atombook.sty

% atombook.sty
\ProvidesPackage{atombook}[2026/03/27 My simple package]

%%%%%%%%%% enumitem setup %%%%%%%%%%%%%
\usepackage{enumitem}
\newcommand*\squarednum[1]{\tikz[baseline=(char.base)]{\node[rectangle, draw, semithick, inner sep=0pt, minimum size = 1em, font=\sffamily] (char) {#1};}}
\setlist[enumerate]{label=\protect\squarednum{\arabic*},nosep}

%%%%%%%%%% plain tcolorbox setup %%%%%%%%%%%%
\usepackage[many]{tcolorbox}
% https://tex.stackexchange.com/a/747203
\tikzset{mybox frame/.style={tcbcolframe, line width=1.5pt}}
\tcbsubskin{mybox}{empty}{
  frame engine=path,
  attach boxed title to top left={xshift=.25cm,yshift=-.7\baselineskip},
  boxed title style={
    skin=empty,frame engine=path,
    frame empty,
  },
  % frame code specific for unbroken boxes
  frame code={
    \draw[mybox frame]
        (title.west) -| (frame.south west) -- (frame.south east) |- (title.east);
  },
  % frame code for broken boxes
  skin first is subskin of={emptyfirst}{
    frame code={
      \draw[mybox frame]
        (title.west) -| (frame.south west)
        (frame.south east) |- (title.east);
    }
  },
  skin middle is subskin of={emptymiddle}{
    frame code={
      \draw[mybox frame]
          (frame.north east) -- (frame.south east)
          (frame.north west) -- (frame.south west);
    }
  },
  skin last is subskin of={emptylast}{
    frame code={
      \draw[mybox frame]
          (frame.north east) -- (frame.south east)
          -- (frame.south west) -- (frame.north west);
    }
  }
}

\NewTColorBox{mybox}{ O{} m }{
  breakable, skin=mybox, top=.5cm,
  before skip=.1cm,
  after skip=.25cm,
  before title={【},after title={】},
% before title={[\,},after title={\,]},
% colframe=green!75!black,
  colframe=violet!85,
  fonttitle=\bfseries\large,
  title={#2},#1,
  coltitle=tcbcolframe,% delay after #1
}


%%%%%%%%%%% margin chapter layout%%%%%%%%%%%%%%
\RequirePackage{tikz}
\usetikzlibrary{matrix}
% https://tex.stackexchange.com/a/761258
\ExplSyntaxOn
\tl_new:N \l_mwe_matrix_content_tl
\tl_new:N \l_atombook_node_fill_color
\tl_new:N \l_atombook_current_fill_color
\tl_new:N \l_atombook_node_draw_color
\tl_new:N \l_atombook_current_draw_color
\dim_new:N \l_atombook_block_size_dim
\dim_new:N \l_atombook_block_sep_dim
\tl_new:N \l_atombook_font_style_tl

% keys
\keys_define:nn { atombook }
{
    node-fill    .tl_set:N   = \l_atombook_node_fill_color,
    node-fill    .initial:n  = cyan,
    current-fill .tl_set:N   = \l_atombook_current_fill_color,
    current-fill .initial:n  = magenta,
    node-draw    .tl_set:N   = \l_atombook_node_draw_color,
    node-draw    .initial:n  = none,
    current-draw .tl_set:N   = \l_atombook_current_draw_color,
    current-draw .initial:n  = none,
    block-size   .dim_set:N  = \l_atombook_block_size_dim,
    block-size   .initial:n  = 1.2cm,
    block-sep    .dim_set:N  = \l_atombook_block_sep_dim,
    block-sep    .initial:n  = 0.5cm,
    font         .tl_set:N   = \l_atombook_font_style_tl,
    font         .initial:n  = { \sffamily\bfseries\Huge },
}

%
\NewDocumentCommand \marginblockset { m } { 
    \keys_set:nn { atombook } { #1 } 
}

\property_new:nnnn { last-chapter } { now } { 1 } {
    \arabic{chapter}
}
\hook_gput_code:nnn { enddocument } { . } {
  \property_record:nn { atombook/matrix } { last-chapter }
}
\hook_gput_code:nnn { shipout/background } { . } {
    \int_compare:nNnF{ \property_ref:nn { atombook/matrix } { last-chapter } } = {0} % add test for no chapter
    {%
        \int_step_inline:nn { \property_ref:nn { atombook/matrix } { last-chapter } } {
            \int_compare:nNnT { #1 } = { \value{chapter} } {
                \tl_put_right:Nn \l_mwe_matrix_content_tl { |[fill=\l_atombook_current_fill_color, draw=\l_atombook_current_draw_color]| }
            }
            \tl_put_right:Nn \l_mwe_matrix_content_tl { #1 \\ }
        }
        \begin{tikzpicture}[%
                overlay,remember~picture,
                marginpage/.style={%
                    matrix~of~nodes,
                    nodes={
                        align=center,
                        draw=\l_atombook_node_draw_color,
                        fill=\l_atombook_node_fill_color, 
                        minimum~size=\l_atombook_block_size_dim,
                        font=\l_atombook_font_style_tl
                    },
                    row~sep=\l_atombook_block_sep_dim,
                    column~sep=0mm,
                    inner~sep=0pt,
                    outer~sep=0pt,
                }%
            ]%
            % \matrix[anchor=east,marginpage] at (current~page.east){\l_mwe_matrix_content_tl};
            \if@twoside
                \ifodd\value{page}\relax
                    \matrix[anchor=east,marginpage] at (current~page.east){\l_mwe_matrix_content_tl};
                \else%
                    \matrix[anchor=west,marginpage] at (current~page.west){\l_mwe_matrix_content_tl};
                \fi%
            \else
                \matrix[anchor=east,marginpage] at (current~page.east){\l_mwe_matrix_content_tl};
            \fi
        \end{tikzpicture}%
    }%
}
\ExplSyntaxOff

\endinput