The font changing commands are often determined by the document class itself. For the standard classes (with size options in the first row), the values are as follows:
Command 10pt 11pt 12pt
\tiny 5 6 6
\scriptsize 7 8 8
\footnotesize 8 9 10
\small 9 10 10.95
\normalsize 10 10.95 12
\large 12 12 14.4
\Large 14.4 14.4 17.28
\LARGE 17.28 17.28 20.74
\huge 20.74 20.74 24.88
\Huge 24.88 24.88 24.88
Other classes (especially the major document classes such as KOMA and Memoir) may have different values. The following document will print out the font sizes for all the standard size changing commands. You can use it to check font sizes for other classes.
\documentclass[11pt]{article}
\makeatletter
\newcommand\thefontsize[1]{{#1 The current font size is: \f@size pt\par}}
\makeatother
\begin{document}
\sffamily
\thefontsize\tiny
\thefontsize\scriptsize
\thefontsize\footnotesize
\thefontsize\small
\thefontsize\normalsize
\thefontsize\large
\thefontsize\Large
\thefontsize\LARGE
\thefontsize\huge
\thefontsize\Huge
\end{document}
For the sizes, you can use the current bounding box together with \pgfgetlastxy:
\documentclass{standalone}
\usepackage{tikz}
\newcommand*{\ExtractCoordinate}[3]{\path (#1); \pgfgetlastxy{#2}{#3};}%
\newdimen\tlx
\newdimen\tlx
\newdimen\brx
\newdimen\bry
\begin{document}
\begin{tikzpicture}
\draw (-3,-1) rectangle (3,1) (-2,-2) rectangle (2,2);
\foreach \x in {north west,south west,south east,north east}
{ \fill[red] (current bounding box.\x) circle (0.01);
}
\ExtractCoordinate{current bounding box.north west}{\tlx}{\tly}
\ExtractCoordinate{current bounding box.south east}{\brx}{\bry}
\pgfmathsetmacro{\myheight}{(+\tly-\bry)/28.452755}
\pgfmathsetmacro{\mywidth}{(-\tlx+\brx)/28.452755}
\node[below right] at (-2,1) {height: \myheight\ cm};
\node[above left] at (2,-1) {width: \mywidth\ cm};
\end{tikzpicture}
\end{document}
Edit 1: Ah, now I get it. Here is a still not automatic version. You set two commands in each tikzpicture:
\maximumdimensions{4}{3}, which is the desired width and height, at the beginning of the picture.
\getscalingfactors which will draw nodes with a recommended scaling factor in the middle of your picture if the image if to high/wide:
\documentclass{scrartcl}
\usepackage{tikz}
\usepackage{lipsum}
\usepackage{xifthen}
\newcommand*{\ExtractCoordinate}[3]{\path (#1); \pgfgetlastxy{#2}{#3};}%
\newdimen\tlx
\newdimen\tlx
\newdimen\brx
\newdimen\bry
\def\xscalefactor{}
\def\yscalefactor{}
\parindent0mm
\newcommand{\getscalingfactors}{%
\ExtractCoordinate{current bounding box.north west}{\tlx}{\tly}
\ExtractCoordinate{current bounding box.south east}{\brx}{\bry}
\pgfmathsetmacro{\myheight}{(+\tly-\bry)/28.452755}
\pgfmathsetmacro{\mywidth}{(-\tlx+\brx)/28.452755}
\pgfmathsetmacro{\xsf}{\maxwidth/\mywidth}
\pgfmathsetmacro{\ysf}{\maxheight/\myheight}
\global\edef\xscalefactor{\xsf}
\global\edef\yscalefactor{\ysf}
\pgfmathtruncatemacro{\xsfc}{\xsf*10000}
\pgfmathtruncatemacro{\ysfc}{\ysf*10000}
\ifthenelse{\xsfc > 10000}{}{\node[fill=white,above] at (current bounding box.center) {x-s: \xsf};}
\ifthenelse{\ysfc > 10000}{}{\node[fill=white,below] at (current bounding box.center) {y-s: \ysf};}
}
\newcommand{\maximumdimensions}[2]{% width, height
\global\edef\maxwidth{#1} % in cm
\global\edef\maxheight{#2} % in cm
}
\begin{document}
\begin{tikzpicture}[scale=1]
\maximumdimensions{4}{3}
\draw[fill=orange] (-3,-1) rectangle (3,1) (-2,-2) rectangle (2,2);
\getscalingfactors
\end{tikzpicture}
\lipsum[1]
\begin{tikzpicture}[scale=1]
\maximumdimensions{4}{3}
\draw[fill=orange!50!gray] (0,0) circle (3);
\draw[fill=red!50!gray] (3,1) circle (1);
\draw[fill=blue!50!gray] (-2,2) circle (1);
\draw[fill=green!50!gray] (-3,-2) circle (1);
\draw[fill=yellow!50!gray] (2,-1) circle (1);
\getscalingfactors
\end{tikzpicture}
\end{document}
If you scale the picture down enough, the nodes inside the picture vanish:
\begin{tikzpicture}[scale=0.66] and \begin{tikzpicture}[scale=0.497]
Best Answer
The standard classes (
article,report,book) only support font size options10pt,11pt, and12pt. The default is10pt.If a different size is specified, e.g.:
and no package can handle that option, then LaTeX complains with a warning:
Then the default
10ptis used instead of the specified18pt.There are other classes that can handle more font size options, examples:
extreport:8pt,9pt,10pt,11pt,12pt,14pt17pt,20ptmemoir:9pt,10pt,11pt,12pt,14pt,17pt,20pt,25pt,30ptSee also How to specify font size less than 10pt (or more than 12pt)?.