<html><head><meta name="color-scheme" content="light dark"></head><body><pre style="word-wrap: break-word; white-space: pre-wrap;">% -*- coding: utf-8 -*-
% This is part of the book TeX for the Impatient.
% Copyright (C) 2003 Paul W. Abrahams, Kathryn A. Hargreaves, Karl Berry.
% See file fdl.tex for copying conditions.

\input macros
%\chapter {Commands for \linebreak composing pages}
\chapter {ç»„é¡µå‘½ä»¤}

\chapterdef{pages}

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æœ¬ç«&nbsp;å†™ä½œæƒ¯ä¾‹çš„è¯´æ˜Žå¯ä»¥åœ¨\headcit{å‘½ä»¤æè¿°}{cmddesc}ä¸­æ‰¾åˆ°.

\begindescriptions

%==========================================================================
%\section {Interline and interparagraph spaces}
\section {è¡Œé—´è·å’Œæ®µé—´è·}

\begindesc
\cts baselineskip {\param{glue}}
\cts lineskiplimit {\param{dimen}}
\cts lineskip {\param{glue}}
\explain
%^^{line spacing}
%\bix^^{interline glue}
%\bix^^|\baselineskip|
%\bix^^|\lineskip|
%\bix^^|\lineskiplimit|
%These three parameters jointly determine how much space \TeX\ leaves between
%consecutive \minref{box}es of an ordinary \minref{vertical list},
%e.g., the lines of a paragraph.
%This space is called ``\minref{interline glue}''.
%It is also inserted between the component boxes of a vbox constructed in
%internal vertical mode.
%^^{vboxes//interline glue for}
%
%In the usual case, when the boxes aren't abnormally high or deep, \TeX\
%makes the distance from the baseline of one box to the baseline of the
%next one equal to |\baselineskip|.  It does this by inserting interline
%glue equal to |\baselineskip| minus the depth of the upper box (as given
%by ^|\prevdepth|) and the height of the lower box.  But if this
%interline glue would be less than |\lineskiplimit|, indicating that the
%two boxes are too close together, \TeX\ inserts the |\lineskip| glue
%instead.\footnote
%{\TeX\ actually accounts for the beginning of a
%vertical list by setting |\prevdepth| to $-1000$\pt\ and testing
%|\prevdepth| before \emph{every} box.  If |\prevdepth|$\&gt;\le-1000$\pt\
%it does not insert any interline glue.} See \knuth{pages~79--80} for a
%precise description.
%
%Note that |\baselineskip| and |\lineskip| measure \emph{different
%things}: the distance between baselines on the one hand and the distance
%between the bottom of one box and the top of the next box on the other
%hand.  See \knuth{page~78} for further details.  The first example below
%shows the effects of |\lineskiplimit|.
%
%You can obtain the effect of ^{double spacing} by doubling the value
%of |\baselineskip| as illustrated in the second example below.
%A change to |\baselineskip| at any point before the end of a paragraph affects
%the entire paragraph.
^^{è¡Œé—´è·}
\bix^^{è¡Œé—´ç²˜è¿ž}
\bix^^|\baselineskip|
\bix^^|\lineskip|
\bix^^|\lineskiplimit|
åœ¨ä¸€ä¸ªæ™®é€š\minref{ç«–ç›´åˆ—}ï¼ˆä¾‹å¦‚æ®µè½å„è¡Œï¼‰ä¸­ï¼Œ
è¿™ä¸‰ä¸ªå‚æ•°å…±åŒç¡®å®šäº† \TeX\ åœ¨ç›¸é‚»ä¸¤ä¸ª\minref{ç›’å­}é—´æ’å…¥çš„é—´éš”ã€‚
è¿™ä¸ªé—´éš”ç§°ä¸ºâ€œ\minref{è¡Œé—´ç²˜è¿ž}â€ã€‚
å¯¹äºŽå†…éƒ¨ç«–ç›´æ¨¡å¼ä¸­æž„é€&nbsp;çš„ç«–ç›´ç›’å­ï¼Œå…¶ä¸­çš„ç»„æˆç›’å­é—´åŒæ&nbsp;·ä¼šæœ‰æ­¤é—´éš”ã€‚
^^{ç«–ç›´ç›’å­//ç«–ç›´ç›’å­çš„è¡Œé—´ç²˜è¿ž}

åœ¨é€šå¸¸æƒ…å†µä¸‹ï¼Œç›’å­çš„é«˜åº¦å’Œæ·±åº¦ä¸ä¼šå¤ªå¤§ï¼Œ
æ­¤æ—¶ \TeX\ è®©ç›¸é‚»ç›’å­çš„ä¸¤åŸºçº¿è·ç¦»ç­‰äºŽ |\baselineskip|ã€‚
ä¸ºæ­¤å¯ä»¥è®©è¡Œé—´ç²˜è¿žç­‰äºŽ |\baselineskip| å‡åŽ»ä¸Šç›’å­æ·±åº¦ï¼ˆç”± ^|\prevdepth| ç»™å‡ºï¼‰%
å’Œä¸‹ç›’å­é«˜åº¦ã€‚
ä½†å¦‚æžœä¸¤ä¸ªç›’å­é&nbsp;å¾—å¤ªè¿‘ï¼Œå³è¡Œé—´ç²˜è¿žå°äºŽ |\lineskiplimit|ï¼Œ
\TeX\ å°†æ”¹ä¸ºæ’å…¥ |\lineskip| å¤§å°çš„é—´è·ã€‚\negthinspace\footnote
{\TeX\ å®žé™…ä¸Šåœ¨ç«–ç›´åˆ—å¼€å¤´è®¾å®š |\prevdepth| ä¸º $-1000$\pt ï¼Œ
ä»Žè€Œå¯ä»¥æµ‹å®š\emph{æ¯ä¸ª}ç›’å­çš„ |\prevdepth|ã€‚
è‹¥ |\prevdepth|$\&gt;\le-1000$\pt ï¼Œ
å®ƒå°±ä¸ä¼šæ’å…¥ä»»ä½•è¡Œé—´ç²˜è¿žã€‚}è¯¦æƒ…å¯è§ \knuth{ç¬¬~79--80~é¡µ}ã€‚

æ³¨æ„ |\baselineskip| å’Œ |\lineskip| æµ‹é‡\emph{ä¸åŒçš„ä¸œè¥¿}ï¼š
å‰è€…ä¸ºä¸¤ç›’å­åŸºçº¿ä¹‹é—´çš„è·ç¦»ï¼Œ
è€ŒåŽè€…ä¸ºä¸Šç›’å­åº•éƒ¨å’Œä¸‹ç›’å­é¡¶éƒ¨çš„è·ç¦»ã€‚
è¯¦æƒ…å¯çœ‹ \knuth{ç¬¬~78~é¡µ}ã€‚
ä¸‹é¢ç¬¬ä¸€ä¸ªä¾‹å­å±•ç¤ºäº†|\lineskiplimit| çš„ä½œç”¨ã€‚

å¦‚ä¸‹é¢ç¬¬äºŒä¸ªä¾‹å­æ‰€ç¤ºï¼Œå°† |\baselineskip| åŠ&nbsp;å€ï¼Œ
å°±èƒ½å¾—åˆ°^{åŒå€è¡Œè·}çš„æ•ˆæžœã€‚
åœ¨æ®µè½ç»“æŸå‰ä»»ä½•ä½ç½®æ”¹å˜ |\baselineskip|ï¼Œéƒ½ä¼šå½±å“æ•´ä¸ªæ®µè½ã€‚
\example
\baselineskip = 11pt \lineskiplimit = 1pt
\lineskip = 2pt plus .5pt
Sometimes you'll need to typeset a paragraph that has
tall material, such as a mathematical formula,  embedded
within it.  An example of such a formula is $n \choose k$.
Note the extra space above and below this line as
compared with the other lines.
(If the formula didn't project below the line,
we'd only get extra space above the line.)
|
\produces
\baselineskip = 11pt \lineskiplimit = 1pt
\lineskip = 2pt plus .5pt
Sometimes you'll need to typeset a paragraph that has
tall material, such as a mathematical formula,  embedded
within it.  An example of such a formula is $n \choose k$.
Note the extra space above and below this line as
compared with the other lines.
(If the formula didn't project below the line,
we'd only get extra space above the line.)
\endexample

\example
\baselineskip = 2\baselineskip % Start double spacing.
|
\endexample

%\eix^^{interline glue}
%\eix^^|\baselineskip|
%\eix^^|\lineskip|
%\eix^^|\lineskiplimit|
%\enddesc
\eix^^{è¡Œé—´ç²˜è¿ž}
\eix^^|\baselineskip|
\eix^^|\lineskip|
\eix^^|\lineskiplimit|
\enddesc

\begindesc
\cts prevdepth {\param{dimen}}
\explain
%When \TeX\ adds a box to a vertical list, it sets |\prevdepth| to the
%depth of that box.  \TeX\ sets |\prevdepth| to $-1000$\pt\ at the start
%of a vertical list, indicating that the usual interline glue should be
%suppressed.
å½“ \TeX\ å°†ç›’å­æ·»åŠ&nbsp;åˆ°ç«–ç›´åˆ—æ—¶ï¼Œå®ƒè®¾å®š |\prevdepth| ä¸ºè¯¥ç›’å­çš„æ·±åº¦ã€‚
åœ¨ç«–ç›´åˆ—çš„å¼€å§‹ï¼Œ \TeX\ è®¾å®š |\prevdepth| ä¸º $-1000$\pt\ ï¼Œè¿™è¡¨ç¤ºä¸æ·»åŠ&nbsp;è¡Œé—´ç²˜è¿žã€‚
\enddesc

\begindesc
\cts normalbaselineskip {\param{glue}}
\cts normallineskiplimit {\param{dimen}}
\cts normallineskip {\param{glue}}
\cts normalbaselines {}
\explain
%The three parameters contain values for |\base!-line!-skip|,
%|\line!-skip|, and |\line!-skip!-limit| respectively.
%^^|\baselineskip| ^^|\lineskip| ^^|\lineskiplimit|
%The |\normalbaselines| command sets |\base!-line!-skip|,
%|\line!-skip|, and |\line!-skip!-limit| to the values contained in the
%three parameters.
å‰ä¸‰ä¸ªå‚æ•°åˆ†åˆ«åŒ…å« |\base!-line!-skip|ï¼Œ|\line!-skip| å’Œ |\line!-skip!-limit| çš„å€¼ã€‚
^^|\baselineskip| ^^|\lineskip| ^^|\lineskiplimit|
è€Œ |\normalbaselines| å‘½ä»¤å°† |\base!-line!-skip|ï¼Œ|\line!-skip| å’Œ |\line!-skip!-limit|
åˆ†åˆ«è®¾å®šä¸ºè¿™ä¸‰ä¸ªå‚æ•°çš„å€¼ã€‚
\enddesc

\begindesc
\cts offinterlineskip {}
\explain
%This command tells \TeX\ to stop inserting interline glue from
%now on.  Unless you want it to be in effect for the rest of the document
%(which you probably don't), you should enclose it in a group
%together with the text you want it to affect.
%Its main purpose is to let you do interline spacing yourself,
%e.g., using ^{struts},
%without interference from \TeX's normal interline glue.
%|\offinterlineskip| is often useful when
%you're constructing a horizontal \minref{alignment}.
%^^{alignments//using \b\tt\\offinterlineskip\e\ in}
æ­¤å‘½ä»¤è®© \TeX\ ä»Žæ­¤ä¹‹åŽåœæ­¢æ’å…¥è¡Œé—´ç²˜è¿žã€‚é™¤éžä½&nbsp;å¸Œæœ›å¯¹æ–‡æ¡£çš„å‰©ä½™éƒ¨åˆ†éƒ½ç”Ÿæ•ˆï¼ˆä½&nbsp;å¤šåŠä¸å¸Œæœ›ï¼‰ï¼Œ
ä½&nbsp;åº”è¯¥å°†æ­¤å‘½ä»¤å’Œä½&nbsp;å¸Œæœ›ç”Ÿæ•ˆçš„æ–‡æœ¬æ”¾åœ¨ä¸€ä¸ªç¼–ç»„ä¸­ã€‚
å®ƒçš„ä¸»è¦ç”¨å¤„åœ¨äºŽå¯ä»¥è®©ä½&nbsp;è‡ªå·±å¤„ç†è¡Œé—´ç©ºéš™ï¼Œæ¯”å¦‚ç”¨^{æ”¯æž¶}ï¼ˆstrutsï¼‰ï¼Œ
è€Œä¸å½±å“ \TeX\ çš„æ­£å¸¸è¡Œé—´ç²˜è¿žã€‚åœ¨æž„é€&nbsp;æ°´å¹³\minref{é˜µåˆ—}æ—¶ç»å¸¸ä¼šç”¨åˆ°|\offinterlineskip|ã€‚
^^{é˜µåˆ—//åœ¨å…¶ä¸­ä½¿ç”¨ \b\tt\\offinterlineskip\e}
\example
\def\entry#1:#2 {\strut\quad#1\quad&amp;\quad#2\quad\cr}
\offinterlineskip \tabskip = 0pt \halign{%
\vrule\quad\hfil#\hfil\quad\vrule&amp;
   \quad\hfil#\hfil\quad\vrule\cr
\noalign{\hrule}
\vphantom{\vrule height 2pt}&amp;\cr \noalign{\hrule}
\entry \it Opera:\it Composer
\vphantom{\vrule height 2pt}&amp;\cr \noalign{\hrule}
\vphantom{\vrule height 2pt}&amp;\cr
\entry Fidelio:Beethoven
\entry Peter Grimes:Britten
\entry Don Giovanni:Mozart
\vphantom{\vrule height 2pt}&amp;\cr \noalign{\hrule}}
|
\produces
\medskip
\def\entry#1:#2 {\strut\quad#1\quad&amp;\quad#2\quad\cr}
\offinterlineskip \tabskip = 0pt \halign{%
\vrule\quad\hfil#\hfil\quad\vrule&amp;
   \quad\hfil#\hfil\quad\vrule\cr
\noalign{\hrule}
\vphantom{\vrule height 2pt}&amp;\cr \noalign{\hrule}
\entry \it Opera:\it Composer
\vphantom{\vrule height 2pt}&amp;\cr \noalign{\hrule}
\vphantom{\vrule height 2pt}&amp;\cr
\entry Fidelio:Beethoven
\entry Peter Grimes:Britten
\entry Don Giovanni:Mozart
\vphantom{\vrule height 2pt}&amp;\cr \noalign{\hrule}}
\endexample
\enddesc

\begindesc
\cts nointerlineskip {}
\explain
%This command tells \TeX\ not to insert interline glue in front of the
%next line.
%It has no effect on subsequent lines.
æ­¤å‘½ä»¤è®© \TeX\ åœæ­¢åœ¨ä¸‹ä¸€è¡Œæ’å…¥è¡Œé—´ç²˜è¿žã€‚å®ƒä¸å½±å“åŽç»­å…¶ä»–è¡Œã€‚
\enddesc

\begindesc
\cts openup {\&lt;dimen&gt;}
\explain
%This command increases ^|\baselineskip| by \&lt;dimen&gt;.
%An |\openup| command before the end of a paragraph affects
%the entire paragraph, so you shouldn't use |\openup| to
%change |\baseline!-skip| within a paragraph.  |\openup| is
%most useful for typesetting tables and math displays---a
%little extra space between rows often makes them more readable.
%^^{alignments//space between rows of}
æ­¤å‘½ä»¤è®© ^|\baselineskip| å¢žåŠ&nbsp; \&lt;dimen&gt;ã€‚
åœ¨æ®µå°¾ä¹‹å‰çš„ |\openup| å‘½ä»¤å°†å½±å“æ•´ä¸ªæ®µè½ï¼Œ
å›&nbsp;æ­¤æƒ³åœ¨æ®µè½ä¸­é—´æ”¹å˜ |\baseline!-skip| æ—¶ä¸è¦ç”¨ |\openup| å‘½ä»¤ã€‚
åœ¨æŽ’ç‰ˆè¡¨æ&nbsp;¼å’Œé™ˆåˆ—å…¬å¼æ—¶ |\openup| éžå¸¸æœ‰ç”¨â€”â€”å¤šç‚¹é—´éš”å°†ä¼šå¢žåŠ&nbsp;å®ƒä»¬çš„å¯è¯»æ€§ã€‚
^^{é˜µåˆ—//å„è¡Œä¹‹é—´çš„é—´éš”}
\example
Alice picked up the White King very gently, and lifted him
across more slowly than she had lifted the Queen; but before
she put him on the table, she thought she might well dust
him a little, he was so covered with ashes.
\openup .5\baselineskip % 1.5 linespacing.
|
\produces
Alice picked up the White King very gently, and lifted him
across more slowly than she had lifted the Queen; but before
she put him on the table, she thought she might well dust
him a little, he was so covered with ashes.
\openup .5\baselineskip %1.5 linespacing
\endexample\enddesc

%==========================================================================
\section{åˆ†é¡µ} %\section {Page breaks}

%==========================================================================
%\subsection {Encouraging or discouraging page breaks}
\subsection{é¼“åŠ±æˆ–é˜»ç¢åˆ†é¡µ}

%\begindesc
%\bix^^{page breaks}
%\bix^^{page breaks//encouraging or discouraging}
%\ctspecial break {} \xrdef{vbreak}
%\explain
\begindesc
\bix^^{åˆ†é¡µ}
\bix^^{åˆ†é¡µ//é¼“åŠ±æˆ–é˜»ç¢åˆ†é¡µ}
\ctspecial break {} \xrdef{vbreak}
\explain
%
\margin{Four commands identical to ones for line breaks (\xref{hbreak})
have been added to correct an omission. The descriptions are exactly parallel.}
%
%This command forces a page break.
%Unless you do something to fill out the page, you're likely to
%get an underfull vbox.
%|\break| can also be used in horizontal mode.
æ­¤å‘½ä»¤å¼ºåˆ¶åœ¨æ­¤å¤„åˆ†é¡µã€‚é™¤éžç”¨æŸç§æ–¹å¼å¡«æ»¡è¯¥é¡µï¼Œä½&nbsp;å°†å¾—åˆ°ä¸€ä¸ªæ¾æ•£çš„ vboxã€‚
|\break| ä¹Ÿèƒ½ç”¨åœ¨æ°´å¹³æ¨¡å¼ä¸­ã€‚
\enddesc

\begindesc
\ctspecial nobreak {} \xrdef{vnobreak}
\explain
%This command prevents a page break where it
%otherwise might occur.
%|\nobreak| can also be used in horizontal mode.
æ­¤å‘½ä»¤é˜»æ­¢åœ¨æ­¤å¤„åˆ†é¡µã€‚
|\nobreak| ä¹Ÿèƒ½ç”¨åœ¨æ°´å¹³æ¨¡å¼ä¸­ã€‚
\enddesc

\begindesc
\ctspecial allowbreak {} \xrdef{vallowbreak}
\explain
%This command tells \TeX\ to
%allow a page break where one could not ordinarily occur.
%|\allowbreak| can also be used in horizontal mode.
åœ¨é€šå¸¸ä¸åˆ†é¡µçš„åœ°æ–¹å…è®¸ \TeX\ åˆ†é¡µã€‚
|\allowbreak| ä¹Ÿèƒ½ç”¨åœ¨æ°´å¹³æ¨¡å¼ä¸­ã€‚
\enddesc

\begindesc
\ctspecial penalty {\&lt;number&gt;} \xrdef{vpenalty}
\explain
%This command produces a \minref{penalty} item.
%The penalty item makes \TeX\ more or less willing to break a page
%at the point where that item occurs.
%A negative penalty, i.e., a bonus, encourages a page break;
%a positive penalty discourages a page break.
%A penalty of $10000$ or more prevents a break altogether,
%while a penalty of $-10000$ or less forces a break.
%|\penalty| can also be used in horizontal mode.
æ­¤å‘½ä»¤ç”Ÿæˆä¸€ä¸ªæƒ©ç½šï¼ˆ\minref{penalty}ï¼‰é¡¹ã€‚
æƒ©ç½šé¡¹ä½¿å¾— \TeX\ æˆ–å¤šæˆ–å°‘æ„¿æ„åœ¨æ­¤å¤„åˆ†é¡µã€‚
è´Ÿæƒ©ç½šå€¼ï¼Œå®žé™…ä¸Šæ˜¯å¥–åŠ±å€¼ï¼Œé¼“åŠ±åˆ†é¡µï¼›æ­£æƒ©ç½šå€¼é˜»ç¢åˆ†é¡µã€‚
å¤§äºŽæˆ–ç­‰äºŽ $10000$ çš„æƒ©ç½šå€¼å½»åº•é˜»æ­¢åˆ†é¡µï¼Œ
è€Œå°äºŽæˆ–ç­‰äºŽ $-10000$ çš„æƒ©ç½šå€¼å¼ºåˆ¶åˆ†é¡µã€‚
æ­¤å‘½ä»¤ä¹Ÿèƒ½ç”¨äºŽæ°´å¹³æ¨¡å¼ã€‚
\example
\def\break{\penalty-10000 } % as in plain TeX
\def\nobreak{\penalty10000 } % as in plain TeX
\def\allowbreak{\penalty0 } % as in plain TeX
|
\endexample
\enddesc

\begindesc
\cts goodbreak {}
\explain
%This command ends a paragraph and also indicates to \TeX\ that
%this is a good place to break the page.
æ­¤å‘½ä»¤ç»“æŸå½“å‰æ®µè½ï¼Œå¹¶å‘Šè¯‰ \TeX\ è¿™é‡Œæ˜¯ä¸€ä¸ªåˆé€‚çš„åˆ†é¡µä½ç½®ã€‚
\enddesc

\begindesc
\cts smallbreak {}
\cts medbreak {}
\cts bigbreak {}
\explain
%These commands indicate increasingly desirable places for \TeX\ to
%break a page.  They also cause \TeX\ to
%insert a ^|\smallskip|, ^|\medskip|, or
%^|\bigskip| (\xref \smallskip) if the page break doesn't actually
%happen.  \TeX\ suppresses this skip if it occurs just after an
%equal or larger skip.
è¿™äº›å‘½ä»¤æŒ‡æ˜Žäº†è¶Šæ¥è¶Šåˆé€‚çš„åˆ†é¡µä½ç½®ã€‚å¦‚æžœå®žé™…ä¸Šæ²¡åœ¨æ­¤å¤„åˆ†é¡µï¼Œ\TeX\ å°†åˆ†åˆ«
æ’å…¥å¤§å°ä¸º ^|\smallskip|ï¼Œ^|\medskip| æˆ– ^|\bigskip| çš„é—´è·ï¼ˆ\xref \smallskip ï¼‰ã€‚
ä½†å¦‚æžœæ­¤ä½ç½®ä¹‹å‰å·²ç»æœ‰å¤§äºŽæˆ–ç­‰äºŽæ­¤å€¼çš„é—´è·ï¼Œ\TeX\ å°±ä¸ä¼šå†æ’å…¥é—´è·ã€‚
\enddesc

\begindesc
\easy\cts eject {}
\cts supereject {}
\explain
%These commands force a page break at the current position
%and end the current paragraph.
%If you don't precede them with |\vfil| (\xref \vfil),
%^^|\vfil//needed with {\tt\\eject}|
%\TeX\ will try to stretch out the page contents
%(and will probably complain about an underfull vbox).
%The |\supereject| command, in addition,
%instructs the \plainTeX\ output routine to
%force out any leftover insertions,
%^^{insertions//forced out by \b\tt\\supereject\e}
%such as long footnotes,
%so that they are produced before any more input
%is processed. Thus |\supereject| is a good command to use at the end of each
%chapter or other major unit of your document.
è¿™ä¸¤ä¸ªå‘½ä»¤å°†ç»“æŸå½“å‰æ®µè½å¹¶å¼ºåˆ¶åœ¨å½“å‰ä½ç½®åˆ†é¡µã€‚å¦‚æžœä½&nbsp;ä¸åœ¨å‰é¢åŠ&nbsp;ä¸Š
|\vfil| (\xref \vfil)ï¼Œ^^|\vfil//åœ¨ {\tt\\eject} æ—¶éœ€è¦|
\TeX\ å°†è¯•ç€å°†ä¼¸å±•é¡µé¢å†…å®¹ï¼ˆå¾ˆå¯èƒ½ä¼šè­¦å‘Šæœ‰æ¾æ•£çš„ç«–ç›´ç›’å­ï¼‰ã€‚
|\supereject| å‘½ä»¤è¿˜è®© \plainTeX\ è¾“å‡ºä¾‹è¡Œç¨‹åºå¤„ç†å‰©ä¸‹çš„æ’å…¥é¡¹ï¼Œ
^^{æ’å…¥é¡¹//ç”¨ \b\tt\\supereject\e å¼ºåˆ¶æŽ’ç‰ˆ}ä¾‹å¦‚é•¿è„šæ³¨ï¼Œ
åœ¨å¤„ç†å…¶ä»–è¾“å…¥ä¹‹å‰ç”Ÿæˆå®ƒä»¬ã€‚å›&nbsp;è€Œï¼Œ
|\supereject| æ›´é€‚åˆåœ¨æ–‡æ¡£å„ç«&nbsp;æˆ–ä¸»è¦å•å…ƒç»“æŸæ—¶ä½¿ç”¨ã€‚
\enddesc

\begindesc
\cts filbreak {}
\explain
%This command provides a kind of conditional page break.
%It tells \TeX\ to
%break the page---but not if the text up to a later |\filbreak| also
%fits on the same page.
%By enclosing a paragraph in a pair of |\filbreak|s,
%you can ensure that \TeX\ will keep a paragraph on a single page if it can.
%You should not use |\filbreak| within a paragraph, since it
%forces \TeX\ into vertical mode and thus ends the paragraph.
%See \xrefpg{filbreak} for more advice on this subject.
æ­¤å‘½ä»¤è§„å®šäº†æœ‰æ¡ä»¶çš„åˆ†é¡µã€‚å®ƒå‘Šè¯‰ \TeX\ ï¼Œå¦‚æžœåŽé¢çš„ |\filbreak| ä¸èƒ½æ”¾åœ¨åŒä¸€é¡µï¼Œå°±åœ¨æ­¤å¤„åˆ†é¡µã€‚
ç”¨ä¸€å¯¹ |\filbreak| å°†ä¸€ä¸ªæ®µè½å›´èµ·æ¥ï¼Œå°±å¯ä»¥ç¡®ä¿ \TeX\ å°½é‡å°†è¯¥æ®µè½æ”¾åœ¨åŒä¸€é¡µã€‚
ä¸è¦åœ¨æ®µè½ä¸­é—´ä½¿ç”¨ |\filbreak|ï¼Œå›&nbsp;ä¸ºè¿™å°†è®© \TeX\ è¿›å…¥ç«–ç›´æ¨¡å¼ï¼Œä»Žè€Œç»“æŸè¯¥æ®µè½ã€‚
åœ¨ \xrefpg{filbreak} ä¸­æœ‰æ­¤ä¸»é¢˜çš„æ›´å¤šå»ºè®®ã€‚
\enddesc

\begindesc
\cts raggedbottom {}
\cts normalbottom {}
\explain
%Normally \TeX\ tries hard to ensure that all pages have the same depth,
%i.e., that their bottom margins are equal.
%The |\raggedbottom| command tells \TeX\ to
%allow some variability among the bottom margins on different pages.
%It's often appropriate to use |\raggedbottom| when you have material that
%contains large blocks of material that should not be split across pages.
%The |\normalbottom| command cancels the effect of |\raggedbottom|.
%\eix^^{page breaks//encouraging or discouraging}
é€šå¸¸ \TeX\ ä¼šå°½å…¨åŠ›è®©æ¯é¡µéƒ½ä¸€æ&nbsp;·é«˜ï¼Œå³è®©å®ƒä»¬çš„ä¸‹è¾¹è·ç›¸ç­‰ã€‚
|\raggedbottom| å‘½ä»¤å…è®¸ \TeX\ ç»™ä¸åŒé¡µé¢çš„ä¸‹è¾¹è·ä¸€äº›å·®åˆ«ã€‚
å¦‚æžœæ–‡æ¡£ä¸­æœ‰äº›ä¸èƒ½è·¨é¡µçš„å¤§åž‹å†…å®¹ï¼Œç”¨ |\raggedbottom| å°±æ¯”è¾ƒåˆé€‚ã€‚
ç”¨ |\normalbottom| å‘½ä»¤å¯ä»¥å–æ¶ˆ |\raggedbottom| çš„æ•ˆæžœ.
\eix^^{åˆ†é¡µ//é¼“åŠ±æˆ–é˜»ç¢åˆ†é¡µ}
\enddesc

%==========================================================================
%\subsection {Page breaking parameters}
\subsection{åˆ†é¡µå‚æ•°}

%\bix^^{page breaks//parameters for}
%\begindesc
%\cts interlinepenalty {\param{number}}
%\explain
%This parameter specifies the \minref{penalty} for
%breaking a page between the lines of a paragraph.
%By setting it to $10000$ you can force all page breaks to occur
%between paragraphs, provided that the pages have enough stretch so
%that \TeX\ can still compose them decently.
%\PlainTeX\ leaves |\inter!-linepenalty| at~$0$.
\bix^^{åˆ†é¡µ//åˆ†é¡µå‚æ•°}
\begindesc
\cts interlinepenalty {\param{number}}
\explain
æ­¤å‚æ•°è®¾å®šåœ¨æ®µè½å†…éƒ¨å„è¡Œé—´åˆ†é¡µæ—¶çš„\minref{æƒ©ç½š}å€¼ã€‚
å°†å®ƒè®¾ä¸º $10000$ å°†å¼ºåˆ¶åœ¨æ®µè½ä¹‹é—´åˆ†é¡µï¼Œ
åªè¦é¡µé¢ä¸­æœ‰è¶³å¤Ÿçš„ä¼¸å±•å€¼è®© \TeX\ æŽ’ç‰ˆã€‚
\PlainTeX\ è®¾å®š |\inter!-linepenalty| ä¸º ~$0$ã€‚
\enddesc

\begindesc
\cts clubpenalty {\param{number}}
\explain
%^^{club line}
%This parameter specifies the \minref{penalty} for
%breaking a page just after the first line of a paragraph.
%A line by itself at the bottom of a page is called a ``club line''.
%\PlainTeX\ sets |\clubpenalty| to $150$.
^^{å­¤è¡Œ}
æ­¤å‚æ•°è®¾å®šåœ¨æ®µè½é¦–è¡Œä¹‹åŽåˆ†é¡µçš„\minref{æƒ©ç½š}å€¼ã€‚
é¡µé¢åº•éƒ¨çš„å•ç‹¬ä¸€è¡Œç§°ä¸º``å­¤è¡Œ''ã€‚
\PlainTeX\ è®¾å®š |\clubpenalty| ä¸º $150$ã€‚
\enddesc

\begindesc
\cts widowpenalty {\param{number}}
\explain
%^^{widow line}
%This parameter specifies the \minref{penalty} for
%breaking a page just before the last line of a paragraph.
%A line by itself at the top of a page is called a ``widow line''.
%\PlainTeX\ sets |\widowpenalty| to $150$.
^^{å¯¡è¡Œ}
æ­¤å‚æ•°è®¾å®šåœ¨æ®µè½å°¾è¡Œä¹‹å‰åˆ†é¡µçš„\minref{æƒ©ç½š}å€¼ã€‚
é¡µé¢é¡¶éƒ¨çš„å•ç‹¬ä¸€è¡Œç§°ä¸º``å¯¡è¡Œ''ã€‚
\PlainTeX\ è®¾å®š |\widowpenalty| ä¸º $150$ã€‚
\enddesc

\begindesc
\cts displaywidowpenalty {\param{number}}
\explain
%^^{widow line}^^{math display}
%This parameter specifies the \minref{penalty} for
%breaking a page just before the last line of a partial paragraph
%that immediately precedes a math display.
%\PlainTeX\ sets |\displaywidowpenalty| to $50$.
^^{å¯¡è¡Œ}^^{é™ˆåˆ—å…¬å¼}
æ­¤å‚æ•°è®¾å®šåœ¨é™ˆåˆ—å…¬å¼ä¸Šä¸€è¡ŒåŒæ—¶ä¹Ÿæ˜¯æ®µè½å°¾è¡Œä¹‹å‰åˆ†é¡µçš„\minref{æƒ©ç½š}å€¼ã€‚
\PlainTeX\ è®¾å®š |\displaywidowpenalty| ä¸º $50$.
\enddesc

\begindesc
\cts predisplaypenalty {\param{number}}
\explain
%^^{math display}
%This parameter specifies the \minref{penalty} for
%breaking a page just before a math display.
%\PlainTeX\ sets |\predisplaypenalty| to $10000$.
^^{é™ˆåˆ—å…¬å¼}
æ­¤å‚æ•°è®¾å®šåœ¨é™ˆåˆ—å…¬å¼ä¹‹å‰åˆ†é¡µçš„\minref{æƒ©ç½š}å€¼ã€‚
\PlainTeX\ è®¾å®š\break |\pre!-display!-penalty| ä¸º $10000$ã€‚
\enddesc

\begindesc
\cts postdisplaypenalty {\param{number}}
\explain
%^^{math display}
%This parameter specifies the \minref{penalty} for
%breaking a page just after a math display.
%\PlainTeX\ leaves |\postdisplaypenalty| at $0$.
^^{é™ˆåˆ—å…¬å¼}
æ­¤å‚æ•°è®¾å®šåœ¨é™ˆåˆ—å…¬å¼ä¹‹åŽåˆ†é¡µçš„\minref{æƒ©ç½š}å€¼ã€‚
\PlainTeX\ è®¾å®š\break |\postdisplaypenalty| ä¸º $0$ã€‚
\enddesc

\begindesc
\cts brokenpenalty {\param{number}}
\explain
%This parameter specifies the \minref{penalty} for
%breaking a page just after a line  that ends in
%a discretionary item (usually a hyphen).
%^^{hyphenation}
%|\brokenpenalty| applies to page breaking, while
%^|\hyphenpenalty| \ctsref{\hyphenpenalty} applies to line breaking.
%\PlainTeX\ sets |\brokenpenalty| to $100$.
æ­¤å‚æ•°è®¾å®šåœ¨ä»¥è‡ªå®šè¿žå­—é¡¹ï¼ˆé€šå¸¸æ˜¯ä¸€ä¸ªè¿žå­—ç¬¦ï¼‰ç»“å°¾çš„ä¸€è¡Œä¹‹åŽåˆ†é¡µçš„\minref{æƒ©ç½š}å€¼ã€‚
^^{è¿žå­—}
|\brokenpenalty| ç”¨äºŽåˆ†é¡µ, è€Œ ^|\hyphenpenalty| \ctsref{\hyphenpenalty} ç”¨äºŽæ–­è¡Œã€‚
\PlainTeX\ è®¾å®š |\brokenpenalty| ä¸º $100$.
\enddesc

\begindesc
\cts insertpenalties {\param{number}}
\explain
%\bix^^{insertions//penalties for}
%\bix^^{floating material}
%This parameter contains the sum of certain penalties \minrefs{penalty}
%that \TeX\ accumulates as it is placing insertions onto the
%current page.
%These penalties are incurred when \TeX\ is processing an |\insert|
%command
%and discovers that a previous insertion  of the same kind on this page has
%been split, leaving part of it for subsequent pages.
%See \knuth{pages~123--125} for the details of this
%calculation.
%
%\margin{Material moved from a footnote to the main text.}
%|\insertpenalties| has an entirely different meaning during an
%^^{output routine//meaning of \b\tt\\insertpenalties\e\ in}
%output routine---it's the number of insertions that have been seen
%but that don't fit on the current page (see \knuth{page~125}).
\bix^^{æ’å…¥é¡¹//æ’å…¥é¡¹çš„æƒ©ç½š}
\bix^^{æµ®åŠ¨ä½“}
æ­¤å‚æ•°åŒ…å« \TeX\ æ”¾ç½®æ’å…¥é¡¹åˆ°å½“å‰é¡µé¢æ—¶æ‰€ç´¯ç§¯çš„æŸäº›\minref{æƒ©ç½š}å€¼ä¹‹å’Œã€‚
åœ¨ \TeX\ å¤„ç† |\insert| å‘½ä»¤æ—¶ï¼Œ
å¦‚æžœå‘çŽ°å‰é¢æœ‰åŒç±»åž‹æ’å…¥é¡¹è¢«åˆ†å¼€ï¼Œç•™ä¸‹ä¸€éƒ¨åˆ†åˆ°ä¹‹åŽçš„é¡µé¢ï¼Œ
å°±ä¼šç®—ä¸Šè¿™äº›æƒ©ç½šå€¼ã€‚
è¯¦ç»†çš„è®¡ç®—è¿‡ç¨‹å¯ä»¥è§ \knuth{ç¬¬~123--125~é¡µ}ã€‚

\margin{Material moved from a footnote to the main text.}
åœ¨è¾“å‡ºä¾‹è¡Œç¨‹åºä¸­ï¼Œ
^^{è¾“å‡ºä¾‹è¡Œç¨‹åº//\b\tt\\insertpenalties\e\ çš„æ„ä¹‰}
|\insertpenalties| æœ‰å®Œå…¨ä¸åŒçš„æ„ä¹‰â€”â€”
å®ƒè¡¨ç¤ºå·²ç»è§åˆ°ä½†æœªèƒ½æ”¾å…¥å½“å‰é¡µçš„æ’å…¥é¡¹çš„æ€»æ•°ï¼ˆè§ \knuth{ç¬¬~125~é¡µ}ï¼‰ã€‚
\enddesc

\begindesc
\cts floatingpenalty {\param{number}}
\explain
%This parameter specifies the \minref{penalty} that
%\TeX\ adds to |\insertpenalties|
%^^|\insertpenalties|
%when the page builder is adding an insertion to the current page
%and discovers that a previous insertion  of the same kind on this page has
%been split, leaving part of it for subsequent pages.
%\PlainTeX\ leaves |\floatingpenalty| at~$0$.
%\eix^^{insertions//penalties for}
%\eix^^{floating material}
åœ¨ \TeX\ å¤„ç†æ’å…¥é¡¹æ—¶ï¼Œ
å¦‚æžœå‘çŽ°å‰é¢æœ‰åŒç±»åž‹æ’å…¥é¡¹è¢«åˆ†å¼€ï¼Œç•™ä¸‹ä¸€éƒ¨åˆ†åˆ°ä¹‹åŽçš„é¡µé¢ï¼Œ
å°±ä¼šæ·»åŠ&nbsp; |\floatingpenalty| \minref{æƒ©ç½š}å€¼åˆ°|\insertpenalties|
^^|\insertpenalties|ã€‚
\PlainTeX\ è®¾å®š |\floatingpenalty| ä¸º $0$ã€‚
\eix^^{æ’å…¥é¡¹//æ’å…¥é¡¹çš„æƒ©ç½š}
\eix^^{æµ®åŠ¨ä½“}
\enddesc

\begindesc
\cts pagegoal {\param{dimen}}
\explain
%This parameter specifies the
%desired height for the current page.
%\TeX\  sets
%|\pagegoal| to the current value of |\vsize|
%when it first puts a box or an insertion on the current page.
%You can shorten a page while \TeX\ is working on it by
%changing the value of |\pagegoal|---even if the new value is
%less than the height of the material already on that page.
%\TeX\ will just put the extra material on the next page.
%But remember---|\pagegoal| is reset to |\vsize| again when \TeX\
%starts the next page.
æ­¤å‚æ•°è®¾å®šå½“å‰é¡µé¢æ‰€éœ€çš„é«˜åº¦ã€‚
å½“æ”¾å…¥ç¬¬ä¸€ä¸ªç›’å­æˆ–è€…æ’å…¥é¡¹åˆ°å½“å‰é¡µé¢æ—¶ï¼Œ
\TeX\ è®¾å®š |\pagegoal| ç­‰äºŽ |\vsize| çš„å½“å‰å€¼ã€‚
æ”¹å˜ |\pagegoal| çš„å€¼å¯ä»¥è®© \TeX\ æŽ’ç‰ˆæ—¶ç¼©çŸ­è¯¥é¡µé¢çš„é«˜åº¦ã€‚
å³ä½¿æ–°çš„å€¼æ¯”é¡µé¢å·²æœ‰å†…å®¹çš„é«˜åº¦è¿˜å°ä¹Ÿå¯ä»¥ï¼Œ
æ­¤æ—¶ \TeX\ å°†æŠŠå¤šä½™çš„å†…å®¹æ”¾åœ¨ä¸‹ä¸€é¡µã€‚
ä½†è®°ä½â€”â€”åœ¨ä¸‹ä¸€é¡µ \TeX\ è¿˜æ˜¯ä¼šé‡ç½® |\pagegoal| ä¸º |\vsize|ã€‚
\enddesc

\begindesc
\cts pagetotal {\param{dimen}}
\explain
%This parameter specifies the
%accumulated natural height of the current page.
%\TeX\ updates |\pagetotal| as it adds
%items to the main \minref{vertical list}.
æ­¤å‚æ•°è¡¨ç¤ºå½“å‰é¡µé¢ç´¯ç§¯çš„è‡ªç„¶é«˜åº¦ã€‚
\TeX\ æ·»åŠ&nbsp;å†…å®¹åˆ°\minref{ç«–ç›´åˆ—}æ—¶ä¼šæ›´æ–° |\pagetotal| çš„å€¼ã€‚
\enddesc

\begindesc
\cts pagedepth {\param{dimen}}
\explain
%This parameter specifies the depth of the current page.
%\TeX\ updates |\pagedepth| as it adds
%items to the main \minref{vertical list}.
æ­¤å‚æ•°è¡¨ç¤ºå½“å‰é¡µé¢çš„æ·±åº¦ã€‚
\TeX\ æ·»åŠ&nbsp;å†…å®¹åˆ°\minref{ç«–ç›´åˆ—}æ—¶ä¼šæ›´æ–° |\pagedepth| çš„å€¼ã€‚
\enddesc

\begindesc
\cts pageshrink {\param{dimen}}
\explain
%This parameter specifies the amount of \minref{shrink}
%in the accumulated \minref{glue} on the current page.
%\TeX\ updates |\pageshrink| as it adds
%items to the main \minref{vertical list}.
æ­¤å‚æ•°è¡¨ç¤ºå½“å‰é¡µé¢ç´¯ç§¯çš„ç²˜è¿žçš„å¯æ”¶ç¼©é‡ã€‚
\TeX\ æ·»åŠ&nbsp;å†…å®¹åˆ°\minref{ç«–ç›´åˆ—}æ—¶ä¼šæ›´æ–° |\pageshrink| çš„å€¼ã€‚
\enddesc

\begindesc
\cts pagestretch {\param{dimen}}
\cts pagefilstretch {\param{dimen}}
\cts pagefillstretch {\param{dimen}}
\cts pagefilllstretch {\param{dimen}}
\explain
%These four parameters together specify the amount of \minref{stretch}
%in the \minref{glue} on the current page.  The amount of stretch has
%the form
%{\def\f#1{\hbox{\tt fi#1}}%
%$n_0 + n_1\f{l} + n_2\f{ll} + n_3\f{lll}$}, with the four parameters
%giving the values of the four $n_i$.
%\TeX\ updates these parameters as it adds
%items to the main \minref{vertical list}.
%
%\eix^^{page breaks//parameters for}
%\eix^^{page breaks}
è¿™å››ä¸ªå‚æ•°åˆèµ·æ¥è¡¨ç¤ºå½“å‰é¡µé¢ç´¯ç§¯çš„ç²˜è¿žçš„å¯ä¼¸é•¿é‡ã€‚å¯ä¼¸é•¿é‡æ€»å…±ç­‰äºŽ
{\def\f#1{\hbox{\tt fi#1}}
$n_0 + n_1\f{l} + n_2\f{ll} + n_3\f{lll}$}ï¼Œ
å…¶ä¸­å››ä¸ªå‚æ•°ç»™å‡ºå››ä¸ª$n_i$çš„å€¼ã€‚
\TeX\ æ·»åŠ&nbsp;å†…å®¹åˆ°\minref{ç«–ç›´åˆ—}æ—¶ä¼šæ›´æ–°è¿™äº›å‚æ•°çš„å€¼ã€‚
\eix^^{åˆ†é¡µ//åˆ†é¡µå‚æ•°}
\eix^^{åˆ†é¡µ}
\enddesc

%==========================================================================
%\section{Page layout}
\section{é¡µé¢å¸ƒå±€}

%\subsection {Page description parameters}
\subsection {é¡µé¢æè¿°å‚æ•°}

\begindesc
\bix^^{é¡µé¢å°ºå¯¸}
\margin{This command was also described in the `Paragraphs' section.
The combined description now appears there.}
\aux\cts hsize {\param{dimen}}
\explain
%This parameter specifies the current line length.
%See \xrefpg{\hsize} for a more complete explanation.
æ­¤å‚æ•°æŒ‡å®šå½“å‰è¡Œçš„é•¿åº¦ã€‚\PlainTeX\ è®¾å®š |\hsize| ä¸º |6.5in|ã€‚
åœ¨\xrefpg{\hsize} æœ‰å®Œæ•´çš„è§£é‡Šã€‚
\enddesc

\begindesc
\cts vsize {\param{dimen}}
\explain
%This parameter specifies the current vertical extent of a page.
%\TeX\ examines it only when it is starting a page.  Thus if you change
%|\vsize| in the
%middle of a page, your change won't affect anything until the following page.
%If you want to change the vertical extent of a page when
%you're in the middle of it, you  should assign the new
%height to ^|\pagegoal| (\xref \pagegoal) instead.  (If you
%want the change to affect the following pages too, you should
%change \emph{both} |\vsize| and |\pagegoal|.)
%\PlainTeX\ sets |\vsize| to |8.9in|.
%\eix^^{page dimensions}
æ­¤å‚æ•°æŒ‡å®šé¡µé¢çš„ç«–ç›´é•¿åº¦ã€‚
\TeX\ ä»…åœ¨é¡µé¢å¼€å§‹æ—¶æ£€æŸ¥æ­¤å€¼ã€‚
å›&nbsp;æ­¤ï¼Œåœ¨é¡µé¢ä¸­é—´æ”¹å˜ |\vsize| åˆ°ä¸‹ä¸€é¡µæ‰ä¼šç”Ÿæ•ˆã€‚
è‹¥è¦åœ¨é¡µé¢ä¸­é—´æ”¹å˜å…¶ç«–ç›´é•¿åº¦ï¼Œåº”è¯¥ä¿®æ”¹ ^|\pagegoal|ï¼ˆ\xref \pagegoal ï¼‰çš„å€¼ã€‚%
ï¼ˆè‹¥è¦æ”¹å˜å½“å‰é¡µé¢å¼€å§‹çš„æ‰€æœ‰é¡µé¢ï¼Œä½&nbsp;éœ€è¦\emph{åŒæ—¶}ä¿®æ”¹ |\vsize| å’Œ |\pagegoal|ã€‚ï¼‰
\PlainTeX\ è®¾å®š |\vsize| ä¸º |8.9in|ã€‚
\eix^^{é¡µé¢å°ºå¯¸}
\enddesc

%\begindesc
%\cts hoffset {\param{dimen}}
%\cts voffset {\param{dimen}}
%\margin{These commands were moved up from later in the subsection.}
%^^{page origin}
%\idxsee{origin}{page origin}
%\explain
%\TeX\ normally takes the ``origin'' of a page, that is, the point where
%it starts printing, as being one inch down from the top of the page and one
%inch to the right of the left end of the page.\footnote{
%\TeX\ itself is indifferent to where the origin of the page is,
%but this information has to be built into the device drivers
%^^{device drivers//page origin known to}
%that convert \dvifile s into printable form so that different devices
%will yield the same results.}
%The values of |\hoffset| and
%|\voffset| give the horizontal and vertical offset of the actual origin
%from this point.  Thus if |\hoffset| and |\voffset| are both
%zero, \TeX\ uses its normal origin.
\begindesc
\cts hoffset {\param{dimen}}
\cts voffset {\param{dimen}}
\margin{These commands were moved up from later in the subsection.}
^^{é¡µé¢èµ·ç‚¹}
\idxsee{origin}{page origin}
\explain
\TeX\ é€šå¸¸è®¾å®šé¡µé¢çš„â€œèµ·ç‚¹â€â€”â€”å³å®ƒå¼€å§‹æ‰“å°çš„åœ°æ–¹â€”â€”åœ¨ç¦»ä¸Šé¡µè¾¹å’Œå·¦é¡µè¾¹å‡ä¸ºä¸€è‹±å¯¸çš„åœ°æ–¹ã€‚\footnote{
\TeX\ æœ¬èº«å¹¶ä¸å…³å¿ƒé¡µé¢èµ·ç‚¹çš„ä½ç½®ï¼Œ
ä½†è®¾å¤‡é©±åŠ¨ç¨‹åºå°† \dvifile è½¬æ¢ä¸ºå¯æ‰“å°å½¢å¼æ—¶è¦ç”¨åˆ°ï¼Œ
æ­¤ä½ç½®ä¿¡æ¯ä½¿å¾—åœ¨ä¸åŒçš„è®¾å¤‡ä¸­èƒ½å¾—åˆ°ç›¸åŒçš„ç»“æžœã€‚
^^{è®¾å¤‡é©±åŠ¨//å®ƒæ‰€çŸ¥çš„é¡µé¢èµ·ç‚¹}}
|\hoffset| å’Œ |\voffset| çš„å€¼åˆ†åˆ«ç»™å‡ºå®žé™…èµ·ç‚¹ç›¸å¯¹è¯¥ç‚¹çš„æ°´å¹³å’Œç«–ç›´åç§»é‡ã€‚
å›&nbsp;æ­¤ï¼Œè‹¥ |\hoffset| å’Œ |\voffset| å‡ä¸ºé›¶ï¼Œ\TeX\ å°±ä½¿ç”¨æ­£å¸¸èµ·ç‚¹ã€‚
\example
\hoffset = -.3in
   % Start printing .7 inches from left edge of paper.
\voffset = 1in
   % Start printing 2 inches from top edge of paper.
|
\endexample
\enddesc

\begindesc
\cts topskip {\param{glue}}
\explain
%\TeX\ inserts glue at the top of each
%page in order to ensure that the baseline of the first box on the page
%always is the same distance $d$ from the top of the page.
%|\topskip| determines the amount of that glue,
%called the ``|\topskip| glue'', by specifying
%what $d$ should be (provided that the first box
%on the page isn't too tall).
%$d$ is given by the natural size of the |\topskip| glue.
%If the height of the first box on the page exceeds $d$,
%so that the glue would be negative, \TeX\ simply inserts no
%|\topskip| glue at all on that page.
ä¸ºç¡®ä¿é¡µé¢ç¬¬ä¸€ä¸ªç›’å­çš„åŸºçº¿åˆ°ä¸Šé¡µè¾¹çš„è·ç¦»æ€»æ˜¯ $d$ï¼Œ
\TeX\ åœ¨æ¯ä¸ªé¡µé¢é¡¶éƒ¨éƒ½æ’å…¥ç²˜è¿žã€‚
|\topskip| ç»™å‡ºäº† $d$ çš„å€¼ï¼Œä»¥æ­¤ç¡®å®šè¯¥ç²˜è¿žå¤§å°
ï¼ˆåªè¦é¡µé¢ç¬¬ä¸€ä¸ªç›’å­ä¸ä¼šå¤ªé«˜ï¼‰ã€‚
$d$ ç­‰äºŽ |\topskip| ç²˜è¿žçš„è‡ªç„¶å¤§å°ã€‚
å¦‚æžœé¡µé¢ç¬¬ä¸€ä¸ªç›’å­çš„é«˜åº¦è¶…è¿‡ $d$ï¼Œ
è®¡ç®—å‡ºçš„ç²˜è¿žå°†ä¸ºè´Ÿå€¼ï¼Œæ­¤æ—¶åœ¨è¯¥é¡µé¡¶éƒ¨ \TeX\ ä¸æ’å…¥|\topskip|ç²˜è¿žã€‚

%To understand better the effect of these rules, assume that |\topskip|
%has no stretch or shrink and that the first item on the page is indeed a box.
%Then if the height of that box is no greater than |\topskip|,
%its baseline will be |\topskip|
%from the top of the page independently of its height.  On the other hand,
%if the height of the box is $e$ greater than |\topskip|, its baseline will be
%|\topskip|\tplus$e$ from the top of the page.
%See \knuth{pages~113--114} for the remaining details of how
%|\topskip| works.
%\PlainTeX\ sets |\topskip| to |10pt|.
ä¸ºæ›´å¥½åœ°ç†è§£è¿™äº›è§„åˆ™ï¼Œæˆ‘ä»¬å‡è®¾ |\topskip| æ—&nbsp;ä¼¸é•¿é‡ä¹Ÿæ—&nbsp;æ”¶ç¼©é‡ï¼Œä¸”é¡µé¢ç¬¬ä¸€é¡¹å°±æ˜¯ä¸ªç›’å­ã€‚
å¦‚æžœè¯¥ç›’å­çš„é«˜åº¦ä¸å¤§äºŽ |\topskip|ï¼Œä¸ç®¡é«˜åº¦ä¸ºå¤šå°‘ï¼Œ
å®ƒçš„åŸºçº¿å’Œä¸Šé¡µè¾¹çš„è·ç¦»å°±å§‹ç»ˆç­‰äºŽ |\topskip|ã€‚
åè¿‡æ¥ï¼Œå¦‚æžœè¯¥ç›’å­çš„é«˜åº¦æ¯” |\topskip| å¤§ $e$ï¼Œ
å®ƒçš„åŸºçº¿å’Œä¸Šé¡µè¾¹çš„è·ç¦»å°±æ˜¯ |\topskip|\tplus$e$ã€‚
åœ¨ \knuth{ç¬¬~113--114~é¡µ} ä¸­è¯¦ç»†è§£é‡Šäº† |\topskip| çš„ä½œç”¨ã€‚
\PlainTeX\ è®¾å®š |\topskip| ä¸º |10pt|ã€‚
\enddesc

\begindesc
\cts parskip {\param{glue}}
\explain
%This parameter specifies the ``^{paragraph skip}'', i.e., the
%vertical glue that \TeX\ inserts at the start of a paragraph.
%^^{paragraphs//glue between}
%See |\par| (\xref{\@par}) for more information about what happens
%when \TeX\ starts a paragraph.
%\PlainTeX\ sets |\parskip| to |0pt plus 0.1pt|.
æ­¤å‚æ•°è®¾å®šâ€œ^{æ®µè½é—´è·}â€ï¼Œå³ \TeX\ åœ¨æ®µè½å¼€å¤´æ’å…¥çš„ç«–ç›´ç²˜è¿žã€‚
^^{æ®µè½//æ®µè½é—´çš„ç²˜è¿ž}
åœ¨ |\par| (\xref{\@par}) é‚£é‡Œä»‹ç»äº† \TeX\ å¼€å§‹æ–°æ®µè½æ—¶æ‰€ä½œçš„äº‹æƒ…ã€‚
\PlainTeX\ è®¾å®š |\parskip| ä¸º |0pt plus 0.1pt|ã€‚
\enddesc

\begindesc
\cts maxdepth {\param{dimen}}
\explain
%This parameter specifies the maximum depth of the bottom \minref{box} on
%a page.  It is related to |\boxmaxdepth| (\xref \boxmaxdepth).  If the
%depth of the bottom box on a page exceeds |\maxdepth|, \TeX\ moves the
%box's reference point down so that it's
%|\maxdepth| from the bottom of that box.
%Without this adjustment, the bottom box on
%a page could extend well into the bottom margin or even off
%the page entirely.  \PlainTeX\ sets |\maxdepth| to |4pt|.
æ­¤å‚æ•°è®¾å®šé¡µé¢åº•éƒ¨\minref{ç›’å­}çš„æœ€å¤§æ·±åº¦ã€‚
å®ƒå’Œ |\boxmaxdepth| å‚æ•°ï¼ˆ\xref \boxmaxdepth ï¼‰ä¹Ÿæœ‰å…³ç³».
å¦‚æžœåº•éƒ¨ç›’å­çš„æ·±åº¦è¶…è¿‡ |\maxdepth|ï¼Œ
\TeX\ ä¸‹ç§»è¯¥ç›’å­çš„åŸºå‡†ç‚¹ï¼Œè®©æ·±åº¦å°±ç­‰äºŽ |\maxdepth|ã€‚
è‹¥ä¸ä½œæ­¤è°ƒæ•´ï¼Œé¡µé¢åº•éƒ¨ç›’å­å¯èƒ½å¤§å¤§è¶…å‡ºä¸‹è¾¹è·ï¼Œç”šè‡³è¶…å‡ºé¡µé¢ï¼Œ
PlainTeX\ è®¾å®š |\maxdepth| ä¸º |4pt|ã€‚
\enddesc

%==========================================================================
%\subsection{Page numbers}
\subsection{é¡µç&nbsp;}

%\begindesc
%\bix^^{page numbering}
%\cts pageno {\param{number}}
%\explain
%This parameter contains the current page number as an integer.  The page
%number is normally negative for front-matter pages that are numbered
%with small roman numerals instead of arabic numerals.  If you change the
%page number within a page,
%the changed number will be used in any headers or footers that
%appear on that page.
%The actual
%printing of page numbers is handled by \TeX's \minref{output routine},
%which you can modify.
\begindesc
\bix^^{é¡µç&nbsp;}
\cts pageno {\param{number}}
\explain
æ­¤å‚æ•°ä»¥æ•´æ•°å€¼è®°å½•å½“å‰é¡µç&nbsp;ã€‚
åœ¨å‰é¡µï¼ˆfront matterï¼‰ä¸­é¡µç&nbsp;é€šå¸¸æ˜¯è´Ÿæ•°ï¼Œæˆ‘ä»¬ç”¨å°å†™ç½—é©¬æ•°å­—è€Œä¸ç”¨é˜¿æ‹‰ä¼¯æ•°å­—ç¼–å·ã€‚
åœ¨é¡µé¢ä¸­é—´å¯¹é¡µç&nbsp;çš„æ”¹åŠ¨ï¼Œä¼šåœ¨è¯¥é¡µçš„é¡µçœ‰å’Œé¡µè„šä¸­ç”¨åˆ°ã€‚
é¡µç&nbsp;äº‹å®žä¸Šç”± \TeX\ çš„\minref{è¾“å‡ºä¾‹è¡Œç¨‹åº}æ‰“å°ï¼Œä½&nbsp;å¯ä»¥ä¿®æ”¹å®ƒä»¬ã€‚

%\PlainTeX\ keeps the page number in the \minref{register} ^|\count0|.
%(|\pageno| is, in fact, a synonym for |\count0|.)
%Whenever it ships out a page to the \dvifile,
%^^|\shipout//{\tt\\count} registers displayed at|
%\TeX\ displays the current value of |\count0| on your
%terminal so that you can tell which page it is working on.
%It's possible to use registers |\count1|--|\count9| for nested
%levels of page numbers (you must program this yourself).
%If any of these registers are nonzero, \TeX\ displays them on your
%terminal also.\footnote{
%More precisely, it displays all registers in sequence from
%|\count0| to |\count9|, but omits trailing zero registers.
%For instance, if the values of |\count0|--|\count3|
%are $(17, 0 , 0, 7)$ and the others are $0$,
%\TeX\ displays the page number as {\tt [17.0.0.7]}.}
\PlainTeX\ å°†é¡µç&nbsp;è®°å½•åœ¨\minref{å¯„å­˜å™¨} ^|\count0| ä¸­ã€‚%
ï¼ˆ|\pageno| å®žé™…ä¸Šå°±æ˜¯|\count0|çš„åˆ«åã€‚ï¼‰
å½“å®ƒè¾“å‡ºä¸€ä¸ªé¡µé¢åˆ° \dvifile æ—¶ï¼Œ
^^|\shipout//æ­¤æ—¶æ˜¾ç¤º {\tt\\count} å¯„å­˜å™¨çš„å€¼|
\TeX\ åœ¨ç»ˆç«¯ä¸­æ˜¾ç¤º  |\count0| çš„å€¼ï¼Œè®©ä½&nbsp;çŸ¥é“å®ƒåœ¨æŽ’ç‰ˆå“ªä¸€é¡µã€‚
ä¹Ÿå¯ä»¥æŠŠå¯„å­˜å™¨ |\count1|--|\count9| ç”¨äºŽåµŒå¥—çš„å¤šçº§é¡µç&nbsp;
ï¼ˆä½†ä½&nbsp;å¿…é¡»è‡ªå·±ç¼–ç¨‹ï¼‰ã€‚
å¦‚æžœè¿™äº›å¯„å­˜å™¨çš„å€¼éžé›¶ï¼Œ\TeX\ åœ¨ç»ˆç«¯ä¸­ä¹Ÿæ˜¾ç¤ºå®ƒä»¬çš„å€¼ã€‚\footnote{
æ›´å‡†ç¡®æ¥è¯´ï¼Œå®ƒä»Ž |\count0| åˆ° |\count9| ä¾æ¬¡æ˜¾ç¤ºå„å¯„å­˜å™¨çš„å€¼ï¼Œä½†å¿½ç•¥æœ«å°¾çš„é›¶å€¼ã€‚
æ¯”å¦‚ï¼Œè‹¥ |\count0| åˆ° |\count3| ä¸º $(17, 0 , 0, 7)$ è€Œå…¶ä»–å€¼éƒ½ä¸º $0$ï¼Œ
åˆ™ \TeX\ æ˜¾ç¤ºé¡µç&nbsp;ä¸º {\tt [17.0.0.7]}ã€‚}
\example
This explanation appears on page \number\pageno\
of our book.
|
\produces
This explanation appears on page \number\pageno\
of our book.

\nextexample
\pageno = 30 % Number the next page as 30.
Don't look for this explanation on page \number\pageno.
|
\produces
Don't look for this explanation on page 30.
\endexample
\enddesc

\begindesc
\cts advancepageno {}
\explain
%This command adds $1$ to the page number
%$n$ in |\pageno| if $n\ge0$
%and subtracts $1$ from it if $n&lt;0$.
å¦‚æžœé¡µç&nbsp; $n\ge0$ï¼Œæ­¤å‘½ä»¤ç»™ $n$ åŠ&nbsp;ä¸Š $1$ï¼›
å¦‚æžœ $n&lt;0$ åˆ™ç»™ $n$ å‡åŽ» $1$ã€‚
\enddesc

\begindesc
\easy\cts nopagenumbers {}
\explain
%By default, \plainTeX\ produces a footer containing a centered page number.
%This command tells \TeX\ to produce a blank footer instead.
é»˜è®¤æƒ…å†µä¸‹ï¼Œ\plainTeX\ ä¼šåœ¨é¡µé¢çš„é¡µè„šç”Ÿæˆå±…ä¸­çš„é¡µç&nbsp;ã€‚
æ­¤å‘½ä»¤è®© \TeX\ ç”Ÿæˆç©ºçš„é¡µè„š.
\enddesc

\begindesc
\cts folio {}
\explain
%This command produces the current page number, whose value is the number
%$n$ contained in ^|\pageno|.
%If  $n\ge0$,
%\TeX\ produces $n$ as a decimal number,
%while if $n&lt;0$,
%\TeX\ produces $-n$ in lowercase roman numerals.
æ­¤å‘½ä»¤ç”Ÿæˆå½“å‰é¡µç&nbsp;ï¼Œå®ƒçš„å€¼ç­‰äºŽè®°å½•åœ¨ ^|\pageno| ä¸­çš„ $n$ã€‚
è‹¥ $n\ge0$ï¼Œ\TeX\ ç”¨åè¿›åˆ¶æ•°å½¢å¼ç”Ÿæˆ $n$ï¼›
è‹¥ $n&lt;0$ï¼Œ\TeX\ ç”¨å°å†™ç½—é©¬æ•°å­—å½¢å¼ç”Ÿæˆ $-n$ã€‚
\example
This explanation appears on page \folio\ of the book.
|
\produces
This explanation appears on page \folio\ of the book.
\endexample

%\eix^^{page numbering}
%\enddesc
\eix^^{é¡µç&nbsp;}
\enddesc

%==========================================================================
%\subsection{Header and footer lines}
\subsection{é¡µçœ‰å’Œé¡µè„š}

\begindesc\secondprinting{\vglue-.75\baselineskip\vskip0pt}
\cts headline {\param{token list}}
\cts footline {\param{token list}}
\explain
%These parameters
%contain, respectively, the current headline (header) and the current
%footline (footer).
%The \plainTeX\ output routine
%places the headline at the top of each page and the footline
%at the bottom of each page.
%The default headline is empty and the default footline is a centered
%page number.
è¿™ä¸¤ä¸ªå‚æ•°åˆ†åˆ«æŒ‡å®šå½“å‰çš„é¡µçœ‰å’Œé¡µè„šã€‚
\PlainTeX\ è¾“å‡ºä¾‹è¡Œç¨‹åºå°†æŠŠé¡µçœ‰æ”¾åœ¨å„é¡µé¡¶éƒ¨ï¼Œé¡µè„šæ”¾åœ¨å„é¡µåº•éƒ¨ã€‚
é»˜è®¤çš„é¡µçœ‰ä¸ºç©ºï¼Œè€Œé»˜è®¤çš„é¡µè„šä¸ºå±…ä¸­çš„é¡µç&nbsp;ã€‚

%The headline and footline should both
%be as wide as |\hsize| (use |\hfil|, \xref{\hfil}, for this
%if necessary).
%You should always include a font-setting command in these lines, since
%the current font is unpredictable when \TeX\ is calling the
%output routine.  If you don't set the font explicitly,
%you'll get whatever font \TeX\ was using when it broke the page.
é¡µçœ‰å’Œé¡µè„šçš„å®½åº¦åº”è¯¥å’Œ |\hsize| ç›¸ç­‰ï¼ˆå¿…è¦æ—¶å¯ä»¥ç”¨ |\hfil|ï¼Œ\xref{\hfil}ï¼‰ã€‚
åœ¨é¡µçœ‰å’Œé¡µè„šä¸­ä½&nbsp;æ°¸è¿œåº”è¯¥åŠ&nbsp;ä¸Šå­—ä½“è®¾å®šå‘½ä»¤ï¼Œ
å›&nbsp;ä¸ºä½&nbsp;æ—&nbsp;æ³•é¢„çŸ¥ \TeX\ è°ƒç”¨è¾“å‡ºä¾‹è¡Œç¨‹åºæ—¶çš„å½“å‰å­—ä½“ã€‚
å¦‚æžœä½&nbsp;ä¸æ˜Žç¡®æŒ‡æ˜Žå­—ä½“ï¼Œ\TeX\ å°†ä½¿ç”¨åˆ†é¡µæ—¶æ‰€ç”¨çš„å­—ä½“ã€‚

%You shouldn't try to use |\headline| or |\footline|
%to produce multiline headers or footers.
%Although \TeX\ won't complain, it will give you something that's very ugly.
%See \xrefpg{bighead} for a method of creating multiline headers or
%footers.
ä¸è¦è¯•å›¾ç”¨ |\headline| æˆ– |\footline| ç”Ÿæˆå¤šè¡Œçš„é¡µçœ‰æˆ–é¡µè„šã€‚
å³ä½¿ \TeX\ ä¸ä¼šæŠ¥é”™ï¼Œå®ƒä¹Ÿåªä¼šå‡ºå¾ˆéš¾çœ‹çš„ç»“æžœã€‚
åœ¨\xrefpg{bighead}ä¸­æœ‰ç”Ÿæˆå¤šè¡Œé¡µçœ‰æˆ–é¡µè„šçš„æ–¹æ³•ã€‚
\example
\headline = {\tenrm My First Reader\hfil Page \folio}
|
\produces
\pageno = 10
\line{\tenrm \noindent My First Reader\hfil Page \folio}
\par ({\it at the top of page \folio}\/)
\nextexample
\footline = {\tenit\ifodd\pageno\hfil\folio
           \else\folio\hfil\fi}
% Produce the page number in ten-point italic at
% the outside bottom corner of each page.
|
\endexample\enddesc

%\secondprinting{\vfill\eject}


%==========================================================================
%\subsection {Marks}
\subsection {æ&nbsp;‡è®°}

\begindesc
\cts mark {\rqbraces{\&lt;text&gt;}}
\explain
%\bix^^{marks}
%This command causes \TeX\ to append a mark
%containing \&lt;mark text&gt;
%to whatever list it is currently constructing.
%Generally you shouldn't use |\mark| within an
%``inner'' construct such as a math formula or a \minref{box}
%you've built with an |\hbox|, |\vbox|, or |\vtop| command, because
%\TeX\ won't see the mark when it's constructing the main box of the page.  But
%if you use |\mark| in ordinary horizontal \minref{mode}
%or directly in an hbox that's part of the main vertical list,
%the mark migrates out
%to the main \minref{vertical list}.
%See \knuth{pages~259--260} for examples showing how |\mark| can be used.
\bix^^{æ&nbsp;‡è®°}
æ­¤å‘½ä»¤è®© \TeX\ æ·»åŠ&nbsp;å†…å®¹ä¸º \&lt;mark text&gt; çš„æ&nbsp;‡è®°åˆ°å½“å‰æ­£æž„é€&nbsp;çš„åˆ—è¡¨ä¸­ã€‚
ä¸€èˆ¬åœ°ï¼Œæ­¤æ&nbsp;‡è®°å‘½ä»¤ä¸åº”è¯¥åœ¨ â€œå†…éƒ¨â€æž„é€&nbsp;ä¸­ä½¿ç”¨ï¼Œ
ä¾‹å¦‚æ•°å­¦å…¬å¼æˆ–è€…ç”¨ |\hbox|ã€|\vbox| æˆ– |\vtop| æž„é€&nbsp;çš„\minref{ç›’å­}ã€‚
è¿™æ˜¯å›&nbsp;ä¸º \TeX\ æž„é€&nbsp;é¡µé¢ä¸»ç›’å­æ—¶å°†çœ‹ä¸åˆ°è¿™æ&nbsp;·çš„æ&nbsp;‡è®°ã€‚
ä½†æ˜¯ï¼Œè‹¥ä½&nbsp;åœ¨æ™®é€šæ°´å¹³\minref{æ¨¡å¼}ä¸­ç”¨ |\mark|ï¼Œ
æˆ–è€…åœ¨ä¸»ç«–ç›´åˆ—çš„ hbox ä¸­ç›´æŽ¥ä½¿ç”¨ |\mark|ï¼Œ
è¯¥æ&nbsp;‡è®°å°†ä¼šè¢«è½¬ç§»åˆ°ä¸»\minref{ç«–ç›´åˆ—}ã€‚
åœ¨\knuth{ç¬¬~259--260~é¡µ}ä¸­æœ‰å¦‚ä½•ä½¿ç”¨ |\mark| çš„ä¾‹å­ã€‚
\enddesc

\begindesc
\cts firstmark {}
\cts botmark {}
\cts topmark {}
\explain
%These commands expand to the mark text in an item generated by an earlier
%^|\mark| command.
%The mark text has the form of a token list.
%\TeX\ sets the values of these commands when it
%finishes placing the contents of a page into ^|\box255|,
%just before calling the \minref{output routine}
%as part of its \minref{page break}ing actions.  \TeX\ determines
%these values as follows:
%\ulist\compact
%\li |\firstmark| contains the tokens of the first mark on the page.
%\li |\botmark| contains the tokens of the last mark on the page.
%\li |\topmark| contains the tokens of the mark that is in effect at
%the very top of the page.
%That mark is the last mark
%that \emph{preceded} the page,
%i.e., the |\botmark| of the previous page.
%It is empty if no marks preceded the page.
%\endulist
%\noindent
%If a page has no marks on it, \TeX\ will set |\firstmark| and |\botmark| to
%the same mark as |\topmark|, i.e., the most recent preceding mark.
%The table at the bottom of \knuth{page~258} illustrates the relation among
%|\firstmark|, |\botmark|, and |\topmark|.
è¿™äº›å‘½ä»¤å±•å¼€ä¸ºä¹‹å‰ç”¨ ^|\mark| ç”Ÿæˆçš„æ&nbsp;‡è®°é¡¹çš„æ&nbsp;‡è®°æ–‡æœ¬ã€‚
æ&nbsp;‡è®°æ–‡æœ¬ä»¥è®°å·åˆ—å½¢å¼è¡¨ç¤ºã€‚
æ‰§è¡Œåˆ†é¡µå·¥ä½œæ—¶ï¼Œ\TeX\ éœ€è¦å°†é¡µé¢å†…å®¹æ”¾å…¥ ^|\box255|ï¼Œ
ç„¶åŽè°ƒç”¨\minref{è¾“å‡ºä¾‹è¡Œç¨‹åº}ï¼›
åœ¨è¿™ä¸¤ä¸ªæ­¥éª¤ä¹‹é—´ \TeX\ è®¾å®šè¿™äº›å‘½ä»¤çš„å€¼å¦‚ä¸‹ï¼š
\ulist\compact
\li |\firstmark| åŒ…å«é¡µé¢ç¬¬ä¸€ä¸ªæ&nbsp;‡è®°çš„è®°å·åˆ—ã€‚
\li |\botmark| åŒ…å«é¡µé¢æœ€åŽä¸€ä¸ªæ&nbsp;‡è®°çš„è®°å·åˆ—ã€‚
\li |\topmark| åŒ…å«ç´§è·Ÿåœ¨é¡µé¢ä¸Šè¾¹çš„é‚£ä¸ªæ&nbsp;‡è®°çš„è®°å·åˆ—ã€‚
è¿™ä¸ªæ&nbsp;‡è®°å°±æ˜¯\emph{ä¸Šä¸€ä¸ª}é¡µé¢çš„æœ€åŽä¸€ä¸ªæ&nbsp;‡è®°ï¼Œå³ä¸Šä¸€é¡µçš„ |\botmark|ã€‚
å¦‚æžœä¸Šä¸€é¡µæ²¡æœ‰æ&nbsp;‡è®°æ­¤å‘½ä»¤ä¸ºç©ºã€‚
\endulist
\noindent
å¦‚æžœæ­¤é¡µé¢æ²¡æœ‰ä»»ä½•æ&nbsp;‡è®°ï¼Œ\TeX\ è®¾å®š |\firstmark| å’Œ |\botmark| éƒ½ç­‰äºŽ |\topmark|ï¼Œ
å³å‰é¢æœ€è¿‘çš„é‚£ä¸ªæ&nbsp;‡è®°ã€‚
\knuth{ç¬¬~258~é¡µ}åº•éƒ¨çš„è¡¨æ&nbsp;¼è¯´æ˜Žäº† |\firstmark|ã€|\botmark| å’Œ |\topmark| è¿™ä¸‰è€…çš„å…³ç³»ã€‚
\enddesc

\begindesc
\cts splitfirstmark {}
\cts splitbotmark {}
\explain
%^^{marks//for split lists}
%These commands expand to the ^{mark text} generated by an earlier
%^|\mark| command that produced an item in the item list of a vbox $V$.
%The mark text has the form of a token list.
%When \TeX\
%splits $V$ in response to a ^|\vsplit| command (\xref \vsplit),
%it sets the values of these commands as follows:
%\ulist\compact
%\li |\splitfirstmark| contains the tokens of the first mark in
%the item list of $V$.
%\li |\splitbotmark| contains the tokens of the last mark in
%the item list of $V$.
%\endulist
%These commands produce no tokens if there was no preceding |\vsplit|,
%or if the most recent preceding |\vsplit| didn't contain any marks.
%\eix^^{marks}
^^{æ&nbsp;‡è®°//ç”¨äºŽåˆ†å‰²åˆ—è¡¨}
è¿™ä¸¤ä¸ªå‘½ä»¤å±•å¼€ä¸ºä¹‹å‰ç”¨ ^|\mark| åœ¨ç«–ç›´ç›’å­ $V$ ä¸­ç”Ÿæˆçš„æ&nbsp;‡è®°é¡¹çš„æ&nbsp;‡è®°æ–‡æœ¬ã€‚
æ&nbsp;‡è®°æ–‡æœ¬ä»¥è®°å·åˆ—å½¢å¼è¡¨ç¤ºã€‚
å½“ä½&nbsp;ç”¨ ^|\vsplit| å‘½ä»¤ï¼ˆ\xref \vsplit ï¼‰åˆ†å‰² $V$ æ—¶ï¼Œ
\TeX\ æŒ‰å¦‚ä¸‹æ–¹å¼è®¾å®šè¿™ä¸¤ä¸ªå‘½ä»¤çš„å€¼ï¼š
\ulist\compact
\li |\splitfirstmark| åŒ…å« $V$ ä¸­ç¬¬ä¸€ä¸ªæ&nbsp;‡è®°çš„è®°å·åˆ—ã€‚
\li |\splitbotmark| åŒ…å« $V$ ä¸­æœ€åŽä¸€ä¸ªæ&nbsp;‡è®°çš„è®°å·åˆ—ã€‚
\endulist
å¦‚æžœæ²¡æœ‰ |\vsplit| å‘½ä»¤ï¼Œæˆ–è€…å‰é¢æœ€è¿‘çš„ |\vsplit| ä¸åŒ…å«ä»»ä½•æ&nbsp;‡è®°ï¼Œ
è¿™ä¸¤ä¸ªå‘½ä»¤ä¸ç”Ÿæˆè®°å·åˆ—ã€‚
\eix^^{æ&nbsp;‡è®°}
\enddesc

%==========================================================================
%\section {Insertions}
\section {æ’å…¥é¡¹}

%\subsection {Footnotes}
\subsection {è„šæ³¨}

\begindesc
\easy\cts footnote {\&lt;argument$_1$&gt; \&lt;argument$_2$&gt;}
\cts vfootnote {\&lt;argument$_1$&gt; \&lt;argument$_2$&gt;}
\explain
%These commands produce footnotes.
%\&lt;argument$_1$&gt; is the ``^{reference mark}''
%for the footnote and \&lt;argument$_2$&gt; is its text.
%The text can be several paragraphs long if necessary and can contain
%constructs such as math displays, but it shouldn't contain any
%\minref{insertion}s (such as other footnotes).
è¿™ä¸¤ä¸ªå‘½ä»¤ç”¨äºŽç”Ÿæˆè„šæ³¨ã€‚
å…¶ä¸­ \&lt;argument$_1$&gt; æ˜¯è„šæ³¨çš„â€œ^{å‚è€ƒç¬¦å·}â€ï¼Œ
è€Œ \&lt;argument$_2$&gt; æ˜¯è„šæ³¨æ–‡æœ¬ã€‚
è„šæ³¨æ–‡æœ¬å¿…è¦æ—¶å¯ä»¥åŒ…å«å¤šä¸ªæ®µè½ï¼Œä¹Ÿå¯ä»¥åŒ…å«é™ˆåˆ—å…¬å¼ç­‰å…¶ä»–æž„é€&nbsp;ï¼Œ
ä½†ä¸åº”è¯¥åŒ…å«ä»»ä½•\minref{æ’å…¥é¡¹}ï¼ˆæ¯”å¦‚å…¶ä»–è„šæ³¨ï¼‰ã€‚

%You shouldn't use these commands inside a subformula of a math formula,
%in a box within a box being contributed to a page,
%or in an insertion of any kind.
%If you're unsure whether these restrictions apply, you can be safe by
%only using |\footnote| and |\vfootnote| directly within a paragraph or
%between paragraphs.
åœ¨æ•°å­¦å…¬å¼çš„å­å…¬å¼ä¸­ï¼Œæˆ–è€…ç»„æˆé¡µé¢çš„ç›’å­çš„å­ç›’å­ä¸­ï¼Œ
æˆ–è€…ä»»ä½•å½¢å¼çš„æ’å…¥é¡¹ä¸­ï¼Œä½&nbsp;éƒ½ä¸åº”è¯¥ä½¿ç”¨è¿™äº›å‘½ä»¤ã€‚
å¦‚æžœä½&nbsp;ä¸ç¡®å®šè¿™äº›é™åˆ¶å‡ºçŽ°åœ¨å“ªé‡Œï¼Œä¸ºå®‰å…¨èµ·è§ï¼Œ
ä½&nbsp;å¯ä»¥åªåœ¨æ®µè½å†…æˆ–è€…æ®µè½é—´ç›´æŽ¥ä½¿ç”¨ |\footnote| å’Œ |\vfootnote|ã€‚

%These restrictions aren't as severe as they seem because you can use
%|\vfootnote| to footnote most anything.
%Both |\foot!-note| and |\vfoot!-note| insert the reference mark in front of the
%footnote itself, but |\vfoot!-note| doesn't insert the reference mark into the
%text.
%Thus, when you use |\vfoot!-note| you can
%explicitly insert the reference mark
%wherever it belongs without concern about the context
%and place the |\vfootnote| in the next paragraph.
%If you find that the footnote lands on
%the page following the one where it belongs, move the |\vfootnote| back
%to the previous paragraph.
%There are rare circumstances where you'll need to
%alter the text of your document in order to get a footnote to appear on
%the same page as its reference mark.
è¿™äº›é™åˆ¶æ²¡çœ‹èµ·æ¥é‚£ä¹ˆä¸¥é‡ï¼Œå›&nbsp;ä¸ºä½&nbsp;å¯ä»¥ç”¨ |\vfootnote| å‘½ä»¤æ·»åŠ&nbsp;å‡&nbsp;ä¹Žä»»ä½•å†…å®¹çš„è„šæ³¨ã€‚
|\foot!-note| å’Œ |\vfoot!-note| éƒ½ä¼šåœ¨è„šæ³¨å‰é¢æ’å…¥å‚è€ƒç¬¦å·ï¼Œ
åŒºåˆ«åœ¨äºŽ |\vfoot!-note| ä¸ä¼šåœ¨æ­£æ–‡ä¸­æ’å…¥å‚è€ƒç¬¦å·ã€‚
å›&nbsp;æ­¤ï¼Œä½&nbsp;å¯ä»¥ä¸ç”¨è€ƒè™‘ä¸Šä¸‹æ–‡çš„é™åˆ¶ï¼Œ
æ˜¾å¼åœ°å°†å‚è€ƒç¬¦å·æ”¾åˆ°å®ƒåº”è¯¥åœ¨çš„åœ°æ–¹ï¼Œç„¶åŽåœ¨ä¸‹ä¸€ä¸ªæ®µè½ä½¿ç”¨ |\vfootnote| å‘½ä»¤ã€‚
è¿™å¯èƒ½ä¼šå¯¼è‡´è„šæ³¨è·‘åˆ°ä¸‹ä¸€é¡µåŽ»ï¼Œæ­¤æ—¶ä½&nbsp;å¯ä»¥å°† |\vfootnote| å‘½ä»¤ç§»åŠ¨åˆ°ä¸Šä¸€ä¸ªæ®µè½ä¸­ã€‚
åœ¨æžå°‘æƒ…å†µä¸‹ï¼Œä½&nbsp;éœ€è¦ä¿®æ”¹æ–‡æ¡£æ­£æ–‡ï¼Œä»¥è®©è„šæ³¨å’Œå‚è€ƒç¬¦å·å‡ºçŽ°åœ¨åŒä¸€é¡µä¸­ã€‚
\example
To quote the mathematician P\'olya is a ploy.\footnote
*{This is an example of an anagram, but not a strict one.}
|
\produces
To quote the mathematician P\'olya is a ploy.*
\par\line{\hskip .5in \vdots\hfil}
\nointerlineskip \bigskip
\footnoterule\par\parindent = 12pt
\textindent{*}This is
an example of an anagram, but not a strict one.
\endexample
\example
$$f(t)=\sigma\sigma t\;\raise 1ex \hbox{\dag}$$
\vfootnote \dag{The $\sigma\sigma$ notation was explained in
the previous section.}
|
\produces
$$f(t)=\sigma\sigma t\&gt;\raise 1ex \hbox{\dag}$$
\par\line{\hskip .5in \vdots\hfil}
\nointerlineskip \bigskip
\footnoterule\par\parindent = 12pt
\textindent{\dag}{The $\sigma\sigma$ notation was explained in
the previous section.}
\endexample
\enddesc

%==========================================================================
%\subsection {General insertions}
\subsection {ä¸€èˆ¬æ’å…¥é¡¹}

%\begindesc
%\bix^^{insertions//commands for}
%\cts topinsert {\&lt;vertical mode material&gt; {\bt \\endinsert}}
%\cts midinsert {\&lt;vertical mode material&gt; {\bt \\endinsert}}
%\cts pageinsert {\&lt;vertical mode material&gt; {\bt \\endinsert}}
%\explain
%These commands produce different forms of insertions that
%instruct
%(or allow) \TeX\ to relocate the \&lt;vertical mode material&gt;:
%\ulist
%\li |\topinsert| attempts to put the material at the top of the current page.
%If it won't fit there, |\topinsert|
%will move the material to the next available top of page.
%\li |\midinsert| attempts to put the material at the current position.
%If it won't fit there, |\midinsert|
%will move the material to the next available top of page.
%\li |\pageinsert| puts the material by itself on the next page.
%To avoid an underfull page, be sure to end the inserted material with
%|\vfil| or fill out the excess space some other way.
%% Knuth doesn't say this, but I tried an experiment that verified it.
%% Nor does he say explicitly that an insertion does a \par.
%\endulist
%\noindent
%The \&lt;vertical mode material&gt;
%is said to be ``floating'' ^^{floating material} because \TeX\
%can move it from one place to another.
%Insertions are very useful for material such as figures and tables because
%you can position such material where you want it without knowing where the
%page breaks will fall.
\begindesc
\bix^^{æ’å…¥é¡¹//ç”¨äºŽæ’å…¥é¡¹çš„å‘½ä»¤}
\cts topinsert {\&lt;vertical mode material&gt; {\bt \\endinsert}}
\cts midinsert {\&lt;vertical mode material&gt; {\bt \\endinsert}}
\cts pageinsert {\&lt;vertical mode material&gt; {\bt \\endinsert}}
\explain
è¿™äº›å‘½ä»¤ç”Ÿæˆä¸åŒå½¢å¼çš„æ’å…¥é¡¹ï¼Œ
å®ƒä»¬æŒ‡ç¤ºï¼ˆæˆ–è€…å…è®¸ï¼‰\TeX\ é‡æ–°æ”¾ç½® \&lt;vertical mode material&gt;ï¼š
\ulist
\li |\topinsert| è¯•å›¾å°†å†…å®¹æ”¾åœ¨å½“å‰é¡µçš„é¡¶éƒ¨ã€‚
å¦‚æžœé‚£é‡Œæ”¾ä¸ä¸‹ï¼Œ|\topinsert| å°†æŠŠè¯¥å†…å®¹ç§»åŠ¨åˆ°é¡¶éƒ¨å¯æ”¾ä¸‹çš„ä¸‹ä¸€ä¸ªé¡µé¢ã€‚
\li |\midinsert| è¯•å›¾å°†å†…å®¹æ”¾åœ¨å½“å‰ä½ç½®ï¼Œ
å¦‚æžœå½“å‰ä½ç½®æ”¾ä¸ä¸‹ï¼Œ|\midinsert| å°†æŠŠè¯¥å†…å®¹ç§»åŠ¨åˆ°é¡¶éƒ¨å¯æ”¾ä¸‹çš„ä¸‹ä¸€ä¸ªé¡µé¢ã€‚
\li |\pageinsert| å°†æŠŠå†…å®¹å•ç‹¬æ”¾åœ¨ä¸‹ä¸€é¡µã€‚
ä¸ºå…å¾—åˆ°æ¾æ•£é¡µé¢ï¼Œä¸è¦å¿˜è®°åœ¨å†…å®¹æœ€åŽç”¨ |\vfil| å‘½ä»¤æˆ–è€…å…¶ä»–æ–¹å¼å¡«æ»¡é¡µé¢ã€‚
% Knuth doesn't say this, but I tried an experiment that verified it.
% Nor does he say explicitly that an insertion does a \par.
\endulist
\noindent
ç”±äºŽ \TeX\ å¯ä»¥ç§»åŠ¨\&lt;vertical mode material&gt;çš„ä½ç½®ï¼Œæˆ‘ä»¬ç§°å®ƒä¸ºâ€œæµ®åŠ¨ä½“â€ã€‚^^{æµ®åŠ¨ä½“}
æ’å…¥é¡¹å¯¹äºŽå›¾å½¢å’Œè¡¨æ&nbsp;¼éžå¸¸æœ‰ç”¨ï¼Œ
å›&nbsp;ä¸ºä½&nbsp;å¯ä»¥å°†å®ƒä»¬æ”¾åœ¨æ‰€éœ€çš„åœ°æ–¹ï¼Œè€Œä¸ç”¨ç®¡å“ªé‡Œä¼šåˆ†é¡µã€‚

%Each of these commands implicitly ends the current paragraph, so
%you should use them only between paragraphs.
%You should not use them within a box or within another insertion.
%If you have several insertions competing for
%the same space, \TeX\ will retain their relative order.
è¿™äº›å‘½ä»¤æ¯ä¸ªéƒ½ä¼šç»“æŸå½“å‰æ®µè½ï¼Œå›&nbsp;æ­¤ä½&nbsp;åº”è¯¥ä»…åœ¨æ®µè½ä¹‹é—´ä½¿ç”¨å®ƒä»¬ã€‚
ä½&nbsp;ä¹Ÿä¸è¦åœ¨ç›’å­å†…éƒ¨æˆ–è€…å¦ä¸€ä¸ªæ’å…¥é¡¹å†…éƒ¨ä½¿ç”¨å®ƒä»¬ã€‚
å¦‚æžœæœ‰å¤šä¸ªæ’å…¥é¡¹è¦æ”¾åœ¨åŒä¸€ä¸ªä½ç½®ï¼Œ\TeX\ å°†ä¿æŒå®ƒä»¬çš„å…ˆåŽé¡ºåºã€‚
\example
\pageinsert
% This text will appear on the following page, by itself.
This page is reserved for a picture of the Queen of Hearts
sharing a plate of oysters with the Walrus and
the Carpenter.
\endinsert
|
\endexample
\enddesc

\begindesc
\cts endinsert {}
\explain
%This command ends an insertion started by
%|\topinsert|, |\midinsert|, or |\pageinsert|.
æ­¤å‘½ä»¤ç»“æŸç”± |\topinsert|ã€|\midinsert| æˆ– |\pageinsert| å‘½ä»¤å¼€å§‹çš„æ’å…¥é¡¹ã€‚
\enddesc

\begindesc
\cts insert {\&lt;number&gt; \rqbraces{\&lt;vertical mode material&gt;}}
\explain
%\minrefs{insertion}
%This primitive command provides the
%underlying mechanism for constructing insertions, but
%it is hardly ever used outside of a \minref{macro} definition.
%The definitions of the
%|\foot!-note|, |\vfoot!-note|,
%|\top!-insert|, |\mid!-insert|, and |\page!-insert| commands are
%all built around |\insert|.
%^^|\topinsert|
%^^|\midinsert| ^^|\pageinsert| ^^|\footnote| ^^|\vfootnote|
\minrefs{insertion}
è¿™ä¸ªåŽŸå§‹å‘½ä»¤æä¾›äº†æž„é€&nbsp;æ’å…¥é¡¹çš„å†…éƒ¨æœºåˆ¶ï¼Œ
ä½†é™¤äº†åœ¨å®šä¹‰\minref{å®}æ—¶ä¼šç”¨åˆ°ï¼Œå…¶ä»–æ—¶å€™å¾ˆå°‘ç”¨åˆ°å®ƒã€‚
|\foot!-note|ã€|\vfoot!-note|ã€|\top!-insert|ã€|\mid!-insert| å’Œ
|\page!-insert| å‘½ä»¤çš„å®šä¹‰éƒ½å»ºç«‹åœ¨ |\insert| å‘½ä»¤ä¹‹ä¸Šã€‚
^^|\topinsert|
^^|\midinsert| ^^|\pageinsert| ^^|\footnote| ^^|\vfootnote|

%When you design insertions for a document, you should assign a different
%integer code\footnote
%{\texbook{} uses the term ``class'' for a code.
%We use a different term to avoid confusion with the other meaning of
%``class'' (\xref{class}).}
%$n$ to each kind of insertion,
%using the ^|\newinsert| command (\xref{\@newinsert}) to obtain the
%integer codes.
%The |\insert| command itself appends the \&lt;vertical mode material&gt;
%to the current horizontal or \minref{vertical list}.
%Your \minref{output routine} is responsible for
%moving the inserted material from where it resides in |\box|$\,n$
%to an output page.
%^^{output routine}
è®¾è®¡æ–‡æ¡£çš„æ’å…¥é¡¹æ—¶ï¼Œä¸åŒçš„æ’å…¥é¡¹éœ€è¦åˆ†é…ä¸åŒçš„æ•´æ•°ä»£ç&nbsp;\footnote
{\texbook{} ç”¨â€œç±»â€è¿™ä¸ªæœ¯è¯­è¡¨ç¤ºæ­¤ä»£ç&nbsp;ã€‚
ä¸ºé¿å…å’Œâ€œç±»â€ï¼ˆ\xref{ç±»}ï¼‰çš„å…¶ä»–æ„æ€æ··æ·†ï¼Œæˆ‘ä»¬ç”¨ä¸åŒçš„æœ¯è¯­ã€‚}
$n$ï¼Œè¿™ä¸ªä»£ç&nbsp;å¯ä»¥ç”¨ ^|\newinsert| å‘½ä»¤ï¼ˆ\xref{\@newinsert}ï¼‰å¾—åˆ°ã€‚
|\insert|å‘½ä»¤æœ¬èº«ä»…æ·»åŠ&nbsp; \&lt;vertical mode material&gt; åˆ°å½“å‰æ°´å¹³åˆ—æˆ–\minref{ç«–ç›´åˆ—}ã€‚
è€Œ\minref{è¾“å‡ºä¾‹è¡Œç¨‹åº}è´Ÿè´£ç§»åŠ¨|\box|$\,n$ä¸­çš„æ’å…¥å†…å®¹åˆ°è¾“å‡ºé¡µé¢ã€‚
^^{è¾“å‡ºä¾‹è¡Œç¨‹åº}

%\TeX\ groups together all insertions having the same code
%number.  Each insertion
%code $n$ has four \minref{register}s associated with it:
%\ulist
%\li |\box|$\,n$ is where \TeX\ accumulates the material for insertions
%with code $n$.  When \TeX\ breaks a page, it puts into |\box|$\,n$
%as much insertion $n$ material as will fit on the page.
%Your output routine should then move this material to the actual page.
%You can use ^|\ifvoid| \ctsref{\@ifvoid}
%to test if there is any material in |\box|$\,n$.
%If not all the material fits, \TeX\ saves the leftovers for the next page.
%\li |\count|$\,n$ is a magnification factor $f.$  When \TeX\ is computing
%the vertical space occupied on the page
%by insertion $n$ material, it multiplies the
%vertical extent of this material by $f/1000$.
%Thus you would ordinarily set $f$ to $500$ for a double-column insertion
%and to $0$ for a marginal~note.
%\li |\dimen|$\,n$ specifies the maximum amount
%of insertion $n$ material that \TeX\ will put on a single page.
%\li |\skip|$\,n$ specifies extra space that \TeX\ allocates on the page
%if the page contains any insertion $n$ material.
%This space is in addition to the space occupied by the insertion itself.
%For example, it would account for the space on a page above the footnotes
%(if there are~any).
%\endulist
%\noindent
%\TeX\ sets |\box|$\,n$, and you should set the other three registers
%so that \TeX\ can correctly compute the vertical space required by the
%insertion.
%See \knuth{pages~122--125} for further details of how \TeX\ processes this
%command and of how insertions interact with page breaking.
%\xrdef{endofinsert}
\TeX\ å°†æ‰€æœ‰æ’å…¥é¡¹æŒ‰ç…§å®ƒä»¬çš„ä»£ç&nbsp;åˆ†ç»„ã€‚æ¯ä¸ªæ’å…¥ä»£ç&nbsp;å…³è”å››ä¸ª\minref{å¯„å­˜å™¨}ï¼š
\ulist
\li |\box|$\,n$ ç»™ \TeX\ ç”¨äºŽç´¯ç§¯ç¬¬ $n$ ç§æ’å…¥å†…å®¹ã€‚
\TeX\ åˆ†é¡µæ—¶ä¼šå°½å¯èƒ½å¤šåœ°å¾€ |\box|$\,n$ ä¸­æ”¾å…¥ç¬¬$n$ ç§æ’å…¥é¡¹ã€‚
ç„¶åŽè¾“å‡ºä¾‹è¡Œç¨‹åºå°†æŠŠè¿™äº›å†…å®¹ç§»åŠ¨äº†å®žé™…é¡µé¢ä¸Šã€‚
ä½&nbsp;å¯ä»¥ç”¨ ^|\ifvoid| å‘½ä»¤\ctsref{\@ifvoid}æ£€æŸ¥ |\box|$\,n$ ä¸­æ˜¯å¦æœ‰ä»»ä½•å†…å®¹ã€‚
å¦‚æžœä¸èƒ½æ”¾ä¸‹å…¨éƒ¨å†…å®¹ï¼Œ\TeX\ å°†æŠŠå‰©ä¸‹å†…å®¹ç•™åˆ°ä¸‹ä¸€é¡µã€‚
\li |\count|$\,n$ ä¸ºæ”¾å¤§å›&nbsp;å­ $f$ã€‚
\TeX\ è®¡ç®—ç¬¬$n$ç§æ’å…¥é¡¹æ‰€å&nbsp;ç”¨çš„é¡µé¢çºµå‘ç©ºé—´æ—¶ï¼Œå°†æŠŠæ’å…¥å†…å®¹çš„çºµå‘é•¿åº¦ä¹˜ä»¥$f/1000$ã€‚
å›&nbsp;æ­¤å¯¹åŒæ&nbsp;æ’å…¥é¡¹é€šå¸¸è®¾ $f$ ä¸º $500$ï¼Œè€Œå¯¹è¾¹æ³¨é¡¹è®¾ä¸º $0$ã€‚
\li |\dimen|$\,n$ è®¾å®šæ¯é¡µæ”¾ç½®çš„ç¬¬$n$ç§æ’å…¥é¡¹çš„æœ€å¤§æ•°ç›®ã€‚
\li |\skip|$\,n$ è®¾å®šé¡µé¢åŒ…å«ç¬¬ $n$ ç§æ’å…¥é¡¹æ—¶ \TeX\ æ·»åŠ&nbsp;çš„é¢å¤–é—´éš”ã€‚
è¿™ä¸ªé—´éš”ä¸åŒ…å«è¯¥æ’å…¥é¡¹æœ¬èº«å&nbsp;ç”¨çš„ç©ºé—´ã€‚
ä¾‹å¦‚ï¼Œå½“é¡µé¢åŒ…å«è„šæ³¨æ—¶ï¼Œå°±ä¼šç”¨åˆ°æ­¤é—´éš”ã€‚
\endulist
\noindent
\TeX\ åªè®¾å®š |\box|$\,n$ï¼Œä½&nbsp;éœ€è¦è®¾å®šå…¶ä»–ä¸‰ä¸ªå¯„å­˜å™¨ï¼Œ
ä»¥è®© \TeX\ æ­£ç¡®è®¡ç®—æ’å…¥é¡¹æ‰€éœ€çš„ç«–ç›´ç©ºé—´ã€‚
\knuth{ç¬¬~122--125~é¡µ} ä¸­è¯¦ç»†ä»‹ç»äº† \TeX\ å¦‚ä½•å¤„ç†æ­¤å‘½ä»¤ï¼Œ
ä»¥åŠæ’å…¥é¡¹å’Œåˆ†é¡µæ–¹å¼ä¹‹é—´çš„å…³ç³»ã€‚
\xrdef{endofinsert}
\enddesc

%\see |\floatingpenalty| (\xref \floatingpenalty).
%\eix^^{insertions//commands for}
\see |\floatingpenalty| (\xref \floatingpenalty).
\eix^^{æ’å…¥é¡¹//ç”¨äºŽæ’å…¥é¡¹çš„å‘½ä»¤}


%==========================================================================
%\section{Modifying the output routine}
\section{ä¿®æ”¹è¾“å‡ºä¾‹è¡Œç¨‹åº}

%\bix^^{output routine}
%\begindesc
%\cts output {\param{token list}}
%\explain
%This parameter contains the current \minref{output routine}, i.e.,
%the token list that \TeX\ expands when it finds a page break.
%\TeX\ puts the page into ^|\box255|, so |\output| is responsible
%for doing something with |\box255|---either shipping it out or
%putting it somewhere else.
%The output routine is also responsible for attaching things such as
%headers and footers.
%\enddesc
\bix^^{è¾“å‡ºä¾‹è¡Œç¨‹åº}
\begindesc
\cts output {\param{token list}}
\explain
è¿™ä¸ªå‚æ•°åŒ…å«äº†å½“å‰çš„ \minref{è¾“å‡ºä¾‹è¡Œç¨‹åº}ï¼Œ
ä¹Ÿå°±æ˜¯ \TeX\ å½“å‘çŽ°ä¸€ä¸ªæ–­é¡µç‚¹çš„æ—¶å€™ä¼šå±•å¼€çš„ä¸€ä¸ªç¬¦å·åˆ—è¡¨ã€‚
\TeX\ æŠŠå½“å‰é¡µé¢æ”¾å…¥ ^|\box255|ï¼Œæ‰€ä»¥ |\output| è´Ÿè´£å¯¹ |\box255| è¿›è¡Œå¤„ç†%
â€”â€”ä¸ç®¡æ˜¯æŠŠå®ƒè¾“å‡ºåˆ° dvi è¿˜æ˜¯æŠŠå®ƒæ”¾åˆ°åˆ«çš„ä»€ä¹ˆåœ°æ–¹åŽ»ã€‚
è¾“å‡ºä¾‹è¡Œç¨‹åºä¹Ÿè´Ÿè´£æŠŠé¡µçœ‰å’Œé¡µè„šé™„åŠ&nbsp;åˆ°é¡µé¢ä¸Šã€‚
\enddesc

%\begindesc
%\cts plainoutput {}
%\explain
%This command invokes \plainTeX's output routine.
%^^{output routine//default in \plainTeX}
%\PlainTeX\ defines ^|\output| as
%a token list containing the single token |\plainoutput|.
%\enddesc

\begindesc
\cts plainoutput {}
\explain
è¿™ä¸ªå‘½ä»¤è°ƒç”¨ \plainTeX\ çš„è¾“å‡ºä¾‹è¡Œç¨‹åºã€‚
^^{è¾“å‡ºä¾‹è¡Œç¨‹åº//\plainTeX\ çš„é»˜è®¤ç¨‹åº}
\PlainTeX\ æŠŠ ^|\output| å®šä¹‰ä¸ºä¸€ä¸ªä»…ä»…åŒ…å« |\plainoutput| çš„ç¬¦å·åˆ—è¡¨ã€‚
\enddesc


%\begindesc
%\cts shipout {\&lt;box&gt;}
%\explain
%This command instructs \TeX\ to send \&lt;box&gt; to the \dvifile.
%^^{\dvifile//receives boxes from \b\tt\\shipout\e}
%\TeX\ expands any |\write| command in \&lt;box&gt; as part of |\shipout|.
%^^|\write//expanded during {\tt\\shipout}|
%The principal use of |\shipout| is in the output routine, but you can
%use it anywhere.
%\enddesc

\begindesc
\cts shipout {\&lt;box&gt;}
\explain
è¿™ä¸ªå‘½ä»¤è®© \TeX\ æŠŠ \&lt;box&gt; è¾“å‡ºåˆ° \dvifile.
^^{\dvifile//æŽ¥æ”¶ \b\tt\\shipout\e çš„ç›’å­}
\TeX\ åœ¨ |\shipout| æ—¶ï¼ŒæŠŠ \&lt;box&gt; ä¸­çš„ä»»ä½• |\write| å‘½ä»¤è¿›è¡Œå±•å¼€ã€‚
^^|\write// åœ¨ {\tt\\shipout} æ—¶è¿›è¡Œå±•å¼€|
|\shipout| çš„ä¸»è¦ç”¨é€”æ˜¯åœ¨è¾“å‡ºä¾‹è¡Œç¨‹åºä¸­ï¼Œä¸è¿‡ä½&nbsp;å¯ä»¥åœ¨ä»»ä½•å…¶ä»–åœ°æ–¹ä½¿ç”¨è¿™ä¸ªå‘½ä»¤ã€‚
\enddesc


%\begindesc
%\cts deadcycles {\param{number}}
%\explain
%This parameter contains the number of times that \TeX\ has initiated
%the \minref{output routine} since the last time it did a
%^^|\shipout| |\ship!-out|.\footnote{
%More precisely, \TeX\ sets |\dead!-cyles| to $0$ whenever it executes
%|\ship!-out|
%and increments it by $1$ whenever it executes |\output|.}
%If |\deadcycles| gets too big, you've probably gotten
%\TeX\ into a loop, e.g., one where the page builder is trying the same page
%break over and over again.
%\enddesc

\begindesc
\cts deadcycles {\param{number}}
\explain
è¿™ä¸ªå‚æ•°åŒ…å«è¿™ \TeX\ åœ¨ä¸Šæ¬¡ ^^|\shipout| |\ship!-out|
åŽå·²ç»åˆå§‹åŒ–çš„\minref{è¾“å‡ºä¾‹è¡Œç¨‹åº}çš„ä¸ªæ•°ã€‚
\footnote{æ›´åŠ&nbsp;å‡†ç¡®åœ°è¯´ï¼Œ \TeX\ åœ¨æ‰§è¡Œ |\ship!-out| çš„æ—¶å€™ï¼Œ
æŠŠ |\dead!-cycles| å½’ $0$ï¼Œç„¶åŽæ¯æ¬¡æ‰§è¡Œ |\output| çš„æ—¶å€™æŠŠå®ƒå¢žåŠ&nbsp; $1$ã€‚}
å¦‚æžœ |\deadcycles| å˜å¾—å¤ªå¤§ï¼Œé‚£ä½&nbsp;å¾ˆæœ‰å¯èƒ½æŠŠ \TeX\ å¼„æ­»å¾ªçŽ¯äº†ï¼Œ
ä¹Ÿå°±æ˜¯è¯´ï¼Œå¾ªçŽ¯å¾€å¤åœ°å¯¹åŒä¸€ä¸ªé¡µé¢è¿›è¡Œåˆ†é¡µæ“ä½œã€‚
\enddesc


%\begindesc
%\cts maxdeadcycles {\param{number}}
%\explain
%If the value of |\deadcycles| exceeds the value of |\maxdeadcycles|,
%\TeX\ assumes that the output routine has gotten into a loop.
%\TeX\ then complains and runs its own simple output routine,
%equivalent to |\shipout!allowbreak\box255|,
%that is likely to break the loop.
%\PlainTeX\ sets |\maxdeadcycles| \hbox{to $25$}.
%\enddesc

\begindesc
\cts maxdeadcycles {\param{number}}
\explain
å¦‚æžœ |\deadcycles| è¶…è¿‡äº† |\maxdeadcycles|ï¼Œé‚£ \TeX\ å°±ä¼šå‡å®šè¾“å‡ºä¾‹è¡Œç¨‹åºè¢«ç”¨æˆ·æ­»å¾ªçŽ¯äº†ï¼Œ
\TeX\ è¿™ä¸ªæ—¶å€™å°±ä¼šæŠ¥é”™ï¼Œå¹¶ä¸”æ‰§è¡Œå®ƒè‡ªå·±é»˜è®¤çš„ç®€å•è¾“å‡ºä¾‹è¡Œç¨‹åºï¼Œä¹Ÿå°±æ˜¯ |\shipout!allowbreak\box255|ï¼Œ
ä»¥æœŸæœ›ä»Žå¾ªçŽ¯ä¸­è·³å‡ºã€‚\PlainTeX\ æŠŠ |\maxdeadcycles| è®¾ç½®ä¸º \hbox{$25$}ã€‚
\enddesc

%\begindesc
%\cts outputpenalty {\param{number}}
%\explain
%\TeX\ sets this parameter when it breaks a page.  If the breakpoint was at a
%\minref{penalty} item, \TeX\ removes the penalty item and
%sets |\outputpenalty| to the penalty value at
%the breakpoint; otherwise it sets |\outputpenalty| \hbox{to $0$}.
%
%Suppose that you are undoing a page break
%in order to break the page at a different place than the one that \TeX\
%has just chosen.  In order to reconstruct the page, you need to recreate
%the penalty at \TeX's chosen breakpoint.
%You can accomplish this with the command
%|\penalty!allowbreak\outputpenalty|.
%\enddesc

\begindesc
\cts outputpenalty {\param{number}}
\explain
\TeX\ åœ¨æ–­é¡µçš„æ—¶å€™è®¾ç½®è¿™ä¸ªå‚æ•°ã€‚
å¦‚æžœæ–­ç‚¹æ˜¯åœ¨ä¸€ä¸ª \minref{æƒ©ç½š} çš„é¡¹ç›®ä¸Šï¼Œ\TeX\ å°±ä¼šç§»é™¤è¿™ä¸ªæƒ©ç½šï¼Œ
ç„¶åŽæŠŠ |\outputpenalty| è®¾ç½®æˆæ–­ç‚¹å¤„çš„å€¼ï¼Œ å¦åˆ™ |\outputpenalty| å°±è¢«è®¾æˆ \hbox{$0$}ã€‚

å¦‚æžœä½&nbsp;å¸Œæœ›åœ¨ \TeX\ é€‰æ‹©çš„æ–­ç‚¹ä¹‹å¤–çš„çš„å…¶ä»–åœ°æ–¹æ–­é¡µï¼Œè€Œä¸åœ¨è¯¥æ–­ç‚¹å¤„æ–­é¡µï¼Œ
é‚£ä¹ˆåœ¨é‡æž„è¿™ä¸ªé¡µé¢æ—¶ï¼Œä½&nbsp;å°±éœ€è¦åœ¨ \TeX\ é€‰æ‹©çš„æ–­ç‚¹å¤„é‡æ–°è®¾ç½®è¿™ä¸ªæƒ©ç½šã€‚
ä½&nbsp;å¯ä»¥é€šè¿‡ |\penalty!allowbreak\outputpenalty| æ¥è¾¾åˆ°è¿™ä¸ªç›®çš„ã€‚
\enddesc


%\begindesc
%\cts holdinginserts {\param{number}}
%\explain
%If this parameter is greater than $0$ when \TeX\
%is processing a page break, \TeX\ will refrain from processing insertions.
%Setting this parameter to $1$
%can be useful when you're writing an output routine
%that needs to reprocess the contents of the page, e.g.,
%an output routine that uses a value of |\vsize| (\xref \vsize) different from
%the one used by the page builder.
%
%\eix^^{output routine}
%\enddesc

\begindesc
\cts holdinginserts {\param{number}}
\explain

å½“ \TeX\ åœ¨å¤„ç†ä¸€ä¸ªæ–­é¡µæ—¶ï¼Œè¿™ä¸ªå‚æ•°å¦‚æžœå¤§äºŽ $0$ï¼Œ é‚£ä¹ˆ \TeX\ å°±ä¼šé˜»æ­¢å¤„ç†æ’å…¥ã€‚
å½“ä½&nbsp;å†™ä¸€ä¸ªè¾“å‡ºä¾‹è¡Œç¨‹åºçš„æ—¶å€™ï¼Œå¦‚æžœä½&nbsp;å¸Œæœ›é‡æ–°å¤„ç†è¯¥é¡µçš„å†…å®¹ï¼Œ
ï¼ˆä¾‹å¦‚è¾“å‡ºä¾‹è¡Œç¨‹åºæœ¬èº«ç”¨çš„ |\vsize| (\xref \vsize) å’Œæ–­é¡µç¨‹åºç”¨çš„å¹¶éžç›¸åŒå€¼ï¼‰ï¼Œ
é‚£ä¹ˆæŠŠè¿™ä¸ªå‚æ•°è®¾ä¸º $1$ å°±ä¼šå¾ˆæœ‰ç”¨ã€‚

\eix^^{è¾“å‡ºä¾‹è¡Œç¨‹åº}
\enddesc


%==========================================================================
%\section {Splitting vertical lists}
\section {åˆ†å‰²ç«–ç›´åˆ—è¡¨}

%\begindesc
%\cts vsplit {\&lt;number&gt; {\bt to} \&lt;dimen&gt;}
%\explain
%This command causes \TeX\ to split the \minref{box} numbered
%\&lt;number&gt;, which we'll call $B_2$, into two parts.
%It uses the same algorithm that it would use if $B_2$ was a page
%and it was breaking that page;
%the division point then corresponds to the page break that it would find.
%The box $B_2$ must be a vbox, not an hbox.
%% we avoid starting the previous sentence with a symbol, a copyediting no-no.
%\TeX\ puts the material preceding the division point into
%another box $B_1$ and leaves the material after the division point in $B_2$.
%The |\vsplit| command then produces $B_1$.
%Normally you'd assign $B_1$ to a different
%box register, as in the example below.
%If the division point is at the end of $B_2$,
%$B_2$ will be empty after the |\vsplit|.

\begindesc
\cts vsplit {\&lt;number&gt; {\bt to} \&lt;dimen&gt;}
\explain
è¿™ä¸ªå‘½ä»¤ä½¿å¾— \TeX\ æŠŠå¯„å­˜å™¨ä¸­ç¼–å·ä¸º \&lt;number&gt; çš„\minref{ç›’å­} $B_2$ åˆ‡å‰²æˆä¸¤ä¸ªéƒ¨åˆ†ã€‚
å¦‚æžœ $B_2$ æ˜¯ä¸€ä¸ªé¡µé¢ï¼Œé‚£è¿™ä¸ªå‘½ä»¤ä¼šä½¿ç”¨ç›¸åŒçš„ç®—æ³•æ¥æŠŠè¿™ä¸ªé¡µé¢åˆ†ä¸ºä¸¤éƒ¨åˆ†ï¼›
è¿™ç§æƒ…å†µä¸‹ï¼Œåˆ†å‰²å¤„å°±æ˜¯æ–­é¡µçš„åœ°æ–¹ã€‚
$B_2$è¿™ä¸ªç›’å­å¿…é¡»æ˜¯ä¸ªç«–ç›´ç›’å­ï¼Œä¸æ˜¯æ°´å¹³ç›’å­ã€‚
\TeX\ æŠŠä»Žå¼€å¤´åˆ°åˆ†å‰²å¤„çš„éƒ¨åˆ†æ”¾åˆ°å¦ä¸€ä¸ªç›’å­ $B_1$ ä¸­ï¼Œè€ŒæŠŠåˆ†å‰²å¤„åˆ°ç»“å°¾çš„éƒ¨åˆ†æ”¾åˆ° $B_2$ ä¸­ã€‚
ç„¶åŽ |\vsplit| å°±è¾“å‡ºäº† $B_1$ è¿™ä¸ªç›’å­ã€‚
ä¸€èˆ¬æƒ…å†µä¸‹ï¼Œä½&nbsp;ä¼šç”¨ç±»ä¼¼ä¸‹é¢ä¾‹å­çš„æ–¹å¼ï¼ŒæŠŠ $B_1$ ç›’å­æŒ‡å®šåˆ°å¦ä¸€ä¸ªç›’å­å¯„å­˜å™¨ä¸­ã€‚
å¦‚æžœåˆ†å‰²å¤„æ°å¥½æ˜¯ $B_2$ ç›’å­çš„ç»“å°¾éƒ¨åˆ†ï¼Œé‚£ $B_2$ ç›’å­å°±ä¼šåœ¨ |\vsplit| åŽå˜æˆä¸€ä¸ªç©ºç›’å­ã€‚


%\TeX\ employs its usual page-breaking algorithm
%^^{page breaks//in split lists}
%for the split.
%It uses \&lt;dimen&gt; for ^|\pagegoal|, the desired height of $B_1$.
%The vertical extent of $B_1$ may not be exactly
%\&lt;dimen&gt; because \TeX\ may not be able to achieve its page goal perfectly.
%\TeX\ does not consider insertions in calculating the split,
%so insertions in the original vertical list of $B_2$ will be retained
%but won't affect the split point.

\TeX\ ä½¿ç”¨å®ƒä¸€è´¯çš„æ–­é¡µç®—æ³•æ¥åˆ†å‰²è¿™ä¸ªç«–ç›´ç›’å­ã€‚
å®ƒä½¿ç”¨ \&lt;dimem&gt; çš„é•¿åº¦æ¥æŒ‡å®š $B_1$ ç›’å­éœ€è¦çš„é«˜åº¦ ^|\pagegoal|ã€‚
è€Œ$B_1$ çš„ç«–ç›´é•¿åº¦æœªå¿…å°±ä¸€å®šæ˜¯ \&lt;dimem&gt;ï¼Œå›&nbsp;ä¸º \TeX\ ä¸ä¸€å®šèƒ½å®Œç¾Žåœ°è¾¾åˆ°å…¶åˆ†é¡µçš„ç›®æ&nbsp;‡ã€‚
\TeX\ åœ¨è®¡ç®—è¿™ä¸ªç«–ç›´åˆ†å‰²çš„æ—¶å€™ï¼Œä¸è€ƒè™‘æ’å…¥ï¼Œå›&nbsp;æ­¤ $B_2$ æ’å…¥çš„åŽŸæœ¬çš„ç«–ç›´åˆ—è¡¨ä¾ç„¶ä¼šè¢«ä¿ç•™ï¼Œä½†å¹¶ä¸ä¼šå—åˆ°åˆ†å‰²çš„å½±å“ã€‚


%\example
%\setbox 20 = \vsplit 30 to 7in
%% Split off the first seven inches or so of material from
%% box 30 and place that material in box 20.
%|
%\endexample
%\enddesc

\example
\setbox 20 = \vsplit 30 to 7in
% æŠŠ30å·ç›’å­æˆªåŽ»7è‹±å¯¸ï¼Œå¹¶æ”¾åˆ°20å·ç›’å­ä¸­ã€‚
|
\endexample
\enddesc


%\begindesc
%\cts splitmaxdepth {\param{dimen}}
%\explain
%This parameter specifies the
%maximum allowable depth of a box resulting from a |\vsplit|.
%|\splitmaxdepth| plays the
%same role that ^|\maxdepth| (\xref \maxdepth) plays for a page.
%\enddesc

\begindesc
\cts splitmaxdepth {\param{dimen}}
\explain
æ­¤å‚æ•°æŒ‡å®š|\vsplit|äº§ç”Ÿçš„ç›’å­çš„æœ€å¤§å…è®¸æ·±åº¦ã€‚
|\splitmaxdepth| åœ¨ç›’å­ä¸­å’Œ ^|\maxdepth| (\xref \maxdepth) åœ¨é¡µé¢ä¸­æ‰®æ¼”çš„è§’è‰²ç›¸åŒã€‚
\enddesc


%\begindesc
%\cts splittopskip {\param{glue}}
%\explain
%This parameter specifies the glue that \TeX\ inserts at the top of
%a box resulting from a |\vsplit|.
%|\splittopskip| plays the
%same role that ^|\topskip| (\xref \topskip) plays for a page.
%\enddesc

\begindesc
\cts splittopskip {\param{glue}}
\explain
è¿™ä¸ªå‚æ•°æŒ‡å®š \TeX åœ¨ |\vsplit| äº§ç”Ÿçš„ç›’å­çš„å¤´éƒ¨æ’å…¥çš„ç²˜è¿žã€‚
|\splittopskip| åœ¨ç›’å­ä¸­å’Œ ^|\topskip| (\xref \topskip) åœ¨é¡µé¢ä¸­æ‰®æ¼”çš„è§’è‰²ç›¸åŒã€‚
\enddesc


%\see |\splitbotmark|, |\splitfirstmark| (\xref \splitfirstmark).

\see |\splitbotmark|, |\splitfirstmark| (\xref \splitfirstmark).

\enddescriptions

\ifoldeplain\else\ifcompletebook\else
\vskip4em{\sectionfonts\leftline{æœ¬ç«&nbsp;ç´¢å¼•}}
\readindexfile{i}
\fi\fi

\endchapter \byebye
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