Package org.apache.fop.layoutmgr
Class AbstractBreaker
java.lang.Object
org.apache.fop.layoutmgr.AbstractBreaker
- Direct Known Subclasses:
LocalBreaker
,PageBreaker
Abstract base class for breakers (page breakers, static region handlers etc.).
-
Nested Class Summary
Modifier and TypeClassDescriptionstatic class
Helper class, extending the functionality of the basicBlockKnuthSequence
.static class
static class
A page break position. -
Field Summary
Modifier and TypeFieldDescriptionprotected int
desired text alignmentprotected int
blockListIndex of the current BlockSequence in blockListsprotected List<AbstractBreaker.BlockSequence>
protected List
protected MinOptMax
footnote separator lengthprotected static final org.apache.commons.logging.Log
logging instanceprotected LayoutManager
protected Position
protected PageSequenceLayoutManager
-
Constructor Summary
-
Method Summary
Modifier and TypeMethodDescriptionprotected void
addAreas
(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int startPart, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList) protected void
addAreas
(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int startPart, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList, LayoutContext childLC) Phase 3 of Knuth algorithm: Adds the areasprotected void
addAreas
(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList) Phase 3 of Knuth algorithm: Adds the areasprotected abstract 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.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) protected boolean
containsNonRestartableLM
(Position position) Returnstrue
if the given position or one of its descendants corresponds to a non-restartable LM.protected LayoutContext
Creates the top-level LayoutContext for the breaker operation.protected org.apache.fop.layoutmgr.PageBreakingAlgorithm.PageBreakingLayoutListener
Creates and returns a PageBreakingLayoutListener for the PageBreakingAlgorithm to notify about layout problems.boolean
doLayout
(int flowBPD, boolean autoHeight) Starts the page breaking process.protected abstract void
doPhase3
(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList) Phase 3 of Knuth algorithm: Adds the areasprotected abstract void
finishPart
(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, AbstractBreaker.PageBreakPosition pbp) Finish part.protected abstract LayoutManager
protected abstract int
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.protected int
getNextBlockList
(LayoutContext childLC, int nextSequenceStartsOn, Position positionAtIPDChange, LayoutManager restartAtLM, List<KnuthElement> firstElements) Gets the next block list (sequence) and adds it to a list of block lists if it's not empty.protected abstract List<KnuthElement>
getNextKnuthElements
(LayoutContext context, int alignment) Get a sequence of KnuthElements representing the content of the node assigned to the LMprotected List<KnuthElement>
getNextKnuthElements
(LayoutContext context, int alignment, Position positionAtIPDChange, LayoutManager restartAtLM) Get a sequence of KnuthElements representing the content of the node assigned to the LMprotected PageProvider
Returns the PageProvider if any.protected abstract LayoutManager
protected void
This method is called when no content is available for a part.protected int
handleFloatLayout
(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int optimalPageCount, AbstractBreaker.BlockSequence blockList, LayoutContext childLC) protected int
handleSpanChange
(LayoutContext childLC, int nextSequenceStartsOn) Handles span changes reported through theLayoutContext
.protected abstract boolean
boolean
isEmpty()
protected boolean
Controls the behaviour of the algorithm in cases where the first element of a part overflows a line/page.protected boolean
protected boolean
lastPageHasIPDChange
(int optimalPageCount) protected void
observeElementList
(List elementList) Used for debugging purposes.protected void
prepareToRedoLayout
(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList) protected boolean
protected void
startPart
(AbstractBreaker.BlockSequence list, int breakClass, boolean emptyContent) Start part.protected void
updateLayoutContext
(LayoutContext context) Used to update the LayoutContext in subclasses prior to starting a new element list.protected boolean
-
Field Details
-
log
protected static final org.apache.commons.logging.Log loglogging instance -
originalRestartAtLM
-
positionAtBreak
-
firstElementsForRestart
-
pslm
-
blockLists
-
blockListIndex
protected int blockListIndexblockListIndex of the current BlockSequence in blockLists -
alignment
protected int alignmentdesired text alignment -
footnoteSeparatorLength
footnote separator length
-
-
Constructor Details
-
AbstractBreaker
public AbstractBreaker()
-
-
Method Details
-
getCurrentDisplayAlign
protected abstract int getCurrentDisplayAlign()- Returns:
- current display alignment
-
hasMoreContent
protected abstract boolean hasMoreContent()- Returns:
- true if content not exhausted
-
addAreas
Tell the layout manager to add all the child areas implied by Position objects which will be returned by the Iterator.- Parameters:
posIter
- the position iteratorcontext
- the context
-
getTopLevelLM
- Returns:
- top level layout manager
-
getCurrentChildLM
- Returns:
- current child layout manager
-
isPartOverflowRecoveryActivated
protected boolean isPartOverflowRecoveryActivated()Controls the behaviour of the algorithm in cases where the first element of a part overflows a line/page.- Returns:
- true if the algorithm should try to send the element to the next line/page.
-
isSinglePartFavored
protected boolean isSinglePartFavored()- Returns:
- true if one a single part should be produced if possible (ex. for block-containers)
-
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.- 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.- Returns:
- the listener instance or null if no notifications are needed
-
getNextKnuthElements
Get a sequence of KnuthElements representing the content of the node assigned to the LM- Parameters:
context
- the LayoutContext used to store layout informationalignment
- the desired text alignment- Returns:
- the list of KnuthElements
-
getNextKnuthElements
protected List<KnuthElement> getNextKnuthElements(LayoutContext context, int alignment, Position positionAtIPDChange, LayoutManager restartAtLM) Get a sequence of KnuthElements representing the content of the node assigned to the LM- Parameters:
context
- the LayoutContext used to store layout informationalignment
- the desired text alignmentpositionAtIPDChange
- last element on the part before an IPD changerestartAtLM
- the layout manager from which to restart, if IPD change occurs between two LMs- Returns:
- the list of KnuthElements
-
isEmpty
public boolean isEmpty()- Returns:
- true if there's no content that could be handled.
-
startPart
Start part.- Parameters:
list
- a block sequencebreakClass
- a break class
-
handleEmptyContent
protected void handleEmptyContent()This method is called when no content is available for a part. Used to force empty pages. -
finishPart
protected abstract void finishPart(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, AbstractBreaker.PageBreakPosition pbp) Finish part.- Parameters:
alg
- a page breaking algorithmpbp
- a page break posittion
-
createLayoutContext
Creates the top-level LayoutContext for the breaker operation.- Returns:
- the top-level LayoutContext
-
updateLayoutContext
Used to update the LayoutContext in subclasses prior to starting a new element list.- Parameters:
context
- the LayoutContext to update
-
observeElementList
Used for debugging purposes. Notifies all registered observers about the element list. Override to set different parameters.- Parameters:
elementList
- the Knuth element list
-
doLayout
public boolean doLayout(int flowBPD, boolean autoHeight) Starts the page breaking process.- Parameters:
flowBPD
- the constant available block-progression-dimension (used for every part)autoHeight
- true if warnings about overflows should be disabled because the the BPD is really undefined (for footnote-separators, for example)
-
containsNonRestartableLM
Returnstrue
if the given position or one of its descendants corresponds to a non-restartable LM.- Parameters:
position
- a position- Returns:
true
if there is a non-restartable LM in the hierarchy
-
doPhase3
protected abstract void doPhase3(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList) Phase 3 of Knuth algorithm: Adds the areas- Parameters:
alg
- PageBreakingAlgorithm instance which determined the breakspartCount
- number of parts (pages) to be renderedoriginalList
- original Knuth element listeffectiveList
- effective Knuth element list (after adjustments)
-
addAreas
protected void addAreas(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList) Phase 3 of Knuth algorithm: Adds the areas- Parameters:
alg
- PageBreakingAlgorithm instance which determined the breakspartCount
- number of parts (pages) to be renderedoriginalList
- original Knuth element listeffectiveList
- effective Knuth element list (after adjustments)
-
addAreas
protected void addAreas(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int startPart, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList) -
addAreas
protected void addAreas(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int startPart, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList, LayoutContext childLC) Phase 3 of Knuth algorithm: Adds the areas- Parameters:
alg
- PageBreakingAlgorithm instance which determined the breaksstartPart
- index of the first part (page) to be renderedpartCount
- number of parts (pages) to be renderedoriginalList
- original Knuth element listeffectiveList
- effective Knuth element list (after adjustments)
-
handleSpanChange
Handles span changes reported through theLayoutContext
. Only used by the PSLM and called bygetNextBlockList()
.- Parameters:
childLC
- the LayoutContextnextSequenceStartsOn
- previous value for break handling- Returns:
- effective value for break handling
-
getNextBlockList
Gets the next block list (sequence) and adds it to a list of block lists if it's not empty.- Parameters:
childLC
- LayoutContext to usenextSequenceStartsOn
- 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 restartAtLM, List<KnuthElement> firstElements) Gets the next block list (sequence) and adds it to a list of block lists if it's not empty.- Parameters:
childLC
- LayoutContext to usenextSequenceStartsOn
- indicates on what page the next sequence should startpositionAtIPDChange
- last element on the part before an IPD changerestartAtLM
- the layout manager from which to restart, if IPD change occurs between two LMsfirstElements
- elements from non-restartable LMs on the new page- Returns:
- the page on which the next content should appear after a hard break
-
shouldRedoLayout
protected boolean shouldRedoLayout() -
prepareToRedoLayout
protected void prepareToRedoLayout(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int partCount, AbstractBreaker.BlockSequence originalList, AbstractBreaker.BlockSequence effectiveList) -
wasLayoutRedone
protected boolean wasLayoutRedone() -
lastPageHasIPDChange
protected boolean lastPageHasIPDChange(int optimalPageCount) -
handleFloatLayout
protected int handleFloatLayout(org.apache.fop.layoutmgr.PageBreakingAlgorithm alg, int optimalPageCount, AbstractBreaker.BlockSequence blockList, LayoutContext childLC) -
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)
-