%%
%% chalk-annotate.sty — Hand-drawn chalk-textured annotations for LaTeX Beamer
%% Based on pre-rendered PNG images with transparent backgrounds.
%%
%% Usage:
%%   \usepackage{chalk-annotate}
%%   \hlellipse{important}            % default red
%%   \hlellipse[blue]{important}      % blue
%%   \hlbox[green]{box content}       % green box with light fill
%%   \hlunderline[orange]{underlined} % orange underline
%%
%% Available colors: red, blue, green, orange, purple
%% Prerequisite: assets/ folder with PNG files from generate-colors.py
%%

\ProvidesPackage{chalk-annotate}[2026/04/25 v1.1 Hand-drawn chalk annotations for Beamer]

% ---- Required packages ----
\RequirePackage{tikz}
\RequirePackage{graphicx}
\RequirePackage{calc}
\usetikzlibrary{calc, backgrounds}

% ---- Asset path (change with \annsetpath{path}) ----
\newcommand{\ann@assetpath}{assets}
\newcommand{\annsetpath}[1]{\renewcommand{\ann@assetpath}{#1}}

\ProcessOptions

% ---- Detect installation mode at load time ----
% Flat mode (CTAN/TeX Live): ann-ellipse-red.png alongside .sty
% Dir mode  (local/Overleaf): assets/<color>/ann-ellipse.png
\IfFileExists{ann-ellipse-red.png}{%
  \newcommand{\ann@img}[2]{ann-#2-#1.png}%
}{%
  \newcommand{\ann@img}[2]{\ann@assetpath/#1/ann-#2.png}%
}

% ---- Internal: measure text and set \imgw, \imgh ----
\newcommand{\annmeasure}[3][4]{%
  \setbox0=\hbox{#3}%
  \pgfmathsetlengthmacro{\imgw}{\wd0+#1*2pt+#2}%
  \pgfmathsetlengthmacro{\imgh}{\ht0+\dp0+#1*2pt+#2}%
}

% ============================================================
%  Annotation commands
%  Each takes an optional [color] argument (default: red)
%  and a mandatory {content} argument.
% ============================================================

% ---- Ellipse \hlellipse[color]{content} ----
\newcommand{\hlellipse}[2][red]{%
  \annmeasure[4]{10pt}{#2}%
  \tikz[baseline=(X.base)]{%
    \node[inner sep=4pt] (X) {#2};%
    \node[anchor=center, inner sep=0pt] at (X.center)
      {\includegraphics[width=\imgw, height=\imgh]{\ann@img{#1}{ellipse}}};%
  }%
}

% ---- Underline \hlunderline[color]{content} ----
\newcommand{\hlunderline}[2][red]{%
  \annmeasure[1]{6pt}{#2}%
  \tikz[baseline=(X.base)]{%
    \node[inner sep=1pt] (X) {#2};%
    \node[anchor=north, inner sep=0pt] at ([yshift=-0.5pt]X.south)
      {\includegraphics[width=\imgw]{\ann@img{#1}{underline}}};%
  }%
}

% ---- Box \hlbox[color]{content} ----
% Light fill behind text (background layer), border on top
\newcommand{\hlbox}[2][red]{%
  \annmeasure[4]{10pt}{#2}%
  \tikz[baseline=(X.base)]{%
    \node[inner sep=4pt] (X) {#2};%
    % Light fill: behind text
    \begin{pgfonlayer}{background}
      \node[anchor=center, inner sep=0pt] at (X.center)
        {\includegraphics[width=\imgw, height=\imgh]{\ann@img{#1}{box-fill}}};%
    \end{pgfonlayer}
    % Border: on top of text
    \node[anchor=center, inner sep=0pt] at (X.center)
      {\includegraphics[width=\imgw, height=\imgh]{\ann@img{#1}{box-border}}};%
  }%
}

% ---- Circle/rounded rect \hlcircle[color]{content} ----
\newcommand{\hlcircle}[2][red]{%
  \annmeasure[3]{8pt}{#2}%
  \tikz[baseline=(X.base)]{%
    \node[inner sep=3pt] (X) {#2};%
    \node[anchor=center, inner sep=0pt] at (X.center)
      {\includegraphics[width=\imgw, height=\imgh]{\ann@img{#1}{ellipse}}};%
  }%
}

% ---- Right arrow \hlarrowright[color]{content} ----
\newcommand{\hlarrowright}[2][red]{%
  \tikz[baseline=(X.base)]{%
    \node[inner sep=2pt] (X) {#2};%
    \node[anchor=west, inner sep=0pt] at ([xshift=3pt]X.east)
      {\includegraphics[height=1.5ex]{\ann@img{#1}{arrow-right}}};%
  }%
}

% ---- Strike-through \hlstrike[color]{content} ----
\newcommand{\hlstrike}[2][red]{%
  \annmeasure[1]{4pt}{#2}%
  \tikz[baseline=(X.base)]{%
    \node[inner sep=1pt] (X) {#2};%
    \node[anchor=center, inner sep=0pt] at (X.center)
      {\includegraphics[width=\imgw, height=\imgh]{\ann@img{#1}{strike}}};%
  }%
}

\endinput