The latest version of the timeline library can be find in the timeline repository.
This is a start of a solution, which provides the experimental timeline library.
The library introduces three main commands:
\timeline for drawing a rectangle with the number of weeks;\phase for drawing bubbles: \phases have to be put in the proper phases environment;\addmilestone for adding milestones to bubbles.
How to use the library?
At first one should declare the number of weeks the timeline spans: the weeks are placed deterministically on the timeline according to their number. The dimensions of the timeline can be customized through the keys timeline width, timeline height and timeline offset (which corresponds to the height of the thin shaded border). For example:
\begin{tikzpicture}[timeline offset=0.2]
For convenience, each week is a node and, as every node, can be accessed for later use; its name is week-<number of the week>; for instance:
\draw (week-1)--++(90:1cm);
will draw a line of 1cm above Week 1.
Then it's the turn of the phases: as stated, they can be inserted through the \phase command within the phases environment. This environment simply puts in the background layer its content so that the timeline will stay in the main layer. Each phase is characterized by a position, a degree and a color; for each property there is a key. The position can be set by between week=<initial> and <end> in <offset> where <intial> is the beginning week, <end> the ending week and <offset> is a number from 0 to 1 which sets the distance from <initial> to <end>. The involvement degree simply sets the radius of the bubble while phase color its color. As well as the weeks, also the phases have an id in the form phase-<number>: it will be useful later on. The <number> is progressive, meaning that it increases each time one adds a phase.
Last, but not least, the milestones. They can be added through the \addmilestone command, which need: a starting position, a direction where the line will go and a text. For the starting position, use the at key, and I suggest to exploit the phase name, i.e. at=phase-1.north (after the dotuse whatever TikZ allows). The direction can be something like 90:1cm and the text sets the label. Some customization of the text can be done through the text options key.
The code of the library:
\usetikzlibrary{backgrounds,calc}
\pgfkeys{/tikz/.cd,
timeline width/.store in=\timelinewidth,
timeline width=20,
timeline height/.store in=\timelineheight,
timeline height=1,
timeline offset/.store in=\timelineoffset,
timeline offset=0.15,
initial week/.store in=\initialweek,
initial week=1,
end week/.store in=\endweek,
end week=2,
time point/.store in=\timepoint,
time point=0.5,
between week/.style args={#1 and #2 in #3}{
initial week=#1,
end week=#2,
time point=#3,
},
involvement degree/.store in=\involvdegree,
involvement degree=2cm,
phase color/.store in=\phasecol,
phase color=red!50!orange,
phase appearance/.style={
circle,
opacity=0.3,
minimum size=\involvdegree,
fill=\phasecol
},
}
\pgfkeys{/tikz/milestone/.cd,
at/.store in=\msstartpoint,
at=phase-1.north,
circle radius/.store in=\milestonecircleradius,
circle radius=0.1cm,
direction/.store in=\msdirection,
direction=90:2cm,
text/.store in=\mstext,
text={},
text options/.code={\tikzset{#1}},
}
\newcommand{\timeline}[1]{
\draw[fill,opacity=0.8] (0,0) rectangle (\timelinewidth,\timelineheight);
\shade[top color=black, bottom color=white,middle color=black!20]
(0,0) rectangle (\timelinewidth,-\timelineoffset);
\shade[top color=white, bottom color=black,middle color=black!20]
(0,\timelineheight) rectangle (\timelinewidth,\timelineheight+\timelineoffset);
\foreach \smitem [count=\xi] in {1,...,#1} {\global\let\maxsmitem\xi}
\pgfmathsetmacro\position{\timelinewidth/(\maxsmitem+1)}
\node at (0,0.5\timelineheight)(week-0){\phantom{Week 0}};
\foreach \x[count=\xi] in {1,...,#1}{
\node[text=white]at +(\xi*\position,0.5\timelineheight) (week-\xi) {Week \x};
}
}
\newcounter{involv}
\setcounter{involv}{0}
\newcommand{\phase}[1]{
\stepcounter{involv}
\node[phase appearance,#1]
(phase-\theinvolv)
at ($(week-\initialweek)!\timepoint!(week-\endweek)$){};
}
\newcommand{\initialphase}[1]{
\node[phase appearance,#1,anchor=west,between week=0 and 1 in 0,]
(phase-\theinvolv)
at ($(week-0)!0!(week-1)$){};
\setcounter{involv}{0}
}
\newenvironment{phases}{\begin{pgfonlayer}{background}}{\end{pgfonlayer}}
\newcommand{\addmilestone}[1]{
\pgfkeys{/tikz/milestone/.cd,#1}
\draw[double,fill] (\msstartpoint) circle [radius=\milestonecircleradius];
\draw(\msstartpoint)--++(\msdirection)node[/tikz/milestone/text options]{\mstext};
}
A document example:
\documentclass[border=10pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{timeline}
\begin{document}
\begin{tikzpicture}
\timeline{8}% number of weeks
% put here the phases
\begin{phases}
\initialphase{involvement degree=1.75cm,phase color=black}
\phase{between week=1 and 2 in 0.1,involvement degree=2.25cm}
\phase{between week=1 and 2 in 0.5,involvement degree=3cm}
\phase{between week=1 and 2 in 0.9,involvement degree=2.125cm}
\phase{between week=3 and 4 in 0.7,phase color=blue!80!cyan}
\end{phases}
% put here the milestones
\addmilestone{at=phase-0.90,direction=90:1cm,text={Initial meeting},text options={above}}
\addmilestone{at=phase-0.270,direction=270:1cm,text={Initial meeting},text options={below}}
\addmilestone{at=phase-2.110,direction=120:1.5cm,text={Research},text options={above}}
\addmilestone{at=phase-2.250,direction=240:1.5cm,text={Need Agreement},text options={below}}
\end{tikzpicture}
\end{document}
The result:
