time-chronology-break-arr+timeline+text+advanced.tex

% https://tex.stackexchange.com/a/439457/173708
\documentclass[10pt]{beamer}

\usetheme[progressbar=frametitle]{metropolis}
\usepackage{appendixnumberbeamer}
\usepackage{chronology}

\newlength{\myunit}
\makeatletter%
\newif\ifchronology@star%
\renewenvironment{chronology}{%
    \@ifstar{\chronology@startrue\chronology@i*}{\chronology@starfalse\chronology@i*}%
}{%
\end{tikzpicture}%
\end{lrbox}%
\usebox{\timelinebox}
}%
\def\chronology@i*{%
\@ifnextchar[{\chronology@ii*}{\chronology@ii*[{5}]}%
}%
\def\chronology@ii*[#1]#2#3#4#5{%
\newif\ifflipped%
\ifchronology@star%
\flippedtrue%
\else%
\flippedfalse%
\fi%
\setcounter{step}{#1}%
\setcounter{yearstart}{#2}\setcounter{yearstop}{#3}%
\setcounter{deltayears}{\theyearstop-\theyearstart}%
\setlength{\timelinewidth}{#4}%
\setlength{\myunit}{#5}%
\pgfmathsetcounter{stepstart}{\theyearstart-mod(\theyearstart,\thestep)}%
\pgfmathsetcounter{stepstop}{\theyearstop-mod(\theyearstop,\thestep)}%
\addtocounter{step}{\thestepstart}%
\begin{lrbox}{\timelinebox}%
\begin{tikzpicture}[baseline={(current bounding box.north)}]%,x=\timelinewidth,y=\p@]%
\draw [|->] (0,0) -- (\timelinewidth, 0);%
%\foreach \x in {1,...,\thedeltayears}%
%\draw[xshift=\x/\thedeltayears*\timelinewidth] (0,-.5\myunit) -- (0,.5\myunit);%
\addtocounter{deltayears}{1}%
\foreach \x in {\thestepstart,\thestep,...,\thestepstop}{%
    \pgfmathsetlength\xstop{(\x-\theyearstart)/\thedeltayears*\timelinewidth}%
    \draw[xshift=\xstop] (0,-\myunit) -- (0,\myunit);%
    \ifflipped%
    \node[chrontickslabel] at (\xstop,0) [above=\myunit] {\x};%
    \else%
    \node[chrontickslabel] at (\xstop,0) [below=\myunit] {\x};%
    \fi%
}%
}%
\makeatother%

\RenewDocumentCommand{\event}{o m m}{%
    \pgfmathsetlength\xstop{(#2-\theyearstart)/\thedeltayears*\timelinewidth}%
    \IfNoValueTF {#1} {%
        \ifflipped%
        \draw[chronevent]%
        (\xstop, 0) circle (.7\myunit);%
        \draw[chronevent]
        (\xstop,-.5\myunit+2pt) node[flippedeventlabel] {#3};%
        \else%
        \draw[chronevent]%
        (\xstop, 0) circle (.7\myunit);%
        \draw[chronevent]
        (\xstop,.5\myunit-2pt) node[eventlabel] {#3} ;%
        \fi%
    }{%
        \pgfmathsetlength\xstart{(#1-\theyearstart)/\thedeltayears*\timelinewidth}%
        \ifflipped%
        \draw[chronevent,rounded corners=.7\myunit]%
        (\xstart,-.7\myunit) rectangle%
        node[flippedeventlabel] {#3} (\xstop,.7\myunit) [below=\myunit];%
        \else%
        \draw[chronevent,rounded corners=.7\myunit]%
        (\xstart,-.7\myunit) rectangle%
        node[eventlabel] {#3} (\xstop,.7\myunit);%
        \fi%
    }%
}


\begin{document}
\begin{frame}{Timeline}
\vspace*{-5ex}
\begin{chronology}[50]{1800}{2020}{.9\linewidth}{1ex}
    \event{\decimaldate{}{}{1812}}{\small Beginnings of Gerrymandering}
    \event[\decimaldate{}{}{1960}]{\decimaldate{}{}{2020}}{}
\end{chronology}

\par
\begin{chronology}[10]{1960}{2020}{.9\linewidth}{1ex}
    \event{\decimaldate{26}{3}{1962}}{\small Baker v. Carr}
    \event{\decimaldate{15}{12}{1964}}{\small Reynold v. Sims}
    \event{\decimaldate{15}{10}{1964}}{\small Alfonso R. Reyes}
    \event{\decimaldate{2}{10}{1985}}{\small Bandermer v. Davis}
    \event{\decimaldate{}{}{1991}}{\small Third Criterion}
    \event{\decimaldate{}{}{2004}}{\small Vieth v. Jubelirer}
    \event{\decimaldate{31}{12}{2006}}{\small LULAC v. Perry}
    \event{\decimaldate{}{}{2015}}{\small Efficiency Gap}
    \event{\decimaldate{}{}{2018}}{\small Gill v. Whitford}
\end{chronology}
\end{frame}
\end{document}