How change pages publishing works

Change pages publishing works best when processing technical manuals and documentation which are composed of a number of small parts, each of which starts on a new page. Such manuals typically use a hierarchical numbering scheme that lends itself to the generation of a unique identifier for each page. The change pages looseleaf model assigns a unique identifier to each page, so that the corresponding page in the previous release can be located for comparison (differencing).

All page identifiers must:

  • be defined in the custom content of a header or footer

  • consist only of characters within the US-ASCII character set

  • contain a maximum of 32 characters

For example, consider a document consisting of a number of chapters, each containing one or more sections. Each section starts a new right-hand page. This diagram shows how the pages are organized and labeled:

In the TopLeaf mappings you could maintain three counters called {ChapterNum}, {SectionNum} and {PageNum}. The mapping for a chapter increments the ChapterNum counter and resets the SectionNum counter to zero. The mapping for a section increments SectionNum and resets PageNum. In the custom content for the footer you generate the page identifier and display the page folio as follows:

<set var="PageNum" value="{PageNum}+1"/>
<page-properties id="{ChapterNum}-{SectionNum}.{PageNum}"/>
Page {ChapterNum}-{SectionNum}.{PageNum}

To generate unique page identifiers, you must call the <page-properties/> command in the custom content for a header or footer. It is not necessary to assign an identifier to every page, but pages with no identifier will always be included in the current release. You can use this technique to ensure that a table of contents, title page, and any other preliminary pages are always printed.

The page identifier is used to label the page in the navigation pane. Pages in the page list that have not been assigned a unique page identifier are listed using the underlying page sequence number.

[Note] Note

It is an error to assign the same identifier to more than one page. If this occurs, all pages will be listed using a page sequence number. The composition log file includes a list of all duplicate page identifiers.

You cannot use the <folio/> command to assign a page identifier as this command always returns the page sequence number.