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diff --git a/doc/groff.html.node/Page-Control.html b/doc/groff.html.node/Page-Control.html new file mode 100644 index 0000000..da2edc3 --- /dev/null +++ b/doc/groff.html.node/Page-Control.html @@ -0,0 +1,218 @@ +<!DOCTYPE html> +<html> +<!-- Created by GNU Texinfo 7.0.3, https://www.gnu.org/software/texinfo/ --> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> +<!-- This manual documents GNU troff version 1.23.0. + +Copyright © 1994-2023 Free Software Foundation, Inc. + +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.3 or +any later version published by the Free Software Foundation; with no +Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A +copy of the license is included in the section entitled "GNU Free +Documentation License". --> +<title>Page Control (The GNU Troff Manual)</title> + +<meta name="description" content="Page Control (The GNU Troff Manual)"> +<meta name="keywords" content="Page Control (The GNU Troff Manual)"> +<meta name="resource-type" content="document"> +<meta name="distribution" content="global"> +<meta name="Generator" content="makeinfo"> +<meta name="viewport" content="width=device-width,initial-scale=1"> + +<link href="index.html" rel="start" title="Top"> +<link href="Request-Index.html" rel="index" title="Request Index"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="GNU-troff-Reference.html" rel="up" title="GNU troff Reference"> +<link href="Using-Fonts.html" rel="next" title="Using Fonts"> +<link href="Page-Layout.html" rel="prev" title="Page Layout"> +<style type="text/css"> +<!-- +a.copiable-link {visibility: hidden; text-decoration: none; line-height: 0em} +div.example {margin-left: 3.2em} +span.r {font-family: initial; font-weight: normal; font-style: normal} +span:hover a.copiable-link {visibility: visible} +strong.def-name {font-family: monospace; font-weight: bold; font-size: larger} +--> +</style> + + +</head> + +<body lang="en"> +<div class="section-level-extent" id="Page-Control"> +<div class="nav-panel"> +<p> +Next: <a href="Using-Fonts.html" accesskey="n" rel="next">Using Fonts</a>, Previous: <a href="Page-Layout.html" accesskey="p" rel="prev">Page Layout</a>, Up: <a href="GNU-troff-Reference.html" accesskey="u" rel="up">GNU <code class="code">troff</code> Reference</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Request-Index.html" title="Index" rel="index">Index</a>]</p> +</div> +<hr> +<h3 class="section" id="Page-Control-1">5.18 Page Control</h3> +<a class="index-entry-id" id="index-page-control"></a> +<a class="index-entry-id" id="index-control_002c-page"></a> + +<a class="index-entry-id" id="index-page-break-1"></a> +<a class="index-entry-id" id="index-break_002c-page-1"></a> +<a class="index-entry-id" id="index-page-ejection-1"></a> +<a class="index-entry-id" id="index-ejection_002c-page-1"></a> +<p>Discretionary page breaks can prevent the unwanted separation of +content. A new page number takes effect during page ejection; see +<a class="ref" href="The-Implicit-Page-Trap.html">The Implicit Page Trap</a>. +</p> +<dl class="first-deffn"> +<dt class="deffn" id="index-_002ebp"><span class="category-def">Request: </span><span><strong class="def-name"><code class="t">.bp</code></strong> <var class="def-var-arguments">[<span class="r"><i class="slanted">page-number</i></span>]</var><a class="copiable-link" href='#index-_002ebp'> ¶</a></span></dt> +<dd><a class="index-entry-id" id="index-bp"></a> +</dd><dt class="deffnx def-cmd-deffn" id="index-_002ebp-1"><span class="category-def">Request: </span><span><strong class="def-name"><code class="t">.bp</code></strong> <var class="def-var-arguments"><code class="t">+</code><span class="r"><i class="slanted">page-number</i></span></var><a class="copiable-link" href='#index-_002ebp-1'> ¶</a></span></dt> +<dt class="deffnx def-cmd-deffn" id="index-_002ebp-2"><span class="category-def">Request: </span><span><strong class="def-name"><code class="t">.bp</code></strong> <var class="def-var-arguments"><code class="t">-</code><span class="r"><i class="slanted">page-number</i></span></var><a class="copiable-link" href='#index-_002ebp-2'> ¶</a></span></dt> +<dt class="deffnx def-cmd-deffn" id="index-_005cn_005b_0025_005d"><span class="category-def">Register: </span><span><strong class="def-name"><code class="t">\n[%]</code></strong><a class="copiable-link" href='#index-_005cn_005b_0025_005d'> ¶</a></span></dt> +<dd><a class="index-entry-id" id="index-_0025-2"></a> +<a class="index-entry-id" id="index-new-page-_0028bp_0029"></a> +<a class="index-entry-id" id="index-page_002c-new-_0028bp_0029"></a> +<p>Break the page and change (increase or decrease) the next page number +per the numeric expression <var class="var">page-number</var>. If <var class="var">page-number</var> is +invalid, GNU <code class="code">troff</code> emits a warning in category ‘<samp class="samp">number</samp>’ and +ignores the argument. This request causes a break. A page break +advances the vertical drawing position to the bottom of the page, +springing traps. See <a class="xref" href="Page-Location-Traps.html">Page Location Traps</a>. +<a class="index-entry-id" id="index-bp-request_002c-and-top_002dlevel-diversion"></a> +<a class="index-entry-id" id="index-top_002dlevel-diversion_002c-and-bp"></a> +<a class="index-entry-id" id="index-diversion_002c-top_002dlevel_002c-and-bp"></a> +<code class="code">bp</code> has effect only if invoked within the top-level +diversion.<a class="footnote" id="DOCF71" href="groff.html_fot.html#FOOT71"><sup>71</sup></a> +<a class="index-entry-id" id="index-CSTR-_002354-errata-2"></a> +<a class="index-entry-id" id="index-CSTR-_002354-erratum_002c-bp-request"></a> +This request is incorrectly documented in the <abbr class="acronym">AT&T</abbr> +<code class="code">troff</code> manual as having a default scaling unit of ‘<samp class="samp">v</samp>’. +</p> +<a class="index-entry-id" id="index-page-number-register-_0028_0025_0029"></a> +<a class="index-entry-id" id="index-current-page-number-_0028_0025_0029"></a> +<p>The register <code class="code">%</code> interpolates the current page number. +</p> +<div class="example"> +<div class="group"><pre class="example-preformatted">.de BP +' bp \" schedule page break once current line is output +.. +</pre></div></div> +</dd></dl> + +<dl class="first-deffn"> +<dt class="deffn" id="index-_002ene"><span class="category-def">Request: </span><span><strong class="def-name"><code class="t">.ne</code></strong> <var class="def-var-arguments">[<span class="r"><i class="slanted">space</i></span>]</var><a class="copiable-link" href='#index-_002ene'> ¶</a></span></dt> +<dd><a class="index-entry-id" id="index-ne"></a> +<a class="index-entry-id" id="index-orphan-lines_002c-preventing-with-ne"></a> +<a class="index-entry-id" id="index-conditional-page-break-_0028ne_0029"></a> +<a class="index-entry-id" id="index-page-break_002c-conditional-_0028ne_0029"></a> +<p>Force a page break if insufficient vertical space is available (assert +“needed” space). <code class="code">ne</code> tests the distance to the next page +location trap; see <a class="ref" href="Page-Location-Traps.html">Page Location Traps</a>, and breaks the page if +that amount is less than <var class="var">space</var>. The default scaling unit is +‘<samp class="samp">v</samp>’. If <var class="var">space</var> is invalid, GNU <code class="code">troff</code> emits a warning +in category ‘<samp class="samp">number</samp>’ and ignores the argument. If <var class="var">space</var> is +not specified, ‘<samp class="samp">1v</samp>’ is assumed. +</p> +<a class="index-entry-id" id="index-widow"></a> +<p>We can require space for at least the first two output lines of a +paragraph, preventing its first line from being <i class="slanted">widowed</i> at the +page bottom. +</p> +<div class="example"> +<div class="group"><pre class="example-preformatted">.ne 2v +Considering how common illness is, +how tremendous the spiritual change that it brings, +how astonishing, +when the lights of health go down, +the undiscovered countries that are then disclosed, +what wastes and deserts of the soul a slight attack +of influenza brings to view, +</pre></div></div> + +<p>This method is reliable only if no output line is pending when <code class="code">ne</code> +is invoked. When macro packages are used, this is often not the case: +their paragraphing macros perform the break. You may need to experiment +with placing the <code class="code">ne</code> after the paragraphing macro, or <code class="code">br</code> +and <code class="code">ne</code> before it. +</p> +<a class="index-entry-id" id="index-orphan"></a> +<a class="index-entry-id" id="index-widow-1"></a> +<p><code class="code">ne</code> is also useful to force grouping of section headings with +their subsequent paragraphs, or tables with their captions and/or +explanations. Macro packages often use <code class="code">ne</code> with diversions to +implement keeps and displays; see <a class="ref" href="Diversions.html">Diversions</a>. They may also offer +parameters for widow and orphan management. +</p></dd></dl> + +<dl class="first-deffn"> +<dt class="deffn" id="index-_002esv"><span class="category-def">Request: </span><span><strong class="def-name"><code class="t">.sv</code></strong> <var class="def-var-arguments">[<span class="r"><i class="slanted">space</i></span>]</var><a class="copiable-link" href='#index-_002esv'> ¶</a></span></dt> +<dd><a class="index-entry-id" id="index-sv"></a> +</dd><dt class="deffnx def-cmd-deffn" id="index-_002eos"><span class="category-def">Request: </span><span><strong class="def-name"><code class="t">.os</code></strong><a class="copiable-link" href='#index-_002eos'> ¶</a></span></dt> +<dd><a class="index-entry-id" id="index-os"></a> +<a class="index-entry-id" id="index-ne-request_002c-comparison-with-sv"></a> +<p>Require vertical space as <code class="code">ne</code> does, but also <i class="slanted">save</i> it for +later output by the <code class="code">os</code> request. If <var class="var">space</var> is available +before the next page location trap, it is output immediately. Both +requests ignore a partially collected line, taking effect at the next +break. +<a class="index-entry-id" id="index-sv-request_002c-and-no_002dspace-mode"></a> +<a class="index-entry-id" id="index-os-request_002c-and-no_002dspace-mode"></a> +<code class="code">sv</code> and <code class="code">os</code> ignore no-space mode (recall <a class="ref" href="Manipulating-Spacing.html">Manipulating Spacing</a>). While the <code class="code">sv</code> request allows negative values for +<var class="var">space</var>, <code class="code">os</code> ignores them. The default scaling unit is +‘<samp class="samp">v</samp>’. If <var class="var">space</var> is not specified, ‘<samp class="samp">1v</samp>’ is assumed. +</p></dd></dl> + +<dl class="first-deffn"> +<dt class="deffn" id="index-_005cn_005bnl_005d"><span class="category-def">Register: </span><span><strong class="def-name"><code class="t">\n[nl]</code></strong><a class="copiable-link" href='#index-_005cn_005bnl_005d'> ¶</a></span></dt> +<dd><a class="index-entry-id" id="index-nl"></a> +<a class="index-entry-id" id="index-vertical-drawing-position-_0028nl_0029"></a> +<a class="index-entry-id" id="index-vertical-position_002c-drawing-_0028nl_0029"></a> +<a class="index-entry-id" id="index-drawing-position_002c-vertical-_0028nl_0029"></a> +<p><code class="code">nl</code> interpolates or sets the vertical drawing position. When the +formatter starts, the first page transition hasn’t happened yet, and +<code class="code">nl</code> is negative. If a header trap has been planted on the page +(typically at vertical position <code class="code">0</code>), you can assign a negative +value to <code class="code">nl</code> to spring it if that page has already started +(see <a class="pxref" href="Page-Location-Traps.html">Page Location Traps</a>). +</p> +<div class="example"> +<div class="group"><pre class="example-preformatted">.de HD +. sp +. tl ''Goldbach Solution'' +. sp +.. +. +First page. +.bp +.wh 0 HD \" plant header trap at top of page +.nr nl (-1) +Second page. + ⇒ First page. + ⇒ + ⇒ <span class="r"><i class="i">(blank lines elided)</i></span> + ⇒ + ⇒ Goldbach Solution + ⇒ + ⇒ <span class="r"><i class="i">(blank lines elided)</i></span> + ⇒ + ⇒ Second page. +</pre></div></div> + +<p>Without resetting <code class="code">nl</code> to a negative value, the trap just planted +would be active beginning with the <em class="emph">next</em> page, not the current +one. +</p> +<p>See <a class="xref" href="Diversions.html">Diversions</a>, for a comparison of <code class="code">nl</code> with the <code class="code">.h</code> and +<code class="code">.d</code> registers. +</p></dd></dl> + + + +</div> +<hr> +<div class="nav-panel"> +<p> +Next: <a href="Using-Fonts.html">Using Fonts</a>, Previous: <a href="Page-Layout.html">Page Layout</a>, Up: <a href="GNU-troff-Reference.html">GNU <code class="code">troff</code> Reference</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Request-Index.html" title="Index" rel="index">Index</a>]</p> +</div> + + + +</body> +</html> |