Symphony.

The Cumulus ensemble uses the following utility to manage font sizes for HTML and Flash text. Play with the $minsize and $maxsize parameters to modify sizes.

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

<xsl:template name="tags">

    <!-- Configure minimum and maximum point sizes for fonts -->
    <xsl:param name="minsize" select="12"/>
    <xsl:param name="maxsize" select="36"/>

    <!-- Size difference in points between each number of topics -->
    <xsl:param name="step" select="4"/>

    <!-- Custom colors for tags and hovers -->
    <xsl:param name="color">
        <xsl:if test="color"><xsl:value-of select="color"/></xsl:if>
    </xsl:param>
    <xsl:param name="hicolor">
        <xsl:if test="hover-color"><xsl:value-of select="hover-color"/></xsl:if>
    </xsl:param>

    <!-- Calculate font size -->
    <xsl:param name="fontsize">
        <xsl:choose>
            <xsl:when test="topics &lt; $minsize div $step"><xsl:value-of select="$minsize"/></xsl:when>
            <xsl:when test="topics &gt; $maxsize div $step"><xsl:value-of select="$maxsize"/></xsl:when>
            <xsl:otherwise><xsl:value-of select="$step * topics"/></xsl:otherwise>
        </xsl:choose>
    </xsl:param>

    <!-- Anchor for each tag -->
    <a href="{uri}" title="{topics} topics" class="tag-link-{@id}" rel="tag" style="font-size: {$fontsize}pt;">
        <xsl:if test="$color != ''">
            <xsl:attribute name="color"><xsl:value-of select="$color"/></xsl:attribute>
        </xsl:if>
        <xsl:if test="$hicolor != ''">
            <xsl:attribute name="hicolor"><xsl:value-of select="$hicolor"/></xsl:attribute>
        </xsl:if>
        <xsl:value-of select="tag"/>
    </a>
</xsl:template>


</xsl:stylesheet>

Great work bauhause! I came up with my own tag cloud template not so long ago, supporting similar functionality (pass a range and it will calculate sizes). One suggestion — I'd be cautious of setting font sizes directly in the XSLT. A preferred method would be to use a set of classes on the anchors so that styling is kept in external CSS files.

Out of interest, what would a uri node look like? For the rel=tag microformat the tag needs to be the last chunk of the URL string. Just wondering, because I'm a microformat nut ;-)

Thanks, nickdunn. I should have taken a look at previous implementations before I created mine. Your XSL looks a lot more elegant at first glance. I believe you are right about setting font sizes in external CSS instead of inline. I first wanted to match the existing functionality of WP-Cumulus so as not to require a more extensive rewrite of the ActionScript. It would be possible to apply a different XSL template, or use a different mode, for rendering the anchors in the HTML so that it is well-formed while maintaining the required format for the XML served to the SWF file.

As a side note, I did try using apply-templates instead of call-template for the tags utility, but even though I was trying to match the entry node, the output include the text value of the section node.

  <xsl:apply-templates match="data/tags/entry"/>

If anyone has any ideas about why that would happen, please let me know.

I need to learn more about microformats. I've only experimented a little with the hCalendar microformat. Moving the rel attribute is an easy fix. Can you explain the usage of the uri node?

Sure. The rel-tag microformat stipulates that the last part of the URL is the tag itself, i.e. after the last forward-slash in the URL.

Therefore for the tag to be a valid microformat, the URL should look along the lines of:

http://domain.com/articles/tags/my-tag

Trailing slashes are ignored.

If that URL structure fits your site, then adding rel=tag to the links is a valid use of the microformat. Simple as that :-)