What follows is the highlighted source code with comments. You can also download this file directly: UnitCircleExample.java.

/* * Copyright (C) 2012 W. Patrick Hooper <wphooper@gmail.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ package path; import geometry.LineSegment; import number.Complex; /** * This demonstrates of the Path interface by constructing a circle. * * An instance of the UnitCircleExample class either represents the full * unit circle or an arc of the unit circle. * * @author W. Patrick Hooper */ public class UnitCircleExample implements Path { private VertexPath path; /** Construct a path representing the unit circle in the plane. */ public UnitCircleExample() { // Begin with a polygonal approximation using the fourth roots of unity. path = new VertexPath( new Complex(1, 0), new Complex(0, 1), new Complex(-1, 0), new Complex(0, -1), new Complex(1, 0)); } /** * Takes a segment with endpoints on the unit circle, and returns a path * constructed from three points on the circle. */ private UnitCircleExample(LineSegment s) { Complex m = s.midpoint(); path = new VertexPath( s.startingPoint(), m.div(m.abs()), // midpoint projected onto circle s.endingPoint()); } /** Return the ending point of this arc or circle. */ @Override public Complex endingPoint() { return path.endingPoint(); } /** Return the starting point of this arc or circle. */ @Override public Complex startingPoint() { return path.startingPoint(); } // Inner class which allows us to build an iterator: private class CircleIterator implements PathIterator { EdgeIterator it; public CircleIterator() { it = path.iterator(); } @Override public boolean hasNext() { return it.hasNext(); } @Override public UnitCircleExample next() { // it.next() returns the next segment in the path. // We convert it to a UnitCircleExample constructed from this segment. return new UnitCircleExample(it.next()); } } /** Return an iterator over the sub-arcs.*/ @Override public PathIterator iterator() { return new CircleIterator(); } /** Print out the first several approximations of the unit circle by polygons. */ public static void main(String args[]) { UnitCircleExample ce = new UnitCircleExample(); System.out.println("First approximation of the unit circle."); PolygonalApproximation approx = new PolygonalApproximation(ce, 0); System.out.println(approx); System.out.println("Second approximation of the unit circle."); approx = new PolygonalApproximation(ce, 1); System.out.println(approx); System.out.println("Third approximation of the unit circle."); approx = new PolygonalApproximation(ce, 2); System.out.println(approx); } }

- View more source code for the FractalCurves1 project.
- Return to the Java Tutorial.

HOOPER >>>>> JAVA TUTORIAL