Re: Duplex printing - how to pad with blank pages

[John Brown <johnbrown105@hotmail.com>]

Bob Stayton <bobs <at> sagehill.net> writes:

> 
> Hi John,
> Profiling does not apply to processing instructions, as a PI has no 
> attributes to select from.  You'd have to create a special element such as 
> an empty para with role="pagebreak" for that.
> 
> Bob Stayton
> Sagehill Enterprises

I have an XML file that looks like this:
<book xmlns="http://docbook.org/ns/docbook"; version="5.0">
   <title>Conditional Hard Page Breaks</title>

   <chapter>
      <title>Blank Pages</title>
      <para>This is a paragraph</para>
      <?hard-pagebreak?>
      <para condition="break-needed">
      <?hard-pagebreak?>
      </para>
      <para>This paragraph always begins on a new page, thanks to the
            unconditional hard page break. If profile.condition =
            break-needed, then a blank page will be inserted. What I
            really want is that the extra page break should be inserted
            when double.sided=1.
      </para>
   </chapter>
</book>

I can process this with:
    xsltproc -o break.fo --stringparam profile.condition break-needed \
       break.xsl break.xml
where break.xsl imports fo/profile-docbook.xsl and defines the hard
page break PI. The only thing is that I would rather not have to
remember to set profile.condition=break-needed when I set double.sided=1.
I want my PI to add one page break or two depending on the value
of double.sided.

I tried this:

<xsl:import href="/path/to/non-profiling/fo/docbook.xsl/>
<xsl:template match="processing-instruction('hard-pagebreak')">
   <!-- always start new page -->
   <fo:block break-after="page"/>
   <xsl:if test="double.sided=1"> <!-- add blank page -->
      <fo:block break-after="page"/>
   </xsl:if>
</xsl:template>


I know that the test for double.sided works, because I have no problems
when double.sided = 0, but when it is 1, then fop gives errors:
java.lang.UnsupportedOperationException: Flow "xsl-region-body" does not map to
the region-body in page-master "blank". FOP presently does not support this.
(See position 2:458). The relevant section of the fo file is:
<fo:simple-page-master master-name="blank" page-width="8.5in" page-height="11in"
margin-top="0.5in" margin-bottom="0.5in" margin-left="0.75in - 0pt"
margin-right="1.25in">
      <fo:region-body display-align="center" margin-bottom="0.5in"
margin-top="0.5in" region-name="blank-body"/>
...
   </fo:region-body>
...
</fo:simple-page-master>
2:458 is where the <fo:region-body> tag starts.

Is it possible for me to do what I want?