Changing starting place for arrow in XY picture

Question

This script

\documentclass{article}
\usepackage[all]{xy}

\begin{document}
\begin{equation}
\xymatrix @R=0.3pc @C=0.3pc{ 
     & N_0\oplus G_1 & N_1\oplus G_2 \ar@/_1.5pc/[l]_u }
\end{equation}
\end{document}

give the following result

I wish that the arrow start from the "G_2" and arrive in "G_1". Thank you

Welcome to TEXSE. Could you make your script in the to form of a MWE? — Raaja_is_at_topanswers.xyz, Aug 04 '19 at 03:53

A Diyanat · Answer 1 · 2019-08-04T06:32:52.713

You can use tikz package. Please consider the following code:

\documentclass{article}

\usepackage{tikz}
\usetikzlibrary{calc}
\tikzstyle{every picture}+=[remember picture]

\begin{document}
\begin{equation}
N_0\oplus \tikz[baseline]{\node[fill=blue!20,circle,inner sep=1pt,anchor=base] (t1){$G_1$}} \quad 
N_1\oplus \tikz[baseline]{\node[fill=red!20,circle,inner sep=1pt,anchor=base] (t2){$G_1$}}
\end{equation}
\begin{tikzpicture}[overlay]
\draw[-latex](t2.90)to[in=60,out=120]node[midway,above]{$u$}(t1);
\end{tikzpicture}
\end{document}

This is the output:

Note: You can easily change or remove nodes color.

\begin{equation}
N_0\oplus \tikz[baseline]{\node[fill=none,draw=none,inner sep=1pt,anchor=base] (t1){$G_1$}} \quad 
N_1\oplus \tikz[baseline]{\node[fill=none,draw=none,inner sep=1pt,anchor=base] (t2){$G_1$}}
\end{equation}

You could also change the output and input angle and position of arrow, by changing the following line in the code:

\draw[-latex]($(t2)+(-1mm,2mm)$)to[in=60,out=120]node[midway,above]{$u$}($(t1)+(-1mm,2mm)$);

Please add anchor=base to each node. – A Diyanat Aug 04 '19 at 06:28 — A Diyanat, Aug 04 '19 at 06:28
I edit my response, please try again. – A Diyanat Aug 04 '19 at 06:33 — A Diyanat, Aug 04 '19 at 06:33

CarLaTeX · Accepted Answer · 2019-08-04T06:56:09.360

A possible solution with tikz-cd:

\documentclass{article} 
\usepackage{amsmath} 
\usepackage{tikz-cd}
\begin{document} 
\[
\begin{tikzcd}
N_0\oplus G_1 
& N_1\oplus G_2 
\arrow[l, bend right=60, "u", swap, start anchor={[xshift=-10pt]north east}, end anchor={[xshift=-10pt]north east}]\\
\end{tikzcd}
\] 
\end{document}

If you want an arrow tip like xymatrix add

\tikzcdset{arrow style=tikz, diagrams={>={Straight Barb[length=5pt,width=5pt]}}}

in your preamble, after \usepackage{tikz-cd}, and you'll get:

Changing starting place for arrow in XY picture

2 Answers2