Decreasing the font size in one node in a TikZ diagram

Question

I have a diagram in which the font size for a node containing the measure of an angle is too big. What is the default font size for a node? What is the font size, in units of pt, for the specification font=\footnotesize in a node command?

\documentclass{amsart}
\usepackage{amsmath}
\usepackage{amsfonts}

\usepackage{tikz}
\usetikzlibrary{calc,angles,positioning,intersections,quotes,decorations.markings,decorations.pathreplacing}


\begin{document}
\begin{tikzpicture}

%A triangle is to be drawn on the Cartesian plane.
\coordinate (E) at (0,0);
\coordinate (A) at (0,{(4/3)*sqrt(3)});
\coordinate (D) at (4/3,0);
\coordinate (B) at ($(A)!{(8/3)*1cm}!90:(D)$);
\coordinate (C) at ($(D)!{(8/3)*1cm}!-90:(A)$);

\node[anchor=-75, inner sep=0] at ($(A) +({-75+180}:0.15)$){$A$};
\node[anchor=-75, inner sep=0] at ($(B) +({-75+180}:0.15)$){$B$};
\node[anchor={-75+180}, inner sep=0] at ($(C) +(-75:0.15)$){$C$};
\node[anchor={-75+180}, inner sep=0] at ($(D) +(-75:0.15)$){$D$};
\node[anchor=north, inner sep=0] at (0,-0.15){$E$};


\draw (A) -- (B) -- (C) -- (D) -- cycle;
\draw (A) -- (E);
\draw (D) -- (E);


\draw node[anchor=east, inner sep=0, font=\footnotesize] at ($($(A)!0.5!(E)$) +(-0.15,0)$){$4\sqrt{3}$};


%A right-angle mark is drawn at D.
\coordinate (U) at ($(D)!3mm!45:(C)$);
\draw[dash dot] (U) -- ($(D)!(U)!(C)$);
\draw[dash dot] (U) -- ($(D)!(U)!(A)$);

%A right-angle mark is drawn at E.
\coordinate (V) at ($(E)!3mm!45:(D)$);
\draw[dash dot] (V) -- ($(E)!(V)!(D)$);
\draw[dash dot] (V) -- ($(E)!(V)!(A)$);

\draw[draw=blue] ($(A) +(-90:0.7)$) arc (-90:-60:0.7);
\node[anchor=west, rotate=-75, inner sep=0, font=\footnotesize] at ($(A) +(-75:0.8)$){$30^{\circ}$};

\end{tikzpicture}


\end{document}

It depends. \footnotesize is not an absolute size in pts (and pts are not absolute either, of course). Rather, it is relative to the default font size for the document. There is no default font size for nodes generally. If you just say \tikz{\node {whatever};} you'll get the default size which, again, will depend on your document and the context within that document. — cfr, Jan 26 '16 at 03:55
Just write \begin{tikzpicture}[font=\small], or when you are using \usepackage{anyfontsize} you can write \begin{tikzpicture}[font=\fontsize{20}{8}\selectfont]. — Giorgi, Jan 26 '16 at 03:56
@Giorgi If \footnotesize is too big, \small will only be worse, surely? — cfr, Jan 26 '16 at 03:57
@cfr What is the size of the text that is typeset in \footnotesize with respect to the font of the file? — Adelyn, Jan 26 '16 at 03:58
@Torbjørn T. Thanks for suggesting the web site. For 12pt font, text is typeset in 10.95pt font using \small, 10pt font using \footnotesize, 8pt font using \scriptsize, and 6pt font using \tiny. My guess is that this give me enough variety. In case I would like to have text in a node command typeset in 9pt font, for example, please tell me the syntax. — Adelyn, Jan 27 '16 at 19:24
See e.g. Half-point size fonts in LaTeX and LaTeX -- specify font point size?: \fontsize{9pt}{11pt}\selectfont. The second number is the baselineskip. — Torbjørn T., Jan 27 '16 at 22:01
@Torbjørn T. I see that the command to specify the font is \fontsize{size}{skip} and that it is suggested that "the baselineskip should be 1.2 times the font size." If the node consists of text on a single line, what would you suggest for the skip? How would I implement this font specification in the command \node[anchor=-75, inner sep=0] at ($(A) +({-75+180}:0.15)$){$A$}; from my code? — Adelyn, Jan 28 '16 at 14:21

score 3 · Accepted Answer · answered Jan 26 '16 at 04:07

3

There is no answer to the question as stated. Not only is a pt relative to the font, but the meaning of commands such as \footnotesize depends on the class and, typically, on the font size option if the class offers the option of different sizes.

There is no default font size for nodes independent of everything else i.e. only in the sense that there is a default size for normal text etc. It picks up the document defaults and is context-sensitive.

amsart.cls uses 10pt by default and defines it in the following way

\DeclareOption{10pt}{\def\@mainsize{10}\def\@ptsize{0}%
  \def\@typesizes{%
    \or{5}{6}\or{6}{7}\or{7}{8}\or{8}{10}\or{9}{11}%
    \or{10}{12}% normalsize
    \or{\@xipt}{13}\or{\@xiipt}{14}\or{\@xivpt}{17}%
    \or{\@xviipt}{20}\or{\@xxpt}{24}}%
  \normalsize \linespacing=\baselineskip
}

\footnotesize is defined as \Small which is defined as the fourth of the text sizes i.e. {8}{10}. So 8pt font with a 10pt baseline skip.

I have no idea why this is supposed to be helpful information.

answered Jan 26 '16 at 04:07

cfr

198,882

I saw a comment from Frank Mittelbach in a response to another post. He said that there is a chapter in The LaTeX Companion book discussing fonts available in LaTeX. So, knowing something about font selection is helpful. Probably, I will just use the commands \tiny, \scriptsize, and \small to specify fonts. You said that \footnotesize is defined as \Small. Why would there be two commands to typeset the same font? (Is \Small the same as \small?) – Adelyn Jan 28 '16 at 14:11
Also, knowing that the unit of pt is relative to the font and the class may be relevant - maybe not in coding but in comments in posts about font selection. I want to at least give the pretense that I know what I am talking about. – Adelyn Jan 28 '16 at 14:11
1

\footnotesize is a standard size. \Small is specific to the AMS classes. \small is different, I believe. I suspect the double-naming is for historical reasons and to make sure standard LaTeX code does something appropriate i.e. it doesn't break if you switch to amsart from article. – cfr Jan 28 '16 at 20:27
pt is not relative to the font, it is 1/72.27 of an inch. the font specified units are em and ex. – David Carlisle Sep 09 '20 at 16:10

Decreasing the font size in one node in a TikZ diagram

1 Answers1