[Tex/LaTex] Bending arrows in tikz-cd

arrowsdiagramstikz-arrowstikz-cdtikz-pgf

Following the advice of LaRiFaRi in an answer to this question,
I switched from XY-Pic to tikz-cd.
The file below contains my diagram in XY-Pic and in tikz-cd.
Please help me to make my diagram in tikz-cd beautiful!

I would like:

  1. To improve the problematic arrow from $\ell-1$ to 1;

  2. To make the arrow tips sharper, as in XY-Pic;

  3. To make the solid lines touch (or at least almost touch) the small circles.

Note that my diagram is an (affine) Dynkin diagram, so it should look as a Dynkin diagram, see these pictures.

EDIT: I took the corrected arrow from LaRiFaRi's answer and found suitable arrow tips in the library following his advice. Now the diagram is nicer than that of XY-Pic. Still I need solid lines coming closer to the small circles. Find below the corrected diagram.

 \documentclass[a4paper,12pt]{amsart}
\usepackage[all]{xy}
\usepackage{tikz-cd}
\usetikzlibrary{arrows.meta}

\def\ccc{{  \lower0.3ex\hbox{{\text{\Large$\circ$}}}}}
\newcommand{\bc}[1]{{\overset{#1}{\ccc}}}
\newcommand{\bcu}[1]{{\underset{#1}{\ccc}}}

\begin{document}
\[   \xymatrix@1@R=-5pt@C=10pt{
& \bc{0} \ar@{-}[rd]\ar@/^0.75pc/@{-->}[rrrr] &&  &&\bc{\ell-1}\ar@{-}[ld]
    \ar@{-->} `l[lld]  `[lldd]  [lllldd] \\
&&\bc{2}\ar@{-}[r] & \cdots  \ar@{-}[r] & \bc{\ell-2} \\
&\bc{1}\ar@{-}[ru] \ar@/_0.7pc/@{-->}[rrrr] & &  & &\bc{\ell}\ar@{-}[lu]
    \ar@{--2>} `d[l] `l[lllll] `[uu]  [lllluu] \\
}   \]
\bigskip

\[  \begin{tikzcd}[every arrow/.append style={dash},row sep=-5pt, column sep=10pt]
\bc{0} \arrow{dr} \arrow[thin,-{Stealth[open]}, dashed,bend left=20]{rrr} 
 & &[.8cm] & \bc{\ell-1}
 \arrow[thin,-{Stealth[open]}, dashed, rounded corners, 
        to path={ -- ([xshift=-1.795cm]\tikztostart.west) |- 
        (\tikztotarget)}]{llldd}
\\
& \bc{2} \arrow{r}[description]{\ldots} & \bc{\ell-2} \arrow{ur}\arrow{dr} &
\\
\bc{1}\arrow[thin,-{Stealth[open]}, dashed,bend right=20]{rrr}\arrow{ur} &
       & & \bc{\ell}
       \arrow[thin,-{Stealth[open]}, dashed, rounded corners, 
            to path={ -- ([yshift=-2ex]\tikztostart.south) -|
            ([xshift=-1.5ex]\tikztotarget.west) -- (\tikztotarget)}]{uulll}
\end{tikzcd}  \]
\end{document}

enter image description here

Best Answer

You can try the dynkin-diagrams package. This example is included in the documentation. Note that by default, the affine root of this D series diagram is marked with a white circle, while the other roots have solid circles; you can easily change this if you don't like it.

enter image description here

\documentclass{amsart}
\usepackage{dynkin-diagrams}
\tikzset{big arrow/.style={
    -Stealth,line cap=round,line width=1mm,
    shorten <=1mm,shorten >=1mm}}
\newcommand\catholic[2]{\draw[big arrow,green!25!white] 
(root #1) to (root #2);}
\newcommand\protestant[2]{
\begin{scope}[transparency group, opacity=.25]
\draw[big arrow,orange] (root #1) to (root #2);
\end{scope}}
\begin{document}
\begin{dynkinDiagram}[edge length=1.2cm,
indefinite edge/.style={thick,loosely dotted},
labels*={0,1,2,3,\ell-3,\ell-2,\ell-1,\ell}]{D}[1]{}
\catholic{0}{6}\catholic{1}{7}
\protestant{7}{0}\protestant{6}{1}
\end{dynkinDiagram}
\end{document}
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