Apparently part and chapter numbering for bookmaps has been broken in the Open Toolkit PDF output since the beginning. Instead of numbering the chapters in a series from beginning to end, chapter numbering resets to 1 for every part so the TOC looks like this:

• Part I
  • Chapter 1
  • Chapter 2
  • Chapter 3
• Part II
  • Chapter 1
  • Chapter 2
  • Chapter 3
• Part III
  • Chapter 1
  • Chapter 2
  • Chapter 3

The correct behavior would be a single chapter series that goes from 1 to 9. OT issue 1418 indicates that this was fixed in OT 1.7 but I didn’t see any change when I tried it out. Instead I changed my PDF plugin and thought I’d document the change here for anyone else who might need to do it in the future since I wasn’t able to find the answer anywhere.

There are two templates that need to be updated: one for the TOC and one for the chapter first page.

The template for the TOC is below.

<xsl:template match="*[contains(@class, ' bookmap/chapter ')] |
  *[contains(@class, ' boookmap/bookmap ')]/opentopic:map/*[contains(@class, ' map/topicref ')]" mode="tocPrefix" priority="-1">
  <xsl:call-template name="insertVariable">
    <xsl:with-param name="theVariableID" select="'Table of Contents Chapter'"/>
    <xsl:with-param name="theParameters">
        <number>
          <xsl:variable name="id" select="@id" />
          <xsl:variable name="topicChapters">
            <xsl:copy-of select="$map//*[contains(@class, ' bookmap/chapter ')]" />
          </xsl:variable>
          <xsl:variable name="chapterNumber">
            <xsl:number format="1"
              value="count($topicChapters/*[@id = $id]/preceding-sibling::*) + 1" />
          </xsl:variable>
          <xsl:value-of select="$chapterNumber" />
        </number>
    </xsl:with-param>
  </xsl:call-template>
</xsl:template>

The significant parts here are the $topicChapters and $chapterNumber variables.

The template for the chapter first page is insertChapterFirstpageStaticContent. It’s too long to reproduce in its entirety here, but the code is the same as what’s inside the number element in the TOC template. The number element that contains the $topicChapters and $chapterNumber variables needs to replace the one inside the xsl:when test="$type = 'chapter'" block.