gitdags.sty

%%
%% Copyright (C) 2014 by Julien Cretel <jubobs.tex at gmail.com>
%%
%% This work may be distributed and/or modified under the
%% conditions of the LaTeX Project Public License, either version 1.3
%% of this license or (at your option) any later version.
%% The latest version of this license is in
%%
%%     http://www.latex-project.org/lppl.txt
%%
%% and version 1.3 or later is part of all distributions of LaTeX
%% version 2005/12/01 or later.
%%
%% This work has the LPPL maintenance status `maintained'.
%%
%% The Current Maintainer of this work is Julien Cretel.
%%
%% This work currently consists of the file gitdags.sty.
%%
\NeedsTeXFormat{LaTeX2e}[2011/06/27]
\ProvidesClass{gitdags}
  [2014/08/28 v0.1 A package for drawing educational Git history graphs]

\DeclareOption*{\PassOptionsToPackage{\CurrentOption}{tikz}}
\ProcessOptions\relax

\RequirePackage{xcolor-solarized}
\RequirePackage{tikz}
\usetikzlibrary{
  arrows.meta,
  graphs,
  positioning,
  shadows,
  shapes,
}

% conflict color
\colorlet{conflictcolor}{red}

% custom shape, adapted from 102.5.3 in the TikZ 3.0 manual
\pgfdeclareshape{dogeared}{
  \inheritsavedanchors[from=rectangle]
  \inheritanchorborder[from=rectangle]
  \inheritanchor[from=rectangle]{center}
  \inheritanchor[from=rectangle]{north}
  \inheritanchor[from=rectangle]{south}
  \inheritanchor[from=rectangle]{west}
  \inheritanchor[from=rectangle]{east}
  \backgroundpath{%
    \southwest \pgf@xa=\pgf@x \pgf@ya=\pgf@y
    \northeast \pgf@xb=\pgf@x \pgf@yb=\pgf@y
    \pgf@xc=\pgf@xb \advance\pgf@xc by-5pt
    \pgf@yc=\pgf@yb \advance\pgf@yc by-5pt
    \pgfpathmoveto{\pgfpoint{\pgf@xa}{\pgf@ya}}
    \pgfpathlineto{\pgfpoint{\pgf@xa}{\pgf@yb}}
    \pgfpathlineto{\pgfpoint{\pgf@xc}{\pgf@yb}}
    \pgfpathlineto{\pgfpoint{\pgf@xb}{\pgf@yc}}
    \pgfpathlineto{\pgfpoint{\pgf@xb}{\pgf@ya}}
    \pgfpathclose
    \pgfpathmoveto{\pgfpoint{\pgf@xc}{\pgf@yb}}
    \pgfpathlineto{\pgfpoint{\pgf@xc}{\pgf@yc}}
    \pgfpathlineto{\pgfpoint{\pgf@xb}{\pgf@yc}}
    \pgfpathclose
  }
}

% To cancel a shadow (see http://tex.stackexchange.com/a/198298/21891)
\tikzset{reset preaction/.code={\def\tikz@preactions{}}}

% --- repository history graphs ---
% style definitions
\tikzset{
  gitdags node/.style={
    draw,
    node distance = 1.4em,
    drop shadow   = {opacity=0.15},
    font          = \fontfamily{lmtt}\selectfont\small,
  },
  DAGref/.style={
    gitdags node,
    shape          = rectangle,
    minimum height = 1.4em,
    draw           = solarized-base01,
    thick,
    font           = \fontfamily{lmtt}\selectfont\scriptsize,
  },
  DAGedge/.style={
    semithick,
    Latex-,
    draw = gray,
  },
  DAGrefedge/.style={
    DAGedge,
    thick,
    densely dotted,
  },
  DAGcommit/.style={
    gitdags node,
    shape                        = rounded rectangle,
    rounded rectangle arc length = 90,
    minimum height               = 1.6em,
    minimum width                = 2em,
    draw                         = solarized-base01,
    fill                         = solarized-green!20,
    very thick,
  },
  graphs/DAG/.style={
    nodes          = DAGcommit,
    edges          = DAGedge,
    branch down    = 3em,
    grow right sep = 1.5em,
  },
  gitareas/.style={
    gitdags node,
    shape           = rectangle,
    rounded corners = .5em,
    minimum width   = 7em,
    minimum height  = 3em,
    text opacity    = 0.75,
    semithick,
  },
  gitSA/.style={
    gitareas,
    anchor = north west,
    xshift = 1em,
    yshift = -1em,
    draw   = solarized-orange,
    fill   = solarized-orange!5,
    text   = solarized-orange,
  },
  gitWT/.style={
    gitareas,
    node distance = .6em,
    draw          = solarized-violet,
    fill          = solarized-violet!5,
    text          = solarized-violet,
  },
  resetarrows/.style={
    -Stealth,
    dashed,
    thick,
    draw         = solarized-base02,
    draw opacity = .75,
  },
  highlighted commit/.style={
    DAGcommit,
    reset preaction,
    fill opacity = 0,
    draw         = solarized-base02,
  },
  problematic commits/.style={
    reset preaction,
    draw opacity = .25,
    fill opacity = .25,
  },
  graphs/unreachable/.style={
    problematic commits,
    target edge style = problematic commits,
  },
  graphs/conflict/.style={
    empty nodes,
    problematic commits,
    target edge style = problematic commits,
    draw              = conflictcolor,
    fill              = conflictcolor!25,
  },
  placeholder commits/.style={
    reset preaction,
    draw opacity = 0,
    fill opacity = 0,
  },
  graphs/placeholder/.style={
    placeholder commits,
    target edge style = placeholder commits,
  },
  blob/.style={
    shape          = dogeared,
    minimum width  = 2em,
    minimum height = 2.82em,
    node distance  = .75em,
    line join      = bevel,
    draw           = black,
    fill           = white,
    align          = left,
    font           = \ttfamily\tiny,
  },
}

% directed acyclic graph
\newcommand\gitDAG[1][]{\graph[DAG,#1]}

% helper macro (let's check the name's availability)
\newcommand\nodename@gitdags{}

% local-branch reference
\newcommand\gitbranch[4][]{%
  \renewcommand\nodename@gitdags{#1}%
  \if\relax\detokenize{#1}\relax% check for empty optional argument
    \renewcommand\nodename@gitdags{#2}%
  \fi
  \node[
    DAGref,
    fill = yellow!30,
  ] (\nodename@gitdags) [#3] {#2};
  \draw[DAGrefedge] (#4) -- (\nodename@gitdags);
}

% remote-branch reference
\newcommand\gitremotebranch[4][]{%
  \renewcommand\nodename@gitdags{#1}%
  \if\relax\detokenize{#1}\relax% check for empty optional argument
    \renewcommand\nodename@gitdags{#2}%
  \fi
  \node[
    DAGref,
    fill = solarized-blue!20,
  ] (\nodename@gitdags) [#3] {#2};
  \draw[DAGrefedge] (#4) -- (\nodename@gitdags);
}

% tag reference
\newcommand\gittag[4][]{%
  \renewcommand\nodename@gitdags{#1}%
  \if\relax\detokenize{#1}\relax% check for empty optional argument
    \renewcommand\nodename@gitdags{#2}%
  \fi
  \node[
    DAGref,
    fill = solarized-magenta!20,
  ] (\nodename@gitdags) [#3] {#2};
  \draw[DAGrefedge] (#4) -- (\nodename@gitdags);
}

% HEAD symbolic reference
\newcommand\gitHEAD[2]{%
  \node[
    DAGref,
    fill          = solarized-red!20,
    node distance = 1em,
  ] (gitHEAD) [#1] {HEAD};
  \draw[DAGrefedge] (#2) -- (gitHEAD);
}

% the following macro is useful for explaining how merge conflicts arise
\newcommand\gitblob[2][]
  {\node[blob,#1] {#2};}

% to highlight a merge conflict arising in a given file
\newcommand\gitblobmc[1]{%
  \node[
    blob,
    draw = conflictcolor,
    text = conflictcolor,
    font = \scriptsize,
    #1] {???};
}

% staging area and worktree
\newcommand\SAandWT{%
  \node[
    gitSA,
  ] (stagingarea) at (current bounding box.south east) {staging area};
  \node[
    gitWT,
    below=of stagingarea,
  ] (workingtree) {working tree};
}

% arrows pointing from a commit to the staging area or working tree
\newcommand\toSAorWT[2]{%
  \node[highlighted commit] at (#1) {\phantom{#1}};
  \draw[resetarrows] (#1.south) to[out=290, in=170]
    ([xshift=1em,yshift=-1em]#2.north west);
}

\newcommand\toSAfrom[1]{\toSAorWT{#1}{stagingarea}}
\newcommand\toWTfrom[1]{\toSAorWT{#1}{workingtree}}

\endinput