com.luciad.view.gxy.labeling

LuciadLightspeedClass TLcdGXYCompositeViewLabelPlacer

java.lang.Object

com.luciad.view.gxy.labeling.TLcdGXYCompositeViewLabelPlacer

All Implemented Interfaces:

ILcdCloneable, ILcdGXYViewLabelPlacer, Cloneable

public class TLcdGXYCompositeViewLabelPlacer
extends Object
implements ILcdGXYViewLabelPlacer

This composite view label placer creates a number of delegate view label placers based on a group ID. It assigns a group ID to every layer. All layers with the same group ID are grouped together. Per group ID, a label placer is created, and all layers to which this group ID is assigned are labeled using the label placer.

A consequence of this is that there can be overlap between labels from layers of different labeling groups.

Because all delegate label placers place their labels independently, it is possible to avoid label placement computations when only layers of one group are invalidated. This class does this using an ILcdGXYViewLabelPlacer. The delegate label placers are only called when at least one of their layers was invalidated. Otherwise, the delegate label placers is not called, and the previous labeling results are reused during painting.

The advantage of using this class is that groups of layers can be labeled completely independently. This makes it possible for example to place labels for a group of fast layers and for a group of slow layers by two different label placers. In that case, the labeling can be executed on two different threads, so they don't block each other. Because of this, the labels of the fast layers will always be up to date. An other advantage is that this class makes it possible to mix synchronous and asynchronous label placing for different groups of layers.

Note: This class will only work correctly when using one of the following ILcdGXYView implementations :

• TLcdGXYViewBufferedImage
• TLcdGXYViewJPanel
• TLcdGXYViewJPanelLightWeight

Since:

10.1

Nested Class Summary

Nested classes/interfaces inherited from interface com.luciad.view.gxy.labeling.ILcdGXYViewLabelPlacer

ILcdGXYViewLabelPlacer.ViewLabelPlacerCallback

Constructor Summary

Constructors

Constructor and Description
TLcdGXYCompositeViewLabelPlacer()

Method Summary

Modifier and Type	Method and Description
void	addStatusListener(ILcdStatusListener aListener) Adds the given status listener to this view label placer.
void	clearViewLabelPlacerCache() This method clears all ILcdGXYViewLabelPlacers which are currently used.
TLcdGXYCompositeViewLabelPlacer	clone() Makes Object.clone() public.
protected ILcdGXYViewLabelPlacer	createViewLabelPlacer(String aGroupID, ILcdGXYView aGXYView) Creates a new view label placer for the given group ID in the given view.
protected String	getGroupID(ILcdGXYLayer aGXYLayer, ILcdGXYView aGXYView) This method returns a group ID for the given layer.
boolean	isBusyPlacing() Checks if any asynchronous label placers are busy label placing or if label placing is scheduled.
void	placeLabels(Graphics aGraphics, ILcdGXYView aGXYView, ILcdGXYViewLabelPlacer.ViewLabelPlacerCallback aCallback) The implementation of this method shall define how to place the labels of all objects in the various ILcdGXYLayers of the given ILcdGXYView.
void	placeLabels(Graphics aGraphics, List<ILcdGXYLayer> aGXYLayers, ILcdGXYView aGXYView, ILcdGXYViewLabelPlacer.ViewLabelPlacerCallback aCallback) The implementation of this method shall define how to place the labels of all objects in the various ILcdGXYLayers from the given List.
void	removeStatusListener(ILcdStatusListener aListener) Removes the given status listener from this view label placer.

Methods inherited from class java.lang.Object

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

Constructor Detail

TLcdGXYCompositeViewLabelPlacer

public TLcdGXYCompositeViewLabelPlacer()

Method Detail

isBusyPlacing

public boolean isBusyPlacing()

Checks if any asynchronous label placers are busy label placing or if label placing is scheduled.

Returns:

true if the label placer is still label placing, and false otherwise.

Since:

2022.0

getGroupID

protected String getGroupID(ILcdGXYLayer aGXYLayer,
                            ILcdGXYView aGXYView)

This method returns a group ID for the given layer. See the class doc for more information about group IDs. Override this method to provide a custom implementation.

By default this method returns the same group ID for every layers.

Parameters:

aGXYLayer - a given gxy layer.

aGXYView - the gxy view which contains the given layer

Returns:

the group ID for the given layer. Should never be null.

createViewLabelPlacer

protected ILcdGXYViewLabelPlacer createViewLabelPlacer(String aGroupID,
                                                       ILcdGXYView aGXYView)

Creates a new view label placer for the given group ID in the given view. If the returned label placer is null, layers associated with the given group ID never have their labels placed.

Override this method to return a custom view label placer.

By default this method creates a TLcdGXYLabelPlacer which uses a TLcdGXYLabelPainterLocationLabelingAlgorithm.

Parameters:

aGroupID - a group ID.

aGXYView - a gxy view.

Returns:

a ILcdGXYViewLabelPlacer for the given group ID. Can be null.

clone

public TLcdGXYCompositeViewLabelPlacer 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:

Object.clone()

clearViewLabelPlacerCache

public void clearViewLabelPlacerCache()

This method clears all ILcdGXYViewLabelPlacers which are currently used. After this method is called, this composite view label placer will create other ILcdGXYViewLabelPlacers again when labels are placed, see createViewLabelPlacer.

placeLabels

public void placeLabels(Graphics aGraphics,
                        ILcdGXYView aGXYView,
                        ILcdGXYViewLabelPlacer.ViewLabelPlacerCallback aCallback)

Description copied from interface: ILcdGXYViewLabelPlacer

The implementation of this method shall define how to place the labels of all objects in the various ILcdGXYLayers of the given ILcdGXYView. Here one can implement or use various smart algorithms to check whether or not to place a label at a certain location.

Layers for which labels are placed should be ILcdGXYEditableLabelsLayers. This method should then inform the ALcdLabelLocations associated with that layer which labels were placed, and where they were placed.

This method should only be called once every time the view is invalidated.

Specified by:

placeLabels in interface ILcdGXYViewLabelPlacer

Parameters:

aGraphics - The current Graphics instance.

aGXYView - The view for which to place the labels.

aCallback - Will be invoked when labels are updated, and when the label placing has ended.

See Also:

ILcdGXYEditableLabelsLayer, ALcdLabelLocations.putLabelLocation(java.lang.Object, int, int, com.luciad.view.ILcdView, com.luciad.view.TLcdLabelLocation, int), ALcdLabelLocations.setPainted(java.lang.Object, int, int, com.luciad.view.ILcdView, boolean, int)

placeLabels

public void placeLabels(Graphics aGraphics,
                        List<ILcdGXYLayer> aGXYLayers,
                        ILcdGXYView aGXYView,
                        ILcdGXYViewLabelPlacer.ViewLabelPlacerCallback aCallback)

Description copied from interface: ILcdGXYViewLabelPlacer

The implementation of this method shall define how to place the labels of all objects in the various ILcdGXYLayers from the given List. Here one can implement or use various smart algorithms to check whether or not to place a label at a certain location.

Layers for which labels are placed should be ILcdGXYEditableLabelsLayers. This method should then inform the ALcdLabelLocations associated with that layer which labels were placed, and where they were placed.

This method should only be called once every time the view is invalidated.

Specified by:

placeLabels in interface ILcdGXYViewLabelPlacer

Parameters:

aGraphics - The current Graphics instance.

aGXYLayers - Only the labels for the layers in this List will be placed.

aGXYView - The view for which to place the labels.

aCallback - Will be invoked when labels are updated, and when the label placing has ended.

See Also:

ILcdGXYEditableLabelsLayer, ALcdLabelLocations.putLabelLocation(java.lang.Object, int, int, com.luciad.view.ILcdView, com.luciad.view.TLcdLabelLocation, int), ALcdLabelLocations.setPainted(java.lang.Object, int, int, com.luciad.view.ILcdView, boolean, int)

addStatusListener

public void addStatusListener(ILcdStatusListener aListener)

Description copied from interface: ILcdGXYViewLabelPlacer

Adds the given status listener to this view label placer. Whenever an event occurs concerning the labeling process, this listener is notified.

Specified by:

addStatusListener in interface ILcdGXYViewLabelPlacer

Parameters:

aListener - a labeling listener.

removeStatusListener

public void removeStatusListener(ILcdStatusListener aListener)

Description copied from interface: ILcdGXYViewLabelPlacer

Removes the given status listener from this view label placer. After calling this method, the given listener will not be notified anymore.

Specified by:

removeStatusListener in interface ILcdGXYViewLabelPlacer

Parameters:

aListener - a labeling listener.