% !TeX root = ./examples/hippo.tex
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%
%% This package is part of the TikZlings package
%% A package to bring cute little animals and other beings into tikz
%% Maintained by samcarter
%%
%% Project repository and bug tracker:
%% https://github.com/samcarter/tikzlings
%%
%% Released under the LaTeX Project Public License v1.3c or later
%% See http://www.latex-project.org/lppl.txt
%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\ProvidesPackage{tikzlings-hippos}[2022/06/17 version v1.0 Drawing hippos in TikZ]

\RequirePackage{tikz}
\RequirePackage{tikzlings-addons}

\newcommand*{\hippo}[1][]{%
  \begin{scope}%
    \tikzset{/hippo/.cd,#1}%
    \hippo@draw%
  \end{scope}%
  \thing[#1]%
  % adding hook for users to customise %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  \csname hippohookforeground\endcsname
  \csname tikzlinghookforeground\endcsname
}

\newif\ifhippo@threeD
\newif\ifhippo@back
\newif\ifhippo@contour

\tikzset{
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  %
  % Pass unknown keys on to tikz
  %
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  /hippo/.search also={/tikz,/pgf,/thing},
  /hippo/.cd,
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  %
  % body
  %
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  body/.store in     = \hippo@body,
  body               = gray,
  eye/.store in      = \hippo@eye,
  eye                = white,   
  pupil/.store in    = \hippo@pupil,
  pupil              = black,  
  toes/.store in     = \hippo@toes,
  toes               = \hippo@body!55!white,
  mouth/.store in    = \hippo@mouth,
  mouth              = \hippo@body!70!black,
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  %
  % options
  %
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  3D/.code           = \hippo@threeDtrue, 
  back/.code         = \hippo@backtrue,
  contour/.code      = \hippo@contourtrue
                       \def\hippo@contour{#1}
                       \def\hippo@mouth{#1},
  contour/.default   = black,  
  outline/.forward to = /hippo/contour,   
}

\def\hippo@draw{%
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  %
  % minimal bounding box size 
  %
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  \path (-0.625,0.1) rectangle (0.625, 2.17);
  %
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  %
  % store the current scale factor
  % from https://github.com/samcarter/tikzlings/issues/3#issuecomment-461373494
  %
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  \pgfgettransformentries{\tmpscaleA}{\tmpscaleB}{\tmpscaleC}{\tmpscaleD}{\tmp}{\tmp}%
  \pgfmathsetmacro{\scalingfactor}{sqrt(abs(\tmpscaleA*\tmpscaleD-\tmpscaleB*\tmpscaleC))*sqrt(abs((\pgf@xx/1cm)*(\pgf@yy/1cm)-(\pgf@xy/1cm)*(\pgf@yx/1cm)))}%
  \pgfmathsetmacro{\xscalefactor}{\tmpscaleA}
  \pgfmathsetmacro{\yscalefactor}{\tmpscaleD}
  %
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  % 
  % switch between 2D, 3D and contours, from
  % https://chat.stackexchange.com/transcript/message/45991801#45991801
  %
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  \ifhippo@threeD
    \def\hippo@part@draw[##1]{\shade[ball color=##1]}
  \else% 3D
    \ifhippo@contour
      \def\hippo@part@draw[##1]{\draw[##1,\hippo@contour,fill=white,line width=\scalingfactor*0.4pt]}
    \else% contour
      \def\hippo@part@draw[##1]{\fill[##1]}
    \fi% contour
  \fi% 3D
  %
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  %
  % Body parts
  % 
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  %
  % adding hook for users to customise %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  \csname hippohookbackground\endcsname
  \csname tikzlinghookbackground\endcsname 
  %
  % Ears %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  \hippo@part@draw[\hippo@body] (0.23,2.03) ellipse[x radius=0.09, y radius=0.13, rotate=-30];
  \hippo@part@draw[\hippo@body] (-0.23,2.03) ellipse[x radius=0.09, y radius=0.13, rotate=30];
  %
  % Feet if back %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  \ifhippo@back
    \begin{scope}
      \clip (-0.5,0.4) rectangle (0.5,0.13);
      \hippo@part@draw[\hippo@body] (-0.25,0.15) ellipse[x radius=0.16, y radius=0.17];
      \hippo@part@draw[\hippo@body] (0.25,0.15) ellipse[x radius=0.16, y radius=0.17];
    \end{scope}
  \fi% back
  %
  % Nose if back %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  \ifhippo@back
    \hippo@part@draw[\hippo@body!80!white] (0, 1.55) ellipse[x radius=0.42, y radius=0.2];
  \fi% back
  %
  % Body %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  \hippo@part@draw[\hippo@body!55!white] ( 0.6,  0.8 ) .. controls ( 0.6 , 0.4) and ( 0.35, 0.19) .. ( 0.0,  0.19) .. controls (-0.35, 0.19) and (-0.6 , 0.4) .. (-0.6,  0.8 ) .. controls (-0.6 , 1.3) and (-0.35, 1.65) .. ( 0.0,  1.65) .. controls ( 0.35, 1.65) and ( 0.6 , 1.3) .. ( 0.6,  0.8) -- cycle;
  %
  % adding hook for users to customise %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  \csname hippohookbelly\endcsname
  \csname tikzlinghookbelly\endcsname
  %    
  % Arms %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  \unless\ifhippo@back
    \hippo@part@draw[\hippo@body] (0.35,1.0) ellipse[x radius=0.24, y radius=0.13, rotate=90];
    \hippo@part@draw[\hippo@body] (-0.35,1.0) ellipse[x radius=0.24, y radius=0.13, rotate=-90];
  \fi% back
  %
  % Head %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  \hippo@part@draw[\hippo@body!55!white] (0, 1.76) circle[radius=0.36];
  %
  % Show details only from the front %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  \unless\ifhippo@back
    %
    % Eyes %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    \ifhippo@contour
      \hippo@part@draw[\hippo@eye] (-0.11, 1.83) ellipse[x radius=0.08, y radius=0.12];
      \hippo@part@draw[\hippo@eye] (0.11, 1.83) ellipse[x radius=0.08, y radius=0.12];
      \hippo@part@draw[\hippo@pupil] (-0.105, 1.78) ellipse[x radius=0.04, y radius=0.07];
      \hippo@part@draw[\hippo@pupil] (0.105, 1.78) ellipse[x radius=0.04, y radius=0.07];
    \else% contour
      \fill[\hippo@eye] (-0.11, 1.83) ellipse[x radius=0.08, y radius=0.12];
      \fill[\hippo@eye] (0.11, 1.83) ellipse[x radius=0.08, y radius=0.12];
      \fill[\hippo@pupil] (-0.105, 1.78) ellipse[x radius=0.04, y radius=0.07];
      \fill[\hippo@pupil] (0.105, 1.78) ellipse[x radius=0.04, y radius=0.07];
    \fi% contour
    %
    % Nose %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    \hippo@part@draw[\hippo@body!80!white] (0, 1.55) ellipse[x radius=0.42, y radius=0.2];
    \hippo@part@draw[\hippo@body!70!black]  (-0.07, 1.63) circle[radius=0.035];
    \hippo@part@draw[\hippo@body!70!black]  (0.07, 1.63) circle[radius=0.035];
    %
    % Mouth %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    \ifhippo@threeD
      \draw[black,line width=\scalingfactor*0.4pt] (0.125, 1.5) arc [start angle=-50, end angle=-130, radius=0.2] ;
    \else% 3D
      \draw[\hippo@mouth,line width=\scalingfactor*0.4pt] (0.125, 1.5) arc [start angle=-50, end angle=-130, radius=0.2];
    \fi% 3D
    %
    % Feet %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    \begin{scope}
      \clip (-0.5,0.4) rectangle (0.5,0.13);
      \hippo@part@draw[\hippo@body] (-0.25,0.15) ellipse[x radius=0.16, y radius=0.17];
      \hippo@part@draw[\hippo@body] (0.25,0.15) ellipse[x radius=0.16, y radius=0.17];
      \hippo@part@draw[\hippo@toes] (0.25,0.13) ellipse[x radius=0.05, y radius=0.1];
      \hippo@part@draw[\hippo@toes] (0.13,0.11) ellipse[x radius=0.05, y radius=0.1];
      \hippo@part@draw[\hippo@toes] (0.37,0.11) ellipse[x radius=0.05, y radius=0.1];
      \hippo@part@draw[\hippo@toes] (-0.25,0.13) ellipse[x radius=0.05, y radius=0.1];
      \hippo@part@draw[\hippo@toes] (-0.13,0.11) ellipse[x radius=0.05, y radius=0.1];
      \hippo@part@draw[\hippo@toes] (-0.37,0.11) ellipse[x radius=0.05, y radius=0.1];  
    \end{scope}
  %
  \fi% back
  %
  % adding hook for users to customise %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  \csname hippohookbody\endcsname
  \csname tikzlinghookbody\endcsname
  %
}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%
%% Documentation
%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%\clearpage
%\section[Hippo]{Sieglinde, the hippo}
%
%\emph{For the winner of the 2019 Groundhog Challenge}
%
%\subsection{Package name}
%
%\begin{tcolorbox}[lower separated=false, lefthand width=.8\linewidth]
%\vspace*{0.5cm}
%\lstinline|\usepackage{tikzlings-hippos}| 
%\vspace*{0.5cm}
%\end{tcolorbox}
%
%\subsection{Basic Usage}
%
%\begin{tcblisting}{}
%\hippo
%\end{tcblisting}
%
%\subsection{Options}
%
%The basic hippo can be modified by changing its colour:
%\begin{tcblisting}{}
%\hippo[body=blue]
%\end{tcblisting}
%
%In addition to the colour of the body, the colour of various body parts can be adjusted:
%\begin{tcblisting}{}
%\hippo[eye=red]
%\end{tcblisting}
%\begin{tcblisting}{}
%\hippo[pupil=red]
%\end{tcblisting}
%\begin{tcblisting}{}
%\hippo[mouth=red]
%\end{tcblisting}
%
%The hippo can also do its nails:
%\begin{tcblisting}{}
%\hippo[toes=red]
%\end{tcblisting}
%
%To view the hippo from behind:
%\begin{tcblisting}{}
%\hippo[back]
%\end{tcblisting}
%
%The key \lstinline|3D| will make the hippo 3-dimensional:
%\begin{tcblisting}{}
%\hippo[3D]
%\end{tcblisting}
%
%And finally the \lstinline|contour| key will only draw the outlines:
%\begin{tcblisting}{}
%\hippo[contour=black]
%\end{tcblisting}