1 /*
2 * Copyright (c) 1996, 2004, 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 scaling images using the simplest algorithm.
35 * This class extends the basic ImageFilter Class to scale an existing
36 * image and provide a source for a new image containing the resampled
37 * image. The pixels in the source image are sampled to produce pixels
38 * for an image of the specified size by replicating rows and columns of
39 * pixels to scale up or omitting rows and columns of pixels to scale
40 * down.
41 * <p>It is meant to be used in conjunction with a FilteredImageSource
42 * object to produce scaled versions of existing images. Due to
43 * implementation dependencies, there may be differences in pixel values
44 * of an image filtered on different platforms.
45 *
46 * @see FilteredImageSource
47 * @see ImageFilter
48 *
49 * @author Jim Graham
50 */
51 public class ReplicateScaleFilter extends ImageFilter {
52
53 /**
54 * The width of the source image.
55 */
56 protected int srcWidth;
57
58 /**
59 * The height of the source image.
60 */
61 protected int srcHeight;
62
63 /**
64 * The target width to scale the image.
65 */
66 protected int destWidth;
67
68 /**
69 * The target height to scale the image.
70 */
71 protected int destHeight;
72
73 /**
74 * An <code>int</code> array containing information about a
75 * row of pixels.
76 */
77 protected int srcrows[];
78
79 /**
80 * An <code>int</code> array containing information about a
81 * column of pixels.
82 */
83 protected int srccols[];
84
85 /**
86 * A <code>byte</code> array initialized with a size of
87 * {@link #destWidth} and used to deliver a row of pixel
88 * data to the {@link ImageConsumer}.
89 */
90 protected Object outpixbuf;
91
92 /**
93 * Constructs a ReplicateScaleFilter that scales the pixels from
94 * its source Image as specified by the width and height parameters.
95 * @param width the target width to scale the image
96 * @param height the target height to scale the image
97 * @throws IllegalArgumentException if <code>width</code> equals
98 * zero or <code>height</code> equals zero
99 */
100 public ReplicateScaleFilter(int width, int height) {
101 if (width == 0 || height == 0) {
102 throw new IllegalArgumentException("Width ("+width+
103 ") and height ("+height+
104 ") must be non-zero");
105 }
106 destWidth = width;
107 destHeight = height;
108 }
109
110 /**
111 * Passes along the properties from the source object after adding a
112 * property indicating the scale applied.
113 * This method invokes <code>super.setProperties</code>,
114 * which might result in additional properties being added.
115 * <p>
116 * Note: This method is intended to be called by the
117 * <code>ImageProducer</code> of the <code>Image</code> whose pixels
118 * are being filtered. Developers using
119 * this class to filter pixels from an image should avoid calling
120 * this method directly since that operation could interfere
121 * with the filtering operation.
122 */
123 public void setProperties(Hashtable<?,?> props) {
124 Hashtable<Object,Object> p = (Hashtable<Object,Object>)props.clone();
125 String key = "rescale";
126 String val = destWidth + "x" + destHeight;
127 Object o = p.get(key);
128 if (o != null && o instanceof String) {
129 val = ((String) o) + ", " + val;
130 }
131 p.put(key, val);
132 super.setProperties(p);
133 }
134
135 /**
136 * Override the dimensions of the source image and pass the dimensions
137 * of the new scaled size to the ImageConsumer.
138 * <p>
139 * Note: This method is intended to be called by the
140 * <code>ImageProducer</code> of the <code>Image</code> whose pixels
141 * are being filtered. Developers using
142 * this class to filter pixels from an image should avoid calling
143 * this method directly since that operation could interfere
144 * with the filtering operation.
145 * @see ImageConsumer
146 */
147 public void setDimensions(int w, int h) {
148 srcWidth = w;
149 srcHeight = h;
150 if (destWidth < 0) {
151 if (destHeight < 0) {
152 destWidth = srcWidth;
153 destHeight = srcHeight;
154 } else {
155 destWidth = srcWidth * destHeight / srcHeight;
156 }
157 } else if (destHeight < 0) {
158 destHeight = srcHeight * destWidth / srcWidth;
159 }
160 consumer.setDimensions(destWidth, destHeight);
161 }
162
163 private void calculateMaps() {
164 srcrows = new int[destHeight + 1];
165 for (int y = 0; y <= destHeight; y++) {
166 srcrows[y] = (2 * y * srcHeight + srcHeight) / (2 * destHeight);
167 }
168 srccols = new int[destWidth + 1];
169 for (int x = 0; x <= destWidth; x++) {
170 srccols[x] = (2 * x * srcWidth + srcWidth) / (2 * destWidth);
171 }
172 }
173
174 /**
175 * Choose which rows and columns of the delivered byte pixels are
176 * needed for the destination scaled image and pass through just
177 * those rows and columns that are needed, replicated as necessary.
178 * <p>
179 * Note: This method is intended to be called by the
180 * <code>ImageProducer</code> of the <code>Image</code> whose pixels
181 * are being filtered. Developers using
182 * this class to filter pixels from an image should avoid calling
183 * this method directly since that operation could interfere
184 * with the filtering operation.
185 */
186 public void setPixels(int x, int y, int w, int h,
187 ColorModel model, byte pixels[], int off,
188 int scansize) {
189 if (srcrows == null || srccols == null) {
190 calculateMaps();
191 }
192 int sx, sy;
193 int dx1 = (2 * x * destWidth + srcWidth - 1) / (2 * srcWidth);
194 int dy1 = (2 * y * destHeight + srcHeight - 1) / (2 * srcHeight);
195 byte outpix[];
196 if (outpixbuf != null && outpixbuf instanceof byte[]) {
197 outpix = (byte[]) outpixbuf;
198 } else {
199 outpix = new byte[destWidth];
200 outpixbuf = outpix;
201 }
202 for (int dy = dy1; (sy = srcrows[dy]) < y + h; dy++) {
203 int srcoff = off + scansize * (sy - y);
204 int dx;
205 for (dx = dx1; (sx = srccols[dx]) < x + w; dx++) {
206 outpix[dx] = pixels[srcoff + sx - x];
207 }
208 if (dx > dx1) {
209 consumer.setPixels(dx1, dy, dx - dx1, 1,
210 model, outpix, dx1, destWidth);
211 }
212 }
213 }
214
215 /**
216 * Choose which rows and columns of the delivered int pixels are
217 * needed for the destination scaled image and pass through just
218 * those rows and columns that are needed, replicated as necessary.
219 * <p>
220 * Note: This method is intended to be called by the
221 * <code>ImageProducer</code> of the <code>Image</code> whose pixels
222 * are being filtered. Developers using
223 * this class to filter pixels from an image should avoid calling
224 * this method directly since that operation could interfere
225 * with the filtering operation.
226 */
227 public void setPixels(int x, int y, int w, int h,
228 ColorModel model, int pixels[], int off,
229 int scansize) {
230 if (srcrows == null || srccols == null) {
231 calculateMaps();
232 }
233 int sx, sy;
234 int dx1 = (2 * x * destWidth + srcWidth - 1) / (2 * srcWidth);
235 int dy1 = (2 * y * destHeight + srcHeight - 1) / (2 * srcHeight);
236 int outpix[];
237 if (outpixbuf != null && outpixbuf instanceof int[]) {
238 outpix = (int[]) outpixbuf;
239 } else {
240 outpix = new int[destWidth];
241 outpixbuf = outpix;
242 }
243 for (int dy = dy1; (sy = srcrows[dy]) < y + h; dy++) {
244 int srcoff = off + scansize * (sy - y);
245 int dx;
246 for (dx = dx1; (sx = srccols[dx]) < x + w; dx++) {
247 outpix[dx] = pixels[srcoff + sx - x];
248 }
249 if (dx > dx1) {
250 consumer.setPixels(dx1, dy, dx - dx1, 1,
251 model, outpix, dx1, destWidth);
252 }
253 }
254 }
255 }