Open triangle arrow in TikZcd

Question

I'm trying to make a diagram in tikz-cd with an arrow of the open triangle form (in stmaryrd it would be \rightarrowtriangle).

If I write something like A\arrow[rightarrowtriangle]{r}{e} &B I get an error. How can I change the arrow type in tikz-cd?

Answer 1

Try \arrow[r,-{Triangle[open]}. Here Triangle[open] is an arrow tip from the arrows.meta library, which tikz-cd loads for you. (See documentation in the manual for pgf/TikZ, section 16.5.) Note this uses the usual TikZ syntax of a hyphen (-) followed by an arrow tip. The curly braces are required due the the brackets giving the open option to Triangle.

If you want to set the default arrow tip for all diagrams, or for a specific diagram, use the technique described in section 2.2 of the tikz-cd manual, shown below.

\documentclass[border=5mm]{standalone}
\usepackage{tikz-cd}
\begin{document}
\begin{tikzcd}
A \arrow[r,-{Triangle[open]}] & B
\end{tikzcd}

\begin{tikzcd}[ % set default options for this diagram
  arrow style=tikz, % use tips from arrows.meta
  >={Triangle[open]} % set default arrow tip
]
A \arrow[r] & B
\end{tikzcd}

% use \tikzcdset to define setting for all following tikzcd-diagrams
\tikzcdset{
  arrow style=tikz,
  >={Triangle[open]}
}
\begin{tikzcd}
A \arrow[r] & B
\end{tikzcd}
\end{document}