1 /*
2 * Copyright (c) 1995, 2014, 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 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 @Override
69 public ImageFilter getScaledFilterInstance(double scaleX, double scaleY) {
70 Object instance = super.getScaledFilterInstance(scaleX, scaleY);
71 CropImageFilter filter = (CropImageFilter) instance;
72 filter.cropX = (int) Math.ceil(cropX * scaleX);
73 filter.cropY = (int) Math.ceil(cropY * scaleY);
74 filter.cropW = (int) Math.floor(cropW * scaleX);
75 filter.cropH = (int) Math.floor(cropH * scaleY);
76 return filter;
77 }
78
79 /**
80 * Passes along the properties from the source object after adding a
81 * property indicating the cropped region.
82 * This method invokes {@code super.setProperties},
83 * which might result in additional properties being added.
84 * <p>
85 * Note: This method is intended to be called by the
86 * {@code ImageProducer} of the {@code Image} whose pixels
87 * are being filtered. Developers using
88 * this class to filter pixels from an image should avoid calling
89 * this method directly since that operation could interfere
90 * with the filtering operation.
91 */
92 public void setProperties(Hashtable<?,?> props) {
93 @SuppressWarnings("unchecked")
94 Hashtable<Object,Object> p = (Hashtable<Object,Object>)props.clone();
95 p.put("croprect", new Rectangle(cropX, cropY, cropW, cropH));
96 super.setProperties(p);
97 }
98
99 /**
100 * Override the source image's dimensions and pass the dimensions
101 * of the rectangular cropped region to the ImageConsumer.
102 * <p>
103 * Note: This method is intended to be called by the
104 * {@code ImageProducer} of the {@code Image} whose
105 * pixels are being filtered. Developers using
106 * this class to filter pixels from an image should avoid calling
107 * this method directly since that operation could interfere
108 * with the filtering operation.
109 * @see ImageConsumer
110 */
111 public void setDimensions(int w, int h) {
112 consumer.setDimensions(cropW, cropH);
113 }
114
115 /**
116 * Determine whether the delivered byte pixels intersect the region to
117 * be extracted and passes through only that subset of pixels that
118 * appear in the output region.
119 * <p>
120 * Note: This method is intended to be called by the
121 * {@code ImageProducer} of the {@code Image} whose
122 * pixels are being filtered. Developers using
123 * this class to filter pixels from an image should avoid calling
124 * this method directly since that operation could interfere
125 * with the filtering operation.
126 */
127 public void setPixels(int x, int y, int w, int h,
128 ColorModel model, byte pixels[], int off,
129 int scansize) {
130 int x1 = x;
131 if (x1 < cropX) {
132 x1 = cropX;
133 }
134 int x2 = addWithoutOverflow(x, w);
135 if (x2 > cropX + cropW) {
136 x2 = cropX + cropW;
137 }
138 int y1 = y;
139 if (y1 < cropY) {
140 y1 = cropY;
141 }
142
143 int y2 = addWithoutOverflow(y, h);
144 if (y2 > cropY + cropH) {
145 y2 = cropY + cropH;
146 }
147 if (x1 >= x2 || y1 >= y2) {
148 return;
149 }
150 consumer.setPixels(x1 - cropX, y1 - cropY, (x2 - x1), (y2 - y1),
151 model, pixels,
152 off + (y1 - y) * scansize + (x1 - x), scansize);
153 }
154
155 /**
156 * Determine if the delivered int pixels intersect the region to
157 * be extracted and pass through only that subset of pixels that
158 * appear in the output region.
159 * <p>
160 * Note: This method is intended to be called by the
161 * {@code ImageProducer} of the {@code Image} whose
162 * pixels are being filtered. Developers using
163 * this class to filter pixels from an image should avoid calling
164 * this method directly since that operation could interfere
165 * with the filtering operation.
166 */
167 public void setPixels(int x, int y, int w, int h,
168 ColorModel model, int pixels[], int off,
169 int scansize) {
170 int x1 = x;
171 if (x1 < cropX) {
172 x1 = cropX;
173 }
174 int x2 = addWithoutOverflow(x, w);
175 if (x2 > cropX + cropW) {
176 x2 = cropX + cropW;
177 }
178 int y1 = y;
179 if (y1 < cropY) {
180 y1 = cropY;
181 }
182
183 int y2 = addWithoutOverflow(y, h);
184 if (y2 > cropY + cropH) {
185 y2 = cropY + cropH;
186 }
187 if (x1 >= x2 || y1 >= y2) {
188 return;
189 }
190 consumer.setPixels(x1 - cropX, y1 - cropY, (x2 - x1), (y2 - y1),
191 model, pixels,
192 off + (y1 - y) * scansize + (x1 - x), scansize);
193 }
194
195 //check for potential overflow (see bug 4801285)
196 private int addWithoutOverflow(int x, int w) {
197 int x2 = x + w;
198 if ( x > 0 && w > 0 && x2 < 0 ) {
199 x2 = Integer.MAX_VALUE;
200 } else if( x < 0 && w < 0 && x2 > 0 ) {
201 x2 = Integer.MIN_VALUE;
202 }
203 return x2;
204 }
205 }