TikZ calendar, multi-day solid lines like Google Calendar

I'm starting with these examples:

I'm looking to add a red bar under and possibly through the numbers indicating a multiday event. I'm interested in how to do this both within a week, and also over weekends (where wraparound would be an issue).

This is not an answer but an attempt to clarify your question. All I did was to copy the code from your second link and to add some basic thingy that I adapted drom p. 526 of the pgfmanual. This allows me to draw a red bar.

\documentclass{article}
% An example how to use the calendar library and modify the layout, i.e. put
% Sunday as the first week day.
%
% Author: Berteun Damman
\usepackage{tikz}
\usetikzlibrary{calendar}
\begin{document}
\makeatletter

% This way you can define your own conditions, for example, you
% could make something as full moon', even week', odd week',
% et cetera. In principle. The math in TeX could be hard.
\pgfkeys{/pgf/calendar/start of year/.code={%
\ifnum\pgfcalendarifdateday=1\relax%
\ifnum\pgfcalendarifdatemonth=1\relax\pgfcalendarmatchestrue\fi%
\fi%
}}%

% Define our own style
\tikzstyle{week list sunday}=[
% Note that we cannot extend from week list,
% the execute before day scope is cumulative
execute before day scope={%
\ifdate{day of month=1}{\ifdate{equals=\pgfcalendarbeginiso}{}{
% On first of month, except when first date in calendar.
\pgfmathsetlength{\pgf@y}{\tikz@lib@cal@month@yshift}%
\pgftransformyshift{-\pgf@y}
}}{}%
},
execute at begin day scope={%
% Because for TikZ Monday is 0 and Sunday is 6,
% we can't directly use \pgfcalendercurrentweekday,
% but instead we define \c@pgf@counta (basically) as:
% (\pgfcalendercurrentweekday + 1) % 7
\pgfmathsetlength\pgf@x{\tikz@lib@cal@xshift}%
\ifnum\pgfcalendarcurrentweekday=6
\c@pgf@counta=0
\else
\c@pgf@counta=\pgfcalendarcurrentweekday
\fi
\pgf@x=\c@pgf@counta\pgf@x
% Shift to the right position for the day.
\pgftransformxshift{\pgf@x}
},
execute after day scope={
% Week is done, shift to the next line.
\ifdate{Saturday}{
\pgfmathsetlength{\pgf@y}{\tikz@lib@cal@yshift}%
\pgftransformyshift{-\pgf@y}
}{}%
},
% This should be defined, glancing from the source code.
tikz@lib@cal@width=7
]

% New style for drawing the year, it is always drawn
% for January
\tikzstyle{year label left}=[
execute before day scope={
\ifdate{start of year}{
\drawyear
}{}
},
% Right align
every year/.append style={
anchor=east,
}
]

% Style to force giving a month a year label.
\tikzset{draw year/.style={
execute before day scope={
\ifdate{day of month=1}{\drawyear}{}
}
}}

% This actually draws the year.
\newcommand{\drawyear}{
\pgfmathsetlength{\pgf@x}{\tikz@lib@cal@xshift}%
\pgftransformxshift{-\pgf@x}
% \tikzyearcode is defined by default
\tikzyearcode
\pgfmathsetlength{\pgf@x}{\tikz@lib@cal@xshift}%
\pgftransformxshift{\pgf@x}
}

\makeatother

% The actual calendar is now rather easy:
\begin{tikzpicture}[every calendar/.style={
month label above centered,
month text={\textit{\%mt}},
year label left,
every year/.append style={font=\Large\sffamily\bfseries,
green!50!black},
if={(Sunday) [blue!70]},
week list sunday,
}]
\matrix[column sep=1em, row sep=1em] {
\calendar[dates=2018-04-01 to 2018-04-last,draw year]; &
\calendar[dates=2018-05-01 to 2018-05-last]; &
\calendar[dates=2018-06-01 to 2018-06-last]; \\
\calendar[dates=2018-07-01 to 2018-07-last]; &
\calendar[dates=2018-08-01 to 2018-08-last]; &
\calendar (mycal) [dates=2018-09-01 to 2018-09-last]; \\
\calendar[dates=2018-10-01 to 2018-10-last]; &
\calendar[dates=2018-11-01 to 2018-11-last]; &
\calendar[dates=2018-12-01 to 2018-12-last]; \\
\calendar[dates=2019-01-01 to 2019-01-last]; &
\calendar[dates=2019-02-01 to 2019-02-last]; &
\calendar[dates=2019-03-01 to 2019-03-last]; \\
};
\draw[red] (mycal-2018-09-20.south west) -- (mycal-2018-09-22.south east);
\draw[red] (mycal-2018-09-23.south west) -- (mycal-2018-09-24.south east);
\end{tikzpicture}
\end{document}


Is your question how to replace the two draw commands by a single macro?

• Thank you, that does essentially answer my question: I was unfamiliar with the syntax for: \draw[red] (mycal-2018-09-23.south west) -- (mycal-2018-09-24.south east); Any chance you could also point me to how I could make the line thicker and change its height? I saw I could use \draw[red] (oct-2018-10-08.mid west) -- (oct-2018-10-12.mid east); the mid command, but I'm looking for something like north-north-mid. – Mittenchops Sep 20 '18 at 2:45
• @Mittenchops You can choose the line width to be e.g. thick, \draw[red,thick]... or ultra thick, or say \draw [line width=2pt,red]..... Then, if you say \draw[red,very thick] ([yshift=2pt]mycal-2018-09-20.south west) -- ([yshift=2pt]mycal-2018-09-22.south east); this will move the line up by 2pt, if you use -2pt` it will move down by the same amount. I also think it will be not too difficult do define a style/macro for that. So if you append some information what you precisely want to your nice question (and ping me again) I'll be happy to give it a shot. – user121799 Sep 20 '18 at 2:50