add two simplified relabel methods to UnionFind without masks

and id generators, also impement them as default methods instead of
static methods

Author: axtimwalde

src/main/java/net/imglib2/algorithm/util/unionfind/UnionFind.java

@@ -126,4 +126,66 @@ static < B extends BooleanType< B >, L extends IntegerType< L > > void relabel(
 		}
 	}
 
+	/**
+	 *
+	 * Relabel all pixels into the representative id of their containing
+	 * sets as defined by {@code unionFind}.
+	 *
+	 * @param labeling
+	 *            Output parameter to store labeling: background pixels are
+	 *            labeled zero, foreground pixels are greater than zero: 1, 2,
+	 *            ..., N. Note that this is expected to be zero as background
+	 *            values will not be written.
+	 * @param unionFind
+	 *            {@link UnionFind}
+	 * @param idForPixel
+	 *            Create id from pixel location and value. Multiple calls with
+	 *            the same argument should always return the same result.
+	 * @param idForSet
+	 *            Create id for a set from the root id of a set. Multiple calls
+	 *            with the same argument should always return the same result.
+	 */
+	public default < B extends BooleanType< B >, L extends IntegerType< L > > void relabel(
+			final RandomAccessibleInterval< L > labeling,
+			final ToLongBiFunction< Localizable, L > idForPixel,
+			final LongUnaryOperator idForSet )
+	{
+		final Cursor< L > label = Views.flatIterable( labeling ).localizingCursor();
+		while ( label.hasNext() )
+		{
+			final L l = label.next();
+			final long root = findRoot( idForPixel.applyAsLong( label, l ) );
+			l.setInteger( idForSet.applyAsLong( root ) );
+		}
+	}
+
+	/**
+	 * Relabel all pixels into the representative id of their containing
+	 * sets as defined by {@code unionFind}.
+	 *
+	 * @param labeling
+	 *            Output parameter to store labeling: background pixels are
+	 *            labeled zero, foreground pixels are greater than zero: 1, 2,
+	 *            ..., N. Note that this is expected to be zero as background
+	 *            values will not be written.
+	 * @param unionFind
+	 *            {@link UnionFind}
+	 * @param idForPixel
+	 *            Create id from pixel location and value. Multiple calls with
+	 *            the same argument should always return the same result.
+	 * @param idForSet
+	 *            Create id for a set from the root id of a set. Multiple calls
+	 *            with the same argument should always return the same result.
+	 */
+	public default < L extends IntegerType< L > > void relabel(
+			final RandomAccessibleInterval< L > labeling )
+	{
+		final Cursor< L > label = Views.flatIterable( labeling ).localizingCursor();
+		while ( label.hasNext() )
+		{
+			final L l = label.next();
+			final long root = findRoot( l.getIntegerLong() );
+			l.setInteger( root );
+		}
+	}
 }