Package org.apache.fop.layoutmgr

Class PageBreaker

java.lang.Object
org.apache.fop.layoutmgr.AbstractBreaker
org.apache.fop.layoutmgr.PageBreaker
public class PageBreaker extends AbstractBreaker
Handles the breaking of pages in an fo:flow

  • Constructor Details

    • PageBreaker

      public PageBreaker(PageSequenceLayoutManager pslm)
      Construct page breaker.
      Parameters:
      pslm - the page sequence layout manager

  • Method Details

    • updateLayoutContext

      protected void updateLayoutContext(LayoutContext context)
      Used to update the LayoutContext in subclasses prior to starting a new element list.
      Overrides:
      updateLayoutContext in class AbstractBreaker
      Parameters:
      context - the LayoutContext to update

    • getTopLevelLM

      protected LayoutManager getTopLevelLM()
      Specified by:
      getTopLevelLM in class AbstractBreaker
      Returns:
      top level layout manager

    • getPageProvider

      protected PageProvider getPageProvider()
      Returns the PageProvider if any. PageBreaker overrides this method because each page may have a different available BPD which needs to be accessible to the breaking algorithm.
      Overrides:
      getPageProvider in class AbstractBreaker
      Returns:
      the applicable PageProvider, or null if not applicable

    • createLayoutListener

      protected org.apache.fop.layoutmgr.PageBreakingAlgorithm.PageBreakingLayoutListener createLayoutListener()
      Creates and returns a PageBreakingLayoutListener for the PageBreakingAlgorithm to notify about layout problems.
      Overrides:
      createLayoutListener in class AbstractBreaker
      Returns:
      the listener instance or null if no notifications are needed

    • handleSpanChange

      protected int handleSpanChange(LayoutContext childLC, int nextSequenceStartsOn)
      Handles span changes reported through the LayoutContext. Only used by the PSLM and called by getNextBlockList().
      Overrides:
      handleSpanChange in class AbstractBreaker
      Parameters:
      childLC - the LayoutContext
      nextSequenceStartsOn - previous value for break handling
      Returns:
      effective value for break handling

    • getNextBlockList

      protected int getNextBlockList(LayoutContext childLC, int nextSequenceStartsOn)
      Gets the next block list (sequence) and adds it to a list of block lists if it's not empty.
      Overrides:
      getNextBlockList in class AbstractBreaker
      Parameters:
      childLC - LayoutContext to use
      nextSequenceStartsOn - indicates on what page the next sequence should start
      Returns:
      the page on which the next content should appear after a hard break

    • getNextBlockList

      protected int getNextBlockList(LayoutContext childLC, int nextSequenceStartsOn, Position positionAtIPDChange, LayoutManager restartLM, List firstElements)
      Gets the next block list (sequence) and adds it to a list of block lists if it's not empty.
      Overrides:
      getNextBlockList in class AbstractBreaker
      Parameters:
      childLC - LayoutContext to use
      nextSequenceStartsOn - indicates on what page the next sequence should start
      positionAtIPDChange - last element on the part before an IPD change
      restartLM - the layout manager from which to restart, if IPD change occurs between two LMs
      firstElements - elements from non-restartable LMs on the new page
      Returns:
      the page on which the next content should appear after a hard break

    • getFootnoteKnuthElements

      public static List<List<KnuthElement>> getFootnoteKnuthElements(FlowLayoutManager flowLM, LayoutContext context, List<FootnoteBodyLayoutManager> footnoteBodyLMs)

    • getNextKnuthElements

      protected List getNextKnuthElements(LayoutContext context, int alignment)
      Get a sequence of KnuthElements representing the content of the node assigned to the LM
      Specified by:
      getNextKnuthElements in class AbstractBreaker
      Parameters:
      context - the LayoutContext used to store layout information
      alignment - the desired text alignment
      Returns:
      the list of KnuthElements

    • getNextKnuthElements

      protected List getNextKnuthElements(LayoutContext context, int alignment, Position positionAtIPDChange, LayoutManager restartAtLM)
      Get a sequence of KnuthElements representing the content of the node assigned to the LM
      Overrides:
      getNextKnuthElements in class AbstractBreaker
      Parameters:
      context - the LayoutContext used to store layout information
      alignment - the desired text alignment
      positionAtIPDChange - last element on the part before an IPD change
      restartAtLM - the layout manager from which to restart, if IPD change occurs between two LMs
      Returns:
      the list of KnuthElements

    • getCurrentDisplayAlign

      protected int getCurrentDisplayAlign()
      Specified by:
      getCurrentDisplayAlign in class AbstractBreaker
      Returns:
      current display alignment

    • hasMoreContent

      protected boolean hasMoreContent()
      Specified by:
      hasMoreContent in class AbstractBreaker
      Returns:
      whether or not this flow has more page break opportunities

    • addAreas

      protected void addAreas(PositionIterator posIter, LayoutContext context)
      Adds an area to the flow layout manager
      Specified by:
      addAreas in class AbstractBreaker
      Parameters:
      posIter - the position iterator
      context - the layout context

    • doPhase3

      protected void doPhase3(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList)
      Phase 3 of Knuth algorithm: Adds the areas This implementation checks whether to trigger column-balancing, or whether to take into account a 'last-page' condition.
      Specified by:
      doPhase3 in class AbstractBreaker
      Parameters:
      alg - PageBreakingAlgorithm instance which determined the breaks
      partCount - number of parts (pages) to be rendered
      originalList - original Knuth element list
      effectiveList - effective Knuth element list (after adjustments)

    • prepareToRedoLayout

      protected void prepareToRedoLayout(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList)
      Overrides:
      prepareToRedoLayout in class AbstractBreaker

    • startPart

      protected void startPart(AbstractBreaker.BlockSequence list, int breakClass, boolean emptyContent)
      Start part.
      Overrides:
      startPart in class AbstractBreaker
      Parameters:
      list - a block sequence
      breakClass - a break class

    • handleEmptyContent

      protected void handleEmptyContent()
      This method is called when no content is available for a part. Used to force empty pages.
      Overrides:
      handleEmptyContent in class AbstractBreaker

    • finishPart

      protected void finishPart(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, AbstractBreaker.PageBreakPosition pbp)
      Finish part.
      Specified by:
      finishPart in class AbstractBreaker
      Parameters:
      alg - a page breaking algorithm
      pbp - a page break posittion

    • getCurrentChildLM

      protected FlowLayoutManager getCurrentChildLM()
      Specified by:
      getCurrentChildLM in class AbstractBreaker
      Returns:
      current child layout manager

    • observeElementList

      protected void observeElementList(List elementList)
      Used for debugging purposes. Notifies all registered observers about the element list. Override to set different parameters.
      Overrides:
      observeElementList in class AbstractBreaker
      Parameters:
      elementList - the Knuth element list

    • shouldRedoLayout

      protected boolean shouldRedoLayout()
      Overrides:
      shouldRedoLayout in class AbstractBreaker

    • shouldRedoLayout

      protected boolean shouldRedoLayout(int partCount)

    • wasLayoutRedone

      protected boolean wasLayoutRedone()
      Overrides:
      wasLayoutRedone in class AbstractBreaker

    • lastPageHasIPDChange

      protected boolean lastPageHasIPDChange(int optimalPageCount)
      Overrides:
      lastPageHasIPDChange in class AbstractBreaker

    • handlingStartOfFloat

      protected boolean handlingStartOfFloat()

    • handleStartOfFloat

      protected void handleStartOfFloat(int fHeight, int fYOffset)

    • getFloatHeight

      protected int getFloatHeight()

    • getFloatYOffset

      protected int getFloatYOffset()

    • handlingEndOfFloat

      protected boolean handlingEndOfFloat()

    • handleEndOfFloat

      protected void handleEndOfFloat(int fHeight)

    • handlingFloat

      protected boolean handlingFloat()

    • getOffsetDueToFloat

      public int getOffsetDueToFloat()

    • handleFloatLayout

      protected int handleFloatLayout(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int optimalPageCount, AbstractBreaker.BlockSequence blockList, LayoutContext childLC)
      Overrides:
      handleFloatLayout in class AbstractBreaker

    • addAreasForFloats

      protected void addAreasForFloats(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int startPart, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList, LayoutContext childLC, int lastBreak, int startElementIndex, int endElementIndex)
      Overrides:
      addAreasForFloats in class AbstractBreaker

    • holdFootnotes

      public void holdFootnotes(List fl, List ll, int tfl, int ifl, boolean fp, boolean nf, int fnfi, int fli, int fei, MinOptMax fsl, int pfli, int pfei)

    • retrieveFootones

      public void retrieveFootones(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg)