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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.geometry.core;
/** Interface representing a region in a space. A region partitions a space
* into sets of points lying on the inside, outside, and boundary.
* @param Point implementation type
*/
public interface Region
> extends Sized {
/** Return true if the region spans the entire space. In other words,
* a region is full if no points in the space are classified as
* {@link RegionLocation#OUTSIDE outside}.
* @return true if the region spans the entire space
*/
boolean isFull();
/** Return true if the region is completely empty, ie all points in
* the space are classified as {@link RegionLocation#OUTSIDE outside}.
* @return true if the region is empty
*/
boolean isEmpty();
/** Get the size of the boundary of the region. The size is a value in
* the {@code d-1} dimension space. For example, in Euclidean space,
* this will be a length in 2D and an area in 3D.
* @return the size of the boundary of the region
*/
double getBoundarySize();
/** Get the centroid, or geometric center, of the region or null if no centroid
* exists or one exists but is not unique. A centroid will not exist for empty or
* infinite regions.
*
*
The centroid of a geometric object is defined as the mean position of
* all points in the object, including interior points, vertices, and other points
* lying on the boundary. If a physical object has a uniform density, then its center
* of mass is the same as its geometric centroid.
*
* @return the centroid of the region or null if no unique centroid exists
* @see Centroid
*/
P getCentroid();
/** Classify the given point with respect to the region.
* @param pt the point to classify
* @return the location of the point with respect to the region
*/
RegionLocation classify(P pt);
/** Return true if the given point is on the inside or boundary
* of the region.
* @param pt the point to test
* @return true if the point is on the inside or boundary of the region
*/
default boolean contains(final P pt) {
final RegionLocation location = classify(pt);
return location != null && location != RegionLocation.OUTSIDE;
}
/** Project a point onto the boundary of the region. Null is returned if
* the region contains no boundaries (ie, is either {@link #isFull() full}
* or {@link #isEmpty() empty}).
* @param pt pt to project
* @return projection of the point on the boundary of the region or null
* if the region does not contain any boundaries
*/
P project(P pt);
}