docbook-apps

Hi Fabien,
There is no class attribute defined for DocBook's imageobject element, so it is
unlikely that its value would be handled by the stylesheet. Were you thinking of the
role attribute? I see both class and role on imagedata, but since you are asking
about role="histogram", I'll assume you mean to use the role attribute.

Also, I'm not able to duplicate your results of getting the imageobject's
class="imgopen2" to appear on the div element. Are you using a stylesheet
customization that does that?

DocBook XSL has some limited support for propagating a role attribute to a class
attribute, but that is not a universal mechanism, simply because people use role for
many things and would not necessarily want to see its values appear in their HTML
output.

The stylesheets have a general mechanism for customizing a class attribute, but it
does not apply to . That would require customizing a rather large template named
'process.image.attributes' to add a class attribute. But the class customization
mechanism does work for mediaobject, however. For example, if your source has a role
on mediaobject:

<mediaobject role="histogram">

when combined with the following stylesheet customization (remove the d: namespace if
using DocBook 4):

<xsl:template match="d:mediaobject" mode="class.value">
<xsl:choose>
<xsl:when test="@role">
<xsl:value-of select="@role"/>
</xsl:when>
<xsl:otherwise>mediaobject</xsl:otherwise>
</xsl:choose>
</xsl:template>

will result in this output: