Package org.apache.fop.layoutmgr

Class AbstractLayoutManager

java.lang.Object
org.apache.fop.layoutmgr.AbstractBaseLayoutManager
org.apache.fop.layoutmgr.AbstractLayoutManager
All Implemented Interfaces:
PercentBaseContext, Constants, LayoutManager
Direct Known Subclasses:
AbstractPageSequenceLayoutManager, BlockStackingLayoutManager, InlineContainerLayoutManager, InlineStackingLayoutManager, LeafNodeLayoutManager
public abstract class AbstractLayoutManager extends AbstractBaseLayoutManager implements Constants
The base class for most LayoutManagers.

  • Field Details

    • parentLayoutManager

      protected LayoutManager parentLayoutManager
      Parent LayoutManager for this LayoutManager

    • childLMs

      protected List<LayoutManager> childLMs
      List of child LayoutManagers

    • fobjIter

      protected ListIterator fobjIter
      Iterator for child LayoutManagers

    • curChildLM

      protected LayoutManager curChildLM
      child LM during getNextKnuthElement phase

    • childLMiter

      protected ListIterator<LayoutManager> childLMiter
      child LM iterator during getNextKnuthElement phase

  • Constructor Details

    • AbstractLayoutManager

      public AbstractLayoutManager()
      Abstract layout manager.

    • AbstractLayoutManager

      public AbstractLayoutManager(FObj fo)
      Abstract layout manager.
      Parameters:
      fo - the formatting object for this layout manager

  • Method Details

    • setParent

      public void setParent(LayoutManager lm)
      Set the parent layout manager. The parent layout manager is required for adding areas.
      Specified by:
      setParent in interface LayoutManager
      Parameters:
      lm - the parent layout manager

    • getParent

      public LayoutManager getParent()
      Get the parent layout manager.
      Specified by:
      getParent in interface LayoutManager
      Returns:
      the parent layout manager.

    • initialize

      public void initialize()
      initialize the layout manager. Allows each layout manager to calculate often used values.
      Specified by:
      initialize in interface LayoutManager

    • getChildLM

      protected LayoutManager getChildLM()
      Return currently active child LayoutManager or null if all children have finished layout. Note: child must implement LayoutManager! If it doesn't, skip it and print a warning.
      Returns:
      the current child LayoutManager

    • setCurrentChildLM

      protected void setCurrentChildLM(LayoutManager childLM)
      Set currently active child layout manager.
      Parameters:
      childLM - the child layout manager

    • hasNextChildLM

      protected boolean hasNextChildLM()
      Return indication if getChildLM will return another LM.
      Returns:
      true if another child LM is still available

    • isFinished

      public boolean isFinished()
      Tell whether this LayoutManager has handled all of its content.
      Specified by:
      isFinished in interface LayoutManager
      Returns:
      True if there are no more break possibilities, ie. the last one returned represents the end of the content.

    • setFinished

      public void setFinished(boolean fin)
      Set the flag indicating the LayoutManager has handled all of its content.
      Specified by:
      setFinished in interface LayoutManager
      Parameters:
      fin - the flag value to be set

    • addAreas

      public void addAreas(PositionIterator posIter, LayoutContext context)
      Tell the layout manager to add all the child areas implied by Position objects which will be returned by the Iterator.
      Specified by:
      addAreas in interface LayoutManager
      Parameters:
      posIter - the position iterator
      context - the context

    • getNextKnuthElements

      public 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 interface LayoutManager
      Parameters:
      context - the LayoutContext used to store layout information
      alignment - the desired text alignment
      Returns:
      the list of KnuthElements

    • getChangedKnuthElements

      public List getChangedKnuthElements(List oldList, int alignment)
      Get a sequence of KnuthElements representing the content of the node assigned to the LM, after changes have been applied In the context of line breaking, this method is called after hyphenation has been performed, in order to receive the sequence of elements representing the text together with all possible hyphenation points. For example, if the text "representation" originates a single box element when getNextKnuthElements() is called, it will be now split in syllables (rep-re-sen-ta-tion) each one originating a box and divided by additional elements allowing a line break. In the context of page breaking, this method is called only if the pages need to be "vertically justified" modifying (also) the quantity of lines created by the paragraphs, and after a first page breaking has been performed. According to the result of the first page breaking, each paragraph now knows how many lines it must create (among the existing layout possibilities) and has to create a sequence of elements representing this layout; in particular, each box, representing a line, will contain a LineBreakPositions that will be used in the addAreas() phase. LMs having children look at the old list of elements in order to know which ones they must get the new elements from, as break conditions of preserved linefeeds can divide children into smaller groups (page sequences or paragraphs). LMs having no children can simply return the old elements if they have nothing to change. Inline LMs need to know the text alignment because it affects the elements representing feasible breaks between syllables.
      Specified by:
      getChangedKnuthElements in interface LayoutManager
      Parameters:
      oldList - the elements to replace
      alignment - the desired text alignment
      Returns:
      the updated list of KnuthElements

    • getParentArea

      public Area getParentArea(Area childArea)
      Return an Area which can contain the passed childArea. The childArea may not yet have any content, but it has essential traits set. In general, if the LayoutManager already has an Area it simply returns it. Otherwise, it makes a new Area of the appropriate class. It gets a parent area for its area by calling its parent LM. Finally, based on the dimensions of the parent area, it initializes its own area. This includes setting the content IPD and the maximum BPD.
      Specified by:
      getParentArea in interface LayoutManager
      Parameters:
      childArea - the child area for which the parent area is wanted
      Returns:
      the parent area for the given child

    • addChildArea

      public void addChildArea(Area childArea)
      Add a child area to the current area. If this causes the maximum dimension of the current area to be exceeded, the parent LM is called to add it.
      Specified by:
      addChildArea in interface LayoutManager
      Parameters:
      childArea - the child area to be added

    • createChildLMs

      protected List<LayoutManager> createChildLMs(int size)
      Create the LM instances for the children of the formatting object being handled by this LM.
      Parameters:
      size - the requested number of child LMs
      Returns:
      the list with the preloaded child LMs

    • getPSLM

      public PageSequenceLayoutManager getPSLM()
      Get the active PageSequenceLayoutManager instance for this layout process.
      Specified by:
      getPSLM in interface LayoutManager
      Returns:
      the PageSequenceLayoutManager

    • getCurrentPage

      public Page getCurrentPage()
      Returns:
      the Page instance corresponding to the current page
      See Also:

    • getCurrentPV

      public PageViewport getCurrentPV()
      Returns:
      the current page viewport

    • createNextChildLMs

      public boolean createNextChildLMs(int pos)
      Create more child LMs of the parent, up to child LM index pos
      Specified by:
      createNextChildLMs in interface LayoutManager
      Parameters:
      pos - index up to which child LMs are requested
      Returns:
      true if requested index does exist

    • getChildLMs

      public List<LayoutManager> getChildLMs()
      Specified by:
      getChildLMs in interface LayoutManager
      Returns:
      the list of child LMs

    • addChildLM

      public void addChildLM(LayoutManager lm)
      Add the LM in the argument to the list of child LMs; set this LM as the parent; initialize the LM.
      Specified by:
      addChildLM in interface LayoutManager
      Parameters:
      lm - the LM to be added

    • addChildLMs

      public void addChildLMs(List newLMs)
      Add the LMs in the argument to the list of child LMs;
      Specified by:
      addChildLMs in interface LayoutManager
      Parameters:
      newLMs - the list of LMs to be added

    • notifyPos

      public Position notifyPos(Position pos)
      Adds a Position to the Position participating in the first|last determination by assigning it a unique position index.
      Specified by:
      notifyPos in interface LayoutManager
      Parameters:
      pos - the Position
      Returns:
      the same Position but with a position index

    • isFirst

      public boolean isFirst(Position pos)
      Indicates whether the given Position is the first area-generating Position of this LM.
      Parameters:
      pos - the Position (must be one with a position index)
      Returns:
      True if it is the first Position

    • isLast

      public boolean isLast(Position pos)
      Indicates whether the given Position is the last area-generating Position of this LM.
      Parameters:
      pos - the Position (must be one with a position index)
      Returns:
      True if it is the last Position

    • hasLineAreaDescendant

      public boolean hasLineAreaDescendant()
      Description copied from interface: LayoutManager
      Whether the FO handled by this layout manager has a descendant (including itself) that will generate a line-area.
      Specified by:
      hasLineAreaDescendant in interface LayoutManager
      Returns:
      true if a descendant line-area will be generated, false otherwise

    • getBaselineOffset

      public int getBaselineOffset()
      Description copied from interface: LayoutManager
      Returns the position of the dominant-baseline of this FO's first descendant line-area.

      The behavior of this method is undefined if this FO has no descendant line-area, and an exception may be thrown. See LayoutManager.hasLineAreaDescendant()

      Specified by:
      getBaselineOffset in interface LayoutManager
      Returns:
      this FO's space-before plus the distance from the before-edge of its allocation-rectangle to the dominant-baseline of the first line-area descendant
      See Also:

    • newNoLineAreaDescendantException

      protected IllegalStateException newNoLineAreaDescendantException()

    • transferForeignAttributes

      protected void transferForeignAttributes(AreaTreeObject targetArea)
      Transfers foreign attributes from the formatting object to the area.
      Parameters:
      targetArea - the area to set the attributes on

    • transferExtensionAttachments

      protected void transferExtensionAttachments(AreaTreeObject targetArea)
      Transfers extension attachments from the formatting object to the area.
      Parameters:
      targetArea - the area to set the extensions on

    • transferExtensions

      protected void transferExtensions(AreaTreeObject targetArea)
      Transfers extensions (foreign attributes and extension attachments) from the formatting object to the area.
      Parameters:
      targetArea - the area to set the extensions on

    • registerMarkers

      protected void registerMarkers(boolean isStarting, boolean isFirst, boolean isLast)
      Registers the FO's markers on the current PageViewport, and if applicable on the parent TableLM.
      Parameters:
      isStarting - boolean indicating whether the markers qualify as 'starting'
      isFirst - boolean indicating whether the markers qualify as 'first'
      isLast - boolean indicating whether the markers qualify as 'last'

    • addId

      protected void addId()
      Registers the FO's id on the current PageViewport

    • notifyEndOfLayout

      protected void notifyEndOfLayout()
      Notifies the PageSequenceLayoutManager that layout for this LM has ended.

    • checkEndOfLayout

      protected void checkEndOfLayout(Position pos)
      Checks to see if the incoming Position is the last one for this LM, and if so, calls notifyEndOfLayout() and cleans up.
      Parameters:
      pos - the Position to check

    • preserveChildrenAtEndOfLayout

      public void preserveChildrenAtEndOfLayout()
      Overrides:
      preserveChildrenAtEndOfLayout in class AbstractBaseLayoutManager

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • reset

      public void reset()
      Re-initializes this layout manager in order to re-generate its Knuth elements according to a new IPD value.
      Specified by:
      reset in interface LayoutManager
      Overrides:
      reset in class AbstractBaseLayoutManager

    • recreateChildrenLMs

      public void recreateChildrenLMs()
      Overrides:
      recreateChildrenLMs in class AbstractBaseLayoutManager

    • possiblyRegisterMarkersForTables

      protected void possiblyRegisterMarkersForTables(Map<String,Marker> markers, boolean isStarting, boolean isFirst, boolean isLast)

    • handlingFloat

      public boolean handlingFloat()