Is it possible to get TikZ-arrows to draw double-headed arrows?

What I'm looking for is a way to achieve

\draw[-triangle 90 triangle 90] (A) -- (B);


and the open triangle equivalent, in the way TikZ would normally read

\draw[->>] (A) -- (B);

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Welcome to TeX.SX! You can have a look on our starter guide to familiarize yourself further with our format. – bersanri Jun 24 '13 at 13:25
You can also define meta arrow heads as described in the manual. They are relatively easier to construct if compared to arrow heads. – percusse Jun 24 '13 at 13:46

See the Section 74 (also 23) of PGF documentation (mine is version 2.10) to obtain a lot of arrow tips.

Just put on preamble

\usetikzlibrary{arrows}
\pgfarrowsdeclarecombine{twotriang}{twotriang}%
{triangle 90}{triangle 90}{triangle 90}{triangle 90}


and then you can use \draw[twotriang-twotriang] (0,0) -- (2,0);

Here is the output.

Here is a part of the documentation

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Great, thanks! This has worked very well. I'd already looked at all the documentation you suggested, but thanks for posting it anyway. – DavidHume Jun 24 '13 at 13:59

A possibility is to use postactions and shorten

\documentclass{article}

\usepackage{tikz}
\usetikzlibrary{arrows}

\begin{document}

\begin{tikzpicture}[font=\sffamily\small]
\draw[-triangle 90, postaction={draw, shorten >=4pt, -triangle 90}] (0,0) -- (1,0);
\draw[-triangle 90, postaction={draw, shorten >=-4pt, -triangle 90}] (0,-.5) -- (1,-.5);
\end{tikzpicture}

\end{document}


In the first case the second head is added before the original one, in the second is added after. This is controlled by the positive or negative shorten value.

If you want to typle less you can do:

\documentclass{article}

\usepackage{tikz}
\usetikzlibrary{arrows}

\begin{document}

\tikzset{dblb/.style={postaction={draw,shorten >=4pt, -triangle 90}}}
\tikzset{dbla/.style={postaction={draw,shorten >=-4pt, -triangle 90}}}
\begin{tikzpicture}[font=\sffamily\small]
\draw[-triangle 90,dblb] (0,0) -- (1,0);
\draw[-triangle 90,dbla] (0,-.5) -- (1,-.5);
\end{tikzpicture}

\end{document}


same result.

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-1. It's misleading. – Leo Liu Jun 24 '13 at 13:59
@LeoLiu I prefer this way because it's actually more powerful than other methods, you can have like five heads, placed wherever you want and you could also have heads with different shapes. – domenico Jun 24 '13 at 14:17

It is easy to use ->> if we set >=triangle 90 first.

An example:

\documentclass{article}

\usepackage{tikz}
\usetikzlibrary{arrows}

\begin{document}

\tikz \draw[>=triangle 90, ->>]
(0,0) -- (2,0);

\end{document}


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+1. I didn't know that it would be possible to do so simple. – Sigur Jun 24 '13 at 13:58
I can't get seem to get the tikz-cd package for some reason. Thanks anyway. – DavidHume Jun 24 '13 at 14:00
@DavidHume: No, tikz-cd is not needed. I misunderstood your question. Now see my update. – Leo Liu Jun 24 '13 at 14:01

With PSTricks. Just for fun!

\documentclass[pstricks,border=12pt]{standalone}
\begin{document}
\begin{pspicture}(2,2)
\psline{->>}(1,1)
\end{pspicture}
\end{document}


The look-up table is given as follows.

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