summaryrefslogtreecommitdiff
path: root/Master/texmf-dist/source/latex/changepage/changepage.tex
blob: 9ec3c1898459337b04773638e215174dca095cee (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
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592

%%%%%%%%%1%%%%%%%%%2%%%%%%%%%3%%%%%%%%%4%%%%%%%%%5
% Please see the accompanying README for author,
% license, documentation and installation information
%%%%%%%%%1%%%%%%%%%2%%%%%%%%%3%%%%%%%%%4%%%%%%%%%5

\RequirePackage{filecontents}
\begin{filecontents}{changepage.sty}
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{changepage}[2009/10/20 v1.0c check page and change page layout]

% Don't use this with memoir
\newcommand*{\cp@whoopsusingmemoir}{}
\@ifclassloaded{memoir}{\def\cp@whoopsusingmemoir{\endinput}}
\cp@whoopsusingmemoir

% New \verb|\if| for the strict option
\newif\ifstrictpagecheck
  \strictpagecheckfalse

% User commands for switching strict page checking on/off
\newcommand*{\strictpagecheck}{\strictpagechecktrue}
\newcommand*{\easypagecheck}{\strictpagecheckfalse}

% Declare and process options
\DeclareOption{strict}{\strictpagechecktrue}
\ProcessOptions\relax

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% New commands for strict checking of odd/even page.
%% Works by writing a label and then checking its pageref.

\newif\ifoddpage
\newcounter{cp@cntr}
\newcount\cp@tempcnt % instead of  \verb|\@memcnta|
\newcommand{\cplabel}{^_}

\gdef\thepmemc@@page{\the\c@page}

\long\def\pmemprotected@write#1#2#3{% modified  \verb|\protected@write|
  \begingroup
  \let\thepmemc@@page\relax
  #2%
  \let\protect\@unexpandable@protect
  \edef\reserved@a{\write#1{#3}}%
  \reserved@a
  \endgroup
  \if@nobreak\ifvmode\nobreak\fi\fi}

\newcommand*{\pmemlabel}[1]{\@bsphack
  \pmemprotected@write\@auxout{}%
    {\string\newpmemlabel{#1}{\thepmemc@@page}}%
  \@esphack}

\newcommand*{\newpmemlabel}[2]{{\global\@namedef{m@#1}{#2}}}
\newcommand*{\pmemlabelref}[1]{%
  \expandafter\ifx\csname m@#1\endcsname\relax
    0%   % 0 if there is no label yet in the aux file
  \else
    \csname m@#1\endcsname
  \fi}

\DeclareRobustCommand{\checkoddpage}{%
  \oddpagefalse%
  \ifstrictpagecheck%
    \stepcounter{cp@cntr}\pmemlabel{\cplabel\thecp@cntr}%
    \cp@tempcnt=\pmemlabelref{\cplabel\thecp@cntr}\relax
    \ifodd\cp@tempcnt\oddpagetrue\fi
  \else
    \ifodd\c@page\oddpagetrue\fi
  \fi}

% End newcommands for strict checking of odd/even page.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% Copy of some of the code from the ifmtarg package to save requiring ifmtarg
\begingroup
\catcode`\Q=3
\long\gdef\@ifmtarg#1{\@xifmtarg#1QQ\@secondoftwo\@firstoftwo\@nil}
\long\gdef\@xifmtarg#1#2Q#3#4#5\@nil{#4}
\endgroup

% Set the page output parameters
\DeclareRobustCommand{\ch@ngetext}{%
  \setlength{\@colht}{\textheight}\setlength{\@colroom}{\textheight}%
  \setlength{\vsize}{\textheight}\setlength{\columnwidth}{\textwidth}%
  \if@twocolumn%
    \advance\columnwidth-\columnsep \divide\columnwidth\tw@%
    \@firstcolumntrue%
  \fi%
  \setlength{\hsize}{\columnwidth}%
  \setlength{\linewidth}{\hsize}}

\DeclareRobustCommand{\changetext}[5]{%
  \@ifmtarg{#1}{}{\addtolength{\textheight}{#1}}%
  \@ifmtarg{#2}{}{\addtolength{\textwidth}{#2}}%
  \@ifmtarg{#3}{}{\addtolength{\evensidemargin}{#3}}%
  \@ifmtarg{#4}{}{\addtolength{\oddsidemargin}{#4}}%
  \@ifmtarg{#5}{}{\addtolength{\columnsep}{#5}}%
  \ch@ngetext}

\DeclareRobustCommand{\changepage}[9]{%
  \@ifmtarg{#1}{}{\addtolength{\textheight}{#1}}%
  \@ifmtarg{#2}{}{\addtolength{\textwidth}{#2}}%
  \@ifmtarg{#3}{}{\addtolength{\evensidemargin}{#3}}%
  \@ifmtarg{#4}{}{\addtolength{\oddsidemargin}{#4}}%
  \@ifmtarg{#5}{}{\addtolength{\columnsep}{#5}}%
  \ch@ngetext%
  \@ifmtarg{#6}{}{\addtolength{\topmargin}{#6}}%
  \@ifmtarg{#7}{}{\addtolength{\headheight}{#7}}%
  \@ifmtarg{#8}{}{\addtolength{\headsep}{#8}}%
  \@ifmtarg{#9}{}{\addtolength{\footskip}{#9}}}

\newenvironment{adjustwidth}[2]{%
  \begin{list}{}{%
    \topsep\z@%
    \listparindent\parindent%
    \parsep\parskip%
    \@ifmtarg{#1}{\setlength{\leftmargin}{\z@}}%
                 {\setlength{\leftmargin}{#1}}%
    \@ifmtarg{#2}{\setlength{\rightmargin}{\z@}}%
                 {\setlength{\rightmargin}{#2}}%
    }
    \item[]}{\end{list}}

\newenvironment{adjustwidth*}[2]{%
  \begin{list}{}{%
    \topsep\z@%
    \listparindent\parindent%
    \parsep\parskip%
    \checkoddpage
    \ifoddpage%     odd numbered page
      \@ifmtarg{#1}{\setlength{\leftmargin}{\z@}}%
                   {\setlength{\leftmargin}{#1}}%
      \@ifmtarg{#2}{\setlength{\rightmargin}{\z@}}%
                   {\setlength{\rightmargin}{#2}}%
    \else%          even numbered page
      \@ifmtarg{#2}{\setlength{\leftmargin}{\z@}}%
                   {\setlength{\leftmargin}{#2}}%
      \@ifmtarg{#1}{\setlength{\rightmargin}{\z@}}%
                   {\setlength{\rightmargin}{#1}}%
    \fi}
    \item[]}{\end{list}}

\endinput

\end{filecontents}
%%%%%%%%%1%%%%%%%%%2%%%%%%%%%3%%%%%%%%%4%%%%%%%%%5




\begin{filecontents}{chngpage.sty}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% PLEASE NOTE:
% THIS PACKAGE IS DEPRECATED IN FAVOUR OF CHANGEPAGE.STY FOR REASONS
% OF COMPATIBILITY WITH THE MEMOIR CLASS. The two are equivalent;
% please do not use this one for new documents or packages.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{chngpage}[2009/10/20 v1.2b change page layout]

%% Note: internal package commands all include the string |cp@|.
%% New \cs{if} for the strict option.
\newif\ifcpstrict
  \cpstrictfalse

%% Declare and process options.
\DeclareOption{strict}{\cpstricttrue}
\ProcessOptions\relax

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% New commands for strict checking of odd/even page.
% Works by writing a label and then checking its pageref.
%
% Rewritten in v1.2 to handle roman, Roman, etc page numbers
% as well as arabic; also eliminates special code to handle
% hyperref. Based on the code in the memoir class.

\newif\ifcpoddpage
\newcounter{cp@cnt}
\newcounter{cp@tempcnt}
\newcommand{\cplabelprefix}{^_}

\gdef\thecp@page{\the\c@page}
\long\def\cp@protected@write#1#2#3{%  % modified \cs{protected@write}
  \begingroup
  \let\thecp@page\relax
  #2%
  \let\protect\@unexpandable@protect
  \edef\reserved@a{\write#1{#3}}%
  \reserved@a
  \endgroup
  \if@nobreak\ifvmode\nobreak\fi\fi}

\DeclareRobustCommand{\checkoddpage}{%
  \cpoddpagefalse
  \stepcounter{cp@cnt}\cplabel{\cplabelprefix\thecp@cnt}%
  \c@cp@tempcnt=\cp@labelref{\cplabelprefix\thecp@cnt}\relax
  \ifodd\c@cp@tempcnt\cpoddpagetrue\fi}

\newcommand{\cplabel}[1]{\@bsphack
  \cp@protected@write\@auxout{}%
    {\string\newcplabel{#1}{\thecp@page}}%
  \@esphack}

\newcommand{\newcplabel}[2]{{\global\@namedef{p@#1}{#2}}}

\newcommand{\cp@labelref}[1]{%
  \expandafter\ifx\csname p@#1\endcsname\relax
    0%  % 0 if there is no label yet in aux file
  \else
    \csname p@#1\endcsname
  \fi}

% End newcommands for strict checking of odd/even page.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% Copy of some of the code from the ifmtarg package to save requiring ifmtarg.
\begingroup
\catcode`\Q=3
\long\gdef\@ifmtarg#1{\@xifmtarg#1QQ\@secondoftwo\@firstoftwo\@nil}
\long\gdef\@xifmtarg#1#2Q#3#4#5\@nil{#4}
\endgroup

% Set the page output parameters.
\DeclareRobustCommand{\ch@ngetext}{%
  \setlength{\@colht}{\textheight}\setlength{\@colroom}{\textheight}%
  \setlength{\vsize}{\textheight}\setlength{\columnwidth}{\textwidth}%
  \if@twocolumn%
    \advance\columnwidth-\columnsep \divide\columnwidth\tw@%
    \@firstcolumntrue%
  \fi%
  \setlength{\hsize}{\columnwidth}%
  \setlength{\linewidth}{\hsize}%
}

\DeclareRobustCommand{\changetext}[5]{%
  \@ifmtarg{#1}{}{\addtolength{\textheight}{#1}}%
  \@ifmtarg{#2}{}{\addtolength{\textwidth}{#2}}%
  \@ifmtarg{#3}{}{\addtolength{\evensidemargin}{#3}}%
  \@ifmtarg{#4}{}{\addtolength{\oddsidemargin}{#4}}%
  \@ifmtarg{#5}{}{\addtolength{\columnsep}{#5}}%
  \ch@ngetext%
}

\DeclareRobustCommand{\changepage}[9]{%
  \@ifmtarg{#1}{}{\addtolength{\textheight}{#1}}%
  \@ifmtarg{#2}{}{\addtolength{\textwidth}{#2}}%
  \@ifmtarg{#3}{}{\addtolength{\evensidemargin}{#3}}%
  \@ifmtarg{#4}{}{\addtolength{\oddsidemargin}{#4}}%
  \@ifmtarg{#5}{}{\addtolength{\columnsep}{#5}}%
  \ch@ngetext%
  \@ifmtarg{#6}{}{\addtolength{\topmargin}{#6}}%
  \@ifmtarg{#7}{}{\addtolength{\headheight}{#7}}%
  \@ifmtarg{#8}{}{\addtolength{\headsep}{#8}}%
  \@ifmtarg{#9}{}{\addtolength{\footskip}{#9}}%
}


\newenvironment{adjustwidth}[3][\@empty]{%
  \begin{list}{}{%
    \topsep\z@%
    \listparindent\parindent%
    \parsep\parskip%
    \@ifmtarg{#2}{\setlength{\leftmargin}{\z@}}{\setlength{\leftmargin}{#2}}%
    \@ifmtarg{#3}{\setlength{\rightmargin}{\z@}}{\setlength{\rightmargin}{#3}}%
    \ifx\@empty #1\relax \else
      \cpoddpagefalse
      \ifcpstrict\checkoddpage\else
        \ifodd\c@page\cpoddpagetrue\fi
      \fi
      \ifcpoddpage\else  % even numbered page
        \@ifmtarg{#3}{\setlength{\leftmargin}{\z@}}{\setlength{\leftmargin}{#3}}%
        \@ifmtarg{#2}{\setlength{\rightmargin}{\z@}}{\setlength{\rightmargin}{#2}}%
      \fi
    \fi}
    \item[]}{\end{list}}

\endinput
\end{filecontents}
%%%%%%%%%1%%%%%%%%%2%%%%%%%%%3%%%%%%%%%4%%%%%%%%%5



% Conditionally compile the documentation & generate the .ins file:
\providecommand\changepageCompile{Y}
\makeatletter
\if\changepageCompile N
  \expandafter\@@end
\fi



\begin{filecontents*}{changepage.ins}
%&latex
\def\changepageCompile{N}
\input changepage.tex
\csname@@end\endcsname
\end{filecontents*}




\makeatletter
\documentclass{article}

\usepackage[it,medium]{titlesec}

\usepackage{bigfoot,xcolor}
\usepackage[colorlinks,linktocpage]{hyperref}

\usepackage{gmdoc}
\usepackage{gmverb}
\dekclubs
\stanzaskip=\bigskipamount 
\CodeSpacesGrey

\usepackage{tocloft,varwidth}
\setcounter{tocdepth}{1}
\def\tocwidthA{0.55}
\def\tocwidthB{0.44}
\def\cftpartfont{\scshape}
\def\cftsecfont{\small}
\cftbeforesecskip=0pt
\def\cftpartleader{}
\def\cftpartafterpnum{\cftparfillskip}
\def\cftsecleader{}
\def\cftsecafterpnum{\cftparfillskip}

\DeclareRobustCommand\pkg{\textsf}
\def\pkgopt#1{\texttt{[#1]}}
\newcommand\chng[1]{\marginpar{\footnotesize\raggedright\textsf{#1}}}

\def\PDF{\textsc{pdf}}
\def\PS{\textsc{ps}}
\def\DVI{\textsc{dvi}}
\def\EPS{\textsc{eps}}

\usepackage{amsmath,listings}
\lstset{basicstyle=\ttfamily,columns=fullflexible}

\begingroup
  \usepackage{chngpage}
  \GetFileInfo{chngpage.sty}
  \global\let\chngpagev\fileversion
\endgroup
\usepackage{changepage}
\usepackage[T1]{fontenc}
\usepackage{microtype}
\usepackage{lmodern}
\usepackage[sc,osf]{mathpazo}
\linespread{1.1}
\frenchspacing

\GetFileInfo{changepage.sty}
\begin{document}
{\addtocontents{toc}{\protect\begin{varwidth}[t]{\tocwidthA\linewidth}}}

\title{The \pkg{changepage} and \pkg{chngpage} packages}
\author{%
 Author: Peter Wilson, Herries Press\\
 Maintainer: Will Robertson\\
 \texttt{will dot robertson at latex-project dot org}%
}
\date{\chngpagev\ and \fileversion, \filedate}

\maketitle

\begin{abstract}
\noindent Provides command
|\ifoddpage| to detect the current page `side',
environment |adjustwidth| to locally change the margins of the text,
and commands |\changetext| and |\changepage| for more
radical changes to the page design mid-way through a document.

\pkg{changepage} is the new version of \pkg{chngpage} to be
compatible with \pkg{memoir}. \pkg{chngpage} is now deprecated
for this reason.
\end{abstract}

\tableofcontents

\part{User documentation}

Load the package like this:
\begin{verbatim}
\usepackage[strict]{changepage}
\end{verbatim}
Or for deprecated uses:
\begin{verbatim}
\usepackage[strict]{chngpage}
\end{verbatim}

\section{Detecting odd or even pages}

The |\checkoddpage| command can be used anywhere in the body of
a document to determine if \TeX\ is typesetting on an odd or
even numbered page. If on an odd page then |\ifoddpage| is
set \meta{true}, otherwise (on an even page) |\ifoddpage| is set
\meta{false}.

\chng{Use \cs{ifcpoddpage} instead if you're using chngpage.}

Strict page checking works by the |\checkoddpage| command generating 
a label and then checking the |\pageref| for the label (actually, a special 
version of |\pageref| is required and is used internally by |\checkoddpage|). 
This mechanism requires at least two \LaTeX\ passes to ensure that 
the labels have settled (on the initial pass there will be no labels
in the *.aux file to be checked).

The label identifier is composed of the command |\cplabel|
and an automatically generated number. |\cplabel|, initially
defined as `|^_|', can be changed in the preamble if it will cause
a clash with any author-defined labels. The default labels will
be of the form `|^_|\meta{N}' where \meta{N} is a positive integer.

\chng{For chngpage, use \cs{cplabelprefix} instead of \cs{cplabel}.}

The package option `strict' turns on strict page checking --- the default
is not to use strict checking. Strict page checking can be turned on or 
off at any time by the commands |\strictpagecheck| or |\easypagecheck|.
The easy page check just tests the page number to see if it is odd or even, 
which does not always give the correct result because of \TeX's asynchronous
output mechanism.


\section{Adjusting the margins}

Within an |adjustwidth| environment the left and right margins can be
adjusted. The environment takes two required length arguments: 
\begin{quote}
\cs{begin}|{adjustwidth}|\marg{leftmargin}\marg{rightmargin}
\end{quote}
A positive length value will increase the relevant margin (shortening
the text lines) while a negative length value will decrease the margin
(lengthening text lines). An empty length argument means no change
to the margin. At the end of the environment the margins revert to
their original values.

For example, to extend the text into the right margin:
\begin{quote}
|\begin{adjustwidth}{}{-8em}|
\end{quote}
The starred version, |adjustwidth*|, causes the values of the
margins to switch between odd and even pages.

\chng{For chngpage use \cs{begin}\texttt{\{adjustwidth\}[]}
instead of \cs{begin}\texttt{\{adjustwidth*\}}.}

For example, if the document is being set twosided it might be
advantageous to have any wider text extending into the outside
margin:
\begin{quote}
|\begin{adjustwidth*}{}{-8em}|
\end{quote}
To have the adjusted text horizontally centered with respect to
any surrounding text, the margins should be adjusted equally:
\begin{quote}
|\begin{adjustwidth}{-4em}{-4em}|
\end{quote}
For interest, \cs{begin}|{quotation}| is pretty much equivalent to 
\begin{quote}
|\begin{adjustwidth}{2.5em}{2.5em}|
\end{quote}
The environment may also be used inside a float if the contents are
a bit too wide for the text block, but can still fit within the physical
page:
\begin{verbatim}
\begin{figure}
  \begin{adjustwidth}{-2em}{-2em}
     \includegraphics{wide}
     \caption{Wide figure}
  \end{adjustwidth}
\end{figure}
\end{verbatim}
Sometimes, because of the asynchronous nature of the TeX output
routine, the margin switching may be incorrect (like |\marginpar| sometimes)
near the top of a page. This can be corrected by using the package
option `strict' (i.e., |\usepackage[strict]{chngpage}|), which causes
adjustwidth to use the |\checkoddpage| command (see below).

A disadvantage of the strict option is that the package generates
a new label for each adjustwidth environment, and \TeX\ may run out
of space if there are an excessive number of labels in the document.

Whether or not the strict option is used, `strict adjustwidths'
can be turned on by putting the command |\strictpagecheck| before
the environment, and turned off by using |\easypagecheck|.

\chng{In chngpage, use \cs{cpstricttrue} and \cs{cpstricttrue}
instead of \cs{strictpagecheck} and \cs{easypagecheck}.}

\textsc{note:}
In a twocolumn document, the adjustwidth environment 
treats both columns equally. For example, if the width is meant
to be wider at the outer margin, then on odd pages the extra width
will be at the right of any column, and on even pages the extra
will be at the left of any column. You can get interesting effects
by careful hand tuning on two column pages.


\section{Changing the text block}

The |\changetext| command is for changing the size and horizontal position
of the text block on a page. The command takes 5 arguments, each of which 
is a length or is empty. i.e.,
\begin{quote}
\cmd\changetext\marg{text height}\marg{text width}\marg{even-side margin}
\newline\null\hfill\marg{odd-side margin}\marg{column sep.}
\end{quote}
The given lengths are added to the corresponding current lengths and
the remainder of the current page is typeset using the changed text block 
layout. The new layout remains in effect until another |\change...| command 
is issued.


\section{Changing the entire page design}

The |\changepage| command is for changing the general layout of
a page. The command takes 9 arguments, each of which is a length or is empty. 
The first 5 arguments are the same as for |\changetext| and have the same effect.
The last four arguments are:
\begin{quote}
\cmd\changepage\meta{5 args}\marg{topmargin}\marg{headheight}\marg{headsep}\marg{footskip}
\end{quote}
These lengths are added to the corresponding current lengths and
thus modify the vertical positions of the elements of the page. The
remainder of the current page is typeset using the changed text block 
and page layout. The new layout remains in effect until another 
|\change...| command is issued.

\begin{itemize}
\item[\textsc{note} 1] Not supplying a value for a length argument is equivalent
         to giving it a zero length value.

\item[\textsc{note} 2] For any given page, everything is constant except for the textwidth
         and columnsep (for example, what is the meaning of two
         topmargins on a single column page?).
         It is therefore best to change anything else at the
         start of a new page. Further, any changes only apply to whole
         paragraphs. If you want an odd shaped paragraph use either
         the \pkg{hanging} package or the \TeX\ |\parshape| command.
\end{itemize}
For example, to change from single column pages to double column
pages where the text block is both shorter and wider, then to revert
back to the initial layout:
\begin{verbatim}
... single column normal page
\newpage % or \clearpage
\changetext{-5\baselineskip}{10em}{-5em}{-5em}{}
\twocolumn
... two column pages
\clearpage 
\changetext{5\baselineskip}{-10em}{5em}{5em}{}
\onecolumn
... normal pages
\end{verbatim}
Note the adjustments to the margins which will keep the vertical centerline
of the textblock at the same position on the page.

As another example, to increase the width of a single paragraph:
\begin{verbatim}
\changetext{0pt}{5em}{}{}{}%
Start of wider paragraph text ...
... end of paragraph.

\changetext{0pt}{-5em}{}{}{}
Start of a normal paragraph ...
\end{verbatim}
Under some circumstances you can include a |\change...| command as part of
the argument to |\afterpage| (from the \pkg{afterpage} package) and it may work.
Similarly it may work in a heading style used for |\thispagestyle| to change
a single page.

{\addtocontents{toc}{\protect\end{varwidth}\protect\hfill}}
{\addtocontents{toc}{\protect\begin{varwidth}[t]{\protect\tocwidthB\protect\linewidth}}}
\clearpage
\parindent=0pt

\part{Implementation}
\section{The \pkg{changepage} package}
\DocInput{changepage.sty}

\clearpage
\section{The \pkg{chngpage} package}
\DocInput{chngpage.sty}

{\addtocontents{toc}{\protect\end{varwidth}}}

\end{document}