% cacography: typeset a LaTeX document, get photographed handwritten notes back.
%
% The first LuaLaTeX run lays the document out with handwriting proportions and
% records every page as a scene file. `cacography render <jobname>` writes each page
% by hand. The next LuaLaTeX run puts those pages in the PDF, keeping the typeset text
% invisible underneath so search, copy and links still work.
%
% Copyright (c) 2026 A. Nader. Part of cacography, under the LaTeX Project Public
% License 1.3c or later (https://www.latex-project.org/lppl.txt).
% Bug reports: https://github.com/aynader/cacography/issues
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{cacography}[2026/11/09 v0.14.0b1 Handwritten notes from LaTeX]

\RequirePackage{iftex}
\RequirePackage{etoolbox}
\ifluatex\else
  \PackageError{cacography}{cacography needs LuaLaTeX}{Compile this document with lualatex.}
\fi

\DeclareKeys[cacography]{
  seed.store        = \cacography@seed,
  paper.store       = \cacography@paper,
  papersize.store   = \cacography@papersize,
  handwriting.store = \cacography@handwriting,
  ink.store         = \cacography@ink,
  sloppiness.store  = \cacography@sloppiness,
  camera.store      = \cacography@camera,
  wear.store        = \cacography@wear,
  background.store  = \cacography@background,
  light.store       = \cacography@light,
  angle.store       = \cacography@angle,
  shadow.store      = \cacography@shadow,
  crumple.store     = \cacography@crumple,
  folds.store       = \cacography@folds,
  creases.store     = \cacography@creases,
  scores.store      = \cacography@scores,
  edges.store       = \cacography@edges,
  stains.store      = \cacography@stains,
  grooves.store     = \cacography@grooves,
  backside.store    = \cacography@backside,
  curl.store        = \cacography@curl,
  age.store         = \cacography@age,
  props.store       = \cacography@props,
  framing.store     = \cacography@framing,
  underline.store   = \cacography@underline,
  reroll.store      = \cacography@reroll,
  render.store      = \cacography@render,
}
\SetKeys[cacography]{
  seed = random, paper = notebook, papersize = letter, handwriting = natural,
  ink = blue, sloppiness = 0.5, camera = phone, wear = 0.3,
  % Each aspect of the photo on its own: set one, or reroll={angle, light=2} for new ones.
  background = random, light = random, angle = random, shadow = random,
  crumple = random, folds = random, creases = random, scores = random, edges = random,
  stains = random, grooves = random, backside = random, curl = random, age = random, props = random, framing = random, underline = random, reroll = {},
  % auto: with --shell-escape, LuaLaTeX draws the pages itself; manual: run `cacography render`.
  render = auto,
}
\ProcessKeyOptions[cacography]

\newattribute\cacography@variant
\newattribute\cacography@crossout
\newattribute\cacography@erased
\newcount\cacography@erasedcount
\directlua{
  local path = kpse.find_file("cacography.lua", "lua") or kpse.find_file("cacography.lua", "tex")
  cacography = dofile(path)
}
\directlua{cacography.setup{
  jobname     = "\luaescapestring{\jobname}",
  seed        = "\luaescapestring{\cacography@seed}",
  paper       = "\luaescapestring{\cacography@paper}",
  papersize   = "\luaescapestring{\cacography@papersize}",
  handwriting = "\luaescapestring{\cacography@handwriting}",
  ink         = "\luaescapestring{\cacography@ink}",
  sloppiness  = "\luaescapestring{\cacography@sloppiness}",
  camera      = "\luaescapestring{\cacography@camera}",
  wear        = "\luaescapestring{\cacography@wear}",
  background  = "\luaescapestring{\cacography@background}",
  light       = "\luaescapestring{\cacography@light}",
  angle       = "\luaescapestring{\cacography@angle}",
  shadow      = "\luaescapestring{\cacography@shadow}",
  crumple     = "\luaescapestring{\cacography@crumple}",
  folds       = "\luaescapestring{\cacography@folds}",
  creases     = "\luaescapestring{\cacography@creases}",
  scores      = "\luaescapestring{\cacography@scores}",
  edges       = "\luaescapestring{\cacography@edges}",
  stains      = "\luaescapestring{\cacography@stains}",
  grooves     = "\luaescapestring{\cacography@grooves}",
  backside    = "\luaescapestring{\cacography@backside}",
  curl        = "\luaescapestring{\cacography@curl}",
  age         = "\luaescapestring{\cacography@age}",
  props       = "\luaescapestring{\cacography@props}",
  framing     = "\luaescapestring{\cacography@framing}",
  underline   = "\luaescapestring{\cacography@underline}",
  reroll      = "\luaescapestring{\cacography@reroll}",
  render      = "\luaescapestring{\cacography@render}",
}}
\AtEndDocument{\directlua{cacography.finish()}}
% Read on every run, rewritten when new pages are drawn: tells latexmk to run again.
\input{\directlua{tex.sprint(cacography.status_file())}}

\RequirePackage{geometry}
\geometry{\cacography@papersize paper, left=1.4in, right=0.6in, top=1.3in, bottom=0.75in}

% Handwriting is about 10% wider per letter than Latin Modern at the same x-height,
% with word gaps 2.3 times as wide (measured on BRUSH and IAM-OnDB). Laying the text
% out at those proportions makes TeX break lines where a hand would run out of room.
\RequirePackage{fontspec}
\RequirePackage{unicode-math}
\setmainfont{Latin Modern Roman}[Scale=1.6, FakeStretch=1.10, WordSpace=2.3, Ligatures={TeX, CommonOff}]
\setsansfont{Latin Modern Sans}[Scale=1.6, FakeStretch=1.10, WordSpace=2.3, Ligatures={TeX, CommonOff}]
\setmonofont{Latin Modern Mono}[Scale=1.6]
\setmathfont{Latin Modern Math}[Scale=1.6]
\AtBeginDocument{%
  \linespread{\fpeval{(\the\dimexpr\cacography@rulespacing\relax)/(\the\dimexpr\baselineskip\relax)}}\selectfont
  \setlength{\parskip}{0pt}%
  \raggedright
  \setlength{\parindent}{1.5em}%
}

% \reroll{word} writes the words inside again with a different seed, leaving every other
% word on the page as it was. \reroll[2]{word}, [3] and so on give further variants.
\NewDocumentCommand\reroll{O{1}m}{{\cacography@variant=\numexpr#1\relax #2}}

% \cacographynote{text} writes a small note in the left margin, beside the line it is
% written on: between the binder holes and the margin line. \cacographynote*{text} also
% draws an arrow from the note to the place in the text where it was written.
% \cacographynote[right]{text} writes it in the right margin instead, narrower.
\reversemarginpar
\AtBeginDocument{\setlength{\marginparwidth}{0.68in}\setlength{\marginparsep}{0.17in}}
\newcounter{cacography@note}
\NewDocumentCommand\cacographynote{sO{left}m}{%
  % A note at the start of a paragraph belongs to its first line, not the space above it.
  \leavevmode
  \begingroup
  % LaTeX picks a margin for all notes at once, so a right-hand note is set in the left
  % margin, narrower, and marked: the renderer writes it in the right margin.
  \ifstrequal{#2}{right}{%
    \setlength{\marginparwidth}{0.42in}%
    \def\cacography@side{\directlua{cacography.note_mark(0, 3)}}%
  }{\let\cacography@side\relax}%
  \IfBooleanTF{#1}{%
    \stepcounter{cacography@note}%
    \directlua{cacography.note_mark(\arabic{cacography@note}, 1)}%
    \marginpar{\raggedright\scriptsize\leavevmode\cacography@side\directlua{cacography.note_mark(\arabic{cacography@note}, 2)}#3}%
  }{\marginpar{\raggedright\scriptsize\leavevmode\cacography@side #3}}%
  \endgroup
}

% Drawings: pgf (TikZ, pgfplots) writes each drawing command through \pgfsys@invoke. A
% readable copy goes beside it, so the renderer can draw the figure again by hand.
\AtBeginDocument{%
  \ifdefined\pgfsys@invoke
    \let\cacography@pgfinvoke\pgfsys@invoke
    \def\pgfsys@invoke#1{\cacography@pgfinvoke{#1}\directlua{cacography.literal("\luaescapestring{#1}")}}%
  \fi
}

% \cacographypage{crumple=0.8, stains=coffee} sets how this one sheet looks and is shot:
% angle, framing, shadow, wear, crumple, folds, creases, scores, edges, stains, grooves, backside, curl, age, props, or
% reroll={...} of those. It applies to the page it lands on.
\NewDocumentCommand\cacographypage{m}{\directlua{cacography.page_options("\luaescapestring{\detokenize{#1}}")}}

% \crossout{text} writes the text and strikes it through by hand, the way this writer
% crosses things out: one line, two, or a scribble. \crossout[line]{text},
% \crossout[double]{...} and \crossout[scribble]{...} choose. Write the right word after it.
\def\cacography@cross@{1}\def\cacography@cross@line{2}\def\cacography@cross@double{3}\def\cacography@cross@scribble{4}
\NewDocumentCommand\crossout{O{}m}{%
  \ifcsname cacography@cross@#1\endcsname
    {\cacography@crossout=\csname cacography@cross@#1\endcsname\relax #2}%
  \else
    \PackageError{cacography}{Unknown crossout style `#1'}{Use line, double or scribble.}#2%
  \fi
}

% \erased{old}{new} writes `new' where `old' was written first and rubbed out: a faint
% ghost of the old word under it, the paper a little grey and roughed up there, and a few
% crumbs of eraser about. Best with ink=pencil (an ink eraser leaves more behind).
\NewDocumentCommand\erased{mm}{%
  \global\advance\cacography@erasedcount by 1
  \directlua{cacography.erased(\the\cacography@erasedcount, "\luaescapestring{\detokenize{#1}}")}%
  {\cacography@erased=\cacography@erasedcount\relax #2}%
}

\endinput