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I know that "scriptstyle" is a style, and "scriptsize" is a font size, but what are the main differences between the two? Is it merely that "scriptstyle" should be used in math mode, and "scriptsize" should generally not? I also understand that both are defined as 30% reduced from the default font size, or no?

NeoVandermonde
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2 Answers2

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While it is true that one is to be used in text mode, the other in math mode, also remember, smaller than \scriptsize is \tiny, but a script of a \scriptstyle is a \scriptscriptstyle. Thus, the context of the two terms (\scriptsize and \scriptstyle), while both using the word script, is actually different. One refers to font size, the other to sub- and super-scripting.

We can see that they are fundamentally different in the following MWE, where \scriptstyle does not produce something in \scriptsize if one was already in \scriptsize to begin with. That is to say, the final X is not in \scriptsize, even though \scriptstyle is invoked at the time.

\documentclass{article}
\begin{document}
$X \scriptstyle X$
versus
\scriptsize$X \scriptstyle X$
\end{document}

enter image description here

As to how it is brought about in TeX, know that \scriptstyle is one of the boxes built via \mathchoice (the other three are \displaystyle, \textstyle, and \scriptscriptstyle) whereas none of that process applies to the invocation of \scriptsize which changes the font size characteristics. You could even say that \scriptstyle shares more in common with \displaystyle (in terms of how it is implemented) than with \scriptsize.

Sigur
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Steven B. Segletes
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  • Is \scriptstyle defined as 30% of the text size in the current environment then? – NeoVandermonde Apr 18 '18 at 10:56
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    @NeoVandermonde I don't know the actual numbers (which may also be font dependent), but the gist is "yes," \scriptstyle will be a fraction of the current math size. – Steven B. Segletes Apr 18 '18 at 11:12
  • Mico indicates that they are, in this question – NeoVandermonde Apr 18 '18 at 11:18
  • @NeoVandermonde Indeed, the \scriptscriptstyle is generally relevant for nested sub- or super-scripting. – Steven B. Segletes Apr 18 '18 at 11:20
  • Yes, it was nested subscripts in particular that led me to consider using \scriptsize or a related sizing command, and hence the difference with \scriptstyle. – NeoVandermonde Apr 18 '18 at 11:40
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    @NeoVandermonde not really: \scriptstyle is a tex primitive and specifies a complete style of math layour (it affects horizontal space as well as the font in use) \scritsize is a latex macro usually defined in a document class which specifies anything that wants specifying and that named size, often the fonts but also some vertical spaces may be specified to depend on the last used size command. – David Carlisle Apr 18 '18 at 12:11
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\scriptstyle is a tex primitive and gives a way to force switching to the style that is automatically used in subscripts. (There are eight math styles, display, text, script and scriptscript, plus "cramped" versions of those four)

The math setup defines which fonts to use for each math family (default, \mathrm etc) completely independently. It is common but in no way forced to specify smaller fonts in scriptstyle that text style.

Conversely \scriptsize is a latex macro defined in the document class that specifies whatever the document class wants to specify for text at that size. the standard classes such as article specify vertical spaces around math and lists as well as font size so \small for example is

\newcommand\small{%
   \@setfontsize\small\@ixpt{11}%
   \abovedisplayskip 8.5\p@ \@plus3\p@ \@minus4\p@
   \abovedisplayshortskip \z@ \@plus2\p@
   \belowdisplayshortskip 4\p@ \@plus2\p@ \@minus2\p@
   \def\@listi{\leftmargin\leftmargini
               \topsep 4\p@ \@plus2\p@ \@minus2\p@
               \parsep 2\p@ \@plus\p@ \@minus\p@
               \itemsep \parsep}%
   \belowdisplayskip \abovedisplayskip
}

For sizes such as \scriptsize that are less likely to be used for large blocks article does in fact just set the font size, \scriptsize is

\newcommand\scriptsize{\@setfontsize\scriptsize\@viipt\@viiipt}

that is, 7pt font on an 8pt baselineskip,

David Carlisle
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