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comparison servlet/src/digilib/image/JAIImageLoaderDocuImage.java @ 339:6d2032b6121d gen2_1

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author robcast
date Wed, 17 Nov 2004 18:17:34 +0100
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3:794a9f25f15c 339:6d2032b6121d
1 /* JAIImageLoaderDocuImage -- Image class implementation using JAI's ImageLoader Plugin
2
3 Digital Image Library servlet components
4
5 Copyright (C) 2002, 2003 Robert Casties (robcast@mail.berlios.de)
6
7 This program is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by the
9 Free Software Foundation; either version 2 of the License, or (at your
10 option) any later version.
11
12 Please read license.txt for the full details. A copy of the GPL
13 may be found at http://www.gnu.org/copyleft/lgpl.html
14
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18
19 */
20
21 package digilib.image;
22
23 import java.awt.Rectangle;
24 import java.awt.image.renderable.ParameterBlock;
25 import java.io.File;
26 import java.io.IOException;
27 import java.io.OutputStream;
28 import java.io.RandomAccessFile;
29 import java.util.Iterator;
30
31 import javax.imageio.ImageIO;
32 import javax.imageio.ImageReadParam;
33 import javax.imageio.ImageReader;
34 import javax.imageio.stream.FileImageInputStream;
35 import javax.imageio.stream.ImageInputStream;
36 import javax.media.jai.JAI;
37
38 import digilib.io.FileOpException;
39 import digilib.io.ImageFile;
40
41 /** DocuImage implementation using the Java Advanced Imaging API and the ImageLoader
42 * API of Java 1.4.
43 */
44 public class JAIImageLoaderDocuImage extends JAIDocuImage {
45
46 /** ImageIO image reader */
47 protected ImageReader reader;
48 /** current image file */
49 protected File imgFile;
50
51 /* loadSubimage is supported. */
52 public boolean isSubimageSupported() {
53 return true;
54 }
55
56 public int getHeight() {
57 int h = 0;
58 try {
59 if (img == null) {
60 h = reader.getHeight(0);
61 } else {
62 h = img.getHeight();
63 }
64 } catch (IOException e) {
65 logger.debug("error in getHeight", e);
66 }
67 return h;
68 }
69
70 public int getWidth() {
71 int w = 0;
72 try {
73 if (img == null) {
74 w = reader.getWidth(0);
75 } else {
76 w = img.getWidth();
77 }
78 } catch (IOException e) {
79 logger.debug("error in getHeight", e);
80 }
81 return w;
82 }
83
84 /* Load an image file into the Object. */
85 public void loadImage(ImageFile f) throws FileOpException {
86 logger.debug("loadImage: "+f);
87 //System.gc();
88 img = JAI.create("ImageRead", f.getAbsolutePath());
89 if (img == null) {
90 throw new FileOpException("Unable to load File!");
91 }
92 }
93
94 /* Get an ImageReader for the image file. */
95 public ImageReader getReader(ImageFile f) throws IOException {
96 logger.debug("preloadImage: "+f);
97 //System.gc();
98 RandomAccessFile rf = new RandomAccessFile(f, "r");
99 ImageInputStream istream = new FileImageInputStream(rf);
100 //Iterator readers = ImageIO.getImageReaders(istream);
101 Iterator readers = ImageIO.getImageReadersByMIMEType(f.getMimetype());
102 if (! readers.hasNext()) {
103 throw new FileOpException("Unable to load File!");
104 }
105 reader = (ImageReader) readers.next();
106 logger.debug("JAIImageIO: this reader: " + reader.getClass());
107 while (readers.hasNext()) {
108 logger.debug(" next reader: " + readers.next().getClass());
109 }
110 reader.setInput(istream);
111 return reader;
112 }
113
114 /* Load an image file into the Object. */
115 public void loadSubimage(ImageFile f, Rectangle region, int prescale)
116 throws FileOpException {
117 logger.debug("loadSubimage: "+f);
118 //System.gc();
119 try {
120 if ((reader == null) || (imgFile != f)) {
121 getReader(f);
122 }
123 ImageReadParam readParam = reader.getDefaultReadParam();
124 readParam.setSourceRegion(region);
125 readParam.setSourceSubsampling(prescale, prescale, 0, 0);
126 img = reader.read(0, readParam);
127 /* JAI imageread seems to ignore the readParam :-(
128 ImageInputStream istream = (ImageInputStream) reader.getInput();
129 ParameterBlockJAI pb = new ParameterBlockJAI("imageread");
130 pb.setParameter("Input", istream);
131 pb.setParameter("ReadParam", readParam);
132 pb.setParameter("Reader", reader);
133 img = JAI.create("imageread", pb);
134 */
135 } catch (IOException e) {
136 throw new FileOpException("Unable to load File!");
137 }
138 if (img == null) {
139 throw new FileOpException("Unable to load File!");
140 }
141 imgFile = f;
142 }
143
144
145 /* Write the current image to an OutputStream. */
146 public void writeImage(String mt, OutputStream ostream)
147 throws FileOpException {
148 logger.debug("writeImage");
149 try {
150 // setup output
151 ParameterBlock pb3 = new ParameterBlock();
152 pb3.addSource(img);
153 pb3.add(ostream);
154 if (mt == "image/jpeg") {
155 pb3.add("JPEG");
156 } else if (mt == "image/png") {
157 pb3.add("PNG");
158 } else {
159 // unknown mime type
160 throw new FileOpException("Unknown mime type: " + mt);
161 }
162 // render output
163 JAI.create("ImageWrite", pb3);
164 } catch (IOException e) {
165 throw new FileOpException("Error writing image.");
166 }
167 }
168
169 /* (non-Javadoc)
170 * @see java.lang.Object#finalize()
171 */
172 protected void finalize() throws Throwable {
173 dispose();
174 super.finalize();
175 }
176
177 public void dispose() {
178 // we must dispose the ImageReader because it keeps the filehandle open!
179 reader.dispose();
180 reader = null;
181 img = null;
182 }
183
184 }