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	/*
	* Copyright (c) 1997, 2003, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code 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
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package java.awt.geom;

	import java.util.*;

	/**
	* A utility class to iterate over the path segments of an ellipse
	* through the PathIterator interface.
	*
	* @author Jim Graham
	*/
	class EllipseIterator implements PathIterator {
	double x, y, w, h;
	AffineTransform affine;
	int index;

	EllipseIterator(Ellipse2D e, AffineTransform at) {
	this.x = e.getX();
	this.y = e.getY();
	this.w = e.getWidth();
	this.h = e.getHeight();
	this.affine = at;
	if (w < 0 \|\| h < 0) {
	index = 6;
	}
	}

	/**
	* Return the winding rule for determining the insideness of the
	* path.
	* @see #WIND_EVEN_ODD
	* @see #WIND_NON_ZERO
	*/
	public int getWindingRule() {
	return WIND_NON_ZERO;
	}

	/**
	* Tests if there are more points to read.
	* @return true if there are more points to read
	*/
	public boolean isDone() {
	return index > 5;
	}

	/**
	* Moves the iterator to the next segment of the path forwards
	* along the primary direction of traversal as long as there are
	* more points in that direction.
	*/
	public void next() {
	index++;
	}

	// ArcIterator.btan(Math.PI/2)
	public static final double CtrlVal = 0.5522847498307933;

	/*
	* ctrlpts contains the control points for a set of 4 cubic
	* bezier curves that approximate a circle of radius 0.5
	* centered at 0.5, 0.5
	*/
	private static final double pcv = 0.5 + CtrlVal * 0.5;
	private static final double ncv = 0.5 - CtrlVal * 0.5;
	private static double ctrlpts[][] = {
	{ 1.0, pcv, pcv, 1.0, 0.5, 1.0 },
	{ ncv, 1.0, 0.0, pcv, 0.0, 0.5 },
	{ 0.0, ncv, ncv, 0.0, 0.5, 0.0 },
	{ pcv, 0.0, 1.0, ncv, 1.0, 0.5 }
	};

	/**
	* Returns the coordinates and type of the current path segment in
	* the iteration.
	* The return value is the path segment type:
	* SEG_MOVETO, SEG_LINETO, SEG_QUADTO, SEG_CUBICTO, or SEG_CLOSE.
	* A float array of length 6 must be passed in and may be used to
	* store the coordinates of the point(s).
	* Each point is stored as a pair of float x,y coordinates.
	* SEG_MOVETO and SEG_LINETO types will return one point,
	* SEG_QUADTO will return two points,
	* SEG_CUBICTO will return 3 points
	* and SEG_CLOSE will not return any points.
	* @see #SEG_MOVETO
	* @see #SEG_LINETO
	* @see #SEG_QUADTO
	* @see #SEG_CUBICTO
	* @see #SEG_CLOSE
	*/
	public int currentSegment(float[] coords) {
	if (isDone()) {
	throw new NoSuchElementException("ellipse iterator out of bounds");
	}
	if (index == 5) {
	return SEG_CLOSE;
	}
	if (index == 0) {
	double ctrls[] = ctrlpts[3];
	coords[0] = (float) (x + ctrls[4] * w);
	coords[1] = (float) (y + ctrls[5] * h);
	if (affine != null) {
	affine.transform(coords, 0, coords, 0, 1);
	}
	return SEG_MOVETO;
	}
	double ctrls[] = ctrlpts[index - 1];
	coords[0] = (float) (x + ctrls[0] * w);
	coords[1] = (float) (y + ctrls[1] * h);
	coords[2] = (float) (x + ctrls[2] * w);
	coords[3] = (float) (y + ctrls[3] * h);
	coords[4] = (float) (x + ctrls[4] * w);
	coords[5] = (float) (y + ctrls[5] * h);
	if (affine != null) {
	affine.transform(coords, 0, coords, 0, 3);
	}
	return SEG_CUBICTO;
	}

	/**
	* Returns the coordinates and type of the current path segment in
	* the iteration.
	* The return value is the path segment type:
	* SEG_MOVETO, SEG_LINETO, SEG_QUADTO, SEG_CUBICTO, or SEG_CLOSE.
	* A double array of length 6 must be passed in and may be used to
	* store the coordinates of the point(s).
	* Each point is stored as a pair of double x,y coordinates.
	* SEG_MOVETO and SEG_LINETO types will return one point,
	* SEG_QUADTO will return two points,
	* SEG_CUBICTO will return 3 points
	* and SEG_CLOSE will not return any points.
	* @see #SEG_MOVETO
	* @see #SEG_LINETO
	* @see #SEG_QUADTO
	* @see #SEG_CUBICTO
	* @see #SEG_CLOSE
	*/
	public int currentSegment(double[] coords) {
	if (isDone()) {
	throw new NoSuchElementException("ellipse iterator out of bounds");
	}
	if (index == 5) {
	return SEG_CLOSE;
	}
	if (index == 0) {
	double ctrls[] = ctrlpts[3];
	coords[0] = x + ctrls[4] * w;
	coords[1] = y + ctrls[5] * h;
	if (affine != null) {
	affine.transform(coords, 0, coords, 0, 1);
	}
	return SEG_MOVETO;
	}
	double ctrls[] = ctrlpts[index - 1];
	coords[0] = x + ctrls[0] * w;
	coords[1] = y + ctrls[1] * h;
	coords[2] = x + ctrls[2] * w;
	coords[3] = y + ctrls[3] * h;
	coords[4] = x + ctrls[4] * w;
	coords[5] = y + ctrls[5] * h;
	if (affine != null) {
	affine.transform(coords, 0, coords, 0, 3);
	}
	return SEG_CUBICTO;
	}
	}

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