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-% \iffalse meta-comment
-%
-%% File: l3box.dtx
-%
-% Copyright (C) 2005-2024 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 "l3kernel 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,kernel]{l3doc}
-\begin{document}
- \DocInput{\jobname.dtx}
-\end{document}
-%</driver>
-% \fi
-%
-% \title{^^A
-% The \pkg{l3box} module\\ Boxes^^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}
-%
-% Box variables contain typeset material that can be inserted on the
-% page or in other boxes. Their contents cannot be converted back to
-% lists of tokens.
-% There are three kinds of box operations: horizontal mode denoted
-% with prefix |\hbox_|, vertical mode with prefix |\vbox_|, and the
-% generic operations working in both modes with prefix |\box_|.
-% For instance, a new box variable containing the words \enquote{Hello,
-% world!} (in a horizontal box) can be obtained by the following code.
-% \begin{verbatim}
-% \box_new:N \l_hello_box
-% \hbox_set:Nn \l_hello_box { Hello, ~ world! }
-% \end{verbatim}
-% The argument is typeset inside a \TeX{} group so that any variables
-% assigned during the construction of this box restores its value
-% afterwards.
-%
-% Box variables from \pkg{l3box} are compatible with those of \LaTeXe{}
-% and plain \TeX{} and can be used interchangeably. The \pkg{l3box}
-% commands to construct boxes, such as \cs{hbox:n} or \cs{hbox_set:Nn},
-% are \enquote{color-safe}, meaning that
-% \begin{verbatim}
-% \hbox:n { \color_select:n { blue } Hello, } ~ world!
-% \end{verbatim}
-% will result in \enquote{Hello,} taking the color blue, but
-% \enquote{world!} remaining with the prevailing color outside the box.
-%
-% \section{Creating and initialising boxes}
-%
-% \begin{function}{\box_new:N, \box_new:c}
-% \begin{syntax}
-% \cs{box_new:N} \meta{box}
-% \end{syntax}
-% Creates a new \meta{box} or raises an error if the name is
-% already taken. The declaration is global. The \meta{box} is
-% initially void.
-% \end{function}
-%
-% \begin{function}{\box_clear:N, \box_clear:c, \box_gclear:N, \box_gclear:c}
-% \begin{syntax}
-% \cs{box_clear:N} \meta{box}
-% \end{syntax}
-% Clears the content of the \meta{box} by setting the box equal to
-% \cs{c_empty_box}.
-% \end{function}
-%
-% \begin{function}
-% {\box_clear_new:N, \box_clear_new:c, \box_gclear_new:N, \box_gclear_new:c}
-% \begin{syntax}
-% \cs{box_clear_new:N} \meta{box}
-% \end{syntax}
-% Ensures that the \meta{box} exists globally by applying
-% \cs{box_new:N} if necessary, then applies
-% \cs[index=box_clear:N]{box_(g)clear:N} to leave
-% the \meta{box} empty.
-% \end{function}
-%
-% \begin{function}
-% {
-% \box_set_eq:NN, \box_set_eq:cN, \box_set_eq:Nc, \box_set_eq:cc,
-% \box_gset_eq:NN, \box_gset_eq:cN, \box_gset_eq:Nc, \box_gset_eq:cc
-% }
-% \begin{syntax}
-% \cs{box_set_eq:NN} \meta{box_1} \meta{box_2}
-% \end{syntax}
-% Sets the content of \meta{box_1} equal to that of \meta{box_2}.
-% \end{function}
-%
-% \begin{function}[EXP, pTF, added=2012-03-03]
-% {\box_if_exist:N, \box_if_exist:c}
-% \begin{syntax}
-% \cs{box_if_exist_p:N} \meta{box}
-% \cs{box_if_exist:NTF} \meta{box} \Arg{true code} \Arg{false code}
-% \end{syntax}
-% Tests whether the \meta{box} is currently defined. This does not
-% check that the \meta{box} really is a box.
-% \end{function}
-%
-% \section{Using boxes}
-%
-% \begin{function}{\box_use:N, \box_use:c}
-% \begin{syntax}
-% \cs{box_use:N} \meta{box}
-% \end{syntax}
-% Inserts the current content of the \meta{box} onto the current
-% list for typesetting. An error is raised if the variable does
-% not exist or if it is invalid.
-% \begin{texnote}
-% This is the \TeX{} primitive \tn{copy}.
-% \end{texnote}
-% \end{function}
-%
-% \begin{function}{\box_move_right:nn, \box_move_left:nn}
-% \begin{syntax}
-% \cs{box_move_right:nn} \Arg{dim expr} \Arg{box function}
-% \end{syntax}
-% This function operates in vertical mode, and inserts the
-% material specified by the \meta{box function}
-% such that its reference point is displaced horizontally by the given
-% \meta{dim expr} from the reference point for typesetting, to the right
-% or left as appropriate. The \meta{box function} should be
-% a box operation such as \cs{box_use:N} |\<box>| or a \enquote{raw}
-% box specification such as \cs{vbox:n} |{ xyz }|.
-% \end{function}
-%
-% \begin{function}{\box_move_up:nn, \box_move_down:nn}
-% \begin{syntax}
-% \cs{box_move_up:nn} \Arg{dim expr} \Arg{box function}
-% \end{syntax}
-% This function operates in horizontal mode, and inserts the
-% material specified by the \meta{box function}
-% such that its reference point is displaced vertically by the given
-% \meta{dim expr} from the reference point for typesetting, up
-% or down as appropriate. The \meta{box function} should be
-% a box operation such as \cs{box_use:N} |\<box>| or a \enquote{raw}
-% box specification such as \cs{vbox:n} |{ xyz }|.
-% \end{function}
-%
-% \section{Measuring and setting box dimensions}
-%
-% \begin{function}{\box_dp:N, \box_dp:c}
-% \begin{syntax}
-% \cs{box_dp:N} \meta{box}
-% \end{syntax}
-% Calculates the depth (below the baseline) of the \meta{box}
-% in a form suitable for use in a \meta{dim expr}.
-% \begin{texnote}
-% This is the \TeX{} primitive \tn{dp}.
-% \end{texnote}
-% \end{function}
-%
-% \begin{function}{\box_ht:N, \box_ht:c}
-% \begin{syntax}
-% \cs{box_ht:N} \meta{box}
-% \end{syntax}
-% Calculates the height (above the baseline) of the \meta{box}
-% in a form suitable for use in a \meta{dim expr}.
-% \begin{texnote}
-% This is the \TeX{} primitive \tn{ht}.
-% \end{texnote}
-% \end{function}
-%
-% \begin{function}{\box_wd:N, \box_wd:c}
-% \begin{syntax}
-% \cs{box_wd:N} \meta{box}
-% \end{syntax}
-% Calculates the width of the \meta{box} in a form
-% suitable for use in a \meta{dim expr}.
-% \begin{texnote}
-% This is the \TeX{} primitive \tn{wd}.
-% \end{texnote}
-% \end{function}
-%
-% \begin{function}[added = 2021-05-05]{\box_ht_plus_dp:N, \box_ht_plus_dp:c}
-% \begin{syntax}
-% \cs{box_ht_plus_dp:N} \meta{box}
-% \end{syntax}
-% Calculates the total vertical size (height plus depth) of the \meta{box}
-% in a form suitable for use in a \meta{dim expr}.
-% \end{function}
-%
-% \begin{function}[updated = 2019-01-22]
-% {
-% \box_set_dp:Nn, \box_set_dp:cn,
-% \box_gset_dp:Nn, \box_gset_dp:cn
-% }
-% \begin{syntax}
-% \cs{box_set_dp:Nn} \meta{box} \Arg{dim expr}
-% \end{syntax}
-% Set the depth (below the baseline) of the \meta{box} to the value of
-% the \Arg{dim expr}.
-% \end{function}
-%
-% \begin{function}[updated = 2019-01-22]
-% {
-% \box_set_ht:Nn, \box_set_ht:cn,
-% \box_gset_ht:Nn, \box_gset_ht:cn
-% }
-% \begin{syntax}
-% \cs{box_set_ht:Nn} \meta{box} \Arg{dim expr}
-% \end{syntax}
-% Set the height (above the baseline) of the \meta{box} to the value of
-% the \Arg{dim expr}.
-% \end{function}
-%
-% \begin{function}[updated = 2019-01-22]
-% {
-% \box_set_wd:Nn, \box_set_wd:cn,
-% \box_gset_wd:Nn, \box_gset_wd:cn
-% }
-% \begin{syntax}
-% \cs{box_set_wd:Nn} \meta{box} \Arg{dim expr}
-% \end{syntax}
-% Set the width of the \meta{box} to the value of the
-% \Arg{dim expr}.
-% \end{function}
-%
-% \section{Box conditionals}
-%
-% \begin{function}[EXP,pTF]{\box_if_empty:N, \box_if_empty:c}
-% \begin{syntax}
-% \cs{box_if_empty_p:N} \meta{box}
-% \cs{box_if_empty:NTF} \meta{box} \Arg{true code} \Arg{false code}
-% \end{syntax}
-% Tests if \meta{box} is a empty (equal to \cs{c_empty_box}).
-% \end{function}
-%
-% \begin{function}[EXP,pTF]{\box_if_horizontal:N, \box_if_horizontal:c}
-% \begin{syntax}
-% \cs{box_if_horizontal_p:N} \meta{box}
-% \cs{box_if_horizontal:NTF} \meta{box} \Arg{true code} \Arg{false code}
-% \end{syntax}
-% Tests if \meta{box} is a horizontal box.
-% \end{function}
-%
-% \begin{function}[EXP,pTF]{\box_if_vertical:N, \box_if_vertical:c}
-% \begin{syntax}
-% \cs{box_if_vertical_p:N} \meta{box}
-% \cs{box_if_vertical:NTF} \meta{box} \Arg{true code} \Arg{false code}
-% \end{syntax}
-% Tests if \meta{box} is a vertical box.
-% \end{function}
-%
-% \section{The last box inserted}
-%
-% \begin{function}
-% {
-% \box_set_to_last:N, \box_set_to_last:c,
-% \box_gset_to_last:N, \box_gset_to_last:c
-% }
-% \begin{syntax}
-% \cs{box_set_to_last:N} \meta{box}
-% \end{syntax}
-% Sets the \meta{box} equal to the last item (box) added to the current
-% partial list, removing the item from the list at the same time. When
-% applied to the main vertical list, the \meta{box} is always void as
-% it is not possible to recover the last added item.
-% \end{function}
-%
-% \section{Constant boxes}
-%
-% \begin{variable}[updated = 2012-11-04]{\c_empty_box}
-% This is a permanently empty box, which is neither set as horizontal
-% nor vertical.
-% \begin{texnote}
-% At the \TeX{} level this is a void box.
-% \end{texnote}
-% \end{variable}
-%
-% \section{Scratch boxes}
-%
-% \begin{variable}[updated = 2012-11-04]{\l_tmpa_box, \l_tmpb_box}
-% Scratch boxes for local assignment. These are never used by
-% the kernel code, and so are safe for use with any \LaTeX3-defined
-% function. However, they may be overwritten by other non-kernel
-% code and so should only be used for short-term storage.
-% \end{variable}
-%
-% \begin{variable}{\g_tmpa_box, \g_tmpb_box}
-% Scratch boxes for global assignment. These are never used by
-% the kernel code, and so are safe for use with any \LaTeX3-defined
-% function. However, they may be overwritten by other non-kernel
-% code and so should only be used for short-term storage.
-% \end{variable}
-%
-% \section{Viewing box contents}
-%
-% \begin{function}[updated = 2012-05-11]{\box_show:N, \box_show:c}
-% \begin{syntax}
-% \cs{box_show:N} \meta{box}
-% \end{syntax}
-% Shows full details of the content of the \meta{box} in the terminal.
-% \end{function}
-%
-% \begin{function}[added = 2012-05-11]{\box_show:Nnn, \box_show:cnn}
-% \begin{syntax}
-% \cs{box_show:Nnn} \meta{box} \Arg{int expr_1} \Arg{int expr_2}
-% \end{syntax}
-% Display the contents of \meta{box} in the terminal, showing the first
-% \meta{int expr_1} items of the box, and descending into \meta{int expr_2}
-% group levels.
-% \end{function}
-%
-% \begin{function}[added = 2012-05-11]{\box_log:N, \box_log:c}
-% \begin{syntax}
-% \cs{box_log:N} \meta{box}
-% \end{syntax}
-% Writes full details of the content of the \meta{box} to the log.
-% \end{function}
-%
-% \begin{function}[added = 2012-05-11]{\box_log:Nnn, \box_log:cnn}
-% \begin{syntax}
-% \cs{box_log:Nnn} \meta{box} \Arg{int expr_1} \Arg{int expr_2}
-% \end{syntax}
-% Writes the contents of \meta{box} to the log, showing the first
-% \meta{int expr_1} items of the box, and descending into \meta{int expr_2}
-% group levels.
-% \end{function}
-%
-% \section{Boxes and color}
-%
-% All \LaTeX{}3 boxes are \enquote{color safe}: a color set inside the box
-% stops applying after the end of the box has occurred.
-%
-% \section{Horizontal mode boxes}
-%
-% \begin{function}[updated = 2017-04-05]{\hbox:n}
-% \begin{syntax}
-% \cs{hbox:n} \Arg{contents}
-% \end{syntax}
-% Typesets the \meta{contents} into a horizontal box of natural
-% width and then includes this box in the current list for typesetting.
-% \end{function}
-%
-% \begin{function}[updated = 2017-04-05]{\hbox_to_wd:nn}
-% \begin{syntax}
-% \cs{hbox_to_wd:nn} \Arg{dim expr} \Arg{contents}
-% \end{syntax}
-% Typesets the \meta{contents} into a horizontal box of width
-% \meta{dim expr} and then includes this box in the current list for
-% typesetting.
-% \end{function}
-%
-% \begin{function}[updated = 2017-04-05]{\hbox_to_zero:n}
-% \begin{syntax}
-% \cs{hbox_to_zero:n} \Arg{contents}
-% \end{syntax}
-% Typesets the \meta{contents} into a horizontal box of zero width
-% and then includes this box in the current list for typesetting.
-% \end{function}
-%
-% \begin{function}[updated = 2017-04-05]
-% {\hbox_set:Nn, \hbox_set:cn, \hbox_gset:Nn, \hbox_gset:cn}
-% \begin{syntax}
-% \cs{hbox_set:Nn} \meta{box} \Arg{contents}
-% \end{syntax}
-% Typesets the \meta{contents} at natural width and then stores the
-% result inside the \meta{box}.
-% \end{function}
-%
-% \begin{function}[updated = 2017-04-05]
-% {
-% \hbox_set_to_wd:Nnn, \hbox_set_to_wd:cnn,
-% \hbox_gset_to_wd:Nnn, \hbox_gset_to_wd:cnn
-% }
-% \begin{syntax}
-% \cs{hbox_set_to_wd:Nnn} \meta{box} \Arg{dim expr} \Arg{contents}
-% \end{syntax}
-% Typesets the \meta{contents} to the width given by the \meta{dim expr}
-% and then stores the result inside the \meta{box}.
-% \end{function}
-%
-% \begin{function}[added = 2020-08-25]{\hbox_overlap_center:n}
-% \begin{syntax}
-% \cs{hbox_overlap_center:n} \Arg{contents}
-% \end{syntax}
-% Typesets the \meta{contents} into a horizontal box of zero width
-% such that material protrudes equally to both sides of the insertion point.
-% \end{function}
-%
-% \begin{function}[updated = 2017-04-05]{\hbox_overlap_right:n}
-% \begin{syntax}
-% \cs{hbox_overlap_right:n} \Arg{contents}
-% \end{syntax}
-% Typesets the \meta{contents} into a horizontal box of zero width
-% such that material protrudes to the right of the insertion point.
-% \end{function}
-%
-% \begin{function}[updated = 2017-04-05]{\hbox_overlap_left:n}
-% \begin{syntax}
-% \cs{hbox_overlap_left:n} \Arg{contents}
-% \end{syntax}
-% Typesets the \meta{contents} into a horizontal box of zero width
-% such that material protrudes to the left of the insertion point.
-% \end{function}
-%
-% \begin{function}[updated = 2017-04-05]
-% {
-% \hbox_set:Nw, \hbox_set:cw,
-% \hbox_set_end:,
-% \hbox_gset:Nw, \hbox_gset:cw,
-% \hbox_gset_end:
-% }
-% \begin{syntax}
-% \cs{hbox_set:Nw} \meta{box} \meta{contents} \cs{hbox_set_end:}
-% \end{syntax}
-% Typesets the \meta{contents} at natural width and then stores the
-% result inside the \meta{box}. In contrast
-% to \cs{hbox_set:Nn} this function does not absorb the argument
-% when finding the \meta{content}, and so can be used in circumstances
-% where the \meta{content} may not be a simple argument.
-% \end{function}
-%
-% \begin{function}[added = 2017-06-08]
-% {
-% \hbox_set_to_wd:Nnw, \hbox_set_to_wd:cnw,
-% \hbox_gset_to_wd:Nnw, \hbox_gset_to_wd:cnw
-% }
-% \begin{syntax}
-% \cs{hbox_set_to_wd:Nnw} \meta{box} \Arg{dim expr} \meta{contents} \cs{hbox_set_end:}
-% \end{syntax}
-% Typesets the \meta{contents} to the width given by the \meta{dim expr}
-% and then stores the result inside the \meta{box}. In contrast
-% to \cs{hbox_set_to_wd:Nnn} this function does not absorb the argument
-% when finding the \meta{content}, and so can be used in circumstances
-% where the \meta{content} may not be a simple argument
-% \end{function}
-%
-% \begin{function}{\hbox_unpack:N, \hbox_unpack:c}
-% \begin{syntax}
-% \cs{hbox_unpack:N} \meta{box}
-% \end{syntax}
-% Unpacks the content of the horizontal \meta{box}, retaining any stretching
-% or shrinking applied when the \meta{box} was set.
-% \begin{texnote}
-% This is the \TeX{} primitive \tn{unhcopy}.
-% \end{texnote}
-% \end{function}
-%
-% \section{Vertical mode boxes}
-%
-% Vertical boxes inherit their baseline from their contents. The
-% standard case is that the baseline of the box is at the same position
-% as that of the last item added to the box. This means that the box
-% has no depth unless the last item added to it had depth. As a
-% result most vertical boxes have a large height value and small or
-% zero depth. The exception are |_top| boxes, where the reference point
-% is that of the first item added. These tend to have a large depth and
-% small height, although the latter is typically non-zero.
-%
-% \begin{function}[updated = 2017-04-05]{\vbox:n}
-% \begin{syntax}
-% \cs{vbox:n} \Arg{contents}
-% \end{syntax}
-% Typesets the \meta{contents} into a vertical box of natural height
-% and includes this box in the current list for typesetting.
-% \end{function}
-%
-% \begin{function}[updated = 2017-04-05]{\vbox_top:n}
-% \begin{syntax}
-% \cs{vbox_top:n} \Arg{contents}
-% \end{syntax}
-% Typesets the \meta{contents} into a vertical box of natural height
-% and includes this box in the current list for typesetting. The
-% baseline of the box is equal to that of the \emph{first}
-% item added to the box.
-% \end{function}
-%
-% \begin{function}[updated = 2017-04-05]{\vbox_to_ht:nn}
-% \begin{syntax}
-% \cs{vbox_to_ht:nn} \Arg{dim expr} \Arg{contents}
-% \end{syntax}
-% Typesets the \meta{contents} into a vertical box of height
-% \meta{dim expr} and then includes this box in the current list for
-% typesetting.
-% \end{function}
-%
-% \begin{function}[updated = 2017-04-05]{\vbox_to_zero:n}
-% \begin{syntax}
-% \cs{vbox_to_zero:n} \Arg{contents}
-% \end{syntax}
-% Typesets the \meta{contents} into a vertical box of zero height
-% and then includes this box in the current list for typesetting.
-% \end{function}
-%
-% \begin{function}[updated = 2017-04-05]
-% {\vbox_set:Nn, \vbox_set:cn, \vbox_gset:Nn, \vbox_gset:cn}
-% \begin{syntax}
-% \cs{vbox_set:Nn} \meta{box} \Arg{contents}
-% \end{syntax}
-% Typesets the \meta{contents} at natural height and then stores the
-% result inside the \meta{box}.
-% \end{function}
-%
-% \begin{function}[updated = 2017-04-05]
-% {\vbox_set_top:Nn, \vbox_set_top:cn, \vbox_gset_top:Nn, \vbox_gset_top:cn}
-% \begin{syntax}
-% \cs{vbox_set_top:Nn} \meta{box} \Arg{contents}
-% \end{syntax}
-% Typesets the \meta{contents} at natural height and then stores the
-% result inside the \meta{box}. The baseline of the box is equal
-% to that of the \emph{first} item added to the box.
-% \end{function}
-%
-% \begin{function}[updated = 2017-04-05]
-% {
-% \vbox_set_to_ht:Nnn, \vbox_set_to_ht:cnn,
-% \vbox_gset_to_ht:Nnn, \vbox_gset_to_ht:cnn
-% }
-% \begin{syntax}
-% \cs{vbox_set_to_ht:Nnn} \meta{box} \Arg{dim expr} \Arg{contents}
-% \end{syntax}
-% Typesets the \meta{contents} to the height given by the
-% \meta{dim expr} and then stores the result inside the \meta{box}.
-% \end{function}
-%
-% \begin{function}[updated = 2017-04-05]
-% {
-% \vbox_set:Nw, \vbox_set:cw,
-% \vbox_set_end:,
-% \vbox_gset:Nw, \vbox_gset:cw,
-% \vbox_gset_end:
-% }
-% \begin{syntax}
-% \cs{vbox_set:Nw} \meta{box} \meta{contents} \cs{vbox_set_end:}
-% \end{syntax}
-% Typesets the \meta{contents} at natural height and then stores the
-% result inside the \meta{box}. In contrast
-% to \cs{vbox_set:Nn} this function does not absorb the argument
-% when finding the \meta{content}, and so can be used in circumstances
-% where the \meta{content} may not be a simple argument.
-% \end{function}
-%
-% \begin{function}[added = 2017-06-08]
-% {
-% \vbox_set_to_ht:Nnw, \vbox_set_to_ht:cnw,
-% \vbox_gset_to_ht:Nnw, \vbox_gset_to_ht:cnw
-% }
-% \begin{syntax}
-% \cs{vbox_set_to_ht:Nnw} \meta{box} \Arg{dim expr} \meta{contents} \cs{vbox_set_end:}
-% \end{syntax}
-% Typesets the \meta{contents} to the height given by the \meta{dim expr}
-% and then stores the result inside the \meta{box}. In contrast
-% to \cs{vbox_set_to_ht:Nnn} this function does not absorb the argument
-% when finding the \meta{content}, and so can be used in circumstances
-% where the \meta{content} may not be a simple argument
-% \end{function}
-%
-%
-% \begin{function}[updated = 2018-12-29]
-% {
-% \vbox_set_split_to_ht:NNn, \vbox_set_split_to_ht:cNn,
-% \vbox_set_split_to_ht:Ncn, \vbox_set_split_to_ht:ccn,
-% \vbox_gset_split_to_ht:NNn, \vbox_gset_split_to_ht:cNn,
-% \vbox_gset_split_to_ht:Ncn, \vbox_gset_split_to_ht:ccn
-% }
-% \begin{syntax}
-% \cs{vbox_set_split_to_ht:NNn} \meta{box_1} \meta{box_2} \Arg{dim expr}
-% \end{syntax}
-% Sets \meta{box_1} to contain material to the height given by the
-% \meta{dim expr} by removing content from the top of \meta{box_2}
-% (which must be a vertical box).
-% \end{function}
-%
-% \begin{function}{\vbox_unpack:N, \vbox_unpack:c}
-% \begin{syntax}
-% \cs{vbox_unpack:N} \meta{box}
-% \end{syntax}
-% Unpacks the content of the vertical \meta{box}, retaining any stretching
-% or shrinking applied when the \meta{box} was set.
-% \begin{texnote}
-% This is the \TeX{} primitive \tn{unvcopy}.
-% \end{texnote}
-% \end{function}
-%
-% \section{Using boxes efficiently}
-%
-% The functions above for using box contents work in exactly the same
-% way as for any other \pkg{expl3} variable. However, for efficiency
-% reasons, it is also useful to have functions which \emph{drop} box
-% contents on use. When a box is dropped, the box becomes empty at the group
-% level \emph{where the box was originally set} rather than necessarily
-% \emph{at the current group level}. For example, with
-% \begin{verbatim}
-% \hbox_set:Nn \l_tmpa_box { A }
-% \group_begin:
-% \hbox_set:Nn \l_tmpa_box { B }
-% \group_begin:
-% \box_use_drop:N \l_tmpa_box
-% \group_end:
-% \box_show:N \l_tmpa_box
-% \group_end:
-% \box_show:N \l_tmpa_box
-% \end{verbatim}
-% the first use of \cs{box_show:N} will show an entirely cleared (void) box, and the
-% second will show the letter |A| in the box.
-%
-% These functions should be preferred when the content of the box is no
-% longer required after use. Note that due to the unusual scoping behaviour of
-% \texttt{drop} functions they may be applied to both local and global boxes:
-% the latter will naturally be set and thus cleared at a global level.
-%
-% \begin{function}{\box_use_drop:N, \box_use_drop:c}
-% \begin{syntax}
-% \cs{box_use_drop:N} \meta{box}
-% \end{syntax}
-% Inserts the current content of the \meta{box} onto the current
-% list for typesetting then drops the box content. An error is raised if the
-% variable does not exist or if it is invalid. This function may be applied to
-% local or global boxes.
-% \begin{texnote}
-% This is the \TeX{} primitive \tn{box}.
-% \end{texnote}
-% \end{function}
-%
-% \begin{function}[added = 2019-01-17]
-% {
-% \box_set_eq_drop:NN, \box_set_eq_drop:cN,
-% \box_set_eq_drop:Nc, \box_set_eq_drop:cc
-% }
-% \begin{syntax}
-% \cs{box_set_eq_drop:NN} \meta{box_1} \meta{box_2}
-% \end{syntax}
-% Sets the content of \meta{box_1} equal to that of \meta{box_2}, then
-% drops \meta{box_2}.
-% \end{function}
-%
-% \begin{function}[added = 2019-01-17]
-% {
-% \box_gset_eq_drop:NN, \box_gset_eq_drop:cN,
-% \box_gset_eq_drop:Nc, \box_gset_eq_drop:cc
-% }
-% \begin{syntax}
-% \cs{box_gset_eq_drop:NN} \meta{box_1} \meta{box_2}
-% \end{syntax}
-% Sets the content of \meta{box_1} globally equal to that of \meta{box_2},
-% then drops \meta{box_2}.
-% \end{function}
-%
-% \begin{function}[added = 2019-01-17]
-% {\hbox_unpack_drop:N, \hbox_unpack_drop:c}
-% \begin{syntax}
-% \cs{hbox_unpack_drop:N} \meta{box}
-% \end{syntax}
-% Unpacks the content of the horizontal \meta{box}, retaining any stretching
-% or shrinking applied when the \meta{box} was set. The original \meta{box}
-% is then dropped.
-% \begin{texnote}
-% This is the \TeX{} primitive \tn{unhbox}.
-% \end{texnote}
-% \end{function}
-%
-% \begin{function}[added = 2019-01-17]
-% {\vbox_unpack_drop:N, \vbox_unpack_drop:c}
-% \begin{syntax}
-% \cs{vbox_unpack_drop:N} \meta{box}
-% \end{syntax}
-% Unpacks the content of the vertical \meta{box}, retaining any stretching
-% or shrinking applied when the \meta{box} was set. The original \meta{box}
-% is then dropped.
-% \begin{texnote}
-% This is the \TeX{} primitive \tn{unvbox}.
-% \end{texnote}
-% \end{function}
-%
-% \section{Affine transformations}
-%
-% Affine transformations are changes which (informally) preserve straight
-% lines. Simple translations are affine transformations, but are better handled
-% in \TeX{} by doing the translation first, then inserting an unmodified box.
-% On the other hand, rotation and resizing of boxed material can best be
-% handled by modifying boxes. These transformations are described here.
-%
-% \begin{function}[added = 2017-04-04, updated = 2019-01-22]
-% {
-% \box_autosize_to_wd_and_ht:Nnn, \box_autosize_to_wd_and_ht:cnn,
-% \box_gautosize_to_wd_and_ht:Nnn, \box_gautosize_to_wd_and_ht:cnn,
-% }
-% \begin{syntax}
-% \cs{box_autosize_to_wd_and_ht:Nnn} \meta{box} \Arg{x-size} \Arg{y-size}
-% \end{syntax}
-% Resizes the \meta{box} to fit within the given \meta{x-size} (horizontally)
-% and \meta{y-size} (vertically); both of the sizes are dimension
-% expressions. The \meta{y-size} is the height only: it does not include any
-% depth. The updated \meta{box} is an |hbox|, irrespective of the nature
-% of the \meta{box} before the resizing is applied. The final size of the
-% \meta{box} is the smaller of \Arg{x-size} and \Arg{y-size},
-% \emph{i.e.}~the result fits within the dimensions specified. Negative
-% sizes cause the material in the \meta{box} to be reversed in direction,
-% but the reference point of the \meta{box} is unchanged. Thus a negative
-% \meta{y-size} results in the \meta{box} having a depth dependent on the
-% height of the original and \emph{vice versa}.
-% \end{function}
-%
-% \begin{function}[added = 2017-04-04, updated = 2019-01-22]
-% {
-% \box_autosize_to_wd_and_ht_plus_dp:Nnn,
-% \box_autosize_to_wd_and_ht_plus_dp:cnn,
-% \box_gautosize_to_wd_and_ht_plus_dp:Nnn,
-% \box_gautosize_to_wd_and_ht_plus_dp:cnn
-% }
-% \begin{syntax}
-% \cs{box_autosize_to_wd_and_ht_plus_dp:Nnn} \meta{box} \Arg{x-size} \Arg{y-size}
-% \end{syntax}
-% Resizes the \meta{box} to fit within the given \meta{x-size} (horizontally)
-% and \meta{y-size} (vertically); both of the sizes are dimension
-% expressions. The \meta{y-size} is the total vertical size (height plus
-% depth). The updated \meta{box} is an |hbox|, irrespective of the nature
-% of the \meta{box} before the resizing is applied. The final size of the
-% \meta{box} is the smaller of \Arg{x-size} and \Arg{y-size},
-% \emph{i.e.}~the result fits within the dimensions specified. Negative
-% sizes cause the material in the \meta{box} to be reversed in direction,
-% but the reference point of the \meta{box} is unchanged. Thus a negative
-% \meta{y-size} results in the \meta{box} having a depth dependent on the
-% height of the original and \emph{vice versa}.
-% \end{function}
-%
-% \begin{function}[updated = 2019-01-22]
-% {
-% \box_resize_to_ht:Nn, \box_resize_to_ht:cn,
-% \box_gresize_to_ht:Nn, \box_gresize_to_ht:cn
-% }
-% \begin{syntax}
-% \cs{box_resize_to_ht:Nn} \meta{box} \Arg{y-size}
-% \end{syntax}
-% Resizes the \meta{box} to \meta{y-size} (vertically), scaling the horizontal
-% size by the same amount; \meta{y-size} is a dimension expression. The
-% \meta{y-size} is the height only: it does not include any depth. The updated
-% \meta{box} is an |hbox|, irrespective of the nature of the \meta{box}
-% before the resizing is applied. A negative \meta{y-size} causes the
-% material in the \meta{box} to be reversed in direction, but the reference
-% point of the \meta{box} is unchanged. Thus a negative \meta{y-size}
-% results in the \meta{box} having a depth dependent on the height of the
-% original and \emph{vice versa}.
-% \end{function}
-%
-% \begin{function}[updated = 2019-01-22]
-% {
-% \box_resize_to_ht_plus_dp:Nn, \box_resize_to_ht_plus_dp:cn,
-% \box_gresize_to_ht_plus_dp:Nn, \box_gresize_to_ht_plus_dp:cn,
-% }
-% \begin{syntax}
-% \cs{box_resize_to_ht_plus_dp:Nn} \meta{box} \Arg{y-size}
-% \end{syntax}
-% Resizes the \meta{box} to \meta{y-size} (vertically), scaling the horizontal
-% size by the same amount; \meta{y-size} is a dimension expression. The
-% \meta{y-size} is the total vertical size (height plus depth). The updated
-% \meta{box} is an |hbox|, irrespective of the nature of the \meta{box}
-% before the resizing is applied. A negative \meta{y-size} causes
-% the material in the \meta{box} to be reversed in direction, but the
-% reference point of the \meta{box} is unchanged. Thus a negative
-% \meta{y-size} results in the \meta{box} having a depth dependent on the
-% height of the original and \emph{vice versa}.
-% \end{function}
-%
-% \begin{function}[updated = 2019-01-22]
-% {
-% \box_resize_to_wd:Nn, \box_resize_to_wd:cn,
-% \box_gresize_to_wd:Nn, \box_gresize_to_wd:cn
-% }
-% \begin{syntax}
-% \cs{box_resize_to_wd:Nn} \meta{box} \Arg{x-size}
-% \end{syntax}
-% Resizes the \meta{box} to \meta{x-size} (horizontally), scaling the vertical
-% size by the same amount; \meta{x-size} is a dimension expression. The updated
-% \meta{box} is an |hbox|, irrespective of the nature of the \meta{box}
-% before the resizing is applied. A negative \meta{x-size} causes the
-% material in the \meta{box} to be reversed in direction, but the reference
-% point of the \meta{box} is unchanged. Thus a negative \meta{x-size}
-% results in the \meta{box} having a depth dependent on the height of the
-% original and \emph{vice versa}.
-% \end{function}
-%
-% \begin{function}[added = 2014-07-03, updated = 2019-01-22]
-% {
-% \box_resize_to_wd_and_ht:Nnn, \box_resize_to_wd_and_ht:cnn,
-% \box_gresize_to_wd_and_ht:Nnn, \box_gresize_to_wd_and_ht:cnn
-% }
-% \begin{syntax}
-% \cs{box_resize_to_wd_and_ht:Nnn} \meta{box} \Arg{x-size} \Arg{y-size}
-% \end{syntax}
-% Resizes the \meta{box} to \meta{x-size} (horizontally) and \meta{y-size}
-% (vertically): both of the sizes are dimension expressions. The
-% \meta{y-size} is the height only and does not include any depth. The updated
-% \meta{box} is an |hbox|, irrespective of the nature of the \meta{box}
-% before the resizing is applied. Negative sizes cause the material in
-% the \meta{box} to be reversed in direction, but the reference point of the
-% \meta{box} is unchanged. Thus a negative \meta{y-size} results in
-% the \meta{box} having a depth dependent on the height of the original and
-% \emph{vice versa}.
-% \end{function}
-%
-% \begin{function}[added = 2017-04-06, updated = 2019-01-22]
-% {
-% \box_resize_to_wd_and_ht_plus_dp:Nnn,
-% \box_resize_to_wd_and_ht_plus_dp:cnn,
-% \box_gresize_to_wd_and_ht_plus_dp:Nnn,
-% \box_gresize_to_wd_and_ht_plus_dp:cnn
-% }
-% \begin{syntax}
-% \cs{box_resize_to_wd_and_ht_plus_dp:Nnn} \meta{box} \Arg{x-size} \Arg{y-size}
-% \end{syntax}
-% Resizes the \meta{box} to \meta{x-size} (horizontally) and \meta{y-size}
-% (vertically): both of the sizes are dimension expressions. The
-% \meta{y-size} is the total vertical size (height plus depth). The updated
-% \meta{box} is an |hbox|, irrespective of the nature of the \meta{box}
-% before the resizing is applied. Negative sizes cause the material in
-% the \meta{box} to be reversed in direction, but the reference point of the
-% \meta{box} is unchanged. Thus a negative \meta{y-size} results in
-% the \meta{box} having a depth dependent on the height of the original and
-% \emph{vice versa}.
-% \end{function}
-%
-% \begin{function}[updated = 2019-01-22]
-% {
-% \box_rotate:Nn, \box_rotate:cn,
-% \box_grotate:Nn, \box_grotate:cn
-% }
-% \begin{syntax}
-% \cs{box_rotate:Nn} \meta{box} \Arg{angle}
-% \end{syntax}
-% Rotates the \meta{box} by \meta{angle} (a \meta{fp expr} in degrees)
-% anti-clockwise about
-% its reference point. The reference point of the updated box is moved
-% horizontally such that it is at the left side of the smallest rectangle
-% enclosing the rotated material. The updated \meta{box} is an |hbox|,
-% irrespective of the nature of the \meta{box} before the rotation is applied.
-% \end{function}
-%
-% \begin{function}[updated = 2019-01-22]
-% {
-% \box_scale:Nnn, \box_scale:cnn,
-% \box_gscale:Nnn, \box_gscale:cnn
-% }
-% \begin{syntax}
-% \cs{box_scale:Nnn} \meta{box} \Arg{x-scale} \Arg{y-scale}
-% \end{syntax}
-% Scales the \meta{box} by factors \meta{x-scale} and \meta{y-scale} in
-% the horizontal and vertical directions, respectively (both scales are
-% \meta{fp expr}). The updated \meta{box} is an |hbox|, irrespective
-% of the nature of the \meta{box} before the scaling is applied. Negative
-% scalings cause the material in the \meta{box} to be reversed in
-% direction, but the reference point of the \meta{box} is unchanged.
-% Thus a negative \meta{y-scale} results in the \meta{box} having a depth
-% dependent on the height of the original and \emph{vice versa}.
-% \end{function}
-%
-% \section{Viewing part of a box}
-%
-% \begin{function}[updated = 2023-04-14]
-% {
-% \box_set_clipped:N, \box_set_clipped:c,
-% \box_gset_clipped:N, \box_gset_clipped:c
-% }
-% \begin{syntax}
-% \cs{box_set_clipped:N} \meta{box}
-% \end{syntax}
-% Clips the \meta{box} in the output so that only material inside the
-% bounding box is displayed in the output. The updated \meta{box} is an
-% hbox, irrespective of the nature of the \meta{box} before the clipping is
-% applied. Additional box levels are also generated by this operation.
-%
-% \begin{texnote}
-% Clipping is implemented by the driver, and as such the full content of
-% the box is placed in the output file. Thus clipping does not remove
-% any information from the raw output, and hidden material can therefore
-% be viewed by direct examination of the file.
-% \end{texnote}
-% \end{function}
-%
-% \begin{function}[added = 2019-01-23]
-% {
-% \box_set_trim:Nnnnn, \box_set_trim:cnnnn,
-% \box_gset_trim:Nnnnn, \box_gset_trim:cnnnn
-% }
-% \begin{syntax}
-% \cs{box_set_trim:Nnnnn} \meta{box} \Arg{left} \Arg{bottom} \Arg{right} \Arg{top}
-% \end{syntax}
-% Adjusts the bounding box of the \meta{box} \meta{left} is removed from
-% the left-hand edge of the bounding box, \meta{right} from the right-hand
-% edge and so fourth. All adjustments are \meta{dim exprs}.
-% Material outside of the bounding box is still displayed in the output
-% unless \cs{box_set_clipped:N} is subsequently applied.
-% The updated \meta{box} is an
-% hbox, irrespective of the nature of the \meta{box} before the trim
-% operation is applied.
-% Additional box levels are also generated by this operation.
-% The behavior of the operation where the trims requested is
-% greater than the size of the box is undefined.
-% \end{function}
-%
-% \begin{function}[added = 2019-01-23]
-% {
-% \box_set_viewport:Nnnnn, \box_set_viewport:cnnnn,
-% \box_gset_viewport:Nnnnn, \box_gset_viewport:cnnnn
-% }
-% \begin{syntax}
-% \cs{box_set_viewport:Nnnnn} \meta{box} \Arg{llx} \Arg{lly} \Arg{urx} \Arg{ury}
-% \end{syntax}
-% Adjusts the bounding box of the \meta{box} such that it has lower-left
-% co-ordinates (\meta{llx}, \meta{lly}) and upper-right co-ordinates
-% (\meta{urx}, \meta{ury}). All four co-ordinate positions are
-% \meta{dim exprs}. Material outside of the bounding box is
-% still displayed in the output unless \cs{box_set_clipped:N} is
-% subsequently applied.
-% The updated \meta{box} is an
-% hbox, irrespective of the nature of the \meta{box} before the viewport
-% operation is applied.
-% Additional box levels are also generated by this operation.
-% \end{function}
-%
-% \section{Primitive box conditionals}
-%
-% \begin{function}[EXP]{\if_hbox:N}
-% \begin{syntax}
-% \cs{if_hbox:N} \meta{box}
-% ~~\meta{true code}
-% \cs{else:}
-% ~~\meta{false code}
-% \cs{fi:}
-% \end{syntax}
-% Tests is \meta{box} is a horizontal box.
-% \begin{texnote}
-% This is the \TeX{} primitive \tn{ifhbox}.
-% \end{texnote}
-% \end{function}
-%
-% \begin{function}[EXP]{\if_vbox:N}
-% \begin{syntax}
-% \cs{if_vbox:N} \meta{box}
-% ~~\meta{true code}
-% \cs{else:}
-% ~~\meta{false code}
-% \cs{fi:}
-% \end{syntax}
-% Tests is \meta{box} is a vertical box.
-% \begin{texnote}
-% This is the \TeX{} primitive \tn{ifvbox}.
-% \end{texnote}
-% \end{function}
-%
-% \begin{function}[EXP]{\if_box_empty:N}
-% \begin{syntax}
-% \cs{if_box_empty:N} \meta{box}
-% ~~\meta{true code}
-% \cs{else:}
-% ~~\meta{false code}
-% \cs{fi:}
-% \end{syntax}
-% Tests is \meta{box} is an empty (void) box.
-% \begin{texnote}
-% This is the \TeX{} primitive \tn{ifvoid}.
-% \end{texnote}
-% \end{function}
-%
-% \end{documentation}
-%
-% \begin{implementation}
-%
-% \section{\pkg{l3box} implementation}
-%
-% \begin{macrocode}
-%<*package>
-% \end{macrocode}
-%
-% \begin{macrocode}
-%<@@=box>
-% \end{macrocode}
-%
-% \subsection{Support code}
-%
-% \begin{macro}{\@@_dim_eval:w}
-% \begin{macro}{\@@_dim_eval:n}
-% Evaluating a dimension expression expandably. The only
-% difference with \cs{dim_eval:n} is the lack of \cs{dim_use:N}, to
-% produce an internal dimension rather than expand it into characters.
-% \begin{macrocode}
-\cs_new_eq:NN \@@_dim_eval:w \tex_dimexpr:D
-\cs_new:Npn \@@_dim_eval:n #1
- { \@@_dim_eval:w #1 \scan_stop: }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\__kernel_kern:n}
-% We need kerns in a few places. At present, we don't have a module for
-% this concept, so it goes in at first use: here. The idea is to avoid
-% repeated use of the bare primitive.
-% \begin{macrocode}
-\cs_new_protected:Npn \__kernel_kern:n #1
- { \tex_kern:D \@@_dim_eval:n {#1} }
-% \end{macrocode}
-% \end{macro}
-%
-% \subsection{Creating and initialising boxes}
-%
-% \TestFiles{m3box001.lvt}
-%
-% \begin{macro}{\box_new:N, \box_new:c}
-% Defining a new \meta{box} register: remember that box $255$ is not
-% generally available.
-% \begin{macrocode}
-\cs_new_protected:Npn \box_new:N #1
- {
- \__kernel_chk_if_free_cs:N #1
- \cs:w newbox \cs_end: #1
- }
-\cs_generate_variant:Nn \box_new:N { c }
-% \end{macrocode}
-%
-% \begin{macro}{\box_clear:N, \box_clear:c}
-% \begin{macro}{\box_gclear:N, \box_gclear:c}
-% \testfile*
-% Clear a \meta{box} register.
-% \begin{macrocode}
-\cs_new_protected:Npn \box_clear:N #1
- { \box_set_eq:NN #1 \c_empty_box }
-\cs_new_protected:Npn \box_gclear:N #1
- { \box_gset_eq:NN #1 \c_empty_box }
-\cs_generate_variant:Nn \box_clear:N { c }
-\cs_generate_variant:Nn \box_gclear:N { c }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\box_clear_new:N, \box_clear_new:c}
-% \begin{macro}{\box_gclear_new:N, \box_gclear_new:c}
-% \testfile*
-% Clear or new.
-% \begin{macrocode}
-\cs_new_protected:Npn \box_clear_new:N #1
- { \box_if_exist:NTF #1 { \box_clear:N #1 } { \box_new:N #1 } }
-\cs_new_protected:Npn \box_gclear_new:N #1
- { \box_if_exist:NTF #1 { \box_gclear:N #1 } { \box_new:N #1 } }
-\cs_generate_variant:Nn \box_clear_new:N { c }
-\cs_generate_variant:Nn \box_gclear_new:N { c }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}
-% {\box_set_eq:NN, \box_set_eq:cN, \box_set_eq:Nc, \box_set_eq:cc}
-% \testfile*
-% \begin{macro}
-% {\box_gset_eq:NN, \box_gset_eq:cN, \box_gset_eq:Nc, \box_gset_eq:cc}
-% \testfile*
-% Assigning the contents of a box to be another box.
-% \begin{macrocode}
-\cs_new_protected:Npn \box_set_eq:NN #1#2
- { \tex_setbox:D #1 \tex_copy:D #2 }
-\cs_new_protected:Npn \box_gset_eq:NN #1#2
- { \tex_global:D \tex_setbox:D #1 \tex_copy:D #2 }
-\cs_generate_variant:Nn \box_set_eq:NN { c , Nc , cc }
-\cs_generate_variant:Nn \box_gset_eq:NN { c , Nc , cc }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}
-% {
-% \box_set_eq_drop:NN, \box_set_eq_drop:cN,
-% \box_set_eq_drop:Nc, \box_set_eq_drop:cc
-% }
-% \begin{macro}
-% {
-% \box_gset_eq_drop:NN, \box_gset_eq_drop:cN,
-% \box_gset_eq_drop:Nc, \box_gset_eq_drop:cc
-% }
-% Assigning the contents of a box to be another box, then drops the
-% original box.
-% \begin{macrocode}
-\cs_new_protected:Npn \box_set_eq_drop:NN #1#2
- { \tex_setbox:D #1 \tex_box:D #2 }
-\cs_new_protected:Npn \box_gset_eq_drop:NN #1#2
- { \tex_global:D \tex_setbox:D #1 \tex_box:D #2 }
-\cs_generate_variant:Nn \box_set_eq_drop:NN { c , Nc , cc }
-\cs_generate_variant:Nn \box_gset_eq_drop:NN { c , Nc , cc }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}[pTF]{\box_if_exist:N, \box_if_exist:c}
-% Copies of the \texttt{cs} functions defined in \pkg{l3basics}.
-% \begin{macrocode}
-\prg_new_eq_conditional:NNn \box_if_exist:N \cs_if_exist:N
- { TF , T , F , p }
-\prg_new_eq_conditional:NNn \box_if_exist:c \cs_if_exist:c
- { TF , T , F , p }
-% \end{macrocode}
-% \end{macro}
-%
-% \subsection{Measuring and setting box dimensions}
-%
-% \begin{macro}{\box_ht:N, \box_ht:c}
-% \begin{macro}{\box_dp:N, \box_dp:c}
-% \begin{macro}{\box_wd:N, \box_wd:c}
-% \testfile*
-% Accessing the height, depth, and width of a \meta{box} register.
-% \begin{macrocode}
-\cs_new_eq:NN \box_ht:N \tex_ht:D
-\cs_new_eq:NN \box_dp:N \tex_dp:D
-\cs_new_eq:NN \box_wd:N \tex_wd:D
-\cs_generate_variant:Nn \box_ht:N { c }
-\cs_generate_variant:Nn \box_dp:N { c }
-\cs_generate_variant:Nn \box_wd:N { c }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\box_ht_plus_dp:N}
-% The \cs{box_ht:N} and \cs{box_dp:N} primitives do not expand but
-% rather are suitable for use after \tn{the} or inside dimension
-% expressions. Here we obtain the same behaviour by using
-% \cs{@@_dim_eval:n} (basically \tn{dimexpr}) rather than
-% \cs{dim_eval:n} (basically \tn{the} \tn{dimexpr}).
-% \begin{macrocode}
-\cs_new_protected:Npn \box_ht_plus_dp:N #1
- { \@@_dim_eval:n { \box_ht:N #1 + \box_dp:N #1 } }
-\cs_generate_variant:Nn \box_ht_plus_dp:N { c }
-% \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\box_set_ht:Nn, \box_set_ht:cn, \box_gset_ht:Nn, \box_gset_ht:cn}
-% \begin{macro}{\box_set_dp:Nn, \box_set_dp:cn, \box_gset_dp:Nn, \box_gset_dp:cn}
-% \begin{macro}{\box_set_wd:Nn, \box_set_wd:cn, \box_gset_wd:Nn, \box_gset_wd:cn}
-% Setting the size whilst respecting local scope requires copying;
-% the same issue does not come up when working globally.
-% When debugging, the dimension expression |#2| is surrounded by
-% parentheses to catch early termination.
-% \begin{macrocode}
-\cs_new_protected:Npn \box_set_dp:Nn #1#2
- {
- \tex_setbox:D #1 = \tex_copy:D #1
- \box_dp:N #1 \@@_dim_eval:n {#2}
- }
-\cs_generate_variant:Nn \box_set_dp:Nn { c }
-\cs_new_protected:Npn \box_gset_dp:Nn #1#2
- { \box_dp:N #1 \@@_dim_eval:n {#2} }
-\cs_generate_variant:Nn \box_gset_dp:Nn { c }
-\cs_new_protected:Npn \box_set_ht:Nn #1#2
- {
- \tex_setbox:D #1 = \tex_copy:D #1
- \box_ht:N #1 \@@_dim_eval:n {#2}
- }
-\cs_generate_variant:Nn \box_set_ht:Nn { c }
-\cs_new_protected:Npn \box_gset_ht:Nn #1#2
- { \box_ht:N #1 \@@_dim_eval:n {#2} }
-\cs_generate_variant:Nn \box_gset_ht:Nn { c }
-\cs_new_protected:Npn \box_set_wd:Nn #1#2
- {
- \tex_setbox:D #1 = \tex_copy:D #1
- \box_wd:N #1 \@@_dim_eval:n {#2}
- }
-\cs_generate_variant:Nn \box_set_wd:Nn { c }
-\cs_new_protected:Npn \box_gset_wd:Nn #1#2
- { \box_wd:N #1 \@@_dim_eval:n {#2} }
-\cs_generate_variant:Nn \box_gset_wd:Nn { c }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \subsection{Using boxes}
-%
-% \begin{macro}{\box_use_drop:N, \box_use_drop:c}
-% \begin{macro}{\box_use:N, \box_use:c}
-% Using a \meta{box}. These are just \TeX{} primitives with meaningful
-% names.
-% \begin{macrocode}
-\cs_new_eq:NN \box_use_drop:N \tex_box:D
-\cs_new_eq:NN \box_use:N \tex_copy:D
-\cs_generate_variant:Nn \box_use_drop:N { c }
-\cs_generate_variant:Nn \box_use:N { c }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\box_move_left:nn, \box_move_right:nn}
-% \begin{macro}{\box_move_up:nn, \box_move_down:nn}
-% \testfile*
-% Move box material in different directions.
-% When debugging, the dimension expression |#1| is surrounded by
-% parentheses to catch early termination.
-% \begin{macrocode}
-\cs_new_protected:Npn \box_move_left:nn #1#2
- { \tex_moveleft:D \@@_dim_eval:n {#1} #2 }
-\cs_new_protected:Npn \box_move_right:nn #1#2
- { \tex_moveright:D \@@_dim_eval:n {#1} #2 }
-\cs_new_protected:Npn \box_move_up:nn #1#2
- { \tex_raise:D \@@_dim_eval:n {#1} #2 }
-\cs_new_protected:Npn \box_move_down:nn #1#2
- { \tex_lower:D \@@_dim_eval:n {#1} #2 }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \subsection{Box conditionals}
-%
-% \begin{macro}{\if_hbox:N}
-% \begin{macro}{\if_vbox:N}
-% \begin{macro}{\if_box_empty:N}
-% \testfile*
-% The primitives for testing if a \meta{box} is empty/void or which
-% type of box it is.
-% \begin{macrocode}
-\cs_new_eq:NN \if_hbox:N \tex_ifhbox:D
-\cs_new_eq:NN \if_vbox:N \tex_ifvbox:D
-\cs_new_eq:NN \if_box_empty:N \tex_ifvoid:D
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}[pTF]{\box_if_horizontal:N, \box_if_horizontal:c}
-% \testfile*
-% \begin{macro}[pTF]{\box_if_vertical:N, \box_if_vertical:c}
-% \testfile*
-% \begin{macrocode}
-\prg_new_conditional:Npnn \box_if_horizontal:N #1 { p , T , F , TF }
- { \if_hbox:N #1 \prg_return_true: \else: \prg_return_false: \fi: }
-\prg_new_conditional:Npnn \box_if_vertical:N #1 { p , T , F , TF }
- { \if_vbox:N #1 \prg_return_true: \else: \prg_return_false: \fi: }
-\prg_generate_conditional_variant:Nnn \box_if_horizontal:N
- { c } { p , T , F , TF }
-\prg_generate_conditional_variant:Nnn \box_if_vertical:N
- { c } { p , T , F , TF }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}[pTF]{\box_if_empty:N, \box_if_empty:c}
-% \testfile*
-% Testing if a \meta{box} is empty/void.
-% \begin{macrocode}
-\prg_new_conditional:Npnn \box_if_empty:N #1 { p , T , F , TF }
- { \if_box_empty:N #1 \prg_return_true: \else: \prg_return_false: \fi: }
-\prg_generate_conditional_variant:Nnn \box_if_empty:N
- { c } { p , T , F , TF }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \subsection{The last box inserted}
-%
-% \begin{macro}{\box_set_to_last:N, \box_set_to_last:c}
-% \begin{macro}{\box_gset_to_last:N, \box_gset_to_last:c}
-% \testfile*
-% Set a box to the previous box.
-% \begin{macrocode}
-\cs_new_protected:Npn \box_set_to_last:N #1
- { \tex_setbox:D #1 \tex_lastbox:D }
-\cs_new_protected:Npn \box_gset_to_last:N #1
- { \tex_global:D \tex_setbox:D #1 \tex_lastbox:D }
-\cs_generate_variant:Nn \box_set_to_last:N { c }
-\cs_generate_variant:Nn \box_gset_to_last:N { c }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \subsection{Constant boxes}
-%
-% \begin{variable}{\c_empty_box}
-% A box we never use.
-% \begin{macrocode}
-\box_new:N \c_empty_box
-% \end{macrocode}
-% \end{variable}
-%
-% \subsection{Scratch boxes}
-%
-% \begin{variable}{\l_tmpa_box, \l_tmpb_box, \g_tmpa_box, \g_tmpb_box}
-% Scratch boxes.
-% \begin{macrocode}
-\box_new:N \l_tmpa_box
-\box_new:N \l_tmpb_box
-\box_new:N \g_tmpa_box
-\box_new:N \g_tmpb_box
-% \end{macrocode}
-% \end{variable}
-%
-% \subsection{Viewing box contents}
-%
-% \TeX{}'s \tn{showbox} is not really that helpful in many cases, and
-% it is also inconsistent with other \LaTeX3{} \texttt{show} functions as it
-% does not actually shows material in the terminal. So we provide a richer
-% set of functionality.
-%
-% \begin{macro}{\box_show:N, \box_show:c}
-% \begin{macro}{\box_show:Nnn, \box_show:cnn}
-% Essentially a wrapper around the internal function, but evaluating
-% the breadth and depth arguments now outside the group.
-% \begin{macrocode}
-\cs_new_protected:Npn \box_show:N #1
- { \box_show:Nnn #1 \c_max_int \c_max_int }
-\cs_generate_variant:Nn \box_show:N { c }
-\cs_new_protected:Npn \box_show:Nnn #1#2#3
- { \@@_show:NNff 1 #1 { \int_eval:n {#2} } { \int_eval:n {#3} } }
-\cs_generate_variant:Nn \box_show:Nnn { c }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\box_log:N, \box_log:c}
-% \begin{macro}{\box_log:Nnn, \box_log:cnn}
-% \begin{macro}{\@@_log:nNnn}
-% Getting \TeX{} to write to the log without interruption the run is done by
-% altering the interaction mode. For that, the \eTeX{} extensions are needed.
-% \begin{macrocode}
-\cs_new_protected:Npn \box_log:N #1
- { \box_log:Nnn #1 \c_max_int \c_max_int }
-\cs_generate_variant:Nn \box_log:N { c }
-\cs_new_protected:Npn \box_log:Nnn
- { \exp_args:No \@@_log:nNnn { \tex_the:D \tex_interactionmode:D } }
-\cs_new_protected:Npn \@@_log:nNnn #1#2#3#4
- {
- \int_gset:Nn \tex_interactionmode:D { 0 }
- \@@_show:NNff 0 #2 { \int_eval:n {#3} } { \int_eval:n {#4} }
- \int_gset:Nn \tex_interactionmode:D {#1}
- }
-\cs_generate_variant:Nn \box_log:Nnn { c }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\@@_show:NNnn, \@@_show:NNff}
-% The internal auxiliary to actually do the output uses a group to deal
-% with breadth and depth values. The \cs{use:n} here gives better output
-% appearance. Setting \tn{tracingonline} and \tn{errorcontextlines} is
-% used to control what appears in the terminal.
-% \begin{macrocode}
-\cs_new_protected:Npn \@@_show:NNnn #1#2#3#4
- {
- \box_if_exist:NTF #2
- {
- \group_begin:
- \int_set:Nn \tex_showboxbreadth:D {#3}
- \int_set:Nn \tex_showboxdepth:D {#4}
- \int_set:Nn \tex_tracingonline:D {#1}
- \int_set:Nn \tex_errorcontextlines:D { -1 }
- \tex_showbox:D \use:n {#2}
- \group_end:
- }
- {
- \msg_error:nne { kernel } { variable-not-defined }
- { \token_to_str:N #2 }
- }
- }
-\cs_generate_variant:Nn \@@_show:NNnn { NNff }
-% \end{macrocode}
-% \end{macro}
-%
-% \subsection{Horizontal mode boxes}
-%
-% \begin{macro}{\hbox:n}
-% \testfile{m3box002.lvt}
-% Put a horizontal box directly into the input stream.
-% \begin{macrocode}
-\cs_new_protected:Npn \hbox:n #1
- { \tex_hbox:D \scan_stop: { \color_group_begin: #1 \color_group_end: } }
-% \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\hbox_set:Nn, \hbox_set:cn}
-% \begin{macro}{\hbox_gset:Nn, \hbox_gset:cn}
-% \testfile*
-% \begin{macrocode}
-\cs_new_protected:Npn \hbox_set:Nn #1#2
- {
- \tex_setbox:D #1 \tex_hbox:D
- { \color_group_begin: #2 \color_group_end: }
- }
-\cs_new_protected:Npn \hbox_gset:Nn #1#2
- {
- \tex_global:D \tex_setbox:D #1 \tex_hbox:D
- { \color_group_begin: #2 \color_group_end: }
- }
-\cs_generate_variant:Nn \hbox_set:Nn { c }
-\cs_generate_variant:Nn \hbox_gset:Nn { c }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\hbox_set_to_wd:Nnn, \hbox_set_to_wd:cnn}
-% \begin{macro}{\hbox_gset_to_wd:Nnn, \hbox_gset_to_wd:cnn}
-% \testfile*
-% Storing material in a horizontal box with a specified width.
-% Again, put the dimension expression in parentheses when debugging.
-% \begin{macrocode}
-\cs_new_protected:Npn \hbox_set_to_wd:Nnn #1#2#3
- {
- \tex_setbox:D #1 \tex_hbox:D to \@@_dim_eval:n {#2}
- { \color_group_begin: #3 \color_group_end: }
- }
-\cs_new_protected:Npn \hbox_gset_to_wd:Nnn #1#2#3
- {
- \tex_global:D \tex_setbox:D #1 \tex_hbox:D to \@@_dim_eval:n {#2}
- { \color_group_begin: #3 \color_group_end: }
- }
-\cs_generate_variant:Nn \hbox_set_to_wd:Nnn { c }
-\cs_generate_variant:Nn \hbox_gset_to_wd:Nnn { c }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\hbox_set:Nw, \hbox_set:cw}
-% \begin{macro}{\hbox_gset:Nw, \hbox_gset:cw}
-% \begin{macro}{\hbox_set_end:, \hbox_gset_end:}
-% \testfile*
-% Storing material in a horizontal box. This type is useful in
-% environment definitions.
-% \begin{macrocode}
-\cs_new_protected:Npn \hbox_set:Nw #1
- {
- \tex_setbox:D #1 \tex_hbox:D
- \c_group_begin_token
- \color_group_begin:
- }
-\cs_new_protected:Npn \hbox_gset:Nw #1
- {
- \tex_global:D \tex_setbox:D #1 \tex_hbox:D
- \c_group_begin_token
- \color_group_begin:
- }
-\cs_generate_variant:Nn \hbox_set:Nw { c }
-\cs_generate_variant:Nn \hbox_gset:Nw { c }
-\cs_new_protected:Npn \hbox_set_end:
- {
- \color_group_end:
- \c_group_end_token
- }
-\cs_new_eq:NN \hbox_gset_end: \hbox_set_end:
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\hbox_set_to_wd:Nnw, \hbox_set_to_wd:cnw}
-% \begin{macro}{\hbox_gset_to_wd:Nnw, \hbox_gset_to_wd:cnw}
-% Combining the above ideas.
-% \begin{macrocode}
-\cs_new_protected:Npn \hbox_set_to_wd:Nnw #1#2
- {
- \tex_setbox:D #1 \tex_hbox:D to \@@_dim_eval:n {#2}
- \c_group_begin_token
- \color_group_begin:
- }
-\cs_new_protected:Npn \hbox_gset_to_wd:Nnw #1#2
- {
- \tex_global:D \tex_setbox:D #1 \tex_hbox:D to \@@_dim_eval:n {#2}
- \c_group_begin_token
- \color_group_begin:
- }
-\cs_generate_variant:Nn \hbox_set_to_wd:Nnw { c }
-\cs_generate_variant:Nn \hbox_gset_to_wd:Nnw { c }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\hbox_to_wd:nn}
-% \begin{macro}{\hbox_to_zero:n}
-% \testfile*
-% Put a horizontal box directly into the input stream.
-% \begin{macrocode}
-\cs_new_protected:Npn \hbox_to_wd:nn #1#2
- {
- \tex_hbox:D to \@@_dim_eval:n {#1}
- { \color_group_begin: #2 \color_group_end: }
- }
-\cs_new_protected:Npn \hbox_to_zero:n #1
- {
- \tex_hbox:D to \c_zero_dim
- { \color_group_begin: #1 \color_group_end: }
- }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\hbox_overlap_center:n, \hbox_overlap_left:n, \hbox_overlap_right:n}
-% Put a zero-sized box with the contents pushed against one side (which
-% makes it stick out on the other) directly into the input stream.
-% \begin{macrocode}
-\cs_new_protected:Npn \hbox_overlap_center:n #1
- { \hbox_to_zero:n { \tex_hss:D #1 \tex_hss:D } }
-\cs_new_protected:Npn \hbox_overlap_left:n #1
- { \hbox_to_zero:n { \tex_hss:D #1 } }
-\cs_new_protected:Npn \hbox_overlap_right:n #1
- { \hbox_to_zero:n { #1 \tex_hss:D } }
-% \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\hbox_unpack:N, \hbox_unpack:c}
-% \begin{macro}{\hbox_unpack_drop:N, \hbox_unpack_drop:c}
-% \testfile*
-% Unpacking a box and if requested also clear it.
-% \begin{macrocode}
-\cs_new_eq:NN \hbox_unpack:N \tex_unhcopy:D
-\cs_new_eq:NN \hbox_unpack_drop:N \tex_unhbox:D
-\cs_generate_variant:Nn \hbox_unpack:N { c }
-\cs_generate_variant:Nn \hbox_unpack_drop:N { c }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \subsection{Vertical mode boxes}
-%
-% \TeX{} ends these boxes directly with the internal \emph{end_graf}
-% routine. This means that there is no \cs{par} at the end of vertical
-% boxes unless we insert one. Thus all vertical boxes include a \cs{par}
-% just before closing the color group.
-%
-% \begin{macro}{\vbox:n}
-% \TestFiles{m3box003.lvt}
-% \begin{macro}{\vbox_top:n}
-% \TestFiles{m3box003.lvt}
-% Put a vertical box directly into the input stream.
-% \begin{macrocode}
-\cs_new_protected:Npn \vbox:n #1
- { \tex_vbox:D { \color_group_begin: #1 \par \color_group_end: } }
-\cs_new_protected:Npn \vbox_top:n #1
- { \tex_vtop:D { \color_group_begin: #1 \par \color_group_end: } }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\vbox_to_ht:nn, \vbox_to_zero:n}
-% \begin{macro}{\vbox_to_ht:nn, \vbox_to_zero:n}
-% \testfile*
-% Put a vertical box directly into the input stream.
-% \begin{macrocode}
-\cs_new_protected:Npn \vbox_to_ht:nn #1#2
- {
- \tex_vbox:D to \@@_dim_eval:n {#1}
- { \color_group_begin: #2 \par \color_group_end: }
- }
-\cs_new_protected:Npn \vbox_to_zero:n #1
- {
- \tex_vbox:D to \c_zero_dim
- { \color_group_begin: #1 \par \color_group_end: }
- }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\vbox_set:Nn, \vbox_set:cn}
-% \begin{macro}{\vbox_gset:Nn, \vbox_gset:cn}
-% \testfile*
-% Storing material in a vertical box with a natural height.
-% \begin{macrocode}
-\cs_new_protected:Npn \vbox_set:Nn #1#2
- {
- \tex_setbox:D #1 \tex_vbox:D
- { \color_group_begin: #2 \par \color_group_end: }
- }
-\cs_new_protected:Npn \vbox_gset:Nn #1#2
- {
- \tex_global:D \tex_setbox:D #1 \tex_vbox:D
- { \color_group_begin: #2 \par \color_group_end: }
- }
-\cs_generate_variant:Nn \vbox_set:Nn { c }
-\cs_generate_variant:Nn \vbox_gset:Nn { c }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\vbox_set_top:Nn, \vbox_set_top:cn}
-% \begin{macro}{\vbox_gset_top:Nn, \vbox_gset_top:cn}
-% \testfile*
-% Storing material in a vertical box with a natural height and reference
-% point at the baseline of the first object in the box.
-% \begin{macrocode}
-\cs_new_protected:Npn \vbox_set_top:Nn #1#2
- {
- \tex_setbox:D #1 \tex_vtop:D
- { \color_group_begin: #2 \par \color_group_end: }
- }
-\cs_new_protected:Npn \vbox_gset_top:Nn #1#2
- {
- \tex_global:D \tex_setbox:D #1 \tex_vtop:D
- { \color_group_begin: #2 \par \color_group_end: }
- }
-\cs_generate_variant:Nn \vbox_set_top:Nn { c }
-\cs_generate_variant:Nn \vbox_gset_top:Nn { c }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\vbox_set_to_ht:Nnn, \vbox_set_to_ht:cnn}
-% \begin{macro}{\vbox_gset_to_ht:Nnn, \vbox_gset_to_ht:cnn}
-% \testfile*
-% Storing material in a vertical box with a specified height.
-% \begin{macrocode}
-\cs_new_protected:Npn \vbox_set_to_ht:Nnn #1#2#3
- {
- \tex_setbox:D #1 \tex_vbox:D to \@@_dim_eval:n {#2}
- { \color_group_begin: #3 \par \color_group_end: }
- }
-\cs_new_protected:Npn \vbox_gset_to_ht:Nnn #1#2#3
- {
- \tex_global:D \tex_setbox:D #1 \tex_vbox:D to \@@_dim_eval:n {#2}
- { \color_group_begin: #3 \par \color_group_end: }
- }
-\cs_generate_variant:Nn \vbox_set_to_ht:Nnn { c }
-\cs_generate_variant:Nn \vbox_gset_to_ht:Nnn { c }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\vbox_set:Nw, \vbox_set:cw}
-% \begin{macro}{\vbox_gset:Nw, \vbox_gset:cw}
-% \begin{macro}{\vbox_set_end:, \vbox_gset_end:}
-% \testfile*
-% Storing material in a vertical box. This type is useful in
-% environment definitions.
-% \begin{macrocode}
-\cs_new_protected:Npn \vbox_set:Nw #1
- {
- \tex_setbox:D #1 \tex_vbox:D
- \c_group_begin_token
- \color_group_begin:
- }
-\cs_new_protected:Npn \vbox_gset:Nw #1
- {
- \tex_global:D \tex_setbox:D #1 \tex_vbox:D
- \c_group_begin_token
- \color_group_begin:
- }
-\cs_generate_variant:Nn \vbox_set:Nw { c }
-\cs_generate_variant:Nn \vbox_gset:Nw { c }
-\cs_new_protected:Npn \vbox_set_end:
- {
- \par
- \color_group_end:
- \c_group_end_token
- }
-\cs_new_eq:NN \vbox_gset_end: \vbox_set_end:
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\vbox_set_to_ht:Nnw, \vbox_set_to_ht:cnw}
-% \begin{macro}{\vbox_gset_to_ht:Nnw, \vbox_gset_to_ht:cnw}
-% A combination of the above ideas.
-% \begin{macrocode}
-\cs_new_protected:Npn \vbox_set_to_ht:Nnw #1#2
- {
- \tex_setbox:D #1 \tex_vbox:D to \@@_dim_eval:n {#2}
- \c_group_begin_token
- \color_group_begin:
- }
-\cs_new_protected:Npn \vbox_gset_to_ht:Nnw #1#2
- {
- \tex_global:D \tex_setbox:D #1 \tex_vbox:D to \@@_dim_eval:n {#2}
- \c_group_begin_token
- \color_group_begin:
- }
-\cs_generate_variant:Nn \vbox_set_to_ht:Nnw { c }
-\cs_generate_variant:Nn \vbox_gset_to_ht:Nnw { c }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\vbox_unpack:N, \vbox_unpack:c}
-% \begin{macro}{\vbox_unpack_drop:N, \vbox_unpack_drop:c}
-% \testfile*
-% Unpacking a box and if requested also clear it.
-% \begin{macrocode}
-\cs_new_eq:NN \vbox_unpack:N \tex_unvcopy:D
-\cs_new_eq:NN \vbox_unpack_drop:N \tex_unvbox:D
-\cs_generate_variant:Nn \vbox_unpack:N { c }
-\cs_generate_variant:Nn \vbox_unpack_drop:N { c }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}
-% {
-% \vbox_set_split_to_ht:NNn, \vbox_set_split_to_ht:cNn,
-% \vbox_set_split_to_ht:Ncn, \vbox_set_split_to_ht:ccn,
-% \vbox_gset_split_to_ht:NNn, \vbox_gset_split_to_ht:cNn,
-% \vbox_gset_split_to_ht:Ncn, \vbox_gset_split_to_ht:ccn,
-% }
-% \testfile*
-% Splitting a vertical box in two.
-% \begin{macrocode}
-\cs_new_protected:Npn \vbox_set_split_to_ht:NNn #1#2#3
- { \tex_setbox:D #1 \tex_vsplit:D #2 to \@@_dim_eval:n {#3} }
-\cs_generate_variant:Nn \vbox_set_split_to_ht:NNn { c , Nc , cc }
-\cs_new_protected:Npn \vbox_gset_split_to_ht:NNn #1#2#3
- {
- \tex_global:D \tex_setbox:D #1
- \tex_vsplit:D #2 to \@@_dim_eval:n {#3}
- }
-\cs_generate_variant:Nn \vbox_gset_split_to_ht:NNn { c , Nc , cc }
-% \end{macrocode}
-% \end{macro}
-%
-% \subsection{Affine transformations}
-%
-% \begin{variable}{\l_@@_angle_fp}
-% When rotating boxes, the angle itself may be needed by the
-% engine-dependent code. This is done using the \pkg{fp} module so
-% that the value is tidied up properly.
-% \begin{macrocode}
-\fp_new:N \l_@@_angle_fp
-% \end{macrocode}
-% \end{variable}
-%
-% \begin{variable}{\l_@@_cos_fp, \l_@@_sin_fp}
-% These are used to hold the calculated sine and cosine values while
-% carrying out a rotation.
-% \begin{macrocode}
-\fp_new:N \l_@@_cos_fp
-\fp_new:N \l_@@_sin_fp
-% \end{macrocode}
-% \end{variable}
-%
-% \begin{variable}
-% {\l_@@_top_dim, \l_@@_bottom_dim, \l_@@_left_dim, \l_@@_right_dim}
-% These are the positions of the four edges of a box before
-% manipulation.
-% \begin{macrocode}
-\dim_new:N \l_@@_top_dim
-\dim_new:N \l_@@_bottom_dim
-\dim_new:N \l_@@_left_dim
-\dim_new:N \l_@@_right_dim
-% \end{macrocode}
-% \end{variable}
-%
-% \begin{variable}
-% {
-% \l_@@_top_new_dim, \l_@@_bottom_new_dim ,
-% \l_@@_left_new_dim, \l_@@_right_new_dim
-% }
-% These are the positions of the four edges of a box after
-% manipulation.
-% \begin{macrocode}
-\dim_new:N \l_@@_top_new_dim
-\dim_new:N \l_@@_bottom_new_dim
-\dim_new:N \l_@@_left_new_dim
-\dim_new:N \l_@@_right_new_dim
-% \end{macrocode}
-% \end{variable}
-%
-% \begin{variable}{\l_@@_internal_box}
-% Scratch space, but also needed by some parts of the driver.
-% \begin{macrocode}
-\box_new:N \l_@@_internal_box
-% \end{macrocode}
-% \end{variable}
-%
-% \begin{macro}
-% {
-% \box_rotate:Nn, \box_rotate:cn,
-% \box_grotate:Nn, \box_grotate:cn
-% }
-% \begin{macro}{\@@_rotate:NnN}
-% \begin{macro}{\@@_rotate:N}
-% \begin{macro}{\@@_rotate_xdir:nnN, \@@_rotate_ydir:nnN}
-% \begin{macro}
-% {
-% \@@_rotate_quadrant_one:, \@@_rotate_quadrant_two:,
-% \@@_rotate_quadrant_three:, \@@_rotate_quadrant_four:
-% }
-% Rotation of a box starts with working out the relevant sine and
-% cosine. The actual rotation is in an auxiliary to keep the flow slightly
-% clearer
-% \begin{macrocode}
-\cs_new_protected:Npn \box_rotate:Nn #1#2
- { \@@_rotate:NnN #1 {#2} \hbox_set:Nn }
-\cs_generate_variant:Nn \box_rotate:Nn { c }
-\cs_new_protected:Npn \box_grotate:Nn #1#2
- { \@@_rotate:NnN #1 {#2} \hbox_gset:Nn }
-\cs_generate_variant:Nn \box_grotate:Nn { c }
-\cs_new_protected:Npn \@@_rotate:NnN #1#2#3
- {
- #3 #1
- {
- \fp_set:Nn \l_@@_angle_fp {#2}
- \fp_set:Nn \l_@@_sin_fp { sind ( \l_@@_angle_fp ) }
- \fp_set:Nn \l_@@_cos_fp { cosd ( \l_@@_angle_fp ) }
- \@@_rotate:N #1
- }
- }
-% \end{macrocode}
-% The edges of the box are then recorded: the left edge is
-% always at zero. Rotation of the four edges then takes place: this is
-% most efficiently done on a quadrant by quadrant basis.
-% \begin{macrocode}
-\cs_new_protected:Npn \@@_rotate:N #1
- {
- \dim_set:Nn \l_@@_top_dim { \box_ht:N #1 }
- \dim_set:Nn \l_@@_bottom_dim { -\box_dp:N #1 }
- \dim_set:Nn \l_@@_right_dim { \box_wd:N #1 }
- \dim_zero:N \l_@@_left_dim
-% \end{macrocode}
-% The next step is to work out the $x$ and $y$ coordinates of vertices of
-% the rotated box in relation to its original coordinates. The box can be
-% visualized with vertices $B$, $C$, $D$ and $E$ is illustrated
-% (Figure~\ref{fig:l3box:rotation}). The vertex $O$ is the reference point
-% on the baseline, and in this implementation is also the centre of rotation.
-% \begin{figure}
-% \centering
-% \setlength{\unitlength}{3pt}^^A
-% \begin{picture}(34,36)(12,44)
-% \thicklines
-% \put(20,52){\dashbox{1}(20,21){}}
-% \put(20,80){\line(0,-1){36}}
-% \put(12,58){\line(1, 0){34}}
-% \put(41,59){A}
-% \put(40,74){B}
-% \put(21,74){C}
-% \put(21,49){D}
-% \put(40,49){E}
-% \put(21,59){O}
-% \end{picture}
-% \caption{Co-ordinates of a box prior to rotation.}
-% \label{fig:l3box:rotation}
-% \end{figure}
-% The formulae are, for a point $P$ and angle $\alpha$:
-% \[
-% \begin{array}{l}
-% P'_x = P_x - O_x \\
-% P'_y = P_y - O_y \\
-% P''_x = ( P'_x \cos(\alpha)) - ( P'_y \sin(\alpha) ) \\
-% P''_y = ( P'_x \sin(\alpha)) + ( P'_y \cos(\alpha) ) \\
-% P'''_x = P''_x + O_x + L_x \\
-% P'''_y = P''_y + O_y
-% \end{array}
-% \]
-% The \enquote{extra} horizontal translation $L_x$ at the end is calculated
-% so that the leftmost point of the resulting box has $x$-coordinate $0$.
-% This is desirable as \TeX{} boxes must have the reference point at
-% the left edge of the box. (As $O$ is always $(0,0)$, this part of the
-% calculation is omitted here.)
-% \begin{macrocode}
- \fp_compare:nNnTF \l_@@_sin_fp > \c_zero_fp
- {
- \fp_compare:nNnTF \l_@@_cos_fp > \c_zero_fp
- { \@@_rotate_quadrant_one: }
- { \@@_rotate_quadrant_two: }
- }
- {
- \fp_compare:nNnTF \l_@@_cos_fp < \c_zero_fp
- { \@@_rotate_quadrant_three: }
- { \@@_rotate_quadrant_four: }
- }
-% \end{macrocode}
-% The position of the box edges are now known, but the box at this
-% stage be misplaced relative to the current \TeX{} reference point. So the
-% content of the box is moved such that the reference point of the
-% rotated box is in the same place as the original.
-% \begin{macrocode}
- \hbox_set:Nn \l_@@_internal_box { \box_use:N #1 }
- \hbox_set:Nn \l_@@_internal_box
- {
- \__kernel_kern:n { -\l_@@_left_new_dim }
- \hbox:n
- {
- \@@_backend_rotate:Nn
- \l_@@_internal_box
- \l_@@_angle_fp
- }
- }
-% \end{macrocode}
-% Tidy up the size of the box so that the material is actually inside
-% the bounding box. The result can then be used to reset the original
-% box.
-% \begin{macrocode}
- \box_set_ht:Nn \l_@@_internal_box { \l_@@_top_new_dim }
- \box_set_dp:Nn \l_@@_internal_box { -\l_@@_bottom_new_dim }
- \box_set_wd:Nn \l_@@_internal_box
- { \l_@@_right_new_dim - \l_@@_left_new_dim }
- \box_use_drop:N \l_@@_internal_box
- }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-% These functions take a general point $(|#1|, |#2|)$ and rotate its
-% location about the origin, using the previously-set sine and cosine
-% values. Each function gives only one component of the location of the
-% updated point. This is because for rotation of a box each step needs
-% only one value, and so performance is gained by avoiding working
-% out both $x'$ and $y'$ at the same time. Contrast this with
-% the equivalent function in the \pkg{l3coffins} module, where both parts
-% are needed.
-% \begin{macrocode}
-\cs_new_protected:Npn \@@_rotate_xdir:nnN #1#2#3
- {
- \dim_set:Nn #3
- {
- \fp_to_dim:n
- {
- \l_@@_cos_fp * \dim_to_fp:n {#1}
- - \l_@@_sin_fp * \dim_to_fp:n {#2}
- }
- }
- }
-\cs_new_protected:Npn \@@_rotate_ydir:nnN #1#2#3
- {
- \dim_set:Nn #3
- {
- \fp_to_dim:n
- {
- \l_@@_sin_fp * \dim_to_fp:n {#1}
- + \l_@@_cos_fp * \dim_to_fp:n {#2}
- }
- }
- }
-% \end{macrocode}
-% Rotation of the edges is done using a different formula for each
-% quadrant. In every case, the top and bottom edges only need the
-% resulting $y$-values, whereas the left and right edges need the
-% $x$-values. Each case is a question of picking out which corner
-% ends up at with the maximum top, bottom, left and right value. Doing
-% this by hand means a lot less calculating and avoids lots of
-% comparisons.
-% \begin{macrocode}
-\cs_new_protected:Npn \@@_rotate_quadrant_one:
- {
- \@@_rotate_ydir:nnN \l_@@_right_dim \l_@@_top_dim
- \l_@@_top_new_dim
- \@@_rotate_ydir:nnN \l_@@_left_dim \l_@@_bottom_dim
- \l_@@_bottom_new_dim
- \@@_rotate_xdir:nnN \l_@@_left_dim \l_@@_top_dim
- \l_@@_left_new_dim
- \@@_rotate_xdir:nnN \l_@@_right_dim \l_@@_bottom_dim
- \l_@@_right_new_dim
- }
-\cs_new_protected:Npn \@@_rotate_quadrant_two:
- {
- \@@_rotate_ydir:nnN \l_@@_right_dim \l_@@_bottom_dim
- \l_@@_top_new_dim
- \@@_rotate_ydir:nnN \l_@@_left_dim \l_@@_top_dim
- \l_@@_bottom_new_dim
- \@@_rotate_xdir:nnN \l_@@_right_dim \l_@@_top_dim
- \l_@@_left_new_dim
- \@@_rotate_xdir:nnN \l_@@_left_dim \l_@@_bottom_dim
- \l_@@_right_new_dim
- }
-\cs_new_protected:Npn \@@_rotate_quadrant_three:
- {
- \@@_rotate_ydir:nnN \l_@@_left_dim \l_@@_bottom_dim
- \l_@@_top_new_dim
- \@@_rotate_ydir:nnN \l_@@_right_dim \l_@@_top_dim
- \l_@@_bottom_new_dim
- \@@_rotate_xdir:nnN \l_@@_right_dim \l_@@_bottom_dim
- \l_@@_left_new_dim
- \@@_rotate_xdir:nnN \l_@@_left_dim \l_@@_top_dim
- \l_@@_right_new_dim
- }
-\cs_new_protected:Npn \@@_rotate_quadrant_four:
- {
- \@@_rotate_ydir:nnN \l_@@_left_dim \l_@@_top_dim
- \l_@@_top_new_dim
- \@@_rotate_ydir:nnN \l_@@_right_dim \l_@@_bottom_dim
- \l_@@_bottom_new_dim
- \@@_rotate_xdir:nnN \l_@@_left_dim \l_@@_bottom_dim
- \l_@@_left_new_dim
- \@@_rotate_xdir:nnN \l_@@_right_dim \l_@@_top_dim
- \l_@@_right_new_dim
- }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{variable}{\l_@@_scale_x_fp, \l_@@_scale_y_fp}
-% Scaling is potentially-different in the two axes.
-% \begin{macrocode}
-\fp_new:N \l_@@_scale_x_fp
-\fp_new:N \l_@@_scale_y_fp
-% \end{macrocode}
-% \end{variable}
-%
-% \begin{macro}
-% {
-% \box_resize_to_wd_and_ht_plus_dp:Nnn,
-% \box_resize_to_wd_and_ht_plus_dp:cnn,
-% \box_gresize_to_wd_and_ht_plus_dp:Nnn,
-% \box_gresize_to_wd_and_ht_plus_dp:cnn
-% }
-% \begin{macro}{\@@_resize_to_wd_and_ht_plus_dp:NnnN}
-% \begin{macro}{\@@_resize_set_corners:N}
-% \begin{macro}{\@@_resize:N}
-% \begin{macro}{\@@_resize:NNN}
-% Resizing a box starts by working out the various dimensions of the
-% existing box.
-% \begin{macrocode}
-\cs_new_protected:Npn \box_resize_to_wd_and_ht_plus_dp:Nnn #1#2#3
- {
- \@@_resize_to_wd_and_ht_plus_dp:NnnN #1 {#2} {#3}
- \hbox_set:Nn
- }
-\cs_generate_variant:Nn \box_resize_to_wd_and_ht_plus_dp:Nnn { c }
-\cs_new_protected:Npn \box_gresize_to_wd_and_ht_plus_dp:Nnn #1#2#3
- {
- \@@_resize_to_wd_and_ht_plus_dp:NnnN #1 {#2} {#3}
- \hbox_gset:Nn
- }
-\cs_generate_variant:Nn \box_gresize_to_wd_and_ht_plus_dp:Nnn { c }
-\cs_new_protected:Npn \@@_resize_to_wd_and_ht_plus_dp:NnnN #1#2#3#4
- {
- #4 #1
- {
- \@@_resize_set_corners:N #1
-% \end{macrocode}
-% The $x$-scaling and resulting box size is easy enough to work
-% out: the dimension is that given as |#2|, and the scale is simply the
-% new width divided by the old one.
-% \begin{macrocode}
- \fp_set:Nn \l_@@_scale_x_fp
- { \dim_to_fp:n {#2} / \dim_to_fp:n { \l_@@_right_dim } }
-% \end{macrocode}
-% The $y$-scaling needs both the height and the depth of the current box.
-% \begin{macrocode}
- \fp_set:Nn \l_@@_scale_y_fp
- {
- \dim_to_fp:n {#3}
- / \dim_to_fp:n { \l_@@_top_dim - \l_@@_bottom_dim }
- }
-% \end{macrocode}
-% Hand off to the auxiliary which does the rest of the work.
-% \begin{macrocode}
- \@@_resize:N #1
- }
- }
-\cs_new_protected:Npn \@@_resize_set_corners:N #1
- {
- \dim_set:Nn \l_@@_top_dim { \box_ht:N #1 }
- \dim_set:Nn \l_@@_bottom_dim { -\box_dp:N #1 }
- \dim_set:Nn \l_@@_right_dim { \box_wd:N #1 }
- \dim_zero:N \l_@@_left_dim
- }
-% \end{macrocode}
-% With at least one real scaling to do, the next phase is to find the new
-% edge co-ordinates. In the $x$~direction this is relatively easy: just
-% scale the right edge. In the $y$~direction, both dimensions have to be
-% scaled, and this again needs the absolute scale value.
-% Once that is all done, the common resize/rescale code can be employed.
-% \begin{macrocode}
-\cs_new_protected:Npn \@@_resize:N #1
- {
- \@@_resize:NNN \l_@@_right_new_dim
- \l_@@_scale_x_fp \l_@@_right_dim
- \@@_resize:NNN \l_@@_bottom_new_dim
- \l_@@_scale_y_fp \l_@@_bottom_dim
- \@@_resize:NNN \l_@@_top_new_dim
- \l_@@_scale_y_fp \l_@@_top_dim
- \@@_resize_common:N #1
- }
-\cs_new_protected:Npn \@@_resize:NNN #1#2#3
- {
- \dim_set:Nn #1
- { \fp_to_dim:n { \fp_abs:n { #2 } * \dim_to_fp:n { #3 } } }
- }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}
-% {
-% \box_resize_to_ht:Nn, \box_resize_to_ht:cn,
-% \box_gresize_to_ht:Nn, \box_gresize_to_ht:cn
-% }
-% \begin{macro}{\@@_resize_to_ht:NnN}
-% \begin{macro}
-% {
-% \box_resize_to_ht_plus_dp:Nn, \box_resize_to_ht_plus_dp:cn,
-% \box_gresize_to_ht_plus_dp:Nn, \box_gresize_to_ht_plus_dp:cn
-% }
-% \begin{macro}{\@@_resize_to_ht_plus_dp:NnN}
-% \begin{macro}
-% {
-% \box_resize_to_wd:Nn, \box_resize_to_wd:cn,
-% \box_gresize_to_wd:Nn, \box_gresize_to_wd:cn
-% }
-% \begin{macro}{\@@_resize_to_wd:NnN}
-% \begin{macro}
-% {
-% \box_resize_to_wd_and_ht:Nnn, \box_resize_to_wd_and_ht:cnn,
-% \box_gresize_to_wd_and_ht:Nnn, \box_gresize_to_wd_and_ht:cnn
-% }
-% \begin{macro}{\@@_resize_to_wd_ht:NnnN}
-% Scaling to a (total) height or to a width is a simplified version of the main
-% resizing operation, with the scale simply copied between the two parts. The
-% internal auxiliary is called using the scaling value twice, as the sign for
-% both parts is needed (as this allows the same internal code to be used as
-% for the general case).
-% \begin{macrocode}
-\cs_new_protected:Npn \box_resize_to_ht:Nn #1#2
- { \@@_resize_to_ht:NnN #1 {#2} \hbox_set:Nn }
-\cs_generate_variant:Nn \box_resize_to_ht:Nn { c }
-\cs_new_protected:Npn \box_gresize_to_ht:Nn #1#2
- { \@@_resize_to_ht:NnN #1 {#2} \hbox_gset:Nn }
-\cs_generate_variant:Nn \box_gresize_to_ht:Nn { c }
-\cs_new_protected:Npn \@@_resize_to_ht:NnN #1#2#3
- {
- #3 #1
- {
- \@@_resize_set_corners:N #1
- \fp_set:Nn \l_@@_scale_y_fp
- {
- \dim_to_fp:n {#2}
- / \dim_to_fp:n { \l_@@_top_dim }
- }
- \fp_set_eq:NN \l_@@_scale_x_fp \l_@@_scale_y_fp
- \@@_resize:N #1
- }
- }
-\cs_new_protected:Npn \box_resize_to_ht_plus_dp:Nn #1#2
- { \@@_resize_to_ht_plus_dp:NnN #1 {#2} \hbox_set:Nn }
-\cs_generate_variant:Nn \box_resize_to_ht_plus_dp:Nn { c }
-\cs_new_protected:Npn \box_gresize_to_ht_plus_dp:Nn #1#2
- { \@@_resize_to_ht_plus_dp:NnN #1 {#2} \hbox_gset:Nn }
-\cs_generate_variant:Nn \box_gresize_to_ht_plus_dp:Nn { c }
-\cs_new_protected:Npn \@@_resize_to_ht_plus_dp:NnN #1#2#3
- {
- #3 #1
- {
- \@@_resize_set_corners:N #1
- \fp_set:Nn \l_@@_scale_y_fp
- {
- \dim_to_fp:n {#2}
- / \dim_to_fp:n { \l_@@_top_dim - \l_@@_bottom_dim }
- }
- \fp_set_eq:NN \l_@@_scale_x_fp \l_@@_scale_y_fp
- \@@_resize:N #1
- }
- }
-\cs_new_protected:Npn \box_resize_to_wd:Nn #1#2
- { \@@_resize_to_wd:NnN #1 {#2} \hbox_set:Nn }
-\cs_generate_variant:Nn \box_resize_to_wd:Nn { c }
-\cs_new_protected:Npn \box_gresize_to_wd:Nn #1#2
- { \@@_resize_to_wd:NnN #1 {#2} \hbox_gset:Nn }
-\cs_generate_variant:Nn \box_gresize_to_wd:Nn { c }
-\cs_new_protected:Npn \@@_resize_to_wd:NnN #1#2#3
- {
- #3 #1
- {
- \@@_resize_set_corners:N #1
- \fp_set:Nn \l_@@_scale_x_fp
- { \dim_to_fp:n {#2} / \dim_to_fp:n { \l_@@_right_dim } }
- \fp_set_eq:NN \l_@@_scale_y_fp \l_@@_scale_x_fp
- \@@_resize:N #1
- }
- }
-\cs_new_protected:Npn \box_resize_to_wd_and_ht:Nnn #1#2#3
- { \@@_resize_to_wd_and_ht:NnnN #1 {#2} {#3} \hbox_set:Nn }
-\cs_generate_variant:Nn \box_resize_to_wd_and_ht:Nnn { c }
-\cs_new_protected:Npn \box_gresize_to_wd_and_ht:Nnn #1#2#3
- { \@@_resize_to_wd_and_ht:NnnN #1 {#2} {#3} \hbox_gset:Nn }
-\cs_generate_variant:Nn \box_gresize_to_wd_and_ht:Nnn { c }
-\cs_new_protected:Npn \@@_resize_to_wd_and_ht:NnnN #1#2#3#4
- {
- #4 #1
- {
- \@@_resize_set_corners:N #1
- \fp_set:Nn \l_@@_scale_x_fp
- { \dim_to_fp:n {#2} / \dim_to_fp:n { \l_@@_right_dim } }
- \fp_set:Nn \l_@@_scale_y_fp
- {
- \dim_to_fp:n {#3}
- / \dim_to_fp:n { \l_@@_top_dim }
- }
- \@@_resize:N #1
- }
- }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}
-% {
-% \box_scale:Nnn, \box_scale:cnn,
-% \box_gscale:Nnn, \box_gscale:cnn
-% }
-% \begin{macro}{\@@_scale:NnnN}
-% \begin{macro}{\@@_scale:N}
-% When scaling a box, setting the scaling itself is easy enough. The
-% new dimensions are also relatively easy to find, allowing only for
-% the need to keep them positive in all cases. Once that is done then
-% after a check for the trivial scaling a hand-off can be made to the
-% common code. The code here is split into two as this allows sharing
-% with the auto-resizing functions.
-% \begin{macrocode}
-\cs_new_protected:Npn \box_scale:Nnn #1#2#3
- { \@@_scale:NnnN #1 {#2} {#3} \hbox_set:Nn }
-\cs_generate_variant:Nn \box_scale:Nnn { c }
-\cs_new_protected:Npn \box_gscale:Nnn #1#2#3
- { \@@_scale:NnnN #1 {#2} {#3} \hbox_gset:Nn }
-\cs_generate_variant:Nn \box_gscale:Nnn { c }
-\cs_new_protected:Npn \@@_scale:NnnN #1#2#3#4
- {
- #4 #1
- {
- \fp_set:Nn \l_@@_scale_x_fp {#2}
- \fp_set:Nn \l_@@_scale_y_fp {#3}
- \@@_scale:N #1
- }
- }
-\cs_new_protected:Npn \@@_scale:N #1
- {
- \dim_set:Nn \l_@@_top_dim { \box_ht:N #1 }
- \dim_set:Nn \l_@@_bottom_dim { -\box_dp:N #1 }
- \dim_set:Nn \l_@@_right_dim { \box_wd:N #1 }
- \dim_zero:N \l_@@_left_dim
- \dim_set:Nn \l_@@_top_new_dim
- { \fp_abs:n { \l_@@_scale_y_fp } \l_@@_top_dim }
- \dim_set:Nn \l_@@_bottom_new_dim
- { \fp_abs:n { \l_@@_scale_y_fp } \l_@@_bottom_dim }
- \dim_set:Nn \l_@@_right_new_dim
- { \fp_abs:n { \l_@@_scale_x_fp } \l_@@_right_dim }
- \@@_resize_common:N #1
- }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}
-% {
-% \box_autosize_to_wd_and_ht:Nnn ,
-% \box_autosize_to_wd_and_ht:cnn ,
-% \box_gautosize_to_wd_and_ht:Nnn ,
-% \box_gautosize_to_wd_and_ht:cnn ,
-% \box_autosize_to_wd_and_ht_plus_dp:Nnn ,
-% \box_autosize_to_wd_and_ht_plus_dp:cnn ,
-% \box_gautosize_to_wd_and_ht_plus_dp:Nnn ,
-% \box_gautosize_to_wd_and_ht_plus_dp:cnn
-% }
-% \begin{macro}{\@@_autosize:NnnnN}
-% Although autosizing a box uses dimensions, it has more in common in
-% implementation with scaling. As such, most of the real work here is
-% done elsewhere.
-% \begin{macrocode}
-\cs_new_protected:Npn \box_autosize_to_wd_and_ht:Nnn #1#2#3
- { \@@_autosize:NnnnN #1 {#2} {#3} { \box_ht:N #1 } \hbox_set:Nn }
-\cs_generate_variant:Nn \box_autosize_to_wd_and_ht:Nnn { c }
-\cs_new_protected:Npn \box_gautosize_to_wd_and_ht:Nnn #1#2#3
- { \@@_autosize:NnnnN #1 {#2} {#3} { \box_ht:N #1 } \hbox_gset:Nn }
-\cs_generate_variant:Nn \box_gautosize_to_wd_and_ht:Nnn { c }
-\cs_new_protected:Npn \box_autosize_to_wd_and_ht_plus_dp:Nnn #1#2#3
- {
- \@@_autosize:NnnnN #1 {#2} {#3} { \box_ht:N #1 + \box_dp:N #1 }
- \hbox_set:Nn
- }
-\cs_generate_variant:Nn \box_autosize_to_wd_and_ht_plus_dp:Nnn { c }
-\cs_new_protected:Npn \box_gautosize_to_wd_and_ht_plus_dp:Nnn #1#2#3
- {
- \@@_autosize:NnnnN #1 {#2} {#3} { \box_ht:N #1 + \box_dp:N #1 }
- \hbox_gset:Nn
- }
-\cs_generate_variant:Nn \box_gautosize_to_wd_and_ht_plus_dp:Nnn { c }
-\cs_new_protected:Npn \@@_autosize:NnnnN #1#2#3#4#5
- {
- #5 #1
- {
- \fp_set:Nn \l_@@_scale_x_fp { ( \dim_to_fp:n {#2} ) / \box_wd:N #1 }
- \fp_set:Nn \l_@@_scale_y_fp
- { ( \dim_to_fp:n {#3} ) / ( \dim_to_fp:n {#4} ) }
- \fp_compare:nNnTF \l_@@_scale_x_fp > \l_@@_scale_y_fp
- { \fp_set_eq:NN \l_@@_scale_x_fp \l_@@_scale_y_fp }
- { \fp_set_eq:NN \l_@@_scale_y_fp \l_@@_scale_x_fp }
- \@@_scale:N #1
- }
- }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}{\@@_resize_common:N}
-% The main resize function places its input into a box which start
-% off with zero width, and includes the handles for engine rescaling.
-% \begin{macrocode}
-\cs_new_protected:Npn \@@_resize_common:N #1
- {
- \hbox_set:Nn \l_@@_internal_box
- {
- \@@_backend_scale:Nnn
- #1
- \l_@@_scale_x_fp
- \l_@@_scale_y_fp
- }
-% \end{macrocode}
-% The new height and depth can be applied directly.
-% \begin{macrocode}
- \fp_compare:nNnTF \l_@@_scale_y_fp > \c_zero_fp
- {
- \box_set_ht:Nn \l_@@_internal_box { \l_@@_top_new_dim }
- \box_set_dp:Nn \l_@@_internal_box { -\l_@@_bottom_new_dim }
- }
- {
- \box_set_dp:Nn \l_@@_internal_box { \l_@@_top_new_dim }
- \box_set_ht:Nn \l_@@_internal_box { -\l_@@_bottom_new_dim }
- }
-% \end{macrocode}
-% Things are not quite as obvious for the width, as the reference point
-% needs to remain unchanged. For positive scaling factors resizing the
-% box is all that is needed. However, for case of a negative scaling
-% the material must be shifted such that the reference point ends up in
-% the right place.
-% \begin{macrocode}
- \fp_compare:nNnTF \l_@@_scale_x_fp < \c_zero_fp
- {
- \hbox_to_wd:nn { \l_@@_right_new_dim }
- {
- \__kernel_kern:n { \l_@@_right_new_dim }
- \box_use_drop:N \l_@@_internal_box
- \tex_hss:D
- }
- }
- {
- \box_set_wd:Nn \l_@@_internal_box { \l_@@_right_new_dim }
- \hbox:n
- {
- \__kernel_kern:n { 0pt }
- \box_use_drop:N \l_@@_internal_box
- \tex_hss:D
- }
- }
- }
-% \end{macrocode}
-% \end{macro}
-%
-% \subsection{Viewing part of a box}
-%
-% \begin{macro}{\box_set_clipped:N, \box_set_clipped:c, \box_gset_clipped:N, \box_gset_clipped:c}
-% A wrapper around the driver-dependent code.
-% \begin{macrocode}
-\cs_new_protected:Npn \box_set_clipped:N #1
- { \hbox_set:Nn #1 { \@@_backend_clip:N #1 } }
-\cs_generate_variant:Nn \box_set_clipped:N { c }
-\cs_new_protected:Npn \box_gset_clipped:N #1
- { \hbox_gset:Nn #1 { \@@_backend_clip:N #1 } }
-\cs_generate_variant:Nn \box_gset_clipped:N { c }
-% \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}
-% {
-% \box_set_trim:Nnnnn, \box_set_trim:cnnnn,
-% \box_gset_trim:Nnnnn, \box_gset_trim:cnnnn
-% }
-% \begin{macro}{\@@_set_trim:NnnnnN}
-% Trimming from the left- and right-hand edges of the box is easy: kern the
-% appropriate parts off each side.
-% \begin{macrocode}
-\cs_new_protected:Npn \box_set_trim:Nnnnn #1#2#3#4#5
- { \@@_set_trim:NnnnnN #1 {#2} {#3} {#4} {#5} \box_set_eq:NN }
-\cs_generate_variant:Nn \box_set_trim:Nnnnn { c }
-\cs_new_protected:Npn \box_gset_trim:Nnnnn #1#2#3#4#5
- { \@@_set_trim:NnnnnN #1 {#2} {#3} {#4} {#5} \box_gset_eq:NN }
-\cs_generate_variant:Nn \box_gset_trim:Nnnnn { c }
-\cs_new_protected:Npn \@@_set_trim:NnnnnN #1#2#3#4#5#6
- {
- \hbox_set:Nn \l_@@_internal_box
- {
- \__kernel_kern:n { -#2 }
- \box_use:N #1
- \__kernel_kern:n { -#4 }
- }
-% \end{macrocode}
-% For the height and depth, there is a need to watch the baseline is
-% respected. Material always has to stay on the correct side, so trimming
-% has to check that there is enough material to trim. First, the bottom
-% edge. If there is enough depth, simply set the depth, or if not move
-% down so the result is zero depth. \cs{box_move_down:nn} is used in both
-% cases so the resulting box always contains a \tn{lower} primitive.
-% The internal box is used here as it allows safe use of \cs{box_set_dp:Nn}.
-% \begin{macrocode}
- \dim_compare:nNnTF { \box_dp:N #1 } > {#3}
- {
- \hbox_set:Nn \l_@@_internal_box
- {
- \box_move_down:nn \c_zero_dim
- { \box_use_drop:N \l_@@_internal_box }
- }
- \box_set_dp:Nn \l_@@_internal_box { \box_dp:N #1 - (#3) }
- }
- {
- \hbox_set:Nn \l_@@_internal_box
- {
- \box_move_down:nn { (#3) - \box_dp:N #1 }
- { \box_use_drop:N \l_@@_internal_box }
- }
- \box_set_dp:Nn \l_@@_internal_box \c_zero_dim
- }
-% \end{macrocode}
-% Same thing, this time from the top of the box.
-% \begin{macrocode}
- \dim_compare:nNnTF { \box_ht:N \l_@@_internal_box } > {#5}
- {
- \hbox_set:Nn \l_@@_internal_box
- {
- \box_move_up:nn \c_zero_dim
- { \box_use_drop:N \l_@@_internal_box }
- }
- \box_set_ht:Nn \l_@@_internal_box
- { \box_ht:N \l_@@_internal_box - (#5) }
- }
- {
- \hbox_set:Nn \l_@@_internal_box
- {
- \box_move_up:nn { (#5) - \box_ht:N \l_@@_internal_box }
- { \box_use_drop:N \l_@@_internal_box }
- }
- \box_set_ht:Nn \l_@@_internal_box \c_zero_dim
- }
- #6 #1 \l_@@_internal_box
- }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}
-% {
-% \box_set_viewport:Nnnnn, \box_set_viewport:cnnnn,
-% \box_gset_viewport:Nnnnn, \box_gset_viewport:cnnnn
-% }
-% \begin{macro}{\@@_viewport:NnnnnN}
-% The same general logic as for the trim operation, but with absolute
-% dimensions. As a result, there are some things to watch out for in the
-% vertical direction.
-% \begin{macrocode}
-\cs_new_protected:Npn \box_set_viewport:Nnnnn #1#2#3#4#5
- { \@@_set_viewport:NnnnnN #1 {#2} {#3} {#4} {#5} \box_set_eq:NN }
-\cs_generate_variant:Nn \box_set_viewport:Nnnnn { c }
-\cs_new_protected:Npn \box_gset_viewport:Nnnnn #1#2#3#4#5
- { \@@_set_viewport:NnnnnN #1 {#2} {#3} {#4} {#5} \box_gset_eq:NN }
-\cs_generate_variant:Nn \box_gset_viewport:Nnnnn { c }
-\cs_new_protected:Npn \@@_set_viewport:NnnnnN #1#2#3#4#5#6
- {
- \hbox_set:Nn \l_@@_internal_box
- {
- \__kernel_kern:n { -#2 }
- \box_use:N #1
- \__kernel_kern:n { #4 - \box_wd:N #1 }
- }
- \dim_compare:nNnTF {#3} < \c_zero_dim
- {
- \hbox_set:Nn \l_@@_internal_box
- {
- \box_move_down:nn \c_zero_dim
- { \box_use_drop:N \l_@@_internal_box }
- }
- \box_set_dp:Nn \l_@@_internal_box { - \@@_dim_eval:n {#3} }
- }
- {
- \hbox_set:Nn \l_@@_internal_box
- { \box_move_down:nn {#3} { \box_use_drop:N \l_@@_internal_box } }
- \box_set_dp:Nn \l_@@_internal_box \c_zero_dim
- }
- \dim_compare:nNnTF {#5} > \c_zero_dim
- {
- \hbox_set:Nn \l_@@_internal_box
- {
- \box_move_up:nn \c_zero_dim
- { \box_use_drop:N \l_@@_internal_box }
- }
- \box_set_ht:Nn \l_@@_internal_box
- {
- (#5)
- \dim_compare:nNnT {#3} > \c_zero_dim
- { - (#3) }
- }
- }
- {
- \hbox_set:Nn \l_@@_internal_box
- {
- \box_move_up:nn { - \@@_dim_eval:n {#5} }
- { \box_use_drop:N \l_@@_internal_box }
- }
- \box_set_ht:Nn \l_@@_internal_box \c_zero_dim
- }
- #6 #1 \l_@@_internal_box
- }
-% \end{macrocode}
-% \end{macro}
-% \end{macro}
-
-%
-% \begin{macrocode}
-%</package>
-% \end{macrocode}
-%
-% \end{implementation}
-%
-% \PrintIndex