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

Class TLcdGXYDependantLabelsRemovalWrapper

java.lang.Object

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

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

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

All Implemented Interfaces:

ILcdCloneable, ILcdGXYLabelingAlgorithm, Cloneable

public class TLcdGXYDependantLabelsRemovalWrapper
extends ALcdGXYDiscretePlacementsLabelingAlgorithmWrapper

This wrapper used a dependency relation between labels to add extra behavior to the labeling. When label 1 depends on a label 2, and label 2 is removed from the labeling results, label 1 is also removed.

It is also possible to define circular dependencies, e.g. label 1 and label 2 depend on each other. When label 1 is removed, label 2 is also removed, and vice versa.

This wrapper only supports dependencies between labels and sublabels from the same object. Not respecting this will cause this wrapper to perform worse, labels that should disappear will not always disappear.

This wrapper works best when the labels returned by the LabelIterator of the delegate algorithm are ordered as follows :

• Clusters of labels should are kept together. If one label of a label cluster is returned, others should follow right after.
• Labels that depend on another label should be returned after this label.

Not having this order doesn't stop the wrapper from working correctly. However the label placement will not be optimal : more labels may be dropped than necessary.

The implementation of this labeling algorithm is thread-safe if the wrapped labeling algorithm is thread safe.

Since:

10.1

Constructor Summary

Constructors

Constructor	Description
TLcdGXYDependantLabelsRemovalWrapper(ALcdGXYDiscretePlacementsLabelingAlgorithm aDelegate, ILcdCollectedLabelInfoDependencyProvider aDependencyProvider)	Creates a new wrapper for the given algorithm, with the given label dependency provider.

Method Summary

Modifier and Type	Method	Description
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.
ILcdCollectedLabelInfoDependencyProvider	getDependencyProvider()	Returns the dependency provider used to define the dependency relation between the labels.

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

clone, collectLabelInfo, createLabelPlacementIterator, getDelegateAlgorithm

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

TLcdGXYDependantLabelsRemovalWrapper

public TLcdGXYDependantLabelsRemovalWrapper(ALcdGXYDiscretePlacementsLabelingAlgorithm aDelegate,
 ILcdCollectedLabelInfoDependencyProvider aDependencyProvider)

Creates a new wrapper for the given algorithm, with the given label dependency provider. When calling ILcdCollectedLabelInfoDependencyProvider.getDependingLabels, the returned labels are those labels that depend on the given label, i.e. if the given label is removed, the returned labels are also removed.

Parameters:

aDelegate - the delegate algorithm.

aDependencyProvider - a dependency provider.

Method Details

getDependencyProvider

public ILcdCollectedLabelInfoDependencyProvider getDependencyProvider()

Returns the dependency provider used to define the dependency relation between the labels. When calling ILcdCollectedLabelInfoDependencyProvider.getDependingLabels, the returned labels are those labels that depend on the given label, i.e. if the given label is removed, the returned labels are also removed.

Returns:

the dependency provider used to define the dependency relation between 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.

Overrides:

createLabelIterator in class ALcdGXYDiscretePlacementsLabelingAlgorithmWrapper

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.

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.

Overrides:

createLabelPlacementEvaluator in class ALcdGXYDiscretePlacementsLabelingAlgorithmWrapper

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