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</head>

<body id="top" lang="en">
<a name="Spaces" class="anchor"></a>
<a name="Spaces-1" class="anchor"></a>
<h2 class="chapter">Spaces</h2>

<a name="index-spaces" class="anchor"></a>
<a name="index-white-space" class="anchor"></a>

<p>LaTeX has many ways to produce white (or filled) space.  Some of
these are best suited to mathematical text; see&nbsp;<a href="latex2e_16.html#Spacing-in-math-mode">Spacing in math mode</a>.  Some spacing commands are suitable for both regular text
and mathematical text; versions of some of these commands are in this
chapter.
</p>


<hr>
<a name="g_t_005censpace-_0026-_005cquad-_0026-_005cqquad" class="anchor"></a>
<a name="g_t_005censpace-_0026-_005cquad-_0026-_005cqquad-1" class="anchor"></a>
<h3 class="section"><code>\enspace</code> &amp; <code>\quad</code> &amp; <code>\qquad</code></h3>

<a name="index-_005censpace" class="anchor"></a>
<a name="index-_005cquad-1" class="anchor"></a>
<a name="index-_005cqquad-1" class="anchor"></a>

<p>Synopsis, one of:
</p>
<div class="example">
<pre class="example">\enspace
\quad
\qquad
</pre></div>

<p>Insert a horizontal space of 1/2em, 1em, or 2em. The
em is a length defined by a font designer, often thought of as being the
width of a capital&nbsp;M.  One advantage of describing space in ems is
that it can be more portable across documents than an absolute
measurement such as points (see <a href="latex2e_14.html#Lengths_002fem">Lengths/em</a>).
</p>
<p>This puts a suitable gap between two graphics.
</p>
<div class="example">
<pre class="example">\begin{center}
  \includegraphics{womensmile.png}%
  \qquad\includegraphics{mensmile.png}
\end{center}
</pre></div>

<p>See <a href="latex2e_16.html#Spacing-in-math-mode">Spacing in math mode</a> for <code>\quad</code> and <code>\qquad</code>.  These
are lengths from centuries of typesetting and so may be a better choice
in many circumstances than arbitrary lengths, such as you get with
<code>\hspace</code>.
</p>

<hr>
<a name="g_t_005chspace" class="anchor"></a>
<a name="g_t_005chspace-1" class="anchor"></a>
<h3 class="section"><code>\hspace</code></h3>

<a name="index-_005chspace" class="anchor"></a>

<p>Synopsis, one of:
</p>
<div class="example">
<pre class="example">\hspace{<var>length</var>}
\hspace*{<var>length</var>}
</pre></div>

<p>Insert the horizontal space <var>length</var>.  The <var>length</var> can be
positive, negative, or zero; adding negative space is like backspacing.
It is a rubber length, that is, it may contain a <code>plus</code> or
<code>minus</code> component, or both (see <a href="latex2e_14.html#Lengths">Lengths</a>).  Because the space is
stretchable and shrinkable, it is sometimes called <em>glue</em>.
</p>
<p>This makes a line with &lsquo;<samp>Name:</samp>&rsquo; an inch from the right margin.
</p>
<div class="example">
<pre class="example">\noindent\makebox[\linewidth][r]{Name:\hspace{1in}}
</pre></div>

<p>The <code>*</code>-version inserts horizontal space that non-discardable.
More precisely, when TeX breaks a paragraph into lines any white
space&mdash;glues and kerns&mdash;that come at a line break are discarded.  The
<code>*</code>-version avoids that (technically, it adds a non-discardable
invisible item in front of the space).
</p>
<p>In this example
</p>
<div class="example">
<pre class="example">\parbox{0.8\linewidth}{%
  Fill in each blank: Four \hspace*{1in} and seven years ago our
  fathers brought forth on this continent, a new \hspace*{1in},
  conceived in \hspace*{1in}, and dedicated to the proposition
  that all men are created \hspace*{1in}.}
</pre></div>

<p>the 1&nbsp;inch blank following &lsquo;<samp>conceived in</samp>&rsquo; falls at the start
of a line.  If you erase the <code>*</code> then LaTeX discards the blank.
</p>
<p>Here, the <code>\hspace</code> separates the three graphics.
</p>
<div class="example">
<pre class="example">\begin{center}
  \includegraphics{lion.png}%   comment keeps out extra space
  \hspace{1cm minus 0.25cm}\includegraphics{tiger.png}%
  \hspace{1cm minus 0.25cm}\includegraphics{bear.png}
\end{center}
</pre></div>

<p>Because the argument to each <code>\hspace</code> has <code>minus 0.25cm</code>,
each can shrink a little if the three figures are too wide.  But each
space won&rsquo;t shrink more than 0.25cm (see <a href="latex2e_14.html#Lengths">Lengths</a>).
</p>

<hr>
<a name="g_t_005chfill" class="anchor"></a>
<a name="g_t_005chfill-1" class="anchor"></a>
<h3 class="section"><code>\hfill</code></h3>

<a name="index-_005chfill" class="anchor"></a>

<a name="index-stretch_002c-infinite-horizontal" class="anchor"></a>
<a name="index-infinite-horizontal-stretch" class="anchor"></a>

<p>Synopsis:
</p>
<div class="example">
<pre class="example">\hfill
</pre></div>

<p>Produce a rubber length which has no natural space but that can stretch
horizontally as far as needed (see <a href="latex2e_14.html#Lengths">Lengths</a>).
</p>
<p>This creates a one-line paragraph with &lsquo;<samp>Name:</samp>&rsquo; on the left side
of the page and &lsquo;<samp>Quiz One</samp>&rsquo; on the right.
</p>
<div class="example">
<pre class="example">\noindent Name:\hfill Quiz One
</pre></div>

<a name="index-_005cfill" class="anchor"></a>
<p>The <code>\hfill</code> command is equivalent to <code>\hspace{\fill}</code> and
so the space can be discarded at line breaks.  To avoid that instead use
<code>\hspace*{\fill}</code> (see <a href="#g_t_005chspace">\hspace</a>).
</p>
<p>Here the graphs are evenly spaced in the middle of the figure.
</p>
<div class="example">
<pre class="example">\newcommand*{\vcenteredhbox}[1]{\begin{tabular}{@{}c@{}}#1\end{tabular}}
  ...
\begin{figure}
  \hspace*{\fill}%
  \vcenteredhbox{\includegraphics{graph0.png}}%
    \hfill\vcenteredhbox{\includegraphics{graph1.png}}%
  \hspace*{\fill}%
  \caption{Comparison of two graphs} \label{fig:twographs}
\end{figure}
</pre></div>

<p>Note the <code>\hspace*</code>&rsquo;s where the space could otherwise be dropped.
</p>

<hr>
<a name="g_t_005chss" class="anchor"></a>
<a name="g_t_005chss-1" class="anchor"></a>
<h3 class="section"><code>\hss</code></h3>

<a name="index-_005chss" class="anchor"></a>
<a name="index-horizontal-space" class="anchor"></a>
<a name="index-horizontal-space_002c-stretchable" class="anchor"></a>
<a name="index-space_002c-inserting-horizontal" class="anchor"></a>

<p>Synopsis:
</p>
<div class="example">
<pre class="example">\hss
</pre></div>

<p>Produce a horizontal space that is infinitely shrinkable as well as
infinitely stretchable (this command is a TeX primitive).  LaTeX
authors should reach first for the <code>\makebox</code> command to get the
effects of <code>\hss</code> (see <a href="latex2e_20.html#g_t_005cmbox-_0026-_005cmakebox">\mbox &amp; \makebox</a>).
</p>
<p>Here, the first line&rsquo;s <code>\hss</code> makes the Z stick out to the right,
overwriting the Y.  In the second line the Z sticks out to the left,
overwriting the X.
</p>
<div class="example">
<pre class="example">X\hbox to 0pt{Z\hss}Y
X\hbox to 0pt{\hss Z}Y
</pre></div>

<p>Without the <code>\hss</code> you get something like &lsquo;<samp>Overfull \hbox
(6.11111pt too wide) detected at line 20</samp>&rsquo;.
</p>

<hr>
<a name="g_t_005cspacefactor" class="anchor"></a>
<a name="g_t_005cspacefactor-1" class="anchor"></a>
<h3 class="section"><code>\spacefactor</code></h3>

<p>Synopsis:
</p>
<div class="example">
<pre class="example">\spacefactor=<var>integer</var>
</pre></div>

<a name="index-_005cspacefactor" class="anchor"></a>
<p>Influence LaTeX&rsquo;s glue stretch and shrink behavior.  Most user-level
documents do not use this command.
</p>
<p>While LaTeX is laying out the material, it may stretch or shrink the
gaps between words.  (This space is not a character; it is called the
<em>interword glue</em>; see <a href="#g_t_005chspace">\hspace</a>).  The <code>\spacefactor</code> command
(from Plain&nbsp;TeX) allows you to, for instance, have the space
after a period stretch more than the space after a word-ending letter.
</p>
<p>After LaTeX places each character, or rule or other box, it sets a
parameter called the <em>space factor</em>.  If the next thing in the input
is a space then this parameter affects how much stretching or shrinking
can happen.  A space factor that is larger than the normal value means
that the glue can stretch more and shrink less.  Normally, the space
factor is 1000. This value is in effect following most characters, and
any non-character box or math formula.  But it is 3000 after a period,
exclamation mark, or question mark, it is 2000 after a colon, 1500 after
a semicolon, 1250 after a comma, and 0 after a right parenthesis or
bracket, or closing double quote or single quote.  Finally, it is 999
after a capital letter.
</p>
<p>If the space factor&nbsp;<var>f</var> is 1000 then the glue gap will be the
font&rsquo;s normal space value (for Computer Modern Roman 10 point this is
3.3333&nbsp;points).  Otherwise, if the space factor <var>f</var> is greater
than 2000 then TeX adds the font&rsquo;s extra space value (for Computer
Modern Roman 10 point this is 1.11111&nbsp;points), and then the font&rsquo;s
normal stretch value is multiplied by <em>f /1000</em> and the normal
shrink value is multiplied by <em>1000/f</em> (for Computer Modern Roman
10 point these are 1.66666 and 1.11111&nbsp;points).
</p>
<p>For example, consider the period ending <code>A man's best friend is his
dog.</code>  After it, TeX puts in a fixed extra space, and also allows the
glue to stretch 3 times as much and shrink 1/3 as much, as the glue
after <code>friend</code>, which does not end in a period.
</p>
<p>The rules for space factors are even more complex because they play
additional roles.  In practice, there are two consequences.  First, if a
period or other punctuation is followed by a right parenthesis or
bracket, or right single or double quote then the spacing effect of that
period carries through those characters (that is, the following glue
will have increased stretch and shrink).  Second, if
punctuation comes after a capital letter then its effect is not in place
so you get an ordinary space.  This second case also affects abbreviations
that do not end in a capital letter (see <a href="#g_t_005c_0040">\@</a>).
</p>
<p>You can only use <code>\spacefactor</code> in paragraph mode or LR mode
(see <a href="latex2e_17.html#Modes">Modes</a>).  You can see the current value with
<code>\the\spacefactor</code> or <code>\showthe\spacefactor</code>.
</p>
<p>(Comment, not really related to <code>\spacefactor</code>: if you get errors
like &lsquo;<samp>You can't use `\spacefactor' in vertical mode</samp>&rsquo;, or &lsquo;<samp>You
can't use `\spacefactor' in math mode.</samp>&rsquo;, or &lsquo;<samp>Improper \spacefactor</samp>&rsquo;
then you have probably tried to redefine an internal command.
See <a href="latex2e_12.html#g_t_005cmakeatletter-_0026-_005cmakeatother">\makeatletter &amp; \makeatother</a>.)
</p>



<hr>
<a name="g_t_005c_0040" class="anchor"></a>
<a name="g_t_005c_0040-1" class="anchor"></a>
<h4 class="subsection"><code>\@</code></h4>

<a name="index-_005c_0040" class="anchor"></a>
<a name="index-at_002dsign" class="anchor"></a>
<a name="index-period_002c-sentence_002dending" class="anchor"></a>
<a name="index-period_002c-abbreviation_002dending" class="anchor"></a>
<a name="index-period_002c-spacing-after" class="anchor"></a>
<a name="g_t_005cAT" class="anchor"></a>
<p>Synopsis:
</p>
<div class="example">
<pre class="example"><var>capital-letter</var>\@.    
</pre></div>

<p>Treat a period as sentence-ending, where LaTeX would otherwise think
it is part of an abbreviation.  LaTeX thinks that a period ends an
abbreviation if the period comes after a capital letter, and otherwise
thinks the period ends the sentence.  By default, in justifying a line
LaTeX adjusts the space after a sentence-ending period (or a question
mark, exclamation point, comma, or colon) more than it adjusts the space
between words (see <a href="#g_t_005cspacefactor">\spacefactor</a>).
</p>
<p>This example shows the two cases to remember.
</p>
<div class="example">
<pre class="example">The songs \textit{Red Guitar}, etc.\ are by Loudon Wainwright~III\@.
</pre></div>

<p>The second period ends the sentence, despite that it is preceded by a
capital.  We tell LaTeX that it ends the sentence by putting
<code>\@</code> before it.  The first period ends the abbreviation
&lsquo;<samp>etc.</samp>&rsquo; but not the sentence.  The backslash-space, <code>\ </code>,
produces a mid-sentence space.
</p>
<p>So: if you have a capital letter followed by a period that ends the
sentence, then put <code>\@</code> before the period.  This holds even if
there is an intervening right parenthesis or bracket, or right single or
double quote, because the spacing effect of that period carries through
those characters.  For example, this
</p>
<div class="example">
<pre class="example">Use the \textit{Instructional Practices Guide},
(a book by the MAA)\@.
</pre></div>

<p>will have correct inter-sentence spacing after the period.
</p>
<p>The <code>\@</code> command is only for a text mode. If you use it outside of
a text mode then you get &lsquo;<samp>You can't use `\spacefactor' in vertical
mode</samp>&rsquo; (see <a href="latex2e_17.html#Modes">Modes</a>).
</p>
<p>Comment: the converse case is a period ending an abbreviation whose last
letter is not a capital letter, and that abbreviation is not the last
word in the sentence.  For that case follow the period with a
backslash-space, (<code>\ </code>), or a tie, (<code>~</code>), or <code>\@</code>.
Examples are <code>Nat.\ Acad.\ Science</code>, and <code>Mr.~Bean</code>, and
<code>(manure, etc.\@) for sale</code> (note in the last one that the
<code>\@</code> comes before the closing parenthesis).
</p>

<hr>
<a name="g_t_005cfrenchspacing" class="anchor"></a>
<a name="g_t_005cfrenchspacing-1" class="anchor"></a>
<h4 class="subsection"><code>\frenchspacing</code></h4>

<a name="index-_005cfrenchspacing" class="anchor"></a>
<a name="index-_005cnonfrenchspacing" class="anchor"></a>
<a name="index-spacing_002c-inter_002dsentence" class="anchor"></a>

<p>Synopsis, one of:
</p>
<div class="example">
<pre class="example">\frenchspacing
\nonfrenchspacing
</pre></div>

<p>The first declaration causes LaTeX to treat spacing between sentences
in the same way as spacing between words in the middle of a sentence.
The second causes spacing between sentences to stretch or shrink more
(see <a href="#g_t_005cspacefactor">\spacefactor</a>); this is the default.
</p>
<p>Some typographic traditions, including English, prefer to adjust the
space between sentences (or spaces following a question mark,
exclamation point, comma, or colon) more than the space between words
that are in the middle of a sentence.  Declaring <code>\frenchspacing</code>
(the command is from Plain TeX) switches to the tradition that all
spaces are treated equally.
</p>

<hr>
<a name="g_t_005cnormalsfcodes" class="anchor"></a>
<a name="g_t_005cnormalsfcodes-1" class="anchor"></a>
<h4 class="subsection"><code>\normalsfcodes</code></h4>

<a name="index-_005cnormalsfcodes" class="anchor"></a>
<a name="index-spacing_002c-inter_002dsentence-1" class="anchor"></a>

<p>Synopsis:
</p>
<div class="example">
<pre class="example">\normalsfcodes
</pre></div>

<p>Reset the LaTeX space factor values to the default
(see <a href="#g_t_005cspacefactor">\spacefactor</a>).
</p>

<hr>
<a name="g_t_005c_0028SPACE_0029" class="anchor"></a>
<a name="Backslash_002dspace_002c-_005c-" class="anchor"></a>
<h3 class="section">Backslash-space, <code>\ </code></h3>

<a name="index-_005cNEWLINE" class="anchor"></a>
<a name="index-_005cSPACE" class="anchor"></a>
<a name="index-_005cTAB" class="anchor"></a>

<p>This section refers to the command consisting of two characters, a
backslash followed by a space. Synopsis:
</p>
<div class="example">
<pre class="example">\    
</pre></div>

<p>Produce a space. By default it produces white space of length
3.33333pt plus 1.66666pt minus 1.11111pt.
</p>
<p>When you type one or more blanks between words, LaTeX produces white
space.  But that is different than an explicit space.  This illustrates.
</p>
<div class="example">
<pre class="example">\begin{tabular}{l}
One blank: makes some space \\
Three blanks:   in a row \\
Three spaces:\ \ \ in a row \\
\end{tabular}
</pre></div>

<p>On the first line LaTeX puts some space after the colon.  On the
second line LaTeX collapses the three blanks to output one
whitespace, so you end with the same space after the colon as in the
first line.  LaTeX would similarly collapse a blank followed by a
tab, or a blank and a newline and a blank.  However, the bottom line
asks for three spaces so the white area is wider.  That is, the
backslash-space command creates a fixed amount of horizontal space.
(Note that you can define a horizontal space of any width at all with
<code>\hspace</code>; see&nbsp;<a href="#g_t_005chspace">\hspace</a>.)
</p>
<p>The backslash-space command has two main uses.  It is often used after
control sequences to keep them from gobbling the space that follows, as
in <code>\TeX\ is nice</code>.  (But using curly parentheses, as in
<code>\TeX{} is best</code>, has the advantage of still working if the next
character is a period.)  The other common use is that it marks a period
as ending an abbreviation instead of ending a sentence, as in <code>So
says Prof.\ Smith</code> (see <a href="#g_t_005c_0040">\@</a>).
</p>
<p>Under normal circumstances, <code>\</code><tt class="key">tab</tt> and <code>\</code><tt class="key">newline</tt>
are equivalent to backslash-space, <code>\ </code>.
</p>


<hr>
<a name="g_t_007e" class="anchor"></a>
<a name="g_t_007e-1" class="anchor"></a>
<h3 class="section"><code>~</code></h3>

<a name="index-_007e" class="anchor"></a>
<a name="index-tie" class="anchor"></a>
<a name="index-space_002c-hard" class="anchor"></a>
<a name="index-space_002c-unbreakable" class="anchor"></a>
<a name="index-NBSP" class="anchor"></a>

<p>Synopsis:
</p>
<div class="example">
<pre class="example"><var>before</var>~<var>after</var>
</pre></div>

<p>The tie character, <code>~</code>, produces a space between <var>before</var> and
<var>after</var> at which the line will not be broken. By default the white
space has length 3.33333pt plus 1.66666pt minus
1.11111pt (see <a href="latex2e_14.html#Lengths">Lengths</a>).
</p>
<p>Here LaTeX will not break the line between the final two words.
</p>
<div class="example">
<pre class="example">Thanks to Prof.~Lerman.
</pre></div>

<p>In addition, despite the period, LaTeX does not use the
end-of-sentence spacing (see <a href="#g_t_005c_0040">\@</a>).
</p>
<p>Ties prevent the end of line separation of things where that could cause
confusion. But they also reduce LaTeX&rsquo;s options when it breaks lines
into paragraphs, so you can use too many. They are also matters of
taste, sometimes alarmingly dogmatic taste, among readers. Nevertheless,
here are some usage models, many of them from the TeXbook.
</p>
<ul>
<li> Between an enumerator and its item, such as in references:
<code>Chapter~12</code>, or <code>Theorem~\ref{th:Wilsons}</code>, or
<code>Figure~\ref{fig:KGraph}</code>. When cases are enumerated inline:
<code>(b)~Show that $f(x)$ is (1)~continuous, and (2)~bounded</code>.

<a name="index-package_002c-siunitx" class="anchor"></a>
<a name="index-siunitx-package" class="anchor"></a>

</li><li> Between a number and its unit: <code>$745.7.8$~watts</code> (the
<samp>siunitx</samp> package has a special facility for this) or
<code>144~eggs</code>. This includes between a month and a date:
<code>October~12</code> or <code>12~Oct</code>. In general, in any expressions where
numbers and abbreviations or symbols are separated by a space:
<code>AD~565</code>, or <code>2:50~pm</code>, or <code>Boeing~747</code>, or
<code>268~Plains Road</code>, or <code>\$$1.4$~billion</code>.

</li><li> When mathematical phrases are rendered in words: <code>equals~$n$</code>, or
<code>less than~$\epsilon$</code>, or <code>given~$X$</code>, or <code>modulo~$p^e$
for all large~$n$</code> (but compare <code>is~$15$</code> with <code>is $15$~times
the height</code>). Between mathematical symbols in apposition with nouns:
<code>dimension~$d$</code> or <code>function~$f(x)$</code> (but compare <code>with
length $l$~or more</code>). When a symbol is a tightly bound object of a
preposition: <code>of~$x$</code>, or <code>from $0$ to~$1$</code>, or <code>in
common with~$m$</code>.

</li><li> Between symbols in series: <code>$1$,~$2$, or~$3$</code> or <code>$1$,~$2$,
\ldots,~$n$</code>.

</li><li> Between a person&rsquo;s forenames and between multiple surnames:
<code>Donald~E. Knuth</code>, or <code>Luis~I. Trabb~Pardo</code>, or
<code>Charles~XII</code> (but you must give TeX places to break the line so
you may do <code>Charles Louis Xavier~Joseph de~la Vall\'ee~Poussin</code>).

</li><li> Before a dash: <code>pages 12~--14</code> or <code>it is~--- it must be
said~--- plausible</code>.

</li></ul>


<hr>
<a name="g_t_005cthinspace-_0026-_005cnegthinspace" class="anchor"></a>
<a name="g_t_005cthinspace-_0026-_005cnegthinspace-1" class="anchor"></a>
<h3 class="section"><code>\thinspace</code> &amp; <code>\negthinspace</code></h3>

<a name="index-_005cthinspace-1" class="anchor"></a>
<a name="index-_005cnegthinspace-1" class="anchor"></a>
<a name="index-thin-space-1" class="anchor"></a>
<a name="index-space_002c-thin" class="anchor"></a>
<a name="index-thin-space_002c-negative-1" class="anchor"></a>
<a name="index-space_002c-negative-thin" class="anchor"></a>

<p>Synopsis, one of:
</p>
<div class="example">
<pre class="example">\thinspace
\negthinspace
</pre></div>

<p>Produce an unbreakable and unstretchable space of 1/6em and
-1/6em.  These are the text mode equivalents of <code>\,</code> and
<code>\!</code> (see <a href="latex2e_16.html#Spacing-in-math-mode_002f_005cthinspace">Spacing in math mode/\thinspace</a>).  You can use
<code>\,</code> as a synonym for <code>\thinspace</code> in text mode.
</p>
<p>The <code>\negthinspace</code> command is used in text mode mostly for
fiddling with spaces.  One common use of <code>\thinspace</code> is as the
space between nested quotes.
</p>
<div class="example">
<pre class="example">Killick replied, ``I heard the Captain say, `Ahoy there.'\thinspace''
</pre></div>

<p>Another use is that some style guides call for a <code>\thinspace</code>
between an ellipsis and a sentence ending period (other style guides,
though, think the three dots are quite enough already).  Still another
use is between initials, as in <code>D.\thinspace E.\ Knuth</code>.
</p>

<hr>
<a name="g_t_005c_002f" class="anchor"></a>
<a name="g_t_005c_002f-1" class="anchor"></a>
<h3 class="section"><code>\/</code></h3>

<a name="index-_005c_002f" class="anchor"></a>
<a name="index-italic-correction" class="anchor"></a>

<p>Synopsis:
</p>
<div class="example">
<pre class="example"><var>before-character</var>\/<var>after-character</var>
</pre></div>

<p>Insert an <em>italic correction</em>, a small space defined by the font
designer for each character, to avoid the character colliding with
whatever follows. When you use <code>\/</code>, LaTeX takes the correction
from the font metric file, scales it by any scaling that has been
applied to the font, and then inserts that much horizontal space.
</p>
<p>Here, were it not for the <code>\/</code>, the <var>before-character</var>
italic&nbsp;f would hit the <var>after-character</var> roman&nbsp;H
</p>
<div class="example">
<pre class="example">\newcommand{\companylogo}{{\it f}\/H}
</pre></div>

<p>because the italic letter leans far to the right.
</p>
<p>If <var>after-character</var> is a period or comma then don&rsquo;t insert an
italic correction since those punctuation symbols have a very small
height.  However, with semicolons or colons as well as with normal
letters, the italic correction can help.
</p>
<p>When you use commands such as <code>\textit</code> or <code>\itshape</code> to
change fonts, LaTeX will automatically insert any needed italic
correction (see <a href="latex2e_4.html#Font-styles">Font styles</a>).
</p>
<p>Roman characters can also have an italic correction.  An example is in
the name <code>pdf\/\TeX</code>.
</p>
<p>There is no concept of italic correction in math mode; spacing is done
in a different way.
</p>

<hr>
<a name="g_t_005chrulefill-_0026-_005cdotfill" class="anchor"></a>
<a name="g_t_005chrulefill-_0026-_005cdotfill-1" class="anchor"></a>
<h3 class="section"><code>\hrulefill</code> &amp; <code>\dotfill</code></h3>

<a name="index-_005chrulefill" class="anchor"></a>
<a name="index-_005cdotfill" class="anchor"></a>

<p>Synopsis, one of:
</p>
<div class="example">
<pre class="example">\hrulefill
\dotfill
</pre></div>

<p>Produce an infinite horizontal rubber length (see <a href="latex2e_14.html#Lengths">Lengths</a>) that
LaTeX fills with a rule (that is, a line) or with dots, instead of
white space.
</p>
<p>This outputs a line 2 inches long.
</p>
<div class="example">
<pre class="example">Name:~\makebox[2in]{\hrulefill}
</pre></div>

<p>This example, when placed between blank lines, creates a paragraph that
is left and right justified and where the middle is filled with evenly
spaced dots.
</p>
<div class="example">
<pre class="example">\noindent John Aubrey, RN \dotfill{} Melbury Lodge
</pre></div>

<p>To make the rule or dots go to the line&rsquo;s end use <code>\null</code> at the
start or end.  
</p>
<p>To change the rule&rsquo;s thickness, copy the definition and adjust it, as
here
</p>
<div class="example">
<pre class="example">\renewcommand{\hrulefill}{%
  \leavevmode\leaders\hrule height 1pt\hfill\kern\z@}
</pre></div>

<p>which changes the default thickness of 0.4pt to 1pt.
Similarly, adjust the dot spacing as with
</p>
<div class="example">
<pre class="example">\renewcommand{\dotfill}{%
  \leavevmode\cleaders\hb@xt@1.00em{\hss .\hss }\hfill\kern\z@}
</pre></div>

<p>which changes the default length of 0.33em to 1.00em.
</p>
<p>This example produces a line for a signature.
</p>
<div class="example">
<pre class="example">\begin{minipage}{4cm}
  \centering
  \hrulefill\\
  Signed
\end{minipage}
</pre></div>

<p>The line is 4cm long.
</p>

<hr>
<a name="g_t_005cbigskip-_0026-_005cmedskip-_0026-_005csmallskip" class="anchor"></a>
<a name="g_t_005cbigskip-_0026-_005cmedskip-_0026-_005csmallskip-1" class="anchor"></a>
<h3 class="section"><code>\bigskip</code> &amp; <code>\medskip</code> &amp; <code>\smallskip</code></h3>

<p>Synopsis, one of:
</p>
<div class="example">
<pre class="example">\bigskip
\medskip
\smallskip
</pre></div>

<p>Produce an amount of vertical space, large or medium-sized or
small. These commands are fragile (see <a href="latex2e_12.html#g_t_005cprotect">\protect</a>).
</p>
<p>Here the skip suggests the passage of time (from <i>The Golden Ocean</i> by
O&rsquo;Brian).
</p>
<div class="example">
<pre class="example">Mr Saumarez would have something rude to say to him, no doubt: he
was at home again, and it was delightful.

\bigskip
``A hundred and fifty-seven miles and one third, in twenty-four hours,''
said Peter.
</pre></div>

<p>Each command is associated with a length defined in the document class
file.
</p>
<dl compact="compact">
<dd><a name="bigskip" class="anchor"></a></dd>
<dt><code>\bigskip</code>
<a name="index-_005cbigskip" class="anchor"></a>
</dt>
<dd><a name="index-_005cbigskipamount" class="anchor"></a>
<p>The same as <code>\vspace{\bigskipamount}</code>, ordinarily about one line
space, with stretch and shrink.  The default for the <code>book</code> and
<code>article</code> classes is <code>12pt plus 4pt minus 4pt</code>.
</p>
<a name="medskip" class="anchor"></a></dd>
<dt><code>\medskip</code>
<a name="index-_005cmedskip" class="anchor"></a>
</dt>
<dd><a name="index-_005cmedskipamount" class="anchor"></a>
<p>The same as <code>\vspace{\medskipamount}</code>, ordinarily about half of a
line space, with stretch and shrink.  The default for the <code>book</code>
and <code>article</code> classes is <code>6pt plus 2pt minus 2pt</code>.
</p>
<a name="smallskip" class="anchor"></a></dd>
<dt><code>\smallskip</code>
<a name="index-_005csmallskip" class="anchor"></a>
</dt>
<dd><a name="index-_005csmallskipamount" class="anchor"></a>
<p>The same as <code>\vspace{\smallskipamount}</code>, ordinarily about a
quarter of a line space, with stretch and shrink.  The default for the
<code>book</code> and <code>article</code> classes is <code>3pt plus 1pt minus 1pt</code>.
</p>
</dd>
</dl>

<p>Because each command is a <code>\vspace</code>, if you use on in mid-paragraph
then it will insert its vertical space between the line in which you use
it and the next line, not necessarily at the place that you use it.  So
these are best between paragraphs.
</p>
<p>The commands <code>\bigbreak</code>, <code>\medbreak</code>, and <code>\smallbreak</code>
are similar but also suggest to LaTeX that this is a good place to
put a page break (see <a href="#g_t_005cbigbreak-_0026-_005cmedbreak-_0026-_005csmallbreak">\bigbreak &amp; \medbreak &amp; \smallbreak</a>.
</p>

<hr>
<a name="g_t_005cbigbreak-_0026-_005cmedbreak-_0026-_005csmallbreak" class="anchor"></a>
<a name="g_t_005cbigbreak-_0026-_005cmedbreak-_0026-_005csmallbreak-1" class="anchor"></a>
<h3 class="section"><code>\bigbreak</code> &amp; <code>\medbreak</code> &amp; <code>\smallbreak</code></h3>

<p>Synopsis, one of:
</p>
<div class="example">
<pre class="example">\bigbreak
\medbreak
\smallbreak
</pre></div>

<p>Produce a vertical space that is big or medium-sized or small, and
suggest to LaTeX that this is a good place to break the page.  (The
associated penalties are -200, -100, and -50.)
</p>
<p>See <a href="#g_t_005cbigskip-_0026-_005cmedskip-_0026-_005csmallskip">\bigskip &amp; \medskip &amp; \smallskip</a>, for more.  These commands
produce the same vertical space but differ in that they also remove a
preceding vertical space if it is less than what they would insert (as
with <code>\addvspace</code>).  In addition, they terminate a paragraph where
they are used: this example
</p>
<div class="example">
<pre class="example">abc\bigbreak def ghi

jkl mno pqr
</pre></div>

<p>will output three paragraphs, the first ending in &lsquo;<samp>abc</samp>&rsquo; and the
second starting, after an extra vertical space and a paragraph indent,
with &lsquo;<samp>def</samp>&rsquo;.
</p>

<hr>
<a name="g_t_005cstrut" class="anchor"></a>
<a name="g_t_005cstrut-1" class="anchor"></a>
<h3 class="section"><code>\strut</code></h3>

<a name="index-_005cstrut" class="anchor"></a>
<a name="index-strut" class="anchor"></a>

<p>Synopsis:
</p>
<div class="example">
<pre class="example">\strut
</pre></div>

<p>Ensure that the current line has height at least <code>0.7\baselineskip</code>
and depth at least <code>0.3\baselineskip</code>.  Essentially, LaTeX
inserts into the line a rectangle having zero width,
<code>\rule[-0.3\baselineskip]{0pt}{\baselineskip}</code> (see <a href="latex2e_23.html#g_t_005crule">\rule</a>).
The <code>\baselineskip</code> changes with the current font and fontsize.
</p>
<p>In this example the <code>\strut</code> keeps the box inside the frame from
having zero height.
</p>
<div class="example">
<pre class="example">\setlength{\fboxsep}{0pt}\framebox[2in]{\strut}
</pre></div>

<p>This example has four lists.  In the first there is a much bigger gap
between items 2 and&nbsp;3 than there is between items 1 and&nbsp;2.
The second list fixes that with a <code>\strut</code> at the end of its first
item&rsquo;s second line.
</p>
<div class="example">
<pre class="example">\setlength{\fboxsep}{0pt}
\noindent\begin{minipage}[t]{0.2\linewidth}
\begin{enumerate}
  \item \parbox[t]{15pt}{test \\ test}
  \item test
  \item test
\end{enumerate}
\end{minipage}%
\begin{minipage}[t]{0.2\linewidth}
\begin{enumerate}
  \item \parbox[t]{15pt}{test \\ test\strut}
  \item test
  \item test
\end{enumerate}
\end{minipage}%
\begin{minipage}[t]{0.2\linewidth}
\begin{enumerate}
  \item \fbox{\parbox[t]{15pt}{test \\ test}}
  \item \fbox{test}
  \item \fbox{test}
\end{enumerate}
\end{minipage}%
\begin{minipage}[t]{0.2\linewidth}
\begin{enumerate}
  \item \fbox{\parbox[t]{15pt}{test \\ test\strut}}
  \item \fbox{test}
  \item \fbox{test}
\end{enumerate}
\end{minipage}%
</pre></div>

<p>The final two lists use <code>\fbox</code> to show what&rsquo;s happening.  The
third list&rsquo;s <code>\parbox</code> goes only to the bottom of its second
&lsquo;<samp>test</samp>&rsquo;, which happens not have any characters that descend below
the baseline.  The fourth list adds the strut that gives the needed
extra below-baseline space.
</p>
<a name="index-package_002c-TikZ-1" class="anchor"></a>
<a name="index-TikZ-package-1" class="anchor"></a>
<a name="index-package_002c-Asymptote-1" class="anchor"></a>
<a name="index-Asymptote-package-1" class="anchor"></a>

<p>The <code>\strut</code> command is often useful in graphics, such as in
<samp>TikZ</samp> or <samp>Asymptote</samp>.  For instance, you may have a command
such as <code>\graphnode{<var>node-name</var>}</code> that fits a circle around
<var>node-name</var>.  However, unless you are careful the <var>node-name</var>&rsquo;s
&lsquo;<samp>x</samp>&rsquo; and &lsquo;<samp>y</samp>&rsquo; will produce different-diameter circles because
the characters are different sizes.  A careful <code>\graphnode</code> might
insert a <code>\strut</code>, then <var>node-name</var>, and then draw the circle.
</p>
<p>The general approach of using a zero width <code>\rule</code> is useful in
many circumstances.  In this table, the zero-width rule keeps the top of
the first integral from hitting the <code>\hline</code>.  Similarly, the
second rule keeps the second integral from hitting the first.
</p>
<div class="example">
<pre class="example">\begin{tabular}{rl}
  \textsc{Integral}   &amp;\textsc{Value}           \\
  \hline
  $\int_0^x t\, dt$   &amp;$x^2/2$  \rule{0em}{2.5ex} \\  
  $\int_0^x t^2\, dt$ &amp;$x^3/3$  \rule{0em}{2.5ex}
\end{tabular}
</pre></div>

<p>(Although the line-ending double backslash command has an available
optional argument to put in more vertical room, that won&rsquo;t work here.
Changing the first double backslash to something like <code>\\[2.5ex]</code>
will put the room between the header line and the <code>\hline</code>, and the
integral would still hit the line.)
</p>

<hr>
<a name="g_t_005cvspace" class="anchor"></a>
<a name="g_t_005cvspace-1" class="anchor"></a>
<h3 class="section"><code>\vspace</code></h3>

<a name="index-_005cvspace" class="anchor"></a>
<a name="index-vertical-space" class="anchor"></a>
<a name="index-space_002c-vertical" class="anchor"></a>

<p>Synopsis, one of:
</p>
<div class="example">
<pre class="example">\vspace{<var>length</var>}
\vspace*{<var>length</var>}
</pre></div>

<p>Add the vertical space <var>length</var>.  The <var>length</var> can be positive,
negative, or zero.  It is a rubber length&mdash;it may contain a <code>plus</code>
or <code>minus</code> component (see <a href="latex2e_14.html#Lengths">Lengths</a>).
</p>
<p>This puts space between the two paragraphs.
</p>
<div class="example">
<pre class="example">And I slept.

\vspace{1ex plus 0.5ex}
The new day dawned cold.
</pre></div>

<p>(See <a href="#g_t_005cbigskip-_0026-_005cmedskip-_0026-_005csmallskip">\bigskip &amp; \medskip &amp; \smallskip</a> for common inter-paragraph
spaces.)
</p>
<p>The <code>*</code>-version inserts vertical space that non-discardable.  More
precisely, LaTeX discards vertical space at a page break and the
<code>*</code>-version causes the space to stay.  This example leaves space
between the two questions.
</p>
<div class="example">
<pre class="example">Question: Find the integral of \( 5x^4+5 \).

\vspace*{2cm plus 0.5cm}
Question: Find the derivative of \( x^5+5x+9 \).
</pre></div>

<p>That space will be present even if the page break happens to fall
between the questions.
</p>
<p>If you use <code>\vspace</code> in the middle of a paragraph (i.e., in
horizontal mode) then the space is inserted after the line containing
the <code>\vspace</code> command; it does not start a new paragraph at the
<code>\vspace</code> command.
</p>
<p>In this example the two questions will be evenly spaced vertically on
the page, with at least one inch of space below each.
</p>
<div class="example">
<pre class="example">\begin{document}
1) Who put the bomp in the bomp bah bomp bah bomp?
\vspace{1in plus 1fill}

2) Who put the ram in the rama lama ding dong?
\vspace{1in plus 1fill}
\end{document}
</pre></div>


<hr>
<a name="g_t_005cvfill" class="anchor"></a>
<a name="g_t_005cvfill-1" class="anchor"></a>
<h3 class="section"><code>\vfill</code></h3>

<a name="index-_005cvfill" class="anchor"></a>

<a name="index-stretch_002c-infinite-vertical" class="anchor"></a>
<a name="index-infinite-vertical-stretch" class="anchor"></a>

<p>Synopsis:
</p>
<div class="example">
<pre class="example">\vfill
</pre></div>

<p>End the current paragraph and insert a vertical rubber length that is
infinite, so it can stretch or shrink as far as needed
(see <a href="latex2e_14.html#Lengths">Lengths</a>).
</p>
<p>It is often used in the same way as <code>\vspace{\fill}</code>, except that
<code>\vfill</code> ends the current paragraph whereas <code>\vspace{\fill}</code>
adds the infinite vertical space below its line, irrespective of the
paragraph structure.  In both cases that space will disappear at a page
boundary; to circumvent this see the starred option
in&nbsp;<a href="#g_t_005cvspace">\vspace</a>.
</p>
<p>In this example the page is filled, so the top and bottom lines contain
the text &lsquo;<samp>Lost Dog!</samp>&rsquo; and the second &lsquo;<samp>Lost Dog!</samp>&rsquo; is exactly
halfway between them.
</p> 
<div class="example">
<pre class="example">\begin{document}
Lost Dog!
\vfill
Lost Dog!  % perfectly in the middle
\vfill
Lost Dog!
\end{document}
</pre></div>


<hr>
<a name="g_t_005caddvspace" class="anchor"></a>
<a name="g_t_005caddvspace-1" class="anchor"></a>
<h3 class="section"><code>\addvspace</code></h3>

<a name="index-_005caddvspace" class="anchor"></a>
<a name="index-vertical-space-1" class="anchor"></a>
<a name="index-space_002c-inserting-vertical" class="anchor"></a>

<p>Synopsis:
</p>
<div class="example">
<pre class="example">\addvspace{<var>vert-length</var>}
</pre></div>

<p>Add a vertical space of <var>vert-length</var>.  However, if there are two or
more <code>\addvspace</code>&rsquo;s in a sequence then together they only add the
space needed to make the natural length equal to the maximum of the
<var>vert-length</var>&rsquo;s in that sequence. This command is fragile
(see <a href="latex2e_12.html#g_t_005cprotect">\protect</a>).  The <var>vert-length</var> is a rubber length
(see <a href="latex2e_14.html#Lengths">Lengths</a>).
</p>
<p>This example illustrates.  The <code>picture</code> draws a scale.  In a
standard LaTeX article the length <code>\baselineskip</code> is 12pt.
The two rules here are 22pt apart: the sum of the
<code>\baselineskip</code> and the 10pt from the first <code>addvspace</code>.
</p>
<div class="example">
<pre class="example">\documentclass{article}
\usepackage{color}
\begin{document}
\setlength{\unitlength}{2pt}%
\noindent\begin{picture}(0,0)%
  \multiput(0,0)(0,-1){25}{{\color{blue}\line(1,0){1}}}
  \multiput(0,0)(0,-5){6}{{\color{red}\line(1,0){2}}}
\end{picture}%
\rule{0.25\linewidth}{0.1pt}% 
\par\addvspace{10pt}% \addvspace{20pt}%
\par\noindent\rule{0.25\linewidth}{0.1pt}%
\end{document}
</pre></div>

<p>Now uncomment the second <code>\addvspace</code>.  It does not make the gap
20pt longer; instead the gap is the sum of <code>\baselineskip</code>
and 20pt.  So <code>\addvspace</code> in a sense does the opposite of
its name &mdash; it makes sure that multiple vertical spaces do not
accumulate, but instead that only the largest one is used.
</p>
<p>LaTeX uses this command to adjust the vertical space above or below
an environment that starts a new paragraph.  For instance, a
<code>theorem</code> environment begins and ends with <code>\addvspace</code> so
that two consecutive <code>theorem</code>&rsquo;s are separated by one vertical
space, not two.
</p>
<p>A error &lsquo;<samp>Something's wrong--perhaps a missing \item</samp>&rsquo; pointing to an
<code>\addvspace</code> means that you were not in vertical mode when you hit
this command. One way to change that is to precede <code>\addvspace</code>
with a <code>\par</code> command (see <a href="latex2e_15.html#g_t_005cpar">\par</a>), as in the above example.
</p>




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</html>