# On arrows in Tikz cd

So I am getting used to using tikz-cd package to draw relatively straightforward commutative diagrams. I have two questions.

Question 1 Here is the code:

\documentclass[10pt, draft]{amsart}
\usepackage{pgf}
\usepackage{tikz}
\usepackage{tikz-cd}
\usetikzlibrary{arrows, matrix}
% With tons of other packages not relevant here I guess
\begin{document}
% With some text ....
$\begin{tikzcd} Y \arrow[dashrightarrow]{d} \arrow{rd} & \\ Y_{0} \arrow{r}{\pi_{0}} & X \\ \end{tikzcd}$
\end{document}


What happens here is that the arrow tips for the diagonal arrow is extremely light compared to the other two, you can see that in the picture below. I would like to know how to fix that.

Question 2 In the following diagram, (which also suffers from the same issues of question 1 above), I would want to fix the hook on the arrow labelled i so that it points the correct way (and perhaps make it more prominent).

Here is the code I am using for that part.

  $\begin{tikzcd}[column sep =small] & (X_{0},x)\arrow[hookrightarrow]{dl}{i}\arrow[hookrightarrow]{dr}{i^{\prime}} & \\ (X,x) \arrow{dr} \arrow{rr} & & (X^{\prime}, x) \arrow{dl} \\ & (U,u) & \end{tikzcd}$

• Re 1: This is most likely a viewer issue. I don’t have the same problem. Try zooming and or using another viewer. Code snippet 2 is not compilable as it is ({i^{\prime} is missing a } and can simply be written as {i'}) and empty lines are not allowed in math-mode. What is the “correct” way. More prominent? It suffers the same rendering issues in your view as the diagonal arrow. – Qrrbrbirlbel Jun 16 '13 at 19:58
• The arrow thickness issue might be caused by an old installation of TikZ? – John Wickerson Jun 16 '13 at 20:03
• I don't see thickness problems. For the hook, say \arrow[left hook->]{dl} – egreg Jun 16 '13 at 22:49
• @Qrrbrbirlbel the issue with { i^{\prime} has been fixed thanks for pointing that out. I was using the document viewer on ubuntu and after changing the document viewer to orca my question one seems to be no question at all. – DBS Jun 17 '13 at 3:23

The thickness problem seems to be a viewer issue. For the hook in the second diagram you can use a direct TikZ expression for the arrow; with the key swap you can change the side of the arrow chosen for the label.
\documentclass{article}
$\begin{tikzcd}[column sep=small] & (X_{0},x) \arrow[hookrightarrow]{dr}{i'} \arrow[left hook->,swap]{dl}{i} % <-- reflect the direction of the hook \\ (X,x) \arrow{dr} \arrow{rr} && (X', x) \arrow{dl} \\ & (U,u) \end{tikzcd}$

It's easier to type i' for i^{\prime} and the output is exactly the same. Never leave blank lines in the code for a tikzcd.