Class PageBreakingAlgorithm

    • Field Detail

      • log

        private static org.apache.commons.logging.Log log
        the logger for the class
      • footnotesList

        private java.util.List<java.util.List<KnuthElement>> footnotesList
        Footnotes which are cited between the currently considered active node (previous break) and the current considered break. Its type is List<List<KnuthElement>>, it contains the sequences of KnuthElement representing the footnotes bodies.
      • lengthList

        private java.util.List<java.lang.Integer> lengthList
        Cumulated bpd of unhandled footnotes.
      • totalFootnotesLength

        private int totalFootnotesLength
        Length of all the footnotes which will be put on the current page.
      • insertedFootnotesLength

        private int insertedFootnotesLength
        Length of all the footnotes which have already been inserted, up to the currently considered element. That is, footnotes from the currently considered page plus footnotes from its preceding pages.
      • footnotesPending

        private boolean footnotesPending
        True if footnote citations have been met since the beginning of the page sequence.
      • newFootnotes

        private boolean newFootnotes
        True if the elements met after the previous break point contain footnote citations.
      • firstNewFootnoteIndex

        private int firstNewFootnoteIndex
        Index of the first footnote met after the previous break point.
      • footnoteListIndex

        private int footnoteListIndex
        Index of the last footnote inserted on the current page.
      • footnoteElementIndex

        private int footnoteElementIndex
        Index of the last element of the last footnote inserted on the current page.
      • footnoteSeparatorLength

        private MinOptMax footnoteSeparatorLength
      • storedPrevBreakIndex

        private int storedPrevBreakIndex
      • storedBreakIndex

        private int storedBreakIndex
      • storedValue

        private boolean storedValue
      • autoHeight

        private boolean autoHeight
      • favorSinglePart

        private boolean favorSinglePart
      • ipdDifference

        private int ipdDifference
      • currentKeepContext

        private int currentKeepContext
      • handlingStartOfFloat

        private boolean handlingStartOfFloat
      • handlingEndOfFloat

        private boolean handlingEndOfFloat
      • floatHeight

        private int floatHeight
      • previousFootnoteListIndex

        private int previousFootnoteListIndex
      • previousFootnoteElementIndex

        private int previousFootnoteElementIndex
      • relayingFootnotes

        private boolean relayingFootnotes
    • Method Detail

      • recoverFromTooLong

        protected BreakingAlgorithm.KnuthNode recoverFromTooLong​(BreakingAlgorithm.KnuthNode lastTooLong)
        Overridden to defer a part to the next page, if it must be kept within one page, but is too large to fit in the last column. Recover from a BreakingAlgorithm.KnuthNode leading to a line that is too long. The default implementation creates a new node corresponding to a break point after the previous node that led to a line that was too short.
        Overrides:
        recoverFromTooLong in class BreakingAlgorithm
        Parameters:
        lastTooLong - the node that leads to a "too long" line
        Returns:
        node corresponding to a breakpoint after the previous "too short" line
      • createNode

        protected BreakingAlgorithm.KnuthNode createNode​(int position,
                                                         int line,
                                                         int fitness,
                                                         int totalWidth,
                                                         int totalStretch,
                                                         int totalShrink,
                                                         double adjustRatio,
                                                         int availableShrink,
                                                         int availableStretch,
                                                         int difference,
                                                         double totalDemerits,
                                                         BreakingAlgorithm.KnuthNode previous)
        Creates a new active node for a feasible breakpoint at the given position. Only called in forced mode.
        Overrides:
        createNode in class BreakingAlgorithm
        Parameters:
        position - index of the element in the Knuth sequence
        line - number of the line ending at the breakpoint
        fitness - fitness class of the line ending at the breakpoint. One of 0, 1, 2, 3.
        totalWidth - accumulated width of the KnuthElements up to after the breakpoint
        totalStretch - accumulated stretchability of the KnuthElements up to after the breakpoint
        totalShrink - accumulated shrinkability of the KnuthElements up to after the breakpoint
        adjustRatio - adjustment ratio if the line ends at this breakpoint
        availableShrink - available stretch of the line ending at this breakpoint
        availableStretch - available shrink of the line ending at this breakpoint
        difference - difference between target and actual line width
        totalDemerits - minimum total demerits up to the breakpoint
        previous - active node for the preceding breakpoint
        Returns:
        a new node
      • handleBox

        protected void handleBox​(KnuthBox box)
        Page-breaking specific handling of the given box. Currently it adds the footnotes cited in the given box to the list of to-be-handled footnotes. Handle a KnuthBox.
        Note: default implementation just adds the box's width to the total content width. Subclasses that do not keep track of this themselves, but override this method, should remember to call super.handleBox(box) to avoid unwanted side-effects.
        Overrides:
        handleBox in class BreakingAlgorithm
        Parameters:
        box - the KnuthBox to handle
      • handlePenaltyAt

        protected void handlePenaltyAt​(KnuthPenalty penalty,
                                       int position,
                                       int allowedBreaks)
        Overridden to consider penalties with value KnuthElement.INFINITE as legal break-points, if the current keep-context allows this (a keep-*.within-page="always" constraint still permits column-breaks) Handle a KnuthPenalty at the given position, taking into account the type of breaks allowed.
        Overrides:
        handlePenaltyAt in class BreakingAlgorithm
        Parameters:
        penalty - the KnuthPenalty to handle
        position - the position of the penalty in the list
        allowedBreaks - the type of breaks that are allowed
      • handleFootnotes

        private void handleFootnotes​(java.util.List<java.util.List<KnuthElement>> elementLists)
        Handles the footnotes cited inside a block-level box. Updates footnotesList and the value of totalFootnotesLength with the lengths of the given footnotes.
        Parameters:
        elementLists - list of KnuthElement sequences corresponding to the footnotes bodies
      • resetFootnotes

        private void resetFootnotes​(java.util.List<java.util.List<KnuthElement>> elementLists)
      • considerLegalBreak

        protected void considerLegalBreak​(KnuthElement element,
                                          int elementIdx)
        Determines if the given breakpoint is a feasible breakpoint. That is, if a decent line may be built between one of the currently active nodes and this breakpoint.
        Overrides:
        considerLegalBreak in class BreakingAlgorithm
        Parameters:
        element - the paragraph's element to consider
        elementIdx - the element's index inside the paragraph
      • elementCanEndLine

        protected boolean elementCanEndLine​(KnuthElement element,
                                            int line,
                                            int difference)
        Check if the given KnuthElement can end the line with the given number.
        Overrides:
        elementCanEndLine in class BreakingAlgorithm
        Parameters:
        element - the element
        line - the line number
        difference - an integer
        Returns:
        true if the element can end the line
      • computeDifference

        protected int computeDifference​(BreakingAlgorithm.KnuthNode activeNode,
                                        KnuthElement element,
                                        int elementIndex)
        Return the difference between the natural width of a line that would be made between the given active node and the given element, and the available width of the real line.
        Overrides:
        computeDifference in class BreakingAlgorithm
        Parameters:
        activeNode - node for the previous breakpoint
        element - currently considered breakpoint
        elementIndex - index of the element that is considered as a breakpoint
        Returns:
        The difference in width. Positive numbers mean extra space in the line, negative number that the line overflows.
      • handleWhitespaceManagementPenalty

        private int handleWhitespaceManagementPenalty​(PageBreakingAlgorithm.KnuthPageNode activeNode,
                                                      WhitespaceManagementPenalty penalty,
                                                      int elementIndex)
        Evaluates the variants corresponding to the given penalty until one that leads to an acceptable adjustment ratio is found. That variant will be added to the list of pending variants in the given active node.
      • canDeferOldFootnotes

        private boolean canDeferOldFootnotes​(PageBreakingAlgorithm.KnuthPageNode node,
                                             int contentElementIndex)
        Checks whether footnotes from preceding pages may be deferred to the page after the given element.
        Parameters:
        node - active node for the preceding page break
        contentElementIndex - index of the Knuth element considered for the current page break
        Returns:
        true if footnotes can be deferred
      • noBreakBetween

        private boolean noBreakBetween​(int prevBreakIndex,
                                       int breakIndex)
        Returns true if there may be no breakpoint between the two given elements.
        Parameters:
        prevBreakIndex - index of the element from the currently considered active node
        breakIndex - index of the currently considered breakpoint
        Returns:
        true if no element between the two can be a breakpoint
      • deferredFootnotes

        private boolean deferredFootnotes​(int listIndex,
                                          int elementIndex,
                                          int length)
        Returns true if their are (pieces of) footnotes to be typeset on the current page.
        Parameters:
        listIndex - index of the last inserted footnote for the currently considered active node
        elementIndex - index of the last element of the last inserted footnote
        length - total length of all footnotes inserted so far
      • getFootnoteSplit

        private int getFootnoteSplit​(PageBreakingAlgorithm.KnuthPageNode activeNode,
                                     int availableLength,
                                     boolean canDeferOldFootnotes)
        Tries to split the flow of footnotes to put one part on the current page.
        Parameters:
        activeNode - currently considered previous page break
        availableLength - available space for footnotes
        canDeferOldFootnotes -
        Returns:
        ...
      • getFootnoteSplit

        private int getFootnoteSplit​(int prevListIndex,
                                     int prevElementIndex,
                                     int prevLength,
                                     int availableLength,
                                     boolean canDeferOldFootnotes)
        Tries to split the flow of footnotes to put one part on the current page.
        Parameters:
        prevListIndex - index of the last footnote on the previous page
        prevElementIndex - index of the last element of the last footnote
        prevLength - total length of footnotes inserted so far
        availableLength - available space for footnotes on this page
        canDeferOldFootnotes -
        Returns:
        ...
      • computeAdjustmentRatio

        protected double computeAdjustmentRatio​(BreakingAlgorithm.KnuthNode activeNode,
                                                int difference)
        Return the adjustment ratio needed to make up for the difference. A ratio of
        • 0 means that the break has the exact right width
        • >= -1 && < 0 means that the break is wider than the line, but within the minimim values of the glues.
        • >0 && < 1 means that the break is smaller than the line width, but within the maximum values of the glues.
        • > 1 means that the break is too small to make up for the glues.
        Overrides:
        computeAdjustmentRatio in class BreakingAlgorithm
        Parameters:
        activeNode - the currently active node
        difference - the difference between content-length and available width
        Returns:
        The adjustment ratio.
      • computeDemerits

        protected double computeDemerits​(BreakingAlgorithm.KnuthNode activeNode,
                                         KnuthElement element,
                                         int fitnessClass,
                                         double r)
        Computes the demerits of the current breaking (that is, up to the given element), if the next-to-last chosen breakpoint is the given active node. This adds to the total demerits of the given active node, the demerits of a line starting at this node and ending at the given element.
        Overrides:
        computeDemerits in class BreakingAlgorithm
        Parameters:
        activeNode - considered preceding line break
        element - considered current line break
        fitnessClass - fitness of the current line
        r - adjustment ratio for the current line
        Returns:
        the demerit of the current line
      • removeAllPageBreaks

        public void removeAllPageBreaks()
        Removes all page breaks from the result list. This is used by block-containers and static-content when it is only desired to know where there is an overflow but later the whole content should be painted as one part.
      • updateData1

        public void updateData1​(int total,
                                double demerits)
        Empty method, hook for subclasses. Called before determining the optimal breakpoints corresponding to a given active node.
        Specified by:
        updateData1 in class BreakingAlgorithm
        Parameters:
        total - number of lines for the active node
        demerits - total demerits of the paragraph for the active node
      • updateData2

        public void updateData2​(BreakingAlgorithm.KnuthNode bestActiveNode,
                                KnuthSequence sequence,
                                int total)
        Empty method, hook for subclasses. Called when determining the optimal breakpoints for a given active node.
        Specified by:
        updateData2 in class BreakingAlgorithm
        Parameters:
        bestActiveNode - a node in the chain of best active nodes, corresponding to one of the optimal breakpoints
        sequence - the corresponding paragraph
        total - the number of lines into which the paragraph will be broken
      • getFootnoteList

        protected final java.util.List<KnuthElement> getFootnoteList​(int index)
        Obtain the element-list corresponding to the footnote at the given index.
        Parameters:
        index - the index in the list of footnotes
        Returns:
        the element-list
      • getFObj

        public FObj getFObj()
        Returns:
        the associated top-level formatting object.
      • getLineWidth

        protected int getLineWidth​(int line)
        Returns the line/part width of a given line/part.
        Overrides:
        getLineWidth in class BreakingAlgorithm
        Parameters:
        line - the line/part number
        Returns:
        the width/length in millipoints
      • addNode

        protected void addNode​(int line,
                               BreakingAlgorithm.KnuthNode node)
        Add a node at the end of the given line's existing active nodes. If this is the first node in the line, adjust endLine accordingly.
        Overrides:
        addNode in class BreakingAlgorithm
        Parameters:
        line - number of the line ending at the node's corresponding breakpoint
        node - the active node to add
      • compareIPDs

        private int compareIPDs​(int line)
      • createForcedNodes

        protected void createForcedNodes​(BreakingAlgorithm.KnuthNode node,
                                         int line,
                                         int elementIdx,
                                         int difference,
                                         double r,
                                         double demerits,
                                         int fitnessClass,
                                         int availableShrink,
                                         int availableStretch,
                                         int newWidth,
                                         int newStretch,
                                         int newShrink)
        Overrides:
        createForcedNodes in class BreakingAlgorithm
      • getFloatHeight

        protected int getFloatHeight()
      • handlingStartOfFloat

        protected boolean handlingStartOfFloat()
      • handlingEndOfFloat

        protected boolean handlingEndOfFloat()
      • loadFootnotes

        public void loadFootnotes​(java.util.List fl,
                                  java.util.List ll,
                                  int tfl,
                                  int ifl,
                                  boolean fp,
                                  boolean nf,
                                  int fnfi,
                                  int fli,
                                  int fei,
                                  MinOptMax fsl,
                                  int pfli,
                                  int pfei)