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
26package java.awt.geom;
27
28import 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 */
36class 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}
190