| /* |
| * 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; |
| } |
| } |
