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

Class TLcdGXYInPathLabelingAlgorithm

java.lang.Object
com.luciad.view.gxy.labeling.algorithm.discrete.ALcdGXYDiscretePlacementsLabelingAlgorithm
com.luciad.view.gxy.labeling.algorithm.discrete.TLcdGXYInPathLabelingAlgorithm
All Implemented Interfaces:
ILcdCloneable, ILcdGXYLabelingAlgorithm, Cloneable
public class TLcdGXYInPathLabelingAlgorithm extends ALcdGXYDiscretePlacementsLabelingAlgorithm
Path aware labeling algorithm. This algorithm checks the painted paths that are within the view and tries to add labels to them. The placed labels are located within the area defined by the path. This labeling algorithm is typically used for labeling polygons or other closed shapes.

Note that this implementation does not support "holes" in paths.

The used label painter must be an ILcdGXYLabelPainter2. If not, the label will be painted at an incorrect location.

The implementation of this labeling algorithm is thread-safe, as long as the set ILcdGXYLabelingPathProvider and label priority provider are thread-safe.

Since:
10.1

  • Constructor Details

    • TLcdGXYInPathLabelingAlgorithm

      public TLcdGXYInPathLabelingAlgorithm()
      Creates a new TLcdGXYInPathLabelingAlgorithm using TLcdGXYLabelingPathProvider as path provider.

    • TLcdGXYInPathLabelingAlgorithm

      public TLcdGXYInPathLabelingAlgorithm(ILcdGXYLabelingPathProvider aPathProvider)
      Creates a new TLcdGXYInPathLabelingAlgorithm using the given path provider.
      Parameters:
      aPathProvider - a path provider.

  • Method Details

    • getMinimumPathLength

      public double getMinimumPathLength()
      Returns the minimum contour length for a clipped polygon to contain a label.
      Returns:
      the minimum contour length for a clipped polygon to contain a label.
      See Also:

    • setMinimumPathLength

      public void setMinimumPathLength(double aMinimumPathLength)
      Sets the minimum outline length for a clipped polygon to contain a label. This length is expressed in pixels and should be positive. When a clipped polygon has an outline length smaller than the given length, it will not be labeled.

      The default value is 0 pixels, i.e. no clipped polygon will be excluded from being labeled.

      Parameters:
      aMinimumPathLength - the minimal length for a clipped polygon to contain a label.

    • getPathProvider

      public ILcdGXYLabelingPathProvider getPathProvider()
      Returns the path provider used by this path labeling algorithm.
      Returns:
      the path provider used by this path labeling algorithm.

    • setPathProvider

      public void setPathProvider(ILcdGXYLabelingPathProvider aPathProvider)
      Sets the path provider to be used by this path labeling algorithm.
      Parameters:
      aPathProvider - the path provider to be used by this path labeling algorithm.

    • getLabelPriorityProvider

      public ILcdGXYMultiLabelPriorityProvider getLabelPriorityProvider()
      Returns the label placing priority provider.
      Returns:
      the label placing priority provider.
      See Also:

    • 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.

    • clone

      public TLcdGXYInPathLabelingAlgorithm 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
      See Also:

    • 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 :

      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:

    • 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.