Length can be specified as 3em, or 3.5ex. What is required to
make 4en also valid? Are there any other font related length units?
[Tex/LaTex] em, ex, en? Which length units are font size dependent
lengths
Related Solutions
For this application, you can just define a new combined arrowhead using \pgfarrowsdeclarecombine{name left}{name right}{outer element left}{outer element right}{inner element left}{inner element right}:
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{arrows,calc,decorations.markings}
\begin{document}
\pgfarrowsdeclarecombine{|<}{>|}{|}{|}{latex}{latex}
\def\Dimline[#1][#2][#3]{
%\node at (0,0) {"test: #1 - #2 ..."};
\begin{scope}[>=latex] % redef arrow for dimension lines
\draw[|<->|,
decoration={markings, % switch on markings
mark=at position .5 with {\node[gray] at (0,0.25) {\tiny{#3}};},
},
postaction=decorate] #1 -- #2 ;
\end{scope}
}
\begin{tikzpicture}
\node at (0,0) (nA) {A};
\node at (3,0) (nB) {B};
\Dimline[($(nA)+(0,1)$)][($(nB)+(0,1)$)]['test'] ;
\end{tikzpicture}
\end{document}
Or, in order to be able to scale the arrow tips at will, here's your approach with the decorations. The latex tips are combined with "empty arrows" to fix the protrusion over the end of the line:
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{arrows,calc,decorations.markings}
\begin{document}
\pgfarrowsdeclarecombine{dimarrow}{dimarrow}{latex}{latex}{}{}
\def\Dimline[#1][#2][#3]{
\draw[|-|,
decoration={markings, % switch on markings
mark=at position 0 with {\arrowreversed[scale=0.5]{dimarrow}};,
mark=at position .5 with {\node[gray] at (0,0.25) {\tiny{#3}};},
mark=at position 1 with {\arrow[scale=0.5]{dimarrow}};,
},
postaction=decorate] #1 -- #2 ;
}
\begin{tikzpicture}
\node at (0,0) (nA) {A};
\node at (3,0) (nB) {B};
\Dimline[($(nA)+(0,1)$)][($(nB)+(0,1)$)]['test'] ;
\end{tikzpicture}
\end{document}
Hmm arguably this is a calc and/or LaTeX bug.
using calc and \widthof would work in most of the places you mention (as in LaTeX2e
such places explicitly changed to use \setlength internally so that they would work with calc. However \hspace appears to have escaped that conversion, the following patch fixes that.....
\documentclass{article}
\usepackage{calc}
\makeatletter
\def\@hspace#1{\begingroup\setlength\dimen@{#1}\hskip\dimen@\endgroup}
\makeatother
\begin{document}
a\hspace{\widthof{some text}}b
\end{document}
The above answers the original question, but the later edits have clarified that this is not needed at all. \widthof is a relatively expensive operation and doing every row just to make space to insert the same text you measured is really just torturing your computer for no real gain. The formulation in the second table matches the version you gave in the first without the over full boxes and without measuring anything.
\documentclass{article}
\usepackage{fixltx2e}
\usepackage{calc}
\begin{document}
\begin{tabular}{p{0em}@{\hspace{1.0em}\quad}l@{\qquad}l}
\(\bullet\) & \(x = y\) & \(z = w\) \\
\(\bullet\) & \(a = b\) & \(c = d\) \\
\end{tabular}
\begin{tabular}{@{\hspace\tabcolsep\rlap{$\bullet$}\hspace{1.0em}\quad}l@{\qquad}l}
\(x = y\) & \(z = w\) \\
\(a = b\) & \(c = d\) \\
\end{tabular}
\end{document}
Best Answer
There is no
enunit. TFM fonts have font dimensions 5 and 6 which may be accessed asexandemno other fontdimen corresponds directly to a unit.see
What do different \fontdimen<num> mean
Note in comments you ask about the width of an
iyou can use e-tex\fontcharwdto find the width of a character or classically\setbox0\hbox{i}... \wd0But thisemandexare not related to the width or height of the m and x characters they are just arbitrary lengths assigned by the font designer.