1 /**
2 * Copyright (c) 2011, The University of Southampton and the individual contributors.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without modification,
6 * are permitted provided that the following conditions are met:
7 *
8 * * Redistributions of source code must retain the above copyright notice,
9 * this list of conditions and the following disclaimer.
10 *
11 * * Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation
13 * and/or other materials provided with the distribution.
14 *
15 * * Neither the name of the University of Southampton nor the names of its
16 * contributors may be used to endorse or promote products derived from this
17 * software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
21 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
22 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
23 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
24 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
26 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
28 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30 package org.openimaj.image.contour;
31
32 import org.openimaj.image.FImage;
33 import org.openimaj.image.pixel.Pixel;
34
35 /**
36 * A pixel direction
37 *
38 * @author Sina Samangooei (ss@ecs.soton.ac.uk)
39 *
40 */
41 enum Direction {
42 NORTH, NORTH_EAST, EAST, SOUTH_EAST, SOUTH, SOUTH_WEST, WEST, NORTH_WEST;
43 static int[] dirx = new int[] { 0, 1, 1, 1, 0, -1, -1, -1 };
44 static int[] diry = new int[] { -1, -1, 0, 1, 1, 1, 0, -1 };
45 static Direction[] entry = new Direction[] {
46 WEST, WEST, NORTH, NORTH, EAST, EAST, SOUTH, SOUTH
47 };
48 static Direction[] ccentry = new Direction[] {
49 EAST, SOUTH, SOUTH, WEST, WEST, NORTH, NORTH, EAST
50 };
51
52 /**
53 * @return the direction clockwise from this direction
54 */
55 public Direction clockwise() {
56 final Direction[] vals = Direction.values();
57 final Direction dir = vals[(ordinal() + 1) % vals.length];
58
59 return dir;
60 }
61
62 /**
63 * @return the direction counterClockwise from this direction
64 */
65 public Direction counterClockwise() {
66 final Direction[] vals = Direction.values();
67 final int desired = ordinal() - 1;
68 final Direction dir = vals[desired == -1 ? desired + vals.length : desired];
69 return dir;
70 }
71
72 /**
73 * @param img
74 * @param point
75 * @return whether the pixel point to from this point on this img in this
76 * direction is active
77 */
78 public Pixel active(FImage img, Pixel point) {
79 final int ord = ordinal();
80 final int yy = point.y + diry[ord];
81 final int xx = point.x + dirx[ord];
82 if (xx < 0 || xx >= img.width || yy < 0 || yy >= img.height)
83 return null;
84 final float pix = img.pixels[yy][xx];
85 return pix != 0 ? new Pixel(xx, yy) : null;
86 }
87
88 /**
89 * @return the direction which this pixel was entered from if it were
90 * entered clockwise
91 */
92 public Direction clockwiseEntryDirection() {
93 return entry[ordinal()];
94 }
95
96 /**
97 * @return the direction which this pixel was entered from if it were
98 * entered clockwise
99 */
100 public Direction counterClockwiseEntryDirection() {
101 return ccentry[ordinal()];
102 }
103
104 /**
105 * @param from
106 * @param to
107 * @return the DIRECTION from and to adjacent pixels
108 */
109 public static Direction fromTo(Pixel from, Pixel to) {
110 if (from.equals(to))
111 return null;
112 if (from.y == to.y) {
113 if (from.x < to.x)
114 return EAST;
115 else
116 return WEST;
117 }
118 else if (from.y < to.y) {
119 if (from.x == to.x)
120 return SOUTH;
121 else if (from.x < to.x)
122 return SOUTH_EAST;
123 else
124 return SOUTH_WEST;
125 }
126 else {
127 if (from.x == to.x)
128 return NORTH;
129 if (from.x < to.x)
130 return NORTH_EAST;
131 else
132 return NORTH_WEST;
133 }
134 }
135
136 /**
137 * @param from
138 * @return the pixel in the direction from some point
139 */
140 public Pixel pixel(Pixel from) {
141 return new Pixel(from.x + dirx[ordinal()], from.y + diry[ordinal()]);
142 }
143 }