Package com.luciad.view.lightspeed.label.algorithm

Class ALspLabelLocationProvider

java.lang.Object

com.luciad.view.lightspeed.label.algorithm.ALspLabelLocationProvider

Direct Known Subclasses:

ALspStampLabelLocationProvider, TLspFixedInPathLabelLocationProvider, TLspFixedOnPathLabelLocationProvider

public abstract class ALspLabelLocationProvider
extends Object

This abstract class is used to provide a fixed number of locations for a label. It is used by TLspLabelingAlgorithm. The algorithm will first call getMaxLocationCount and will then call getLocation.

Since:

2012.0

Constructor Summary

Constructors

Constructor	Description
ALspLabelLocationProvider()

Method Summary

Modifier and Type	Method	Description
abstract TLspLabelPlacement	getLocation(TLspLabelID aLabel, int aLocationIndex, ALspLabelLocations aCurrentLabelLocations, TLspPaintState aPaintState, ILspLabelingAlgorithm.LabelContext aLabelContext, ILspView aView)	This method returns a location for the given label using the given location index.
int	getMaxLocationCount(TLspLabelID aLabel, TLspPaintState aPaintState, ILspLabelingAlgorithm.LabelContext aLabelContext, ILspView aView)	Returns the maximal number of locations to be tried for the given label.
boolean	isValidLocation(TLspLabelPlacement aLocation, ALspLabelLocations aCurrentLabelLocations, TLspPaintState aPaintState, ILspLabelingAlgorithm.LabelContext aLabelContext, ILspView aView)	Checks if the given location is a valid location.

Methods inherited from class java.lang.Object

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

Constructor Details

ALspLabelLocationProvider

public ALspLabelLocationProvider()

Method Details

getMaxLocationCount

public int getMaxLocationCount(TLspLabelID aLabel,
 TLspPaintState aPaintState,
 ILspLabelingAlgorithm.LabelContext aLabelContext,
 ILspView aView)

Returns the maximal number of locations to be tried for the given label. Override this method to return a custom number of locations. When overriding this method, one should also make sure that the getLocation method can create the same number of locations as returned by this method. By default, this method returns 1.

Parameters:

aLabel - the label.

aPaintState - the paint state.

aLabelContext - provides context information, such as priorities, PaintState, ...

aView - the view.

Returns:

the maximal number of locations to be tried.

getLocation

public abstract TLspLabelPlacement getLocation(TLspLabelID aLabel,
 int aLocationIndex,
 ALspLabelLocations aCurrentLabelLocations,
 TLspPaintState aPaintState,
 ILspLabelingAlgorithm.LabelContext aLabelContext,
 ILspView aView)

This method returns a location for the given label using the given location index. Override this method to create custom locations for a label.

Parameters:

aLabel - a label.

aLocationIndex - the location index.

aCurrentLabelLocations - an ALspLabelLocations object containing locations for the currently placed labels.

aPaintState - the paint state

aLabelContext - provides context information, such as priorities, PaintState, ...

aView - the view.

Returns:

the label location for the given label and index, or null if no location could be calculated.

isValidLocation

public boolean isValidLocation(TLspLabelPlacement aLocation,
 ALspLabelLocations aCurrentLabelLocations,
 TLspPaintState aPaintState,
 ILspLabelingAlgorithm.LabelContext aLabelContext,
 ILspView aView)

Checks if the given location is a valid location. This check should be used if this label location provider is capable of producing the given location. Labeling algorithms may use this method for previous label locations. I.e. when using a previous label locations, this method can be used to verify if the previous label location can be used.

By default, this method returns true.

Parameters:

aLocation - the location to check.

aCurrentLabelLocations - an ALspLabelLocations object containing locations for the currently placed labels.

aPaintState - the paint state.

aLabelContext - provides context information, such as priorities, PaintState, ...

aView - the view.

Returns:

if the given location is a valid location.