An absolutely wonderful package for timelines exists. I was attempting to use it to produce a timeline starting from one part of the previous day (the evening) through the next day. So times within days. Is there a way of doing this?
MWE (more on the non-working side)
\documentclass[tikz,multi,border=10pt]{standalone}
\usepackage{datenumber}
\usetikzlibrary{arrows.meta}
\newcounter{chronosstartdate}
\newcounter{chronosenddate}
\newcounter{chronosstartyear}
\newcounter{chronosendyear}
\newcounter{chronosyeardate}
\newcounter{chronosthingdate}
\pgfkeys{/pgf/number format,
int detect,
set thousands separator={},
}
\tikzset{
chronos/.code={% https://tex.stackexchange.com/a/159856/ - Claudio Fiandrino
\tikzset{%
align=center,
anchor=mid,
/chronos/.cd,
#1
}%
\setstartyear{\chronosstartyear}%
\setmydatenumber{chronosstartdate}{\chronosstartyear}{\chronosstartmonth}{\chronosstartday}%
\setmydatenumber{chronosenddate}{\chronosendyear}{\chronosendmonth}{\chronosendday}%
\pgfmathsetmacro\chronosunit{(\chronoswidth-20pt)/(\thechronosenddate-\thechronosstartdate)}%
\draw [line width=\chronosheight] (-10pt,0) coordinate (chronos pre) -- +(\chronoswidth,0) coordinate (chronos post);
\coordinate (chronos start) at (0,0);
\coordinate (chronos end) at ([xshift=-10pt]chronos post);
\setcounter{chronosstartyear}{\chronosstartyear}%
\setcounter{chronosendyear}{\chronosendyear}%
\def\tempa{01}%
\ifx\chronosstartmonth\tempa
\ifx\chronosstartday\tempa
\else\stepcounter{chronosstartyear}%
\fi
\else\stepcounter{chronosstartyear}%
\fi
\def\tempa{12}%
\def\tempb{31}%
\ifx\chronosendmonth\tempa
\ifx\chronosendday\tempb
\stepcounter{chronosendyear}%
\fi
\fi
\foreach \i in {\thechronosstartyear,...,\thechronosendyear} {%
\setmydatenumber{chronosyeardate}{\i}{01}{01}%
\node [above, anchor=south] at ({(\thechronosyeardate-\thechronosstartdate)*\chronosunit pt},0) {\i}; }
},
chronos date/.code args={#1-#2-#3}{%
\tikzset{%
/chronos/.cd,
thing year={#1},
thing month={#2},
thing day={#3},
}%
\setmydatenumber{chronosthingdate}{\chronosthingyear}{\chronosthingmonth}{\chronosthingday}%
},
/chronos/.search also={/tikz},
/chronos/.cd,
start year/.store in=\chronosstartyear,
start month/.store in=\chronosstartmonth,
start day/.store in=\chronosstartday,
end year/.store in=\chronosendyear,
end month/.store in=\chronosendmonth,
end day/.store in=\chronosendday,
thing year/.store in=\chronosthingyear,
thing month/.store in=\chronosthingmonth,
thing day/.store in=\chronosthingday,
start date/.style args={#1-#2-#3}{%
start year={#1},
start month={#2},
start day={#3},
},
end date/.style args={#1-#2-#3}{%
end year={#1},
end month={#2},
end day={#3},
},
width/.store in=\chronoswidth,
height/.store in=\chronosheight,
start date=2023-06-01,
end date=2023-06-02,
width=100mm,
height=1pt,
chronos date=1850-01-01,
}
\begin{document}
\begin{tikzpicture}
[chronos]
\foreach \i/\j/\k in {{2023-06-01}/{No fireworks}/20pt,{2023-06-01}/{No fireworks}/80pt,{2023-06-01}/{May Day}/50pt,{2023-06-01}/{Summer Solstice}/10pt}
{%
\path [postaction={draw=gray, -{Triangle[width=1.5pt,reversed,length=.75pt,fill=gray]}}, chronos date/.expanded={\i}] ({(\thechronosthingdate-\thechronosstartdate)*\chronosunit pt},0) -- +(0,-\k) node [anchor=north, fill opacity=.75, fill=gray!25, draw=gray, rounded corners, font=\footnotesize\sffamily] {\chronosthingday/\chronosthingmonth/\chronosthingyear\\\j};
}
\end{tikzpicture}
\end{document}

chronos, I would try to do something but, honestly, it isn't. Unless somebody can suggest an easy way of adding support for time of day, I'm going to say the package isn't intended to do it. The code usespgfcalendaranddatenumber. At least, it may not, but it currently claims to. (I really should comment my code.) Adding support for fractions of days would be a whole other thing. – cfr Jul 02 '23 at 05:47datenumber, but it definitely uses\pgfcalendardatetojulian. This the basis for all the calculations placement depends on from where to put marks on the timeline to where to place links to boxes marking events etc. It wouldn't be that hard to do something similar for periods of time as opposed to durations of years, but I don't think it makes sense forchronosto try to do it. My impression was there were already packages available for presenting timelines limited to months/weeks/days/hours which worked pretty well, but perhaps I'm mistaken about that. – cfr Jul 15 '23 at 01:56