Class GeometricShapeBuilder

1	/*
2	* Copyright (c) 2016 Martin Davis.
3	*
4	* All rights reserved. This program and the accompanying materials
5	* are made available under the terms of the Eclipse Public License 2.0
6	* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
7	* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v20.html
8	* and the Eclipse Distribution License is available at
9	*
10	* http://www.eclipse.org/org/documents/edl-v10.php.
11	*/
12
13	package org.locationtech.jts.shape;
14
15	import org.locationtech.jts.geom.Coordinate;
16	import org.locationtech.jts.geom.Envelope;
17	import org.locationtech.jts.geom.Geometry;
18	import org.locationtech.jts.geom.GeometryFactory;
19	import org.locationtech.jts.geom.LineSegment;
20
21	public abstract class GeometricShapeBuilder
22	{
23	protected Envelope extent = new Envelope(0, 1, 0, 1);
24	protected int numPts = 0;
25	protected GeometryFactory geomFactory;
26
27	public GeometricShapeBuilder(GeometryFactory geomFactory)
28	{
29	this.geomFactory = geomFactory;
30	}
31
32	public void setExtent(Envelope extent)
33	{
34	this.extent = extent;
35	}
36
37	public Envelope getExtent()
38	{
39	return extent;
40	}
41
42	public Coordinate getCentre()
43	{
44	return extent.centre();
45	}
46
47	public double getDiameter()
48	{
49	return Math.min(extent.getHeight(), extent.getWidth());
50	}
51
52	public double getRadius()
53	{
54	return getDiameter() / 2;
55	}
56
57	public LineSegment getSquareBaseLine()
58	{
59	double radius = getRadius();
60
61	Coordinate centre = getCentre();
62	Coordinate p0 = new Coordinate(centre.x - radius, centre.y - radius);
63	Coordinate p1 = new Coordinate(centre.x + radius, centre.y - radius);
64	return new LineSegment(p0, p1);
65	}
66
67	public Envelope getSquareExtent()
68	{
69	double radius = getRadius();
70
71	Coordinate centre = getCentre();
72	return new Envelope(centre.x - radius, centre.x + radius,
73	centre.y - radius, centre.y + radius);
74	}
75
76
77	/**
78	* Sets the total number of points in the created {@link Geometry}.
79	* The created geometry will have no more than this number of points,
80	* unless more are needed to create a valid geometry.
81	*/
82	public void setNumPoints(int numPts) { this.numPts = numPts; }
83
84	public abstract Geometry getGeometry();
85
86	protected Coordinate createCoord(double x, double y)
87	{
88	Coordinate pt = new Coordinate(x, y);
89	geomFactory.getPrecisionModel().makePrecise(pt);
90	return pt;
91	}
92
93
94	}
95