org.apache.fop.layoutmgr

Interface LayoutManager

All Superinterfaces:

PercentBaseContext

All Known Subinterfaces:

BlockLevelLayoutManager, InlineLevelLayoutManager

All Known Implementing Classes:

AbstractBaseLayoutManager, AbstractGraphicsLayoutManager, AbstractLayoutManager, AbstractPageNumberCitationLayoutManager, AbstractPageSequenceLayoutManager, BasicLinkLayoutManager, BidiLayoutManager, BlockContainerLayoutManager, BlockLayoutManager, BlockStackingLayoutManager, CharacterLayoutManager, ContentLayoutManager, ExternalDocumentLayoutManager, ExternalGraphicLayoutManager, FloatContentLayoutManager, FloatLayoutManager, FlowLayoutManager, FootnoteBodyLayoutManager, FootnoteLayoutManager, InlineContainerLayoutManager, InlineLayoutManager, InlineStackingLayoutManager, InstreamForeignObjectLM, LeaderLayoutManager, LeafNodeLayoutManager, LineLayoutManager, ListBlockLayoutManager, ListItemContentLayoutManager, ListItemLayoutManager, MultiCaseLayoutManager, MultiSwitchLayoutManager, PageNumberCitationLastLayoutManager, PageNumberCitationLayoutManager, PageNumberLayoutManager, PageSequenceLayoutManager, RetrieveTableMarkerLayoutManager, SpacedBorderedPaddedBlockLayoutManager, StaticContentLayoutManager, TableAndCaptionLayoutManager, TableCaptionLayoutManager, TableCellLayoutManager, TableLayoutManager, TextLayoutManager, WrapperLayoutManager

public interface LayoutManager
extends PercentBaseContext

The interface for all LayoutManagers.

Method Summary

Methods

Modifier and Type	Method and Description
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.
void	addChildArea(Area childArea) Add the area as a child of the current area.
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.
void	addChildLMs(List newLMs) Add the LMs in the argument to the list of child LMs;
boolean	createNextChildLMs(int pos) Create more child LMs of the parent, up to child LM index pos
int	getBaselineOffset() Returns the position of the dominant-baseline of this FO's first descendant line-area.
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.
List	getChildLMs()
int	getContentAreaBPD() Returns the BPD of the content area
int	getContentAreaIPD() Returns the IPD of the content area
FObj	getFObj() Returns the fo this layout manager is associated with.
boolean	getGeneratesBlockArea() Returns an indication if the layout manager generates a block area.
boolean	getGeneratesLineArea() Returns an indication if the layout manager generates a line area.
boolean	getGeneratesReferenceArea() Returns an indication if the layout manager generates a reference area.
List	getNextKnuthElements(LayoutContext context, int alignment) Get a sequence of KnuthElements representing the content of the node assigned to the LM.
List	getNextKnuthElements(LayoutContext context, int alignment, Stack lmStack, Position positionAtIPDChange, LayoutManager restartAtLM) Returns an updated list of Knuth elements corresponding to this layout manager, after a change of IPD has been detected.
LayoutManager	getParent() Get the parent layout manager.
Area	getParentArea(Area childArea) Get the parent area for an area.
PageSequenceLayoutManager	getPSLM() Get the active PageSequenceLayoutManager instance for this layout process.
boolean	hasLineAreaDescendant() Whether the FO handled by this layout manager has a descendant (including itself) that will generate a line-area.
void	initialize() initialize the layout manager.
boolean	isFinished() Return a value indicating whether this LayoutManager has laid out all its content (or generated BreakPossibilities for all content.)
boolean	isRestartable() Returns true if this layout manager is able to re-generate its Knuth elements after an IPD change.
Position	notifyPos(Position pos) Adds a Position to the Position participating in the first|last determination by assigning it a unique position index.
void	reset() Re-initializes this layout manager in order to re-generate its Knuth elements according to a new IPD value.
void	setFinished(boolean isFinished) Set a flag indicating whether the LayoutManager has laid out all its content.
void	setParent(LayoutManager lm) Set the parent layout manager.

Methods inherited from interface org.apache.fop.datatypes.PercentBaseContext

getBaseLength

Method Detail

setParent

void setParent(LayoutManager lm)

Set the parent layout manager. The parent layout manager is required for adding areas.

Parameters:

lm - the parent layout manager

getParent

LayoutManager getParent()

Get the parent layout manager.

Returns:

the parent layout manager.

initialize

void initialize()

initialize the layout manager. Allows each layout manager to calculate often used values.

getPSLM

PageSequenceLayoutManager getPSLM()

Get the active PageSequenceLayoutManager instance for this layout process.

Returns:

the PageSequenceLayoutManager

isFinished

boolean isFinished()

Return a value indicating whether this LayoutManager has laid out all its content (or generated BreakPossibilities for all content.)

Returns:

true if this layout manager is finished

setFinished

void setFinished(boolean isFinished)

Set a flag indicating whether the LayoutManager has laid out all its content. This is generally called by the LM itself, but can be called by a parentLM when backtracking.

Parameters:

isFinished - the value to set the finished flag to

getParentArea

Area getParentArea(Area childArea)

Get the parent area for an area. This should get the parent depending on the class of the area passed in.

Parameters:

childArea - the child area to get the parent for

Returns:

the parent Area

addChildArea

void addChildArea(Area childArea)

Add the area as a child of the current area. This is called by child layout managers to add their areas as children of the current area.

Parameters:

childArea - the child area to add

addAreas

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.

Parameters:

posIter - the position iterator

context - the context

createNextChildLMs

boolean createNextChildLMs(int pos)

Create more child LMs of the parent, up to child LM index pos

Parameters:

pos - index up to which child LMs are requested

Returns:

true if requested index does exist

getChildLMs

List getChildLMs()

Returns:

the list of child LMs

addChildLM

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.

Parameters:

lm - the LM to be added

addChildLMs

void addChildLMs(List newLMs)

Add the LMs in the argument to the list of child LMs;

Parameters:

newLMs - the list of LMs to be added

getNextKnuthElements

List getNextKnuthElements(LayoutContext context,
                        int alignment)

Get a sequence of KnuthElements representing the content of the node assigned to the LM.

Parameters:

context - the LayoutContext used to store layout information

alignment - the desired text alignment

Returns:

the list of KnuthElements

getChangedKnuthElements

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.

Parameters:

oldList - the elements to replace

alignment - the desired text alignment

Returns:

the updated list of KnuthElements

hasLineAreaDescendant

boolean hasLineAreaDescendant()

Whether the FO handled by this layout manager has a descendant (including itself) that will generate a line-area.

Returns:

true if a descendant line-area will be generated, false otherwise

getBaselineOffset

int getBaselineOffset()

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 hasLineAreaDescendant()

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:

hasLineAreaDescendant()

getContentAreaIPD

int getContentAreaIPD()

Returns the IPD of the content area

Returns:

the IPD of the content area

getContentAreaBPD

int getContentAreaBPD()

Returns the BPD of the content area

Returns:

the BPD of the content area

getGeneratesReferenceArea

boolean getGeneratesReferenceArea()

Returns an indication if the layout manager generates a reference area.

Returns:

True if the layout manager generates a reference area

getGeneratesBlockArea

boolean getGeneratesBlockArea()

Returns an indication if the layout manager generates a block area.

Returns:

True if the layout manager generates a block area

getGeneratesLineArea

boolean getGeneratesLineArea()

Returns an indication if the layout manager generates a line area.

Returns:

True if the layout manager generates a line area

getFObj

FObj getFObj()

Returns the fo this layout manager is associated with.

Returns:

The fo for this layout manager or null.

notifyPos

Position notifyPos(Position pos)

Adds a Position to the Position participating in the first|last determination by assigning it a unique position index.

Parameters:

pos - the Position

Returns:

the same Position but with a position index

reset

void reset()

Re-initializes this layout manager in order to re-generate its Knuth elements according to a new IPD value.

isRestartable

boolean isRestartable()

Returns true if this layout manager is able to re-generate its Knuth elements after an IPD change.

Returns:

true if this layout manager can be restarted after an IPD change

getNextKnuthElements

List getNextKnuthElements(LayoutContext context,
                        int alignment,
                        Stack lmStack,
                        Position positionAtIPDChange,
                        LayoutManager restartAtLM)

Returns an updated list of Knuth elements corresponding to this layout manager, after a change of IPD has been detected.

Parameters:

context - the layout context

alignment - the alignment

lmStack - the stack of LMs that are active at the IPD change

positionAtIPDChange - the position corresponding to the element finishing the page before the IPD change

restartAtLM - if not null, the layout manager from which to restart. That is, the IPD change occurs between two block elements and not inside a paragraph

Returns:

an updated list of elements, taking the new IPD into account