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diff --git a/Master/texmf-dist/doc/generic/FAQ-en/html/FAQ-oddpage.html b/Master/texmf-dist/doc/generic/FAQ-en/html/FAQ-oddpage.html new file mode 100644 index 00000000000..2640db821fe --- /dev/null +++ b/Master/texmf-dist/doc/generic/FAQ-en/html/FAQ-oddpage.html @@ -0,0 +1,49 @@ +<head> +<title>UK TeX FAQ -- question label oddpage</title> +</head><body> +<h3>Finding if you’re on an odd or an even page</h3> +<p/><a href="FAQ-marginparside.html">Another question</a> discusses the issue +of getting <code>\</code><code>marginpar</code> commands to put their output in the correct +margin of two-sided documents. This is an example of the general +problem of knowing where a particular bit of text lies: the output +routine is asynchronous, and (La)TeX will usually process quite a +bit of the “next” page before deciding to output any page. As a +result, the <code>page</code> counter (known internally in LaTeX as +<code>\</code><code>c@page</code>) is normally only reliable when you’re actually <em>in</em> +the output routine. +<p/>The solution is to use some version of the <code>\</code><code>label</code> mechanism to +determine which side of the page you’re on; the value of the page +counter that appears in a <code>\</code><code>pageref</code> command has been inserted in +the course of the output routine, and is therefore safe. +<p/>However, <code>\</code><code>pageref</code> itself isn’t reliable: one might hope that +<pre> +\ifthenelse{\isodd{\pageref{foo}}}{odd}{even} +</pre> +would do the necessary, but both the <i>babel</i> and +<i>hyperref</i> packages have been known to interfere with the +output of <code>\</code><code>pageref</code>; be careful! +<p/>The <i>changepage</i> package needs to provide this functionality for +its own use, and therefore provides a command <code>\</code><code>checkoddpage</code>; this +sets a private-use label, and the page reference part of that label is +then examined (in a <i>hyperref</i>-safe way) to set a conditional +<code>\</code><code>ifoddpage</code> true if the command was issued on an odd page. The +<i>memoir</i> class has the same command setting a conditional +<code>\</code><code>ifoddpage</code>. Of course, the <code>\</code><code>label</code> contributes to LaTeX’s +“Rerun to get cross-references right” error messages... +<p/>The (older) <i>chngpage</i> provides the same facilities (though it +provides a <code>\</code><code>ifcpoddpage</code> command; <i>changepage</i> (whose +functions are extracted from the author’s <i>memoir</i> class) is the +designated successor to <i>chngpage</i>. +<p/>The Koma-Script classes have an <code>addmargin*</code> environment +that also provides the sorts of facilities that the <i>chngpage</i> +offers. Koma-Script’s supporting command is +<code>\</code><code>ifthispageodd{<true>}{<false>}</code> executes different things +depending on the page number. +<dl> +<dt><tt><i>changepage.sty</i></tt><dd><a href="ftp://cam.ctan.org/tex-archive/macros/latex/contrib/misc/changepage.sty">macros/latex/contrib/misc/changepage.sty</a> +<dt><tt><i>chngpage.sty</i></tt><dd><a href="ftp://cam.ctan.org/tex-archive/macros/latex/contrib/misc/chngpage.sty">macros/latex/contrib/misc/chngpage.sty</a> +<dt><tt><i>KOMA script bundle</i></tt><dd><a href="ftp://cam.ctan.org/tex-archive/macros/latex/contrib/koma-script.zip">macros/latex/contrib/koma-script</a> (<a href="ftp://cam.ctan.org/tex-archive/macros/latex/contrib/koma-script.tar.gz">gzipped tar</a>, <a href="http://www.tex.ac.uk/tex-archive/macros/latex/contrib/koma-script/">browse</a>) +<dt><tt><i>memoir.cls</i></tt><dd><a href="ftp://cam.ctan.org/tex-archive/macros/latex/contrib/memoir.zip">macros/latex/contrib/memoir</a> (<a href="ftp://cam.ctan.org/tex-archive/macros/latex/contrib/memoir.tar.gz">gzipped tar</a>, <a href="http://www.tex.ac.uk/tex-archive/macros/latex/contrib/memoir/">browse</a>) +</dl> +<p/><p>This question on the Web: <a href="http://www.tex.ac.uk/cgi-bin/texfaq2html?label=oddpage">http://www.tex.ac.uk/cgi-bin/texfaq2html?label=oddpage</a> +</body> |