ViewerPanel.add/removeGroup() methods

src/main/java/bdv/viewer/ViewerPanel.java

@@ -33,6 +33,7 @@ import static bdv.viewer.VisibilityAndGrouping.Event.CURRENT_SOURCE_CHANGED;
 import static bdv.viewer.VisibilityAndGrouping.Event.DISPLAY_MODE_CHANGED;
 import static bdv.viewer.VisibilityAndGrouping.Event.GROUP_ACTIVITY_CHANGED;
 import static bdv.viewer.VisibilityAndGrouping.Event.GROUP_NAME_CHANGED;
+import static bdv.viewer.VisibilityAndGrouping.Event.NUM_GROUPS_CHANGED;
 import static bdv.viewer.VisibilityAndGrouping.Event.NUM_SOURCES_CHANGED;
 import static bdv.viewer.VisibilityAndGrouping.Event.SOURCE_ACTVITY_CHANGED;
 import static bdv.viewer.VisibilityAndGrouping.Event.VISIBILITY_CHANGED;
@@ -358,6 +359,26 @@ public class ViewerPanel extends JPanel implements OverlayRenderer, TransformLis
 		requestRepaint();
 	}
 
+	public void addGroup( final SourceGroup group )
+	{
+		synchronized ( visibilityAndGrouping )
+		{
+			state.addGroup( group );
+			visibilityAndGrouping.update( NUM_GROUPS_CHANGED );
+		}
+		requestRepaint();
+	}
+
+	public void removeGroup( final SourceGroup group )
+	{
+		synchronized ( visibilityAndGrouping )
+		{
+			state.removeGroup( group );
+			visibilityAndGrouping.update( NUM_GROUPS_CHANGED );
+		}
+		requestRepaint();
+	}
+
 	/**
 	 * Set {@code gPos} to the display coordinates at gPos transformed into the
 	 * global coordinate system.

src/main/java/bdv/viewer/VisibilityAndGrouping.java

@@ -80,6 +80,8 @@ public class VisibilityAndGrouping
 
 		public static final int NUM_SOURCES_CHANGED = 8;
 
+		public static final int NUM_GROUPS_CHANGED = 9;
+
 		public final int id;
 
 		public final VisibilityAndGrouping visibilityAndGrouping;

src/main/java/bdv/viewer/state/ViewerState.java

@@ -136,7 +136,7 @@ public class ViewerState
 		interpolation = NEARESTNEIGHBOR;
 		displayMode = SINGLE;
 		currentSource = sources.isEmpty() ? -1 : 0;
-		currentGroup = 0;
+		currentGroup = groups.isEmpty() ? -1 : 0;
 		currentTimepoint = 0;
 	}
 
@@ -247,6 +247,16 @@ public class ViewerState
 		}
 	}
 
+	/**
+	 * Make the given group current.
+	 */
+	public synchronized void setCurrentGroup( final SourceGroup group )
+	{
+		final int i = getGroupIndex( group );
+		if ( i >= 0 )
+			setCurrentGroup( i );
+	}
+
 	/**
 	 * Get the interpolation method.
 	 *
@@ -441,6 +451,38 @@ public class ViewerState
 		}
 	}
 
+	public synchronized void addGroup( final SourceGroup group )
+	{
+		if ( group.owner == this )
+			groups.add( group );
+		else
+			groups.add( group.copy( this ) );
+		if ( currentGroup < 0 )
+			currentGroup = 0;
+	}
+
+	public synchronized void removeGroup( final SourceGroup group )
+	{
+		for ( int i = 0; i < groups.size(); )
+		{
+			if ( groups.get( i ) == group )
+				removeGroup( i );
+			else
+				i++;
+		}
+	}
+
+	protected void removeGroup( final int index )
+	{
+		groups.remove( index );
+		if ( groups.isEmpty() )
+			currentGroup = -1;
+		else if ( currentGroup == index )
+			currentGroup = 0;
+		else if ( currentGroup > index )
+			--currentGroup;
+	}
+
 	public synchronized boolean isSourceVisible( final int index )
 	{
 		switch ( displayMode )
@@ -573,4 +615,13 @@ public class ViewerState
 		}
 		return -1;
 	}
+
+	/**
+	 * Get index of (first) {@link SourceGroup} that matches the given
+	 * {@code group} or {@code -1} if not found.
+	 */
+	private int getGroupIndex( final SourceGroup group )
+	{
+		return groups.indexOf( group );
+	}
 }