summaryrefslogtreecommitdiff
path: root/Master/texmf-dist/source/latex/tools/afterpage.dtx
blob: 284b5b167496891a13541858cc5a0bad87030c44 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
% \iffalse meta-comment
%
% Copyright 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
% The LaTeX3 Project and any individual authors listed elsewhere
% in this file. 
% 
% This file is part of the Standard LaTeX `Tools Bundle'.
% -------------------------------------------------------
% 
% It may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either version 1.3c
% of this license or (at your option) any later version.
% The latest version of this license is in
%    http://www.latex-project.org/lppl.txt
% and version 1.3c or later is part of all distributions of LaTeX 
% version 2005/12/01 or later.
% 
% The list of all files belonging to the LaTeX `Tools Bundle' is
% given in the file `manifest.txt'.
% 
% \fi
% \iffalse
%% File: afterpage.dtx Copyright (C) 1994 1994 1995 David Carlisle
%
%<package>\NeedsTeXFormat{LaTeX2e}
%<package>\ProvidesPackage{afterpage}
%<package>         [1995/10/27 v1.08 After-Page Package (DPC)]
%
%<*driver>
\documentclass{ltxdoc}
\usepackage{afterpage}
\GetFileInfo{afterpage.sty}
\begin{document}
\title{The \textsf{afterpage} package\thanks{This file
        has version number \fileversion, last
        revised \filedate.}}
\author{David Carlisle\\carlisle@cs.man.ac.uk}
\date{\filedate}
\maketitle
\DocInput{afterpage.dtx}
\end{document}
%</driver>
% \fi
%
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% \changes{v1.00}{1993/01/25}{Initial version}
% \changes{v1.05}{1993/07/14}{First public version}
% \changes{v1.06}{1994/02/01}{Update for LaTeX2e}
% \changes{v1.07}{1994/05/23}{Documentation Changes}
% \changes{v1.08}{1995/10/27}
%      {Use \cs{par} not \cs{endgraf}, for tools/1579}
% \changes{v1.08}{1995/10/27}
%      {Try and do something sensible with nested \cs{clearpage},
%       for tools/1880}
% \changes{v1.08}{1995/10/27}
%      {Try and do something sensible with footnotes, for tools/1884}
%
% \CheckSum{269}
%
% This package implements a command, |\afterpage|, that causes the
% commands specified in its argument to be expanded after the curent
% page is output.\footnote{This is really a pre-release, to see whether
% people like the idea of a command like this. This implementation is
% \emph{not} particularly robust. This implementation does not work in
% two column mode, and can get `confused' by \LaTeX's floating
% environments.}
%
% \begin{enumerate}
% \item Sometimes \LaTeX's float positioning mechanism gets overloaded,
% and all floating |figure|s and |table|s drift to the end of the
% document. One may flush out all the unprocessed floats by issuing a
% |\clearpage| command, but this has the effect of making the current
% page end prematurely. Now you can issue |\afterpage{\clearpage}| and
% the current page will be filled up with text as usual, but then a
% |\clearpage| command will flush out all the floats before the next
% text page begins.
% \item An earlier mechanism to help with float placement was the
% optional argument |[H]| (meaning {\bf HERE!}) which was originally
% added to the standard floating environments by |here.sty|, and is now
% provided by |float.sty|. However some |[H]| users have commented that
% they did not really mean `Here!' They actually wanted `Somewhere
% close'. This can now be achieved by\\
%  |\afterpage{\clearpage\begin{figure}[H] |\ldots
%  |\end{figure}}|\\
% This ensures that the figure is at the top of the next page. (The
% |\clearpage| stops any other figures drifting past the |[H]| figure.)
% \item Floating longtables. |longtable.sty| provides the |longtable|
% environment, a multi-page version of |tabular|. Many |longtable| users
% have told me that it is difficult to set the text surrounding the long
% table, and that they wanted a `floating' version. As, presumably,
% |longtable|s are long, they are probably too large to hold in memory,
% and float in the way that the |table| environment is floated, however
% if the table is in a separate file, say |ltfile.tex|, you can now
% use one of:\\
% |\afterpage{\clearpage\input{ltfile}}|\\
% |\afterpage{\clearpage\input{ltfile}\clearpage}|.\\
% The first form lets text apear on the same page as the end of the
% longtable, the second ensures that the surrounding text starts again
% on a new page.
% \end{enumerate}
%
% \StopEventually{}
%
%    \begin{macrocode}
%<*package>
%    \end{macrocode}
%
% \begin{macro}{\afterpage}
% The token register used to save the old output routine.
%    \begin{macrocode}
\newtoks\AP@output
\global\AP@output\expandafter{\the\output}
%    \end{macrocode}
%
% A box register used to save any part of the next page which has
% already been processed.
%    \begin{macrocode}
\newbox\AP@partial
%    \end{macrocode}
%
% A box register used to save any footnote texts that are `tied' to
% the text that gets saved in |\AP@partial|.
%    \begin{macrocode}
\newbox\AP@footins
%    \end{macrocode}
%
% The following macro attempts to get safely into vertical mode, and
% then invokes a special output routine to grab the current page into
% |\AP@partial|.
%    \begin{macrocode}
\def\AP@savetop{%
%    \end{macrocode}
% Now begins a test to see what state we are in. |\AP@noindent|  will
% be defined so as to return to this state (well, almost!) after
% afterpage has finished.
%    \begin{macrocode}
  \ifvmode
%    \end{macrocode}
% Vertical mode. This is the simplest case, do nothing.
%    \begin{macrocode}
    \let\AP@noindent\empty
  \else\ifhmode
%    \end{macrocode}
% Horizontal mode.
% `Back out' into vertical mode, removing the indentation box as we go.
% If in fact there was no indentation box, the output routine was
% invoked by |\noindent| (what bad luck!) so we have to remember to
% re-insert the |\noindent| before the paragraph is seen again.
% |\everypar| tokens have already been inserted, so don't insert them
% again.
%    \begin{macrocode}
    \setbox\z@\lastbox
    \edef\AP@noindent
      {{\everypar{}\ifvoid\z@\noindent\else\indent\fi}}%
    \par
  \else
%    \end{macrocode}
% The remaining (even worse) possibility that the ouput routine
% was triggered by the start of displaymath within a paragraph.
%
% Come out of displaymath with |$$|, then adjust the spacing (getting
% into vmode at the same time). |\AP@noindent| will restart display math
% later. |\everydisplay| tokens have already been inserted (they apply
% to the math list that will be started by |\AP@noindent|, even though
% they were triggered by the display math that was closed by the lines
% below!). Save the values |\prevgraf| and |\predisplaysize| for use in
% the re-started math list.
%    \begin{macrocode}
    \abovedisplayshortskip\z@\abovedisplayskip\z@
    \belowdisplayshortskip\z@\belowdisplayskip\z@
    \xdef\AP@disp{%
      \predisplaysize\the\predisplaysize
      \prevgraf\the\prevgraf\relax}%
    $$\vskip-\baselineskip\vskip-\parskip
    \edef\AP@noindent{%
%    \end{macrocode}
% Do not insert |\everydisplay| tokens again.
%    \begin{macrocode}
      \toks@{\the\everydisplay}\everydisplay{}%
%    \end{macrocode}
% Start displaymath mode with no spurious paragraph line above it.
% Restore |\prevgraf| and |\predisplaysize|.  Use |\aftergroup| to
% restore the correct setting for |\everydisplay| after this display
% has finished.
%    \begin{macrocode}
      {\everypar{}\noindent}$$\AP@disp\aftergroup\noexpand\AP@ed}%
  \fi\fi
%    \end{macrocode}
% Now switch the  output routine and remove everything from the current
% page into the box |\AP@partial|.
%    \begin{macrocode}
  \begingroup
  \nointerlineskip\null
    \output{%
      \global\setbox\AP@partial\vbox{%
        \unvbox\@cclv
         \global\setbox\@ne\lastbox}%
%    \end{macrocode}
% If the text that is saved in |\AP@partial| had footnotes, we'd
% better grab them as well otherwise they may come out on a page
% with the `afterpage' text, before the page that has the
% footnote mark! (Added at v1.08.)
%    \begin{macrocode}
       \global\setbox\AP@footins\box\footins}%
%    \end{macrocode}
% Having defined the output routine, trigger it\ldots
%    \begin{macrocode}
  \eject
  \endgroup}
%    \end{macrocode}
%
% |\AP@| stores all the commands that must be executed after the page
% break.
%    \begin{macrocode}
\let\AP@\relax
%    \end{macrocode}
%
% Restore the |\everydisplay| register. |\ignorespaces| prevents a space
% or newline after |$$| creating rogue a indentation or paragraph.
%    \begin{macrocode}
\def\AP@ed{\everydisplay\expandafter{\the\toks@}\ignorespaces}
%    \end{macrocode}
%
% Remove the current vertical list, insert the commands |\AP@|
% at the top of the page, and then re-insert the saved text.
%    \begin{macrocode}
\def\AP@@{%
  \AP@savetop
  \global\expandafter\let\expandafter\AP@\expandafter\relax\AP@
  \par
%    \end{macrocode}
% The text originally at the top of this page is now stored in the box
% |\AP@partial|, including  |\topskip| glue. Now we want to unbox
% |\AP@partial|, placing the baseline of the first row |\baselineskip|
% below the baseline of the last line coming from the afterpage text.
% If we assumed nothing has too much height or depth (and |\topskip| is
% rigid), it would be fairly trivial to position the contents of
% |\AP@partial| so that the baseline of the first row was
% |\baselineskip| below the last row just added.
%
% In this version, I thought it might be fun to try to exactly achieve
% the |\baselineskip|--or--|\lineskip| calculation that \TeX\ normally
% does internally.  The call to |\addboxcontents| does the right thing
% (I hope).
%    \begin{macrocode}
   \addboxcontents\AP@partial
%    \end{macrocode}
% Now re-insert any footnote text. This may not be quite the right
% place, as the text that has just been unboxed may break over a page
% in its new position. Also it may not be the right number if the text
% from |\afterpage| itself contains footnotes. Too bad!
%    \begin{macrocode}
  \ifvoid\AP@footins\else
         \insert\footins{\unvbox\AP@footins}\fi
%    \end{macrocode}
% Now repair things if we started off in horizontal mode.
%    \begin{macrocode}
  \AP@noindent}
%    \end{macrocode}
%
% If |\AP@| is not |\relax| then the current page already has some
% `afterpage' commands, so just add the new commands to the end of the
% list. Otherwise save the commands in |\AP@|. (within a local group),
% and switch the output routine. (The new output routine just calls the
% old one if it is invoked by a \LaTeX{} float.
%    \begin{macrocode}
\long\def\afterpage#1{%
  \ifx\AP@\relax
    \gdef\AP@{{#1\par}}%
    \global\output{%
      \the\AP@output
      \ifnum\outputpenalty>-\@Mi
        \global\output\expandafter{\the\AP@output}%
        \aftergroup\AP@@
      \fi}%
  \else
    \expandafter\gdef\expandafter\AP@\expandafter{\AP@{#1\par}}%
  \fi}
%    \end{macrocode}
%
% If we have got to the end of the document or clearpage
% just put the stuff out  without any trickery.
%    \begin{macrocode}
\let\AP@clearpage\clearpage
\def\clearpage{%
  \ifx\AP@\relax
    \AP@clearpage
  \else
    \global\output\expandafter{\the\AP@output}%
    \AP@clearpage
%    \end{macrocode}
% At this point (since v1.08) Need to clear |\AP@| \emph{before}
% using its expansion, as otherwise hit an infinite loop. Sigh.
%    \begin{macrocode}
    \global\expandafter\let\expandafter\AP@\expandafter\relax
    \expandafter\expandafter\AP@
  \fi}
\let\AP@enddocument\enddocument
\def\enddocument{%
  \ifx\AP@\relax\else
    \global\output\expandafter{\the\AP@output}%
    \AP@clearpage
    \global\expandafter\let\expandafter\AP@\expandafter\relax
    \expandafter\expandafter\AP@
  \fi
    \AP@enddocument}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\addboxcontents}
% Given a vbox |#1|, add to the current vertical list such that the end
% result is equivalent to the list that \TeX\ would have built had the
% contents of |#1| (apart from any initial glue) been added individually
% to the current list.

% So essentially, the problem is that of unboxing |#1|, but replacing
% the glue at the top of |#1| with (something equivalent to) the
% |\baselineskip| or |\lineskip| glue that \TeX\ would normally have
% placed before the first box in |#1|. Also |\prevdepth| must be set at
% the end.
%    \begin{macrocode}
\def\addboxcontents#1{{%
%    \end{macrocode}
% Perhaps I shouldnt use grouping here, as I probably don't really want
% to save |#1|. If it is removed, |\splittopskip| and |\splitmaxdepth|
% would need to be restored by hand.
%
% First replace any glue at the top by |\vskip 0pt|.
%    \begin{macrocode}
  \splittopskip\z@
  \splitmaxdepth\maxdimen
  \setbox#1\vbox{\break\unvbox#1}%
  \setbox\z@\vsplit#1to\z@
%    \end{macrocode}
% Put the breakpoint back.
%    \begin{macrocode}
  \setbox#1\vbox{\break\unvbox#1}%
%    \end{macrocode}
% Set |\skip@| to be height of |#1| (without top glue)
%    \begin{macrocode}
  \skip@\ht#1%
%    \end{macrocode}
% Now make the first baseline of the first row be |\vsize| from the top.
% (This assumes that the first row has height less than |\vsize|.)
%    \begin{macrocode}
  \splittopskip\vsize
  \setbox\z@\vsplit#1to\z@
%    \end{macrocode}
% Subtract the new height of |#1| from |\skip@|, and add back on
% |\splittopskip|, so |\skip@| is now the height of the first row of
% |#1| This may still be 0pt if (eg) a mark or whatsit is between the
% top glue and the first box. Save (this height${}-{}$|\splittopskip|)
% in |\skip\tw@|.
%    \begin{macrocode}
  \advance\skip@-\ht#1%
  \skip\tw@\skip@
  \advance\skip@\splittopskip
%    \end{macrocode}
% Now fake \TeX's |\baselineskip| calculation.
%    \begin{macrocode}
  \advance\skip@\prevdepth
  \advance\skip@-\baselineskip
  \advance\skip\tw@\ifdim-\skip@<\lineskiplimit\lineskip\else-\skip@\fi
%    \end{macrocode}
% Finally add the glue.
%    \begin{macrocode}
  \vskip\skip\tw@
%    \end{macrocode}
% Now unbox the box, setting |\prevdepth| by hand, as |\unvbox| (unlike
% |\box|) does not automatically set it.
%    \begin{macrocode}
  \global\dimen@i\dp#1%
  \unvbox#1}%
  \prevdepth\dimen@i}
%    \end{macrocode}
% \end{macro}
%
%    \begin{macrocode}
%</package>
%    \end{macrocode}
%
% \Finale
%