1 /*
2 * Copyright (c) 1997, 2018, 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.image;
27
28
29 /**
30 * The {@code Kernel} class defines a matrix that describes how a
31 * specified pixel and its surrounding pixels affect the value
32 * computed for the pixel's position in the output image of a filtering
33 * operation. The X origin and Y origin indicate the kernel matrix element
34 * that corresponds to the pixel position for which an output value is
35 * being computed.
36 *
37 * @see ConvolveOp
38 */
39 public class Kernel implements Cloneable {
40 private int width;
41 private int height;
42 private int xOrigin;
43 private int yOrigin;
44 private float[] data;
45
46 private static native void initIDs();
47 static {
48 ColorModel.loadLibraries();
49 initIDs();
50 }
51
52 /**
53 * Constructs a {@code Kernel} object from an array of floats.
54 * The first {@code width}*{@code height} elements of
55 * the {@code data} array are copied.
56 * If the length of the {@code data} array is less
57 * than width*height, an {@code IllegalArgumentException} is thrown.
58 * The X origin is (width-1)/2 and the Y origin is (height-1)/2.
59 * @param width width of the kernel
60 * @param height height of the kernel
61 * @param data kernel data in row major order
62 * @throws IllegalArgumentException if the length of {@code data}
63 * is less than the product of {@code width} and
64 * {@code height}
65 */
66 public Kernel(int width, int height, float[] data) {
67 this.width = width;
68 this.height = height;
69 this.xOrigin = (width-1)>>1;
70 this.yOrigin = (height-1)>>1;
71 int len = width*height;
72 if (data.length < len) {
73 throw new IllegalArgumentException("Data array too small "+
74 "(is "+data.length+
75 " and should be "+len);
76 }
77 this.data = new float[len];
78 System.arraycopy(data, 0, this.data, 0, len);
79
80 }
81
82 /**
83 * Returns the X origin of this {@code Kernel}.
84 * @return the X origin.
85 */
86 public final int getXOrigin(){
87 return xOrigin;
88 }
89
90 /**
91 * Returns the Y origin of this {@code Kernel}.
92 * @return the Y origin.
93 */
94 public final int getYOrigin() {
95 return yOrigin;
96 }
97
98 /**
99 * Returns the width of this {@code Kernel}.
100 * @return the width of this {@code Kernel}.
101 */
102 public final int getWidth() {
103 return width;
104 }
105
106 /**
107 * Returns the height of this {@code Kernel}.
108 * @return the height of this {@code Kernel}.
109 */
110 public final int getHeight() {
111 return height;
112 }
113
114 /**
115 * Returns the kernel data in row major order.
116 * The {@code data} array is returned. If {@code data}
117 * is {@code null}, a new array is allocated.
118 * @param data if non-null, contains the returned kernel data
119 * @return the {@code data} array containing the kernel data
120 * in row major order or, if {@code data} is
121 * {@code null}, a newly allocated array containing
122 * the kernel data in row major order
123 * @throws IllegalArgumentException if {@code data} is less
124 * than the size of this {@code Kernel}
125 */
126 public final float[] getKernelData(float[] data) {
127 if (data == null) {
128 data = new float[this.data.length];
129 }
130 else if (data.length < this.data.length) {
131 throw new IllegalArgumentException("Data array too small "+
132 "(should be "+this.data.length+
133 " but is "+
134 data.length+" )");
135 }
136 System.arraycopy(this.data, 0, data, 0, this.data.length);
137
138 return data;
139 }
140
141 /**
142 * Clones this object.
143 * @return a clone of this object.
144 */
145 public Object clone() {
146 try {
147 return super.clone();
148 } catch (CloneNotSupportedException e) {
149 // this shouldn't happen, since we are Cloneable
150 throw new InternalError(e);
151 }
152 }
153 }