1 /*
2 * Copyright (c) 1997, Oracle and/or its affiliates. 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * 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 rounded rectangle
32 * through the PathIterator interface.
33 *
34 * @author Jim Graham
35 */
36 class RoundRectIterator implements PathIterator {
37 double x, y, w, h, aw, ah;
38 AffineTransform affine;
39 int index;
40
41 RoundRectIterator(RoundRectangle2D rr, AffineTransform at) {
42 this.x = rr.getX();
43 this.y = rr.getY();
44 this.w = rr.getWidth();
45 this.h = rr.getHeight();
46 this.aw = Math.min(w, Math.abs(rr.getArcWidth()));
47 this.ah = Math.min(h, Math.abs(rr.getArcHeight()));
48 this.affine = at;
49 if (aw < 0 || ah < 0) {
50 // Don't draw anything...
51 index = ctrlpts.length;
52 }
53 }
54
55 /**
56 * Return the winding rule for determining the insideness of the
57 * path.
58 * @see #WIND_EVEN_ODD
59 * @see #WIND_NON_ZERO
60 */
61 public int getWindingRule() {
62 return WIND_NON_ZERO;
63 }
64
65 /**
66 * Tests if there are more points to read.
67 * @return true if there are more points to read
68 */
69 public boolean isDone() {
70 return index >= ctrlpts.length;
71 }
72
73 /**
74 * Moves the iterator to the next segment of the path forwards
75 * along the primary direction of traversal as long as there are
76 * more points in that direction.
77 */
78 public void next() {
79 index++;
80 }
81
82 private static final double angle = Math.PI / 4.0;
83 private static final double a = 1.0 - Math.cos(angle);
84 private static final double b = Math.tan(angle);
85 private static final double c = Math.sqrt(1.0 + b * b) - 1 + a;
86 private static final double cv = 4.0 / 3.0 * a * b / c;
87 private static final double acv = (1.0 - cv) / 2.0;
88
89 // For each array:
90 // 4 values for each point {v0, v1, v2, v3}:
91 // point = (x + v0 * w + v1 * arcWidth,
92 // y + v2 * h + v3 * arcHeight);
93 private static double ctrlpts[][] = {
94 { 0.0, 0.0, 0.0, 0.5 },
95 { 0.0, 0.0, 1.0, -0.5 },
96 { 0.0, 0.0, 1.0, -acv,
97 0.0, acv, 1.0, 0.0,
98 0.0, 0.5, 1.0, 0.0 },
99 { 1.0, -0.5, 1.0, 0.0 },
100 { 1.0, -acv, 1.0, 0.0,
101 1.0, 0.0, 1.0, -acv,
102 1.0, 0.0, 1.0, -0.5 },
103 { 1.0, 0.0, 0.0, 0.5 },
104 { 1.0, 0.0, 0.0, acv,
105 1.0, -acv, 0.0, 0.0,
106 1.0, -0.5, 0.0, 0.0 },
107 { 0.0, 0.5, 0.0, 0.0 },
108 { 0.0, acv, 0.0, 0.0,
109 0.0, 0.0, 0.0, acv,
110 0.0, 0.0, 0.0, 0.5 },
111 {},
112 };
113 private static int types[] = {
114 SEG_MOVETO,
115 SEG_LINETO, SEG_CUBICTO,
116 SEG_LINETO, SEG_CUBICTO,
117 SEG_LINETO, SEG_CUBICTO,
118 SEG_LINETO, SEG_CUBICTO,
119 SEG_CLOSE,
120 };
121
122 /**
123 * Returns the coordinates and type of the current path segment in
124 * the iteration.
125 * The return value is the path segment type:
126 * SEG_MOVETO, SEG_LINETO, SEG_QUADTO, SEG_CUBICTO, or SEG_CLOSE.
127 * A float array of length 6 must be passed in and may be used to
128 * store the coordinates of the point(s).
129 * Each point is stored as a pair of float x,y coordinates.
130 * SEG_MOVETO and SEG_LINETO types will return one point,
131 * SEG_QUADTO will return two points,
132 * SEG_CUBICTO will return 3 points
133 * and SEG_CLOSE will not return any points.
134 * @see #SEG_MOVETO
135 * @see #SEG_LINETO
136 * @see #SEG_QUADTO
137 * @see #SEG_CUBICTO
138 * @see #SEG_CLOSE
139 */
140 public int currentSegment(float[] coords) {
141 if (isDone()) {
142 throw new NoSuchElementException("roundrect iterator out of bounds");
143 }
144 double ctrls[] = ctrlpts[index];
145 int nc = 0;
146 for (int i = 0; i < ctrls.length; i += 4) {
147 coords[nc++] = (float) (x + ctrls[i + 0] * w + ctrls[i + 1] * aw);
148 coords[nc++] = (float) (y + ctrls[i + 2] * h + ctrls[i + 3] * ah);
149 }
150 if (affine != null) {
151 affine.transform(coords, 0, coords, 0, nc / 2);
152 }
153 return types[index];
154 }
155
156 /**
157 * Returns the coordinates and type of the current path segment in
158 * the iteration.
159 * The return value is the path segment type:
160 * SEG_MOVETO, SEG_LINETO, SEG_QUADTO, SEG_CUBICTO, or SEG_CLOSE.
161 * A double array of length 6 must be passed in and may be used to
162 * store the coordinates of the point(s).
163 * Each point is stored as a pair of double x,y coordinates.
164 * SEG_MOVETO and SEG_LINETO types will return one point,
165 * SEG_QUADTO will return two points,
166 * SEG_CUBICTO will return 3 points
167 * and SEG_CLOSE will not return any points.
168 * @see #SEG_MOVETO
169 * @see #SEG_LINETO
170 * @see #SEG_QUADTO
171 * @see #SEG_CUBICTO
172 * @see #SEG_CLOSE
173 */
174 public int currentSegment(double[] coords) {
175 if (isDone()) {
176 throw new NoSuchElementException("roundrect iterator out of bounds");
177 }
178 double ctrls[] = ctrlpts[index];
179 int nc = 0;
180 for (int i = 0; i < ctrls.length; i += 4) {
181 coords[nc++] = (x + ctrls[i + 0] * w + ctrls[i + 1] * aw);
182 coords[nc++] = (y + ctrls[i + 2] * h + ctrls[i + 3] * ah);
183 }
184 if (affine != null) {
185 affine.transform(coords, 0, coords, 0, nc / 2);
186 }
187 return types[index];
188 }
189 }