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

Class TLcdGXYCompositeLabelingAlgorithm

java.lang.Object
com.luciad.view.gxy.labeling.algorithm.TLcdGXYCompositeLabelingAlgorithm
All Implemented Interfaces:
ILcdCloneable, ILcdGXYLabelingAlgorithm, Cloneable
public class TLcdGXYCompositeLabelingAlgorithm extends Object implements ILcdGXYLabelingAlgorithm
This composite labeling algorithm combines several ILcdGXYLabelingAlgorithms. It works by assigning labeling algorithms to labels using getLabelingAlgorithmProvider(). Labels that have the same labeling algorithm are grouped, and then handled by this labeling algorithm.

The order in which the labeling algorithms are executed is determined by the sortLabelingAlgorithms method. By default it sorts the labeling algorithms based on the priorities of the labels that are placed by them. The highest priority of all of its labels is assigned to each labeling algorithm (see TLcdCollectedLabelInfo.PRIORITY_KEY). The labeling algorithms are then sorted based on this priority. When two algorithms have the same priority assigned, the original order in which the algorithms are given is respected.

The default labeling order can be customized by overriding the sortLabelingAlgorithms method.

The implementation of this labeling algorithm is thread-safe, as long as the set ILcdGXYLabelLabelingAlgorithmProvider is thread-safe.

Since:
10.1

  • Constructor Details

    • TLcdGXYCompositeLabelingAlgorithm

      public TLcdGXYCompositeLabelingAlgorithm(ILcdGXYLabelLabelingAlgorithmProvider<? extends ILcdGXYLabelingAlgorithm> aAlgorithmProvider)
      Creates a composite labeling algorithm that uses the given ILcdGXYLabelLabelingAlgorithmProvider to assign labeling algorithms to labels.
      Parameters:
      aAlgorithmProvider - a labeling algorithm provider that returns algorithms for a given label.

  • Method Details

    • getLabelingAlgorithmProvider

      public ILcdGXYLabelLabelingAlgorithmProvider<? extends ILcdGXYLabelingAlgorithm> getLabelingAlgorithmProvider()
      Returns the used labeling algorithm provider.
      Returns:
      the used labeling algorithm provider.

    • sortLabelingAlgorithms

      protected void sortLabelingAlgorithms(List<ILcdGXYLabelingAlgorithm> aLabelingAlgorithmsSFCT, TLcdCollectedLabelInfoList aLabelInfoList)
      This method sorts the given List of labeling algorithms. The labeling algorithms will be used in this order to place labels. The original order of the labeling algorithms is determined by the order of the labels in the given TLcdCollectedLabelInfoList.

      The default implementation sorts the labeling algorithms based on the priorities of the labels that are placed by them. The highest priority of all of its labels is assigned to each labeling algorithm (see TLcdCollectedLabelInfo.PRIORITY_KEY). The labeling algorithms are then sorted based on this priority. When two algorithms have the same priority assigned, the original order in which the algorithms are given is respected.

      Override this method to provide a custom label placing order.

      Parameters:
      aLabelingAlgorithmsSFCT - the List of labeling algorithms to be sorted.
      aLabelInfoList - the label info list containing the labels to be placed the labeling algorithms in the given List.

    • clone

      public TLcdGXYCompositeLabelingAlgorithm 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 Object
      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.

    • computeLabelPlacements

      public List<TLcdLabelPlacement> computeLabelPlacements(TLcdCollectedLabelInfoList aLabelInfoList, ILcdLabelConflictChecker aLabelConflictChecker, ILcdGXYView aView)
      Description copied from interface: ILcdGXYLabelingAlgorithm
      This method computes a list of TLcdLabelPlacements using the given TLcdCollectedLabelInfoList. The returned label placements should contain a valid TLcdLabelLocation and label bounds. They should also point to their corresponding TLcdCollectedLabelInfo, which in turn should point to its corresponding TLcdCollectedLabeledObjectInfo.

      The given TLcdCollectedLabelInfoList should always be an object created or returned by collectLabelInfo.

      The returned List of TLcdLabelPlacements contains label placements that are either visible or invisible. When a placement is present in the list, it means that the location should be stored. When a placement in the list is marked as visible, it means that its location should be marked as to-be-painted.

      The labels should by preference be placed in the order in which the labels are returned by TLcdCollectedLabelInfoList.getLabels().

      Specified by:
      computeLabelPlacements in interface ILcdGXYLabelingAlgorithm
      Parameters:
      aLabelInfoList - the info object that contains all information needed to place the labels.
      aLabelConflictChecker - the bounds conflict checker that can be used to detect conflicts between labels.
      aView - the view.
      Returns:
      a list of labels to be rendered.