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  1. FOP
  2. FOP-1120

[patch] force-page-count property implementation


    • Type: Improvement
    • Status: Closed
    • Resolution: Fixed
    • Affects Version/s: trunk
    • Fix Version/s: None
    • Component/s: layout/unqualified
    • Labels:
    • Environment:
      Operating System: other
      Platform: Other
    • External issue ID:


      This patch (re)implements the force-page-count property.

      I tried to implement it with as little changes to the
      code as possible. Therefore some design issues and questions
      remain - see later.

      The force-page-count property is handled by adding a method
      to the PageSequenceLayoutManger, because there are is a
      method that has all informations (static content, pagenumber,
      ...) about creating a new page (makeNewPage).
      The main problem was that the force-page-count property needs
      the initial-page-number of the next page-sequence which does
      not exist at this time.
      I solved this by preserving the current PageSequenceLayoutManger
      after the end of the page-sequence. I used the Root object
      for this because the last pagenumber of the sequence and other
      informations are also handed over this object from one
      page-sequence to the other. At the beginning of the following
      page-sequence the (stored) previous PageSequenceLayoutManger
      is called with the now current PageSequence object to finish
      this work.

      Changes to Root.java:

      • insert the variable previousPageSeqLM to store a
        PageSequenceLayoutManger for later use
        (and import the necessary class definition).

      Changes to PageSequenceLayoutManger.java:

      • split off the last part of activateLayout into a separate
        method (finishLeayout) because i need the same functionality
        after the force-page-count handling.
      • preserve the current PageSequenceLayoutManger object to the
        Root object at the end of the finishLayout method.
      • implement the force-page-count propterty in the
        checkForcePageCount method. This method needs the next
        PageSequence object as parameter. To get the initial-page-number
        property of this next page-sequence i copied the code from

      Changes to PageSequence.java:

      • call the checkForcePageCount method of the preserved previous
        PageSequenceLayoutManger inside the startOfNode method
        immediately before initPageNumber so that this method is
        waware of possibly inserted pages of the previous page-sequence.
      • insert a getFocePageCount method to get the private variable.
      • insert a getInitialPageNumber method to get the private variable.

      Open issues / questions:

      • i think it very likely that the previousPageSeqLM variable of
        the Root class should be privat and there should be a
        setPreviousPageSeqLM and a getPreviousPageSeqLM method to
        hand the variable into and out of the object.
      • there was a second possiblity to implement this all
        by using the AreaTreeHandler:
      • instead of saving the PageSequenceLayoutManger object
        at the end of the finishLayout method of the
        PageSequenceLayoutManger it could be preserved at the
        end of the endPageSequence method of the AreaTreeHandler.
      • instead of calling the checkForcePageCount from the
        startOfNode method of PageSequence it could be called
        from the startPageSequence method of the AreaTreeHandler
        after receiving the rootFObj.
      • all other could be left nearly as with this patch with
        the exception that the startingPageNumber of the PageSequence
        has to be recalced after calling the checkForcePageCount
        because it is already calced at this point and does not
        know about possibly inserted pages from the
        checkForcePageCount method before.
        someone who has a more overall sight of the code has to
        decide where it fits best.

      I know the force-page-count property is of low priority, but
      it would be nice to get feedback, if someone can spare time
      to have a look at this patch.

      I hope i was not too verbose and that my patch is more
      usefull than the review is time-consuming and that i dont
      violate too much design guidelines.

      happy new year


        1. page-sequence_force-page-count_noauto.xml
          6 kB
          gerhard oettl
        2. page-sequence_force-page-count_auto.xml
          5 kB
          gerhard oettl
        3. force-page-count.patch
          7 kB
          gerhard oettl
        4. force-page-count.patch
          8 kB
          gerhard oettl
        5. force-page-count.fo
          10 kB
          gerhard oettl
        6. force-page-count.fo
          11 kB
          gerhard oettl



            • Assignee:
              fop-dev@xmlgraphics.apache.org fop-dev
              gerhard.oettl@oesoft.at gerhard oettl
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              • Created: