '21 at 15:04

Whit this function you can define and then declare you new math operators. But I consille you my first answer. Anyway in preamble

\makeatletter
\DeclareRobustCommand\bigop[2][1]{%
  \mathop{\vphantom{\sum}\mathpalette\bigop@{{#1}{#2}}}\slimits@
}
\newcommand{\bigop@}[2]{\bigop@@#1#2}
\newcommand{\bigop@@}[3]{%
  \vcenter{%
    \sbox\z@{$#1\sum$}%
    \hbox{\resizebox{\ifx#1\displaystyle#2\fi\dimexpr\ht\z@+\dp\z@}{!}{$\m@th#3$}}%
  }%
}
\makeatother
\renewcommand{\bigstar}{\DOTSB\bigop{\star}}
\newcommand{\bigA}{\DOTSB\bigop[0.92]{\mathrm{A}}}
\newcommand{\bigDelta}{\DOTSB\bigop[1.05]{\Delta}}
\newcommand{\BigCircleSquare}{\bigcomp\square}
\newcommand{\bigcomp}{%
  \DOTSB
  \mathop{\vphantom{\sum}\mathpalette\bigcomp@\relax}%
  \slimits@
}
\newcommand{\bigplus}{\DOTSB\bigop{+}}
\newcommand{\bigComplementare}{\DOTSB\bigop{\complement}}

I took this function from my old document but I prefer \bigcirc with first answer. With this function is more complex and difficult. I gave you some examples of these functions. Best again Puck

How may I augment or diminish the size of a symbol?

3 Answers3