Package com.luciad.view.gxy.labeling.algorithm.discrete

Class TLcdGXYLabelPainterLocationLabelingAlgorithm

java.lang.Object

com.luciad.view.gxy.labeling.algorithm.discrete.ALcdGXYDiscretePlacementsLabelingAlgorithm

com.luciad.view.gxy.labeling.algorithm.discrete.TLcdGXYLabelPainterLocationLabelingAlgorithm

All Implemented Interfaces:

ILcdCloneable, ILcdGXYLabelingAlgorithm, Cloneable

Direct Known Subclasses:

TLcdGXYSinglePlacementLabelingAlgorithm

public class TLcdGXYLabelPainterLocationLabelingAlgorithm
extends ALcdGXYDiscretePlacementsLabelingAlgorithm

This labeling algorithm is a greedy algorithm based on the label locations provided by each label's label painter. This makes this algorithm behave similarly to TLcdGXYViewLabelPainter and TLcdGXYLayerLabelPainter.

It tries to place labels in the order provided by the input TLcdCollectedLabelInfoList object (see TLcdCollectedLabelInfoList.getLabels()). It tries to place the labels one by one, and when a label cannot be placed without overlap, it is omitted.

This algorithm also uses a forced painting threshold priority to force labels to be placed, even if they overlap with other labels, see setForcedPaintingThresholdPriority(int).

The implementation of this labeling algorithm is thread-safe if the set label priority provider is thread-safe.

Since:

10.1

Constructor Summary

Constructors

Constructor	Description
TLcdGXYLabelPainterLocationLabelingAlgorithm()

Method Summary

Modifier and Type	Method	Description
TLcdGXYLabelPainterLocationLabelingAlgorithm	clone()	Makes Object.clone() public.
TLcdCollectedLabelInfoList	collectLabelInfo(List<TLcdLabelIdentifier> aLabelsToCollect, Graphics aGraphics, ILcdGXYView aGXYView)	This method returns a TLcdCollectedLabelInfoList object based on the given list of TLcdLabelIdentifiers.
protected Iterator<TLcdCollectedLabelInfo>	createLabelIterator(TLcdCollectedLabelInfoList aLabelInfoList, ILcdLabelConflictChecker aBoundsConflictChecker, ILcdGXYView aView)	Creates a new Iterator that iterates over the TLcdCollectedLabelInfos.
protected ILcdLabelPlacementEvaluator	createLabelPlacementEvaluator(TLcdCollectedLabelInfoList aLabelInfoList, ILcdLabelConflictChecker aBoundsConflictChecker, ILcdGXYView aView)	Creates a new ILcdLabelPlacementEvaluator using the given parameters.
protected Iterator<TLcdLabelPlacement>	createLabelPlacementIterator(TLcdCollectedLabelInfo aLabel, TLcdCollectedLabelInfoList aLabelInfoList, ILcdLabelConflictChecker aBoundsConflictChecker, ILcdGXYView aView)	Creates a new Iterator that iterates over the TLcdLabelPlacements for the given label.
int	getForcedPaintingThresholdPriority()	Returns the threshold priority for forced label painting.
ILcdGXYMultiLabelPriorityProvider	getLabelPriorityProvider()	Returns the label placing priority provider.
void	setForcedPaintingThresholdPriority(int aPriority)	Sets the threshold priority for forced label painting.
void	setLabelPriorityProvider(ILcdGXYMultiLabelPriorityProvider aLabelPriorityProvider)	Sets the label placing priority provider, specifying the priority for individual labels.

Methods inherited from class com.luciad.view.gxy.labeling.algorithm.discrete.ALcdGXYDiscretePlacementsLabelingAlgorithm

computeLabelPlacements

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

TLcdGXYLabelPainterLocationLabelingAlgorithm

public TLcdGXYLabelPainterLocationLabelingAlgorithm()

Method Details

clone

public TLcdGXYLabelPainterLocationLabelingAlgorithm clone()

Description copied from interface: ILcdCloneable

Makes Object.clone() public.

When for example extending from java.lang.Object, it can be implemented like this:

 public Object clone() {
   try {
     return super.clone();
   } catch ( CloneNotSupportedException e ) {
     // Cannot happen: extends from Object and implements Cloneable (see also Object.clone)
     throw new RuntimeException( e );
   }
 }
 

Specified by:

clone in interface ILcdCloneable

Overrides:

clone in class ALcdGXYDiscretePlacementsLabelingAlgorithm

See Also:

• Object.clone()

setForcedPaintingThresholdPriority

public void setForcedPaintingThresholdPriority(int aPriority)

Sets the threshold priority for forced label painting. The labels of objects with a priority value less than or equal to the threshold priority value will always be painted, even if the labeling algorithm could not find any suitable place for the label. This makes it possible for labels to overlap. The default value is -1, in which case no forced painting is done.

Parameters:

aPriority - the threshold priority for forced label painting.

See Also:

• getForcedPaintingThresholdPriority()

getForcedPaintingThresholdPriority

public int getForcedPaintingThresholdPriority()

Returns the threshold priority for forced label painting.

Returns:

the threshold priority for forced label painting.

See Also:

• setForcedPaintingThresholdPriority(int)

getLabelPriorityProvider

public ILcdGXYMultiLabelPriorityProvider getLabelPriorityProvider()

Returns the label placing priority provider.

Returns:

the label placing priority provider.

See Also:

• setLabelPriorityProvider(com.luciad.view.gxy.ILcdGXYMultiLabelPriorityProvider)

setLabelPriorityProvider

public void setLabelPriorityProvider(ILcdGXYMultiLabelPriorityProvider aLabelPriorityProvider)

Sets the label placing priority provider, specifying the priority for individual labels. This priority provider specifies the order in which labels are placed. In the event labels overlap, those with higher priority are painted on top of labels with lower priority. So lower priority labels are the first candidates if labels need to be obscured.

When no label priority provider is set, a default label priority provider is used which returns Integer.MAX_VALUE for all labels.

The priority provider is used to sort the list of labels before their placements are computed.

Parameters:

aLabelPriorityProvider - The priority provider to set.

collectLabelInfo

public TLcdCollectedLabelInfoList collectLabelInfo(List<TLcdLabelIdentifier> aLabelsToCollect,
 Graphics aGraphics,
 ILcdGXYView aGXYView)

Description copied from interface: ILcdGXYLabelingAlgorithm

This method returns a TLcdCollectedLabelInfoList object based on the given list of TLcdLabelIdentifiers. The returned TLcdCollectedLabelInfoList should contain a TLcdCollectedLabelInfo object for each label that should be placed.

Each TLcdCollectedLabelInfo should also contain all information needed by computeLabelPlacements to place the labels. In order to enable correct asynchronous label placing, all calls to the layer and the (label) painters should be done in this method. The results should then be stored in the info objects.

It is possible that the returned TLcdCollectedLabelInfoList doesn't contain a TLcdCollectedLabelInfo object for every given TLcdLabelIdentifier. In that case the missing labels are not placed.

Specified by:

collectLabelInfo in interface ILcdGXYLabelingAlgorithm

Parameters:

aLabelsToCollect - the labels for which a TLcdCollectedLabelInfoList should be created.

aGraphics - the graphics.

aGXYView - the view.

Returns:

a TLcdCollectedLabelInfoList which contains all the information needed to place the labels.

createLabelIterator

protected Iterator<TLcdCollectedLabelInfo> createLabelIterator(TLcdCollectedLabelInfoList aLabelInfoList,
 ILcdLabelConflictChecker aBoundsConflictChecker,
 ILcdGXYView aView)

Description copied from class: ALcdGXYDiscretePlacementsLabelingAlgorithm

Creates a new Iterator that iterates over the TLcdCollectedLabelInfos. The abstract labeling algorithm will continue iterating over TLcdCollectedLabelInfos as long as Iterator.hasNext() returns true. When it returns false, no more labels will be tried, and computeLabelPlacements returns. Iterator.hasNext() should always be called before calling Iterator.next(), and if it returns true, Iterator.next() should never return null.

The implementation of this method should be as independent as possible. It should not rely on createLabelPlacementIterator or createLabelPlacementEvaluator. Not respecting this might result in unexpected behaviour when wrapping or extending this class.

The returned TLcdCollectedLabelInfo should be correctly initialized, i.e. it should contain all information needed to create valid TLcdLabelPlacements using createLabelPlacementIterator. It should also always point to its corresponding TLcdCollectedLabeledObjectInfo.

Override this method to provide a custom implementation.

Specified by:

createLabelIterator in class ALcdGXYDiscretePlacementsLabelingAlgorithm

Parameters:

aLabelInfoList - the label infos object that contains all information needed to place the labels.

aBoundsConflictChecker - the bounds conflict checker to be used when evaluating label placements.

aView - the view.

Returns:

a new Iterator that iterates over TLcdCollectedLabelInfos.

createLabelPlacementIterator

protected Iterator<TLcdLabelPlacement> createLabelPlacementIterator(TLcdCollectedLabelInfo aLabel,
 TLcdCollectedLabelInfoList aLabelInfoList,
 ILcdLabelConflictChecker aBoundsConflictChecker,
 ILcdGXYView aView)

Description copied from class: ALcdGXYDiscretePlacementsLabelingAlgorithm

Creates a new Iterator that iterates over the TLcdLabelPlacements for the given label. The abstract labeling algorithm will continue iterating over TLcdLabelPlacements as long as Iterator.hasNext() returns true. When it returns false, a new label will be tried. Iterator.hasNext() should always be called before calling Iterator.next(), and if it returns true, Iterator.next() should never return null.

The implementation of this method should be as independent as possible. It should not rely on createLabelIterator or createLabelPlacementEvaluator. Not respecting this might result in unexpected behaviour when wrapping or extending this class.

The returned TLcdLabelPlacement should be correctly initialized, i.e. it should at least be able to return a valid label location, bounds rectangle and bounds rotation. It should also reference its corresponding TLcdCollectedLabelInfo.

Override this method to provide a custom implementation.

Specified by:

createLabelPlacementIterator in class ALcdGXYDiscretePlacementsLabelingAlgorithm

Parameters:

aLabel - the label for which an iterator should be created.

aLabelInfoList - the info object that contains all information needed to place the labels.

aBoundsConflictChecker - the bounds conflict checker to be used when evaluating label placements.

aView - the view.

Returns:

a new Iterator that iterates over TLcdLabelPlacements.

createLabelPlacementEvaluator

protected ILcdLabelPlacementEvaluator createLabelPlacementEvaluator(TLcdCollectedLabelInfoList aLabelInfoList,
 ILcdLabelConflictChecker aBoundsConflictChecker,
 ILcdGXYView aView)

Description copied from class: ALcdGXYDiscretePlacementsLabelingAlgorithm

Creates a new ILcdLabelPlacementEvaluator using the given parameters. It evaluates the placements returned by createLabelPlacementIterator, and returns a PlacementResult to denote if the placement should be used for its label or not.

The following actions are undertaken for the following placement results :

• PlacementResult.SUCCESS : the given label placement will be used for its label, it will be added to the list of placed labels, and it will be added to the given ILcdLabelConflictChecker. After that, ILcdLabelPlacementEvaluator.placementApplied will be called and no more placements are tried for the label.
• PlacementResult.FALLBACK : the abstract algorithm will try to find an other placements which returns PlacementResult.SUCCESS. When no such placement is found, this placement will be added to the list of placed labels, and it will be added to the given ILcdLabelConflictChecker. After that, ILcdLabelPlacementEvaluator.placementApplied will be called.
• PlacementResult.TRY_NEW_PLACEMENT : the abstract algorithm will try to find an other placement which returns PlacementResult.SUCCESS or PlacementResult.FALLBACK. When no such placement is found, ILcdLabelPlacementEvaluator.noPlacementApplied is called.
• PlacementResult.FAILED : the abstract algorithm will immediately call ILcdLabelPlacementEvaluator.noPlacementApplied and will not try to find other placements for the label.

Override this method to provide a custom implementation.

Specified by:

createLabelPlacementEvaluator in class ALcdGXYDiscretePlacementsLabelingAlgorithm

Parameters:

aLabelInfoList - the info object that contains all information needed to place the labels.

aBoundsConflictChecker - the bounds conflict checker to be used when evaluating label placements.

aView - the view

Returns:

a new LabelPlacementEvaluator

See Also:

• ILcdLabelPlacementEvaluator