<refentry xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xi="http://www.w3.org/2001/XInclude" xmlns:src="http://nwalsh.com/xmlns/litprog/fragment" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="5.0" xml:id="nominal.image.width"> <refmeta> <refentrytitle>nominal.image.width</refentrytitle> <refmiscinfo class="other" otherclass="datatype">length</refmiscinfo> </refmeta> <refnamediv> <refname>nominal.image.width</refname> <refpurpose>The nominal image width</refpurpose> </refnamediv> <refsynopsisdiv> <src:fragment xml:id="nominal.image.width.frag"> <xsl:param name="nominal.image.width" select="6 * $pixels.per.inch"/> </src:fragment> </refsynopsisdiv> <refsection><info><title>Description</title></info> <para>Graphic widths expressed as a percentage are problematic. In the following discussion, we speak of width and contentwidth, but the same issues apply to depth and contentdepth.</para> <para>A width of 50% means "half of the available space for the image." That's fine. But note that in HTML, this is a dynamic property and the image size will vary if the browser window is resized.</para> <para>A contentwidth of 50% means "half of the actual image width". But what does that mean if the stylesheets cannot assess the image's actual size? Treating this as a width of 50% is one possibility, but it produces behavior (dynamic scaling) that seems entirely out of character with the meaning.</para> <para>Instead, the stylesheets define a <parameter>nominal.image.width</parameter> and convert percentages to actual values based on that nominal size.</para> </refsection> </refentry>