J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1995-2004 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package java.awt.image; |
| 27 | |
| 28 | import java.awt.image.ImageConsumer; |
| 29 | import java.awt.image.ColorModel; |
| 30 | import java.util.Hashtable; |
| 31 | import java.awt.Rectangle; |
| 32 | |
| 33 | /** |
| 34 | * An ImageFilter class for cropping images. |
| 35 | * This class extends the basic ImageFilter Class to extract a given |
| 36 | * rectangular region of an existing Image and provide a source for a |
| 37 | * new image containing just the extracted region. It is meant to |
| 38 | * be used in conjunction with a FilteredImageSource object to produce |
| 39 | * cropped versions of existing images. |
| 40 | * |
| 41 | * @see FilteredImageSource |
| 42 | * @see ImageFilter |
| 43 | * |
| 44 | * @author Jim Graham |
| 45 | */ |
| 46 | public class CropImageFilter extends ImageFilter { |
| 47 | int cropX; |
| 48 | int cropY; |
| 49 | int cropW; |
| 50 | int cropH; |
| 51 | |
| 52 | /** |
| 53 | * Constructs a CropImageFilter that extracts the absolute rectangular |
| 54 | * region of pixels from its source Image as specified by the x, y, |
| 55 | * w, and h parameters. |
| 56 | * @param x the x location of the top of the rectangle to be extracted |
| 57 | * @param y the y location of the top of the rectangle to be extracted |
| 58 | * @param w the width of the rectangle to be extracted |
| 59 | * @param h the height of the rectangle to be extracted |
| 60 | */ |
| 61 | public CropImageFilter(int x, int y, int w, int h) { |
| 62 | cropX = x; |
| 63 | cropY = y; |
| 64 | cropW = w; |
| 65 | cropH = h; |
| 66 | } |
| 67 | |
| 68 | /** |
| 69 | * Passes along the properties from the source object after adding a |
| 70 | * property indicating the cropped region. |
| 71 | * This method invokes <code>super.setProperties</code>, |
| 72 | * which might result in additional properties being added. |
| 73 | * <p> |
| 74 | * Note: This method is intended to be called by the |
| 75 | * <code>ImageProducer</code> of the <code>Image</code> whose pixels |
| 76 | * are being filtered. Developers using |
| 77 | * this class to filter pixels from an image should avoid calling |
| 78 | * this method directly since that operation could interfere |
| 79 | * with the filtering operation. |
| 80 | */ |
| 81 | public void setProperties(Hashtable<?,?> props) { |
| 82 | Hashtable<Object,Object> p = (Hashtable<Object,Object>)props.clone(); |
| 83 | p.put("croprect", new Rectangle(cropX, cropY, cropW, cropH)); |
| 84 | super.setProperties(p); |
| 85 | } |
| 86 | |
| 87 | /** |
| 88 | * Override the source image's dimensions and pass the dimensions |
| 89 | * of the rectangular cropped region to the ImageConsumer. |
| 90 | * <p> |
| 91 | * Note: This method is intended to be called by the |
| 92 | * <code>ImageProducer</code> of the <code>Image</code> whose |
| 93 | * pixels are being filtered. Developers using |
| 94 | * this class to filter pixels from an image should avoid calling |
| 95 | * this method directly since that operation could interfere |
| 96 | * with the filtering operation. |
| 97 | * @see ImageConsumer |
| 98 | */ |
| 99 | public void setDimensions(int w, int h) { |
| 100 | consumer.setDimensions(cropW, cropH); |
| 101 | } |
| 102 | |
| 103 | /** |
| 104 | * Determine whether the delivered byte pixels intersect the region to |
| 105 | * be extracted and passes through only that subset of pixels that |
| 106 | * appear in the output region. |
| 107 | * <p> |
| 108 | * Note: This method is intended to be called by the |
| 109 | * <code>ImageProducer</code> of the <code>Image</code> whose |
| 110 | * pixels are being filtered. Developers using |
| 111 | * this class to filter pixels from an image should avoid calling |
| 112 | * this method directly since that operation could interfere |
| 113 | * with the filtering operation. |
| 114 | */ |
| 115 | public void setPixels(int x, int y, int w, int h, |
| 116 | ColorModel model, byte pixels[], int off, |
| 117 | int scansize) { |
| 118 | int x1 = x; |
| 119 | if (x1 < cropX) { |
| 120 | x1 = cropX; |
| 121 | } |
| 122 | int x2 = addWithoutOverflow(x, w); |
| 123 | if (x2 > cropX + cropW) { |
| 124 | x2 = cropX + cropW; |
| 125 | } |
| 126 | int y1 = y; |
| 127 | if (y1 < cropY) { |
| 128 | y1 = cropY; |
| 129 | } |
| 130 | |
| 131 | int y2 = addWithoutOverflow(y, h); |
| 132 | if (y2 > cropY + cropH) { |
| 133 | y2 = cropY + cropH; |
| 134 | } |
| 135 | if (x1 >= x2 || y1 >= y2) { |
| 136 | return; |
| 137 | } |
| 138 | consumer.setPixels(x1 - cropX, y1 - cropY, (x2 - x1), (y2 - y1), |
| 139 | model, pixels, |
| 140 | off + (y1 - y) * scansize + (x1 - x), scansize); |
| 141 | } |
| 142 | |
| 143 | /** |
| 144 | * Determine if the delivered int pixels intersect the region to |
| 145 | * be extracted and pass through only that subset of pixels that |
| 146 | * appear in the output region. |
| 147 | * <p> |
| 148 | * Note: This method is intended to be called by the |
| 149 | * <code>ImageProducer</code> of the <code>Image</code> whose |
| 150 | * pixels are being filtered. Developers using |
| 151 | * this class to filter pixels from an image should avoid calling |
| 152 | * this method directly since that operation could interfere |
| 153 | * with the filtering operation. |
| 154 | */ |
| 155 | public void setPixels(int x, int y, int w, int h, |
| 156 | ColorModel model, int pixels[], int off, |
| 157 | int scansize) { |
| 158 | int x1 = x; |
| 159 | if (x1 < cropX) { |
| 160 | x1 = cropX; |
| 161 | } |
| 162 | int x2 = addWithoutOverflow(x, w); |
| 163 | if (x2 > cropX + cropW) { |
| 164 | x2 = cropX + cropW; |
| 165 | } |
| 166 | int y1 = y; |
| 167 | if (y1 < cropY) { |
| 168 | y1 = cropY; |
| 169 | } |
| 170 | |
| 171 | int y2 = addWithoutOverflow(y, h); |
| 172 | if (y2 > cropY + cropH) { |
| 173 | y2 = cropY + cropH; |
| 174 | } |
| 175 | if (x1 >= x2 || y1 >= y2) { |
| 176 | return; |
| 177 | } |
| 178 | consumer.setPixels(x1 - cropX, y1 - cropY, (x2 - x1), (y2 - y1), |
| 179 | model, pixels, |
| 180 | off + (y1 - y) * scansize + (x1 - x), scansize); |
| 181 | } |
| 182 | |
| 183 | //check for potential overflow (see bug 4801285) |
| 184 | private int addWithoutOverflow(int x, int w) { |
| 185 | int x2 = x + w; |
| 186 | if ( x > 0 && w > 0 && x2 < 0 ) { |
| 187 | x2 = Integer.MAX_VALUE; |
| 188 | } else if( x < 0 && w < 0 && x2 > 0 ) { |
| 189 | x2 = Integer.MIN_VALUE; |
| 190 | } |
| 191 | return x2; |
| 192 | } |
| 193 | } |