Layout events and listeners

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The label layout framework provides the same event mechanism as the graph layout framework. Various events may occur.

Label layout events

The class GraphLayoutEvent corresponds to the class GraphLayoutEvent (see Graph layout event listeners). You can install a listener for these events at the layout instance by using the method:

labelLayout.addLabelLayoutEventListener(listener);

The listener must implement the LabelLayoutEventListener interface and receives events while the layout is running. A typical example is to check how much of the layout has already completed:

class MyLabelLayoutListener
  implements LabelLayoutEventListener 
{ 
  public void layoutStepPerformed(LabelLayoutEvent event)
  { 
    IlvLabelLayoutReport layoutReport = event.getLayoutReport(); 
    System.out.println("percentage of completion: " + 
                       layoutReport.getPercentageComplete()); 
  }
}

Label layout parameter events

The class LabelLayoutParameterEvent corresponds to the class GraphLayoutParameterEvent (see Parameter event listeners). You can install a listener to these events at the layout instance by

labelLayout.addLabelLayoutParameterEventListener(listener);

The listener must implement the LabelLayoutParameterEventListener interface and receives events when layout parameters change. It also receives a special event at the end of a successful layout. For example:

class MyLabelLayoutParameterListener 
  implements LabelLayoutParameterEventListener 
{ 
  public void parametersUpToDate(LabelLayoutParameterEvent event)
  { 
    if (!event.isParametersUpToDate())
      System.out.println("Any label layout parameter has changed.”);
  } 
}

Current section

Using the label layout API