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 }