% \iffalse meta-comment
%
%% File: xcoffins.dtx
%
% Copyright (C) 2010-2024 The LaTeX Project
%
% It may be distributed and/or modified under the conditions of the
% LaTeX Project Public License (LPPL), either version 1.3c of this
% license or (at your option) any later version. The latest version
% of this license is in the file
%
% https://www.latex-project.org/lppl.txt
%
% This file is part of the "l3experimental bundle" (The Work in LPPL)
% and all files in that bundle must be distributed together.
%
% -----------------------------------------------------------------------
%
% The development version of the bundle can be found at
%
% https://github.com/latex3/latex3
%
% for those people who are interested.
%
%<*driver>
\documentclass[full]{l3doc}
\usepackage{xcoffins} % Not yet part of expl3, so not in l3doc
\usepackage{xcolor} % As coffins only loads basic color support
\NewCoffin \ExampleCoffin
\NewCoffin \SmallCoffin
\NewCoffin \OutputCoffin
\NewCoffin \RedCoffin
\NewCoffin \BlueCoffin
\NewCoffin \GreenCoffin
\NewCoffin \YellowCoffin
\NewCoffin \OrangeCoffin
\begin{document}
\DocInput{\jobname.dtx}
\end{document}
%</driver>
% \fi
%
% \title{^^A
% The \pkg{xcoffins} package\\ Design-level coffins^^A
% }
%
% \author{^^A
% The \LaTeX{} Project\thanks
% {^^A
% E-mail:
% \href{mailto:latex-team@latex-project.org}
% {latex-team@latex-project.org}^^A
% }^^A
% }
%
% \date{Released 2024-03-14}
%
% \maketitle
%
% \begin{documentation}
%
% \section{Introduction: the coffin concept}
%
% In \LaTeX3 terminology, a \enquote{coffin} is a box containing
% typeset material. Along with the box itself, the coffin structure
% includes information on the size and shape of the box, which makes
% it possible to align two or more coffins easily. This is achieved
% by providing a series of `poles' for each coffin. These
% are horizontal and vertical lines through the coffin at defined
% positions, for example the top or horizontal centre. The points
% where these poles intersect are called \enquote{handles}. Two
% coffins can then be aligned by describing the relationship between
% a handle on one coffin with a handle on the second. In words, an
% example might then read
% \begin{quote}
% Align the top-left handle of coffin A with the bottom-right
% handle of coffin B.
% \end{quote}
%
% The locations of coffin handles are much easier to understand
% visually. Figure~\ref{fgr:handles} shows the standard handle
% positions for a coffin typeset in horizontal mode (left) and in
% vertical mode (right). Notice that the later case results in a greater
% number of handles being available. As illustrated, each handle
% results from the intersection of two poles. For example, the centre
% of the coffin is marked |(hc,vc)|, \emph{i.e.}~it is the
% point of intersection of the horizontal centre pole with the
% vertical centre pole. New handles are generated automatically when
% poles are added to a coffin: handles are \enquote{dynamic} entities.
%
% \begin{figure}
% \hfil
% \begin{minipage}{0.4\textwidth}
% \SetHorizontalCoffin\ExampleCoffin
% {\color{black!10!white}\rule{1 in}{1 in}}
% \DisplayCoffinHandles\ExampleCoffin{blue}
% \end{minipage}
% \hfil
% \begin{minipage}{0.4\textwidth}
% \SetVerticalCoffin\ExampleCoffin{1 in}
% {\color{black!10!white}\rule{1 in}{1 in}}
% \DisplayCoffinHandles\ExampleCoffin{blue}
% \end{minipage}
% \hfil
% \caption{Standard coffin handles: left, horizontal coffin; right,
% vertical coffin}
% \label{fgr:handles}
% \end{figure}
%
%\section{Creating and setting coffins}
%
% Before any alignment can take place, coffins must be created and
% their contents must be created. All coffin operations are local
% to the current \TeX{} group with the exception of coffin creation.
% \begin{function}{\NewCoffin}
% \begin{syntax}
% \cs{NewCoffin} \meta{coffin}
% \end{syntax}
% Before a \meta{coffin} can be used, it must be allocated using
% \cs{NewCoffin}. The name of the \meta{coffin} should be a
% control sequence (starting with the escape character, usually
% |\|), for example
% \begin{verbatim}
% \NewCoffin\MyCoffin
% \end{verbatim}
% Coffins are allocated globally, and an error will be raised if the
% name of the \meta{coffin} is not globally-unique.
% \end{function}
%
% \begin{function}{\SetHorizontalCoffin}
% \begin{syntax}
% \cs{SetHorizontalCoffin} \meta{coffin} \Arg{material}
% \end{syntax}
% Typesets the \meta{material} in horizontal mode, storing the result
% in the \meta{coffin}. The standard poles for the \meta{coffin} are
% then set up based on the size of the typeset material.
% \end{function}
%
% \begin{function}{\SetVerticalCoffin}
% \begin{syntax}
% \cs{SetVerticalCoffin} \meta{coffin} \Arg{width} \Arg{material}
% \end{syntax}
% Typesets the \meta{material} in vertical mode constrained to the
% given \meta{width} and stores the result in the \meta{coffin}. The
% standard poles for the \meta{coffin} are then set up based on the
% size of the typeset material.
% \end{function}
%
% \section{Controlling coffin poles}
%
% A number of standard poles are automatically generated when the coffin
% is set or an alignment takes place. The standard poles for all coffins
% are:
% \begin{itemize}[font = \ttfamily]
% \item[l] a pole running along the left-hand edge of the bounding
% box of the coffin;
% \item[hc] a pole running vertically through the centre of the coffin
% half-way between the left- and right-hand edges of the bounding
% box (\emph{i.e.}~the \enquote{horizontal centre});
% \item[r] a pole running along the right-hand edge of the bounding
% box of the coffin;
% \item[b] a pole running along the bottom edge of the bounding
% box of the coffin;
% \item[vc] a pole running horizontally through the centre of the
% coffin half-way between the bottom and top edges of the bounding
% box (\emph{i.e.}~the \enquote{vertical centre});
% \item[t] a pole running along the top edge of the bounding
% box of the coffin;
% \item[H] a pole running along the baseline of the typeset material
% contained in the coffin.
% \end{itemize}
% In addition, coffins containing vertical-mode material also
% feature poles which reflect the richer nature of these systems:
% \begin{itemize}
% \item[B] a pole running along the baseline of the material at the
% bottom of the coffin.
% \item[T] a pole running along the baseline of the material at the top
% of the coffin.
% \end{itemize}
%
% \begin{function}{\SetHorizontalPole}
% \begin{syntax}
% \cs{SetHorizontalPole} \meta{coffin} \Arg{pole} \Arg{offset}
% \end{syntax}
% Sets the \meta{pole} to run horizontally through the \meta{coffin}.
% The \meta{pole} will be located at the \meta{offset} from the
% baseline of the \meta{coffin}. The
% \meta{offset} should be given as a dimension expression; this may
% include the terms \cs{TotalHeight}, \cs{Height}, \cs{Depth} and
% \cs{Width}, which will evaluate to the appropriate dimensions of
% the \meta{coffin}. For example, to create a pole running
% horizontally through the coffin at one third of the distance from
% the base of the coffin to the top, the appropriate instruction would
% be
% \begin{verbatim}
% \SetHorizontalPole \MyCoffin {height/3} {\TotalHeight/3}
% \end{verbatim}
% Note that poles which run \emph{horizontally} are described in terms
% of their \emph{vertical} location in the coffin. Also notice that
% the total height of the coffin is described by the sum of
% \cs{Height} and \cs{Depth}: these are both measured from the
% horizontal baseline of the material in the coffin.
% \end{function}
%
% \begin{function}{\SetVerticalPole}
% \begin{syntax}
% \cs{SetVerticalPole} \meta{coffin} \Arg{pole} \Arg{offset}
% \end{syntax}
% Sets the \meta{pole} to run vertically through the \meta{coffin}.
% The \meta{pole} will be located at the \meta{offset} from the
% left-hand edge of the bounding box of the \meta{coffin}. The
% \meta{offset} should be given as a dimension expression; this may
% include the terms \cs{TotalHeight}, \cs{Height}, \cs{Depth} and
% \cs{Width}, which will evaluate to the appropriate dimensions of
% the \meta{coffin}. For example, to create a pole running vertically
% through the coffin at one third of the distance from the left-hand
% edge, the appropriate instruction would be
% \begin{verbatim}
% \SetVerticalPole \MyCoffin {width/3} {\Width/3}
% \end{verbatim}
% Note that poles which run \emph{vertically} are described in terms
% of their \emph{horizontal} location in the coffin.
% \end{function}
%
% \begin{function}{\TotalHeight}
% \begin{syntax}
% \cs{TotalHeight}
% \end{syntax}
% Within the \meta{offset} argument of \cs{SetHorizontalPole} and
% \cs{SetVerticalPole}, \cs{TotalHeight} will give the distance from
% the base to the top of the bounding box of the relevant coffin.
% \end{function}
%
% \begin{function}{\Height}
% \begin{syntax}
% \cs{Height}
% \end{syntax}
% Within the \meta{offset} argument of \cs{SetHorizontalPole} and
% \cs{SetVerticalPole}, \cs{Height} will give the distance from the
% baseline to the top of the bounding box of the relevant coffin.
% \end{function}
%
% \begin{function}{\Depth}
% \begin{syntax}
% \cs{Depth}
% \end{syntax}
% Within the \meta{offset} argument of \cs{SetHorizontalPole} and
% \cs{SetVerticalPole}, \cs{Depth} will give the distance from the
% baseline to the bottom of the bounding box of the relevant coffin.
% \end{function}
%
% \begin{function}{\Width}
% \begin{syntax}
% \cs{Width}
% \end{syntax}
% Within the \meta{offset} argument of \cs{SetHorizontalPole} and
% \cs{SetVerticalPole}, \cs{Width} will give the distance from the
% right edge to the left edge of the bounding box of the relevant
% coffin.
% \end{function}
%
% \section{Rotating coffins}
%
% \begin{function}{\RotateCoffin}
% \begin{syntax}
% \cs{RotateCoffin} \meta{coffin} \Arg{angle}
% \end{syntax}
% Rotates the \meta{coffin} by the given \meta{angle} about its reference
% point (given in degrees counter-clockwise) . This process will rotate both
% the coffin content and poles. Multiple rotations will not result in
% the bounding box of the coffin growing unnecessarily.
%
% The effect of rotation on a coffin is illustrated in
% Figure~\ref{fgr:rotation}. As is shown, the coffin handles will
% remain correctly positioned relative to the content of the coffin.
% The \enquote{top} of a rotated coffin may of course no longer be the
% edge closest to the top of the physical page.
% \end{function}
%
% \begin{figure}
% \hfil
% \SetHorizontalCoffin\ExampleCoffin
% {^^A
% \color{black!10!white}\rule{0.5 in}{1 in}^^A
% \color{black!20!white}\rule{0.5 in}{1 in}^^A
% }
% \begin{minipage}{0.4\textwidth}
% \DisplayCoffinHandles\ExampleCoffin{blue}
% \end{minipage}
% \hfil
% \begin{minipage}{0.4\textwidth}
% \RotateCoffin\ExampleCoffin{45}
% \DisplayCoffinHandles\ExampleCoffin{blue}
% \end{minipage}
% \hfil
% \caption{Coffin rotation: left, unrotated; right, rotated by
% $45$\textdegree.}
% \label{fgr:rotation}
% \end{figure}
%
% \section{Resizing coffins}
%
% \begin{function}{\ResizeCoffin}
% \begin{syntax}
% \cs{ResizeCoffin} \meta{coffin} \Arg{width} \Arg{total-height}
% \end{syntax}
% Resized the \meta{coffin} to \meta{width} and \meta{total-height},
% both of which should be given as dimension expressions.
% \end{function}
%
% \begin{function}{\ScaleCoffin}
% \begin{syntax}
% \cs{ScaleCoffin} \meta{coffin} \Arg{x-scale} \Arg{y-scale}
% \end{syntax}
% Scales the \meta{coffin} by a factors \meta{x-scale} and
% \meta{y-scale} in the horizontal and vertical directions,
% respectively. The two scale factors should be given as real numbers.
% \end{function}
%
% \cs{ResizeCoffin} and \cs{ScaleCoffin} can be used interchangeably:
% whether scale factors or absolute values are the best form for the
% resizing will depend upon the context (Figure~\ref{fgr:resizing}).
%
% \begin{figure}
% \hfil
% \SetHorizontalCoffin\ExampleCoffin
% {^^A
% \color{black!10!white}\rule{0.5 in}{1 in}^^A
% \color{black!20!white}\rule{0.5 in}{1 in}^^A
% }
% \begin{minipage}{0.4\textwidth}
% \ResizeCoffin \ExampleCoffin {4 cm} {3 cm}
% \DisplayCoffinHandles \ExampleCoffin {blue}
% \end{minipage}
% \hfil
% \begin{minipage}{0.4\textwidth}
% \ScaleCoffin \ExampleCoffin {2.0} {0.5}
% \DisplayCoffinHandles \ExampleCoffin {blue}
% \end{minipage}
% \hfil
% \caption{Coffin resizing: left, resized to exactly $4$\,cm by
% $6$\,cm; right, scaled a factors of $2$ and $0.5$ in
% $x$ and $y$, respectively (example coffin as in
% Figure~\ref{fgr:rotation}).}
% \label{fgr:resizing}
% \end{figure}
%
% \section{Joining coffins}
%
% The key operation for coffins is joining coffins to each other. This
% is always carried out such that the first coffin is the
% \enquote{parent}, and is updated by the alignment. The second
% \enquote{child} coffin is not altered by the alignment process.
%
% \begin{function}{\JoinCoffins}
% \begin{syntax}
% \cs{JoinCoffins} *
% ~~\meta{coffin1} [ \meta{coffin1-pole1} , \meta{coffin1-pole2} ]
% ~~\meta{coffin2} [ \meta{coffin2-pole1} , \meta{coffin2-pole2} ]
% ~~( \meta{x-offset} , \meta{y-offset} )
% \end{syntax}
% Joining of two coffins is carried out by the \cs{JoinCoffins}
% function, which takes two mandatory arguments: the \enquote{parent}
% \meta{coffin1} and the \enquote{child} \meta{coffin2}. All of the
% other arguments shown are optional.
% \end{function}
%
% The standard \cs{JoinCoffins} functions joins \meta{coffin2} to
% \meta{coffin1} such that the bounding box of \meta{coffin1} after the
% process will expand. The new bounding box will be the smallest
% rectangle covering the bounding boxes of the two input coffins.
% When the starred variant of \cs{JoinCoffins} is used, the bounding
% box of \meta{coffin1} is not altered, \emph{i.e.}~\meta{coffin2} may
% protrude outside of the bounding box of the updated \meta{coffin1}.
% The difference between the two forms of alignment is best illustrated
% using a visual example. In Figure~\ref{fgr:alignment}, the two
% processes are contrasted. In both cases, the small red coffin has been
% aligned with the large grey coffin. In the left-hand illustration,
% the \cs{JoinCoffins} function was used, resulting in an expanded
% bounding box. In contrast, on the right \cs{AttachCoffin} was used,
% meaning that the bounding box does not include the area of the
% smaller coffin.
%
% \begin{figure}
% \fboxsep 0 pt\relax
% \SetHorizontalCoffin\ExampleCoffin
% {\color{black!20!white}\rule{1 in}{1 in}}
% \SetHorizontalCoffin \SmallCoffin
% {\color{red!20!white}\rule{0.1 in}{0.1 in}}
% \hfil
% \begin{minipage}{0.4\textwidth}
% \centering
% \JoinCoffins\ExampleCoffin[vc,r]\SmallCoffin[vc,l]
% \fbox{\TypesetCoffin\ExampleCoffin}
% \end{minipage}
% \hfil
% \begin{minipage}{0.4\textwidth}
% \centering
% \JoinCoffins*\ExampleCoffin[vc,r]\SmallCoffin[vc,l]
% \fbox{\TypesetCoffin\ExampleCoffin}%
% \end{minipage}
% \hfil
% \caption{Contrast between \cs{JoinCoffins} (left) and
% \cs{JoinCoffins*} (right); the bounding box of the coffin is show
% in black.}
% \label{fgr:alignment}
% \end{figure}
%
% The alignment is carried out by first calculating \meta{handle1}, the
% point of intersection of \meta{coffin1-pole1} and
% \meta{coffin1-pole2}, and \meta{handle2}, the point of intersection
% of \meta{coffin2-pole1} and \meta{coffin2-pole2}. If the two
% \meta{poles} are not specified, \cs{JoinCoffins} will use the
% default value |(H,l)|, \emph{i.e.}~the reference point used by \TeX\
% for the underlying box. Once the two \meta{handles} have been
% located, \meta{coffin2} is then attached to \meta{coffin1} such that
% the relationship between \meta{handle1} and \meta{handle2} is
% described by the \meta{x-offset} and \meta{y-offset}. This
% \meta{offset} is an optional argument, and if it is not given then
% |(0 pt, 0 pt)| is used.
%
% Notice that when \cs{JoinCoffins} is used the new bounding box is
% the smallest rectangle containing the bounding boxes of the two input
% coffins. As a result, it will include additional white space unless
% one coffin entirely overlaps the other (Figure~\ref{fgr:bounding},
% left). Rotation of coffins will take account of the extent of the
% material after rotation when re-calculating the bounding box. This
% means that no \emph{unnecessary} white space will be added on
% rotation (Figure~\ref{fgr:bounding}, right).
%
% \begin{figure}
% \fboxsep 0 pt\relax
% \SetHorizontalCoffin\ExampleCoffin
% {\color{black!20!white}\rule{1 in}{1 in}}
% \SetHorizontalCoffin\SmallCoffin
% {\color{red!20!white}\rule{0.1 in}{0.1 in}}
% \JoinCoffins\ExampleCoffin[vc,r]\SmallCoffin[vc,l]
% \hfil
% \begin{minipage}{0.4\textwidth}
% \centering
% \fbox{\copy\ExampleCoffin}
% \end{minipage}
% \hfil
% \begin{minipage}{0.4\textwidth}
% \centering
% \RotateCoffin\ExampleCoffin{135}
% \fbox{\copy\ExampleCoffin}
% \end{minipage}
% \hfil
% \caption{The effect of rotation of a joined coffin: the black line
% shows the coffin bounding box.}
% \label{fgr:bounding}
% \end{figure}
%
% As part of the joining procedure, the poles of the two input coffins
% are preserved within the structure of the updated coffin. In this way
% it is possible to carry out complex alignment procedures. The poles of
% a coffin after alignment may therefore be divided into three groups:
% \begin{enumerate}
% \item The \enquote{native} poles of the updated coffin, such as
% \texttt{l}, \texttt{r}, \texttt{hc}, \emph{etc}.
% \item Poles derived from \meta{coffin1}, such as
% \texttt{\meta{coffin1}-l}, \texttt{\meta{coffin1}-r},
% \texttt{\meta{coffin1}-hc}, \emph{etc.}
% \item Poles derived from \meta{coffin2}, such as
% \texttt{\meta{coffin2}-l}, \texttt{\meta{coffin2}-r},
% \texttt{\meta{coffin2}-hc}, \emph{etc.}
% \end{enumerate}
%
% Applying this ability allows a series of joining operations to
% take place, as illustrated in Figure~\ref{fgr:nested}. In this
% example, the scheme used for alignment was as follows:
% \begin{verbatim}
% \SetHorizontalCoffin\OutputCoffin{}
% \SetHorizontalCoffin\RedCoffin
% {\color{red!20!white}\rule{0.2 in}{0.2 in}}
% \JoinCoffins\OutputCoffin[vc,hc]\RedCoffin[vc,hc]
% \SetHorizontalCoffin\BlueCoffin
% {\color{blue!20!white}\rule{0.2 in}{0.2 in}}
% \JoinCoffins\OutputCoffin[\RedCoffin-vc,\RedCoffin-hc]
% \BlueCoffin[b,l]
% \SetHorizontalCoffin\GreenCoffin
% {\color{green!20!white}\rule{0.2 in}{0.2 in}}
% \JoinCoffins\OutputCoffin[\BlueCoffin-vc,\BlueCoffin-hc]
% \GreenCoffin[b,l]
% \SetHorizontalCoffin\YellowCoffin
% {\color{yellow!20!white}\rule{0.2 in}{0.2 in}}
% \JoinCoffins\OutputCoffin[\GreenCoffin-vc,\GreenCoffin-hc]
% \YellowCoffin[b,l]
% \SetHorizontalCoffin \OrangeCoffin
% {\color{orange!20!white}\rule{0.2 in}{0.2 in}}
% \JoinCoffins\OutputCoffin[\BlueCoffin-t,\BlueCoffin-l]
% \OrangeCoffin[b,r]
% \TypesetCoffin\OutputCoffin
% \end{verbatim}
% This process begins by setting up \cs{OutputCoffin} to hold the joined
% output. Each join then takes place placing the new addition relative
% to the previous one. As each coffin joined has a unique name it is
% possible to align relative to each one of the component parts of the
% assembly. This is illustrated by the addition of the final
% \cs{OrangeCoffin} based on the earlier placement of the
% \cs{BlueCoffin}.
%
% \begin{figure}
% \centering
% \SetHorizontalCoffin\OutputCoffin{}
% \SetHorizontalCoffin\RedCoffin
% {\color{red!20!white}\rule{0.2 in}{0.2 in}}
% \JoinCoffins\OutputCoffin[vc,hc]\RedCoffin[vc,hc]
% \SetHorizontalCoffin\BlueCoffin
% {\color{blue!20!white}\rule{0.2 in}{0.2 in}}
% \JoinCoffins\OutputCoffin[\RedCoffin-vc,\RedCoffin-hc]
% \BlueCoffin[b,l]
% \SetHorizontalCoffin\GreenCoffin
% {\color{green!20!white}\rule{0.2 in}{0.2 in}}
% \JoinCoffins\OutputCoffin[\BlueCoffin-vc,\BlueCoffin-hc]
% \GreenCoffin[b,l]
% \SetHorizontalCoffin\YellowCoffin
% {\color{yellow!20!white}\rule{0.2 in}{0.2 in}}
% \JoinCoffins\OutputCoffin[\GreenCoffin-vc,\GreenCoffin-hc]
% \YellowCoffin[b,l]
% \SetHorizontalCoffin \OrangeCoffin
% {\color{orange!20!white}\rule{0.2 in}{0.2 in}}
% \JoinCoffins\OutputCoffin[\BlueCoffin-t,\BlueCoffin-l]
% \OrangeCoffin[b,r]
% \TypesetCoffin\OutputCoffin
% \caption{Aligning coffins using poles from previous operations.}
% \label{fgr:nested}
% \end{figure}
%
% \section{Typesetting coffins}
%
% \begin{function}{\TypesetCoffin}
% \begin{syntax}
% \cs{TypesetCoffin}
% ~~\meta{coffin} [ \meta{pole1} , \meta{pole2} ]
% ~~( \meta{x-offset} , \meta{y-offset} )
% \end{syntax}
% Typesetting is carried out by first calculating \meta{handle}, the
% point of intersection of \meta{pole1} and \meta{pole2}. This is an
% optional argument, and if not given then |(H,l)|, the \TeX{}
% reference point of the underlying box, is used. The coffin
% is then typeset such that the relationship between the current
% reference point in the document and the \meta{handle} is described
% by the \meta{x-offset} and \meta{y-offset}. This \meta{offset} is
% optional, and if not given |(0 pt, 0 pt)| is used. Typesetting a
% coffin is therefore analogous to carrying out an alignment where the
% \enquote{parent} coffin is the current insertion point.
% \end{function}
%
% \section{Measuring coffins}
%
% There are places in the design process where it is useful to be able to
% measure coffins outside of pole-setting procedures.
%
% \begin{function}{\CoffinDepth}
% \begin{syntax}
% \cs{CoffinDepth} \meta{coffin}
% \end{syntax}
% Calculates the depth (below the baseline) of the \meta{coffin}
% in a form suitable for use in a \meta{dimension expression}, for example
% |\setlength{\mylength}{\CoffinDepth\ExampleCoffin}|.
% \end{function}
%
% \begin{function}{\CoffinHeight}
% \begin{syntax}
% \cs{CoffinHeight} \meta{coffin}
% \end{syntax}
% Calculates the height (above the baseline) of the \meta{coffin}
% in a form suitable for use in a \meta{dimension expression}, for example
% |\setlength{\mylength}{\CoffinHeight\ExampleCoffin}|.
% \end{function}
%
% \begin{function}{\CoffinTotalHeight}
% \begin{syntax}
% \cs{CoffinTotalHeight} \meta{coffin}
% \end{syntax}
% Calculates the total height of the \meta{coffin}
% in a form suitable for use in a \meta{dimension expression}, for example
% |\setlength{\mylength}{\CoffinTotalHeight\ExampleCoffin}|.
% \end{function}
%
% \begin{function}{\CoffinWidth}
% \begin{syntax}
% \cs{CoffinWidth} \meta{coffin}
% \end{syntax}
% Calculates the width of the \meta{coffin} in a form
% suitable for use in a \meta{dimension expression}, for example
% |\setlength{\mylength}{\CoffinWidth\ExampleCoffin}|.
% \end{function}
%
% \section{Diagnostic functions}
%
% Diagnostic data for following the coffin-building process is
% available both graphically and at the terminal. This reflects the
% fact that coffins are visual constructs.
%
% \begin{function}{\DisplayCoffinHandles}
% \begin{syntax}
% \cs{DisplayCoffinHandles} \meta{coffin} \Arg{color}
% \end{syntax}
% This function first calculates the intersections between all of
% the \meta{poles} of the \meta{coffin} to give a set of
% \meta{handles}. It then prints the \meta{coffin} at the current
% location in the source, with the position of the \meta{handles}
% marked on the coffin. The \meta{handles} will be labelled as part
% of this process: the locations of the \meta{handles} and the labels
% are both printed in the \meta{color} specified.
% \end{function}
%
% \begin{function}{\MarkCoffinHandle}
% \begin{syntax}
% \cs{MarkCoffinHandle} \meta{coffin}
% ~~[ \meta{pole1} , \meta{pole2} ] \Arg{color}
% \end{syntax}
% This function first calculates the \meta{handle} for the
% \meta{coffin} as defined by the intersection of \meta{pole1} and
% \meta{pole2}. It then marks the position of the \meta{handle}
% on the \meta{coffin}. The \meta{handle} will be labelled as part of
% this process: the location of the \meta{handle} and the label are
% both printed in the \meta{color} specified. If no \meta{poles} are
% give, the default |(H,l)| is used.
% \end{function}
%
% \begin{function}{\ShowCoffinStructure}
% \begin{syntax}
% \cs{ShowCoffinStructure} \meta{coffin}
% \end{syntax}
% This function shows the structural information about the
% \meta{coffin} in the terminal. The width, height and depth of the
% typeset material are given, along with the location of all of the
% poles of the coffin. For example, for the rotated coffin in
% Figure~\ref{fgr:rotation}, the output of \cs{ShowCoffinStructure}
% is:
% \begin{verbatim}
% Size of coffin \ExampleCoffin:
% > ht = 72.26999pt
% > dp = 0.0pt
% > wd = 72.26999pt
% Poles of coffin \ExampleCoffin:
% > l => {0pt}{0pt}{0pt}{1000pt}
% > B => {0pt}{0pt}{1000pt}{0pt}
% > H => {0pt}{0pt}{1000pt}{0pt}
% > T => {0pt}{0pt}{1000pt}{0pt}
% > hc => {36.135pt}{0pt}{0pt}{1000pt}
% > r => {72.26999pt}{0pt}{0pt}{1000pt}
% > vc => {0pt}{36.135pt}{1000pt}{0pt}
% > t => {0pt}{72.26999pt}{1000pt}{0pt}
% > b => {0pt}{0.0pt}{1000pt}{0pt}.
% <recently read> }
% \end{verbatim}
% Notice that the poles of a coffin are defined by four values:
% the $x$ and $y$ co-ordinates of a point that the pole
% passes through and the $x$- and $y$-components of a
% vector denoting the direction of the pole. It is the ratio between
% the later, rather than the absolute values, which determines the
% direction of the pole.
% \end{function}
%
% \end{documentation}
%
% \begin{implementation}
%
% \section{Implementation}
%
% \begin{macrocode}
%<*package>
% \end{macrocode}
%
% \begin{macrocode}
%<@@=coffin>
% \end{macrocode}
%
% \begin{macrocode}
\ProvidesExplPackage{xcoffins}{2024-03-14}{}
{L3 Experimental design level coffins}
% \end{macrocode}
%
% \begin{variable}
% {
% \l_@@_A_hpole_tl ,
% \l_@@_A_vpole_tl ,
% \l_@@_B_hpole_tl ,
% \l_@@_B_vpole_tl ,
% \l_@@_bound_box_grow_bool ,
% \l_@@_hoffset_dim ,
% \l_@@_voffset_dim
% }
% Key--value definitions for the alignment system. With the exception
% of \texttt{grow-bounding-box}, all of these have to be given with a
% value.
% \begin{macrocode}
\keys_define:nn { coffin }
{
coffin1-hpole .tl_set:N = \l_@@_A_hpole_tl ,
coffin1-hpole .value_required:n = true ,
coffin1-vpole .tl_set:N = \l_@@_A_vpole_tl ,
coffin1-vpole .value_required:n = true ,
coffin2-hpole .tl_set:N = \l_@@_B_hpole_tl ,
coffin2-hpole .value_required:n = true ,
coffin2-vpole .tl_set:N = \l_@@_B_vpole_tl ,
coffin2-vpole .value_required:n = true ,
grow-bounding-box .bool_set:N = \l_@@_bound_box_grow_bool ,
grow-bounding-box .default:n = true ,
hoffset .dim_set:N = \l_@@_hoffset_dim ,
hoffset .value_required:n = true ,
voffset .dim_set:N = \l_@@_voffset_dim ,
voffset .value_required:n = true
}
\keys_set:nn { coffin }
{
coffin1-hpole = H ,
coffin1-vpole = l ,
coffin2-hpole = H ,
coffin2-vpole = l ,
grow-bounding-box = true ,
hoffset = 0 pt ,
voffset = 0 pt
}
% \end{macrocode}
% \end{variable}
%
% \begin{macro}{\@@_design_names:N}
% \begin{variable}{\Height, \Depth, \Width, \TotalHeight}
% \begin{variable}
% {\l_@@_height_dim, \l_@@_depth_dim, \l_@@_width_dim, \l_@@_totalheight_dim}
% Sets up design-level names for the various coffin dimensions. These are
% not defined outside of this scope, and are dimensions so that they work
% correctly inside for example \cs{fp_eval:n}.
% \begin{macrocode}
\cs_new_protected:Npn \@@_design_names:N #1
{
\dim_set:Nn \l_@@_height_dim { \coffin_ht:N #1 }
\dim_set:Nn \l_@@_depth_dim { \coffin_dp:N #1 }
\dim_set:Nn \l_@@_width_dim { \coffin_wd:N #1 }
\dim_set:Nn \l_@@_totalheight_dim
{ \l_@@_height_dim + \l_@@_depth_dim }
\cs_set_eq:NN \Height \l_@@_height_dim
\cs_set_eq:NN \Depth \l_@@_depth_dim
\cs_set_eq:NN \Width \l_@@_width_dim
\cs_set_eq:NN \TotalHeight \l_@@_totalheight_dim
}
\dim_new:N \l_@@_height_dim
\dim_new:N \l_@@_depth_dim
\dim_new:N \l_@@_width_dim
\dim_new:N \l_@@_totalheight_dim
% \end{macrocode}
% \end{variable}
% \end{variable}
% \end{macro}
%
% A lot of this is more-or-less just passing data straight through.
%
% \begin{macro}{\NewCoffin}
% This is a very easy conversion.
% \begin{macrocode}
\NewDocumentCommand \NewCoffin { m }
{ \coffin_new:N #1 }
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\SetHorizontalCoffin}
% \begin{macro}{\SetVerticalCoffin}
% These are again straight-forward translations.
% \begin{macrocode}
\NewDocumentCommand \SetHorizontalCoffin { m +m }
{ \hcoffin_set:Nn #1 {#2} }
\NewDocumentCommand \SetVerticalCoffin { m m +m }
{ \vcoffin_set:Nnn #1 {#2} {#3} }
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\SetHorizontalPole}
% \begin{macro}{\SetVerticalPole}
% Here, there is a need to set up the design-level names for coffin
% dimensions. This requires grouping, but the coffin work has to occur
% outside of the group. Hence there is a bit of expansion trickery.
% \begin{macrocode}
\NewDocumentCommand \SetHorizontalPole { m m m }
{
\group_begin:
\@@_design_names:N #1
\use:e
{
\group_end:
\coffin_set_horizontal_pole:Nnn #1
{ \exp_not:n {#2} } { \dim_eval:n {#3} }
}
}
\NewDocumentCommand \SetVerticalPole { m m m }
{
\group_begin:
\@@_design_names:N #1
\use:e
{
\group_end:
\coffin_set_vertical_pole:Nnn #1
{ \exp_not:n {#2} } { \dim_eval:n {#3} }
}
}
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\JoinCoffins}
% The \cs{JoinCoffins} function needs to do a bit of work on the input
% syntax, as there are a number of optional arguments to worry about.
% The idea here is that \cs{JoinCoffins} can be used to either expand
% the bounding box of \meta{coffin1} or add \meta{coffin2} without any
% expansion of the bounding box. There are also the two handle positions
% and the offset to sort out.
% \begin{macrocode}
\NewDocumentCommand \JoinCoffins
{
o
s
m
> { \SplitArgument { 1 } { , } } O { H , l }
m
> { \SplitArgument { 1 } { , } } O { H , l }
> { \SplitArgument { 1 } { , } } D ( ) { 0 pt , 0 pt }
}
{
\IfNoValueTF {#1}
{
\IfBooleanTF #2
{ \coffin_attach:NnnNnnnn #3 #4 #5 #6 #7 }
{ \coffin_join:NnnNnnnn #3 #4 #5 #6 #7 }
}
{
\group_begin:
\keys_set:nn { coffin } {#1}
\tl_set:Ne \l_@@_tmp_tl
{
\group_end:
\bool_if:NTF \l_@@_bound_box_grow_bool
{ \coffin_join:NnnNnnnn }
{ \coffin_attach:NnnNnnnn }
\exp_not:N #3
{ \exp_not:o { \l_@@_A_hpole_tl } }
{ \exp_not:o { \l_@@_A_vpole_tl } }
\exp_not:N #5
{ \exp_not:o { \l_@@_B_hpole_tl } }
{ \exp_not:o { \l_@@_B_vpole_tl } }
{ \dim_use:N \l_@@_hoffset_dim }
{ \dim_use:N \l_@@_voffset_dim }
}
\l_@@_tmp_tl
}
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\TypesetCoffin}
% For typesetting coffins there are two optional arguments, both of
% which need to be split. This is a simpler case of the code needed for
% \cs{JoinCoffins}.
% \begin{macrocode}
\NewDocumentCommand \TypesetCoffin
{
m
> { \SplitArgument { 1 } { , } } O { H , l }
> { \SplitArgument { 1 } { , } } D ( ) { 0 pt , 0 pt }
}
{ \coffin_typeset:Nnnnn #1 #2 #3 }
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\RotateCoffin}
% \begin{macro}{\ResizeCoffin}
% \begin{macro}{\ScaleCoffin}
% Mores straight-forward copies.
% \begin{macrocode}
\NewDocumentCommand \RotateCoffin { m m }
{ \coffin_rotate:Nn #1 {#2} }
\NewDocumentCommand \ResizeCoffin { m m m }
{ \coffin_resize:Nnn #1 {#2} {#3} }
\NewDocumentCommand \ScaleCoffin { m m m }
{ \coffin_scale:Nnn #1 {#2} {#3} }
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\CoffinDepth, \CoffinHeight, \CoffinTotalHeigth, \CoffinWidth}
% Nothing too complex, except that the total height is set up as an
% expression so that it will act correctly if prefixed with a negative
% sign, \emph{etc.}
% \begin{macrocode}
\NewDocumentCommand \CoffinDepth { m }
{ \dim_eval:n { \coffin_dp:N #1 } }
\NewDocumentCommand \CoffinHeight { m }
{ \dim_eval:n { \coffin_ht:N #1 } }
\NewDocumentCommand \CoffinTotalHeight { m }
{ \dim_eval:n { \coffin_ht:N #1 + \coffin_dp:N #1 } }
\NewDocumentCommand \CoffinWidth { m }
{ \dim_eval:n { \coffin_wd:N #1 } }
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\DisplayCoffinHandles}
% Displaying all of the handles is a bit easier, as there is no need
% to worry about the handle.
% \begin{macrocode}
\NewDocumentCommand \DisplayCoffinHandles { m m }
{ \coffin_if_exist:NT #1 { \coffin_display_handles:Nn #1 {#2} } }
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\MarkCoffinHandle}
% Marking a handle requires a bit of work with the input, so that
% the design-level interface is \enquote{nice}.
% \begin{macrocode}
\NewDocumentCommand \MarkCoffinHandle
{ m > { \SplitArgument { 1 } { , } } O { H , l } m }
{ \coffin_if_exist:NT #1 { \coffin_mark_handle:Nnnn #1 #2 {#3} } }
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\ShowCoffinStructure}
% Back again to easy-to-implement functions.
% \begin{macrocode}
\NewDocumentCommand \ShowCoffinStructure { m }
{ \coffin_show_structure:N #1 }
% \end{macrocode}
% \end{macro}
%
% \begin{macrocode}
%</package>
% \end{macrocode}
%
% \end{implementation}
%
% \PrintIndex