J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1997-2003 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package java.awt.geom; |
| 27 | |
| 28 | import java.util.*; |
| 29 | |
| 30 | /** |
| 31 | * A utility class to iterate over the path segments of an ellipse |
| 32 | * through the PathIterator interface. |
| 33 | * |
| 34 | * @author Jim Graham |
| 35 | */ |
| 36 | class EllipseIterator implements PathIterator { |
| 37 | double x, y, w, h; |
| 38 | AffineTransform affine; |
| 39 | int index; |
| 40 | |
| 41 | EllipseIterator(Ellipse2D e, AffineTransform at) { |
| 42 | this.x = e.getX(); |
| 43 | this.y = e.getY(); |
| 44 | this.w = e.getWidth(); |
| 45 | this.h = e.getHeight(); |
| 46 | this.affine = at; |
| 47 | if (w < 0 || h < 0) { |
| 48 | index = 6; |
| 49 | } |
| 50 | } |
| 51 | |
| 52 | /** |
| 53 | * Return the winding rule for determining the insideness of the |
| 54 | * path. |
| 55 | * @see #WIND_EVEN_ODD |
| 56 | * @see #WIND_NON_ZERO |
| 57 | */ |
| 58 | public int getWindingRule() { |
| 59 | return WIND_NON_ZERO; |
| 60 | } |
| 61 | |
| 62 | /** |
| 63 | * Tests if there are more points to read. |
| 64 | * @return true if there are more points to read |
| 65 | */ |
| 66 | public boolean isDone() { |
| 67 | return index > 5; |
| 68 | } |
| 69 | |
| 70 | /** |
| 71 | * Moves the iterator to the next segment of the path forwards |
| 72 | * along the primary direction of traversal as long as there are |
| 73 | * more points in that direction. |
| 74 | */ |
| 75 | public void next() { |
| 76 | index++; |
| 77 | } |
| 78 | |
| 79 | // ArcIterator.btan(Math.PI/2) |
| 80 | public static final double CtrlVal = 0.5522847498307933; |
| 81 | |
| 82 | /* |
| 83 | * ctrlpts contains the control points for a set of 4 cubic |
| 84 | * bezier curves that approximate a circle of radius 0.5 |
| 85 | * centered at 0.5, 0.5 |
| 86 | */ |
| 87 | private static final double pcv = 0.5 + CtrlVal * 0.5; |
| 88 | private static final double ncv = 0.5 - CtrlVal * 0.5; |
| 89 | private static double ctrlpts[][] = { |
| 90 | { 1.0, pcv, pcv, 1.0, 0.5, 1.0 }, |
| 91 | { ncv, 1.0, 0.0, pcv, 0.0, 0.5 }, |
| 92 | { 0.0, ncv, ncv, 0.0, 0.5, 0.0 }, |
| 93 | { pcv, 0.0, 1.0, ncv, 1.0, 0.5 } |
| 94 | }; |
| 95 | |
| 96 | /** |
| 97 | * Returns the coordinates and type of the current path segment in |
| 98 | * the iteration. |
| 99 | * The return value is the path segment type: |
| 100 | * SEG_MOVETO, SEG_LINETO, SEG_QUADTO, SEG_CUBICTO, or SEG_CLOSE. |
| 101 | * A float array of length 6 must be passed in and may be used to |
| 102 | * store the coordinates of the point(s). |
| 103 | * Each point is stored as a pair of float x,y coordinates. |
| 104 | * SEG_MOVETO and SEG_LINETO types will return one point, |
| 105 | * SEG_QUADTO will return two points, |
| 106 | * SEG_CUBICTO will return 3 points |
| 107 | * and SEG_CLOSE will not return any points. |
| 108 | * @see #SEG_MOVETO |
| 109 | * @see #SEG_LINETO |
| 110 | * @see #SEG_QUADTO |
| 111 | * @see #SEG_CUBICTO |
| 112 | * @see #SEG_CLOSE |
| 113 | */ |
| 114 | public int currentSegment(float[] coords) { |
| 115 | if (isDone()) { |
| 116 | throw new NoSuchElementException("ellipse iterator out of bounds"); |
| 117 | } |
| 118 | if (index == 5) { |
| 119 | return SEG_CLOSE; |
| 120 | } |
| 121 | if (index == 0) { |
| 122 | double ctrls[] = ctrlpts[3]; |
| 123 | coords[0] = (float) (x + ctrls[4] * w); |
| 124 | coords[1] = (float) (y + ctrls[5] * h); |
| 125 | if (affine != null) { |
| 126 | affine.transform(coords, 0, coords, 0, 1); |
| 127 | } |
| 128 | return SEG_MOVETO; |
| 129 | } |
| 130 | double ctrls[] = ctrlpts[index - 1]; |
| 131 | coords[0] = (float) (x + ctrls[0] * w); |
| 132 | coords[1] = (float) (y + ctrls[1] * h); |
| 133 | coords[2] = (float) (x + ctrls[2] * w); |
| 134 | coords[3] = (float) (y + ctrls[3] * h); |
| 135 | coords[4] = (float) (x + ctrls[4] * w); |
| 136 | coords[5] = (float) (y + ctrls[5] * h); |
| 137 | if (affine != null) { |
| 138 | affine.transform(coords, 0, coords, 0, 3); |
| 139 | } |
| 140 | return SEG_CUBICTO; |
| 141 | } |
| 142 | |
| 143 | /** |
| 144 | * Returns the coordinates and type of the current path segment in |
| 145 | * the iteration. |
| 146 | * The return value is the path segment type: |
| 147 | * SEG_MOVETO, SEG_LINETO, SEG_QUADTO, SEG_CUBICTO, or SEG_CLOSE. |
| 148 | * A double array of length 6 must be passed in and may be used to |
| 149 | * store the coordinates of the point(s). |
| 150 | * Each point is stored as a pair of double x,y coordinates. |
| 151 | * SEG_MOVETO and SEG_LINETO types will return one point, |
| 152 | * SEG_QUADTO will return two points, |
| 153 | * SEG_CUBICTO will return 3 points |
| 154 | * and SEG_CLOSE will not return any points. |
| 155 | * @see #SEG_MOVETO |
| 156 | * @see #SEG_LINETO |
| 157 | * @see #SEG_QUADTO |
| 158 | * @see #SEG_CUBICTO |
| 159 | * @see #SEG_CLOSE |
| 160 | */ |
| 161 | public int currentSegment(double[] coords) { |
| 162 | if (isDone()) { |
| 163 | throw new NoSuchElementException("ellipse iterator out of bounds"); |
| 164 | } |
| 165 | if (index == 5) { |
| 166 | return SEG_CLOSE; |
| 167 | } |
| 168 | if (index == 0) { |
| 169 | double ctrls[] = ctrlpts[3]; |
| 170 | coords[0] = x + ctrls[4] * w; |
| 171 | coords[1] = y + ctrls[5] * h; |
| 172 | if (affine != null) { |
| 173 | affine.transform(coords, 0, coords, 0, 1); |
| 174 | } |
| 175 | return SEG_MOVETO; |
| 176 | } |
| 177 | double ctrls[] = ctrlpts[index - 1]; |
| 178 | coords[0] = x + ctrls[0] * w; |
| 179 | coords[1] = y + ctrls[1] * h; |
| 180 | coords[2] = x + ctrls[2] * w; |
| 181 | coords[3] = y + ctrls[3] * h; |
| 182 | coords[4] = x + ctrls[4] * w; |
| 183 | coords[5] = y + ctrls[5] * h; |
| 184 | if (affine != null) { |
| 185 | affine.transform(coords, 0, coords, 0, 3); |
| 186 | } |
| 187 | return SEG_CUBICTO; |
| 188 | } |
| 189 | } |