001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2008, by Object Refinery Limited and Contributors.
006 *
007 * Project Info:  http://www.jfree.org/jfreechart/index.html
008 *
009 * This library is free software; you can redistribute it and/or modify it
010 * under the terms of the GNU Lesser General Public License as published by
011 * the Free Software Foundation; either version 2.1 of the License, or
012 * (at your option) any later version.
013 *
014 * This library is distributed in the hope that it will be useful, but
015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
017 * License for more details.
018 *
019 * You should have received a copy of the GNU Lesser General Public
020 * License along with this library; if not, write to the Free Software
021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
022 * USA.
023 *
024 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
025 * in the United States and other countries.]
026 *
027 * ------------------------
028 * ImageEncoderFactory.java
029 * ------------------------
030 * (C) Copyright 2004-2008, by Richard Atkinson and Contributors.
031 *
032 * Original Author:  Richard Atkinson;
033 * Contributor(s):   David Gilbert (for Object Refinery Limited);
034 *
035 * Changes
036 * -------
037 * 01-Aug-2004 : Initial version (RA);
038 * 01-Nov-2005 : Now using ImageIO for JPEG encoding, so we no longer have a
039 *               dependency on com.sun.* which isn't available on all
040 *               implementations (DG);
041 * 02-Feb-2007 : Removed author tags all over JFreeChart sources (DG);
042 *
043 */
044
045package org.jfree.chart.encoders;
046
047import java.util.Hashtable;
048
049/**
050 * Factory class for returning {@link ImageEncoder}s for different
051 * {@link ImageFormat}s.
052 */
053public class ImageEncoderFactory {
054
055    /** Storage for the encoders. */
056    private static Hashtable encoders = null;
057
058    static {
059        init();
060    }
061
062    /**
063     * Sets up default encoders (uses Sun PNG Encoder if JDK 1.4+ and the
064     * SunPNGEncoderAdapter class is available).
065     */
066    private static void init() {
067        encoders = new Hashtable();
068        encoders.put("jpeg", "org.jfree.chart.encoders.SunJPEGEncoderAdapter");
069        try {
070            //  Test for being run under JDK 1.4+
071            Class.forName("javax.imageio.ImageIO");
072            //  Test for JFreeChart being compiled under JDK 1.4+
073            Class.forName("org.jfree.chart.encoders.SunPNGEncoderAdapter");
074            encoders.put("png",
075                    "org.jfree.chart.encoders.SunPNGEncoderAdapter");
076            encoders.put("jpeg",
077                    "org.jfree.chart.encoders.SunJPEGEncoderAdapter");
078        }
079        catch (ClassNotFoundException e) {
080            encoders.put("png",
081                    "org.jfree.chart.encoders.KeypointPNGEncoderAdapter");
082        }
083    }
084
085    /**
086     * Used to set additional encoders or replace default ones.
087     *
088     * @param format  The image format name.
089     * @param imageEncoderClassName  The name of the ImageEncoder class.
090     */
091    public static void setImageEncoder(String format,
092                                       String imageEncoderClassName) {
093        encoders.put(format, imageEncoderClassName);
094    }
095
096    /**
097     * Used to retrieve an ImageEncoder for a specific image format.
098     *
099     * @param format  The image format required.
100     *
101     * @return The ImageEncoder or <code>null</code> if none available.
102     */
103    public static ImageEncoder newInstance(String format) {
104        ImageEncoder imageEncoder = null;
105        String className = (String) encoders.get(format);
106        if (className == null) {
107            throw new IllegalArgumentException("Unsupported image format - "
108                    + format);
109        }
110        try {
111            Class imageEncoderClass = Class.forName(className);
112            imageEncoder = (ImageEncoder) imageEncoderClass.newInstance();
113        }
114        catch (Exception e) {
115            throw new IllegalArgumentException(e.toString());
116        }
117        return imageEncoder;
118    }
119
120    /**
121     * Used to retrieve an ImageEncoder for a specific image format.
122     *
123     * @param format  The image format required.
124     * @param quality  The quality to be set before returning.
125     *
126     * @return The ImageEncoder or <code>null</code> if none available.
127     */
128    public static ImageEncoder newInstance(String format, float quality) {
129        ImageEncoder imageEncoder = newInstance(format);
130        imageEncoder.setQuality(quality);
131        return imageEncoder;
132    }
133
134    /**
135     * Used to retrieve an ImageEncoder for a specific image format.
136     *
137     * @param format  The image format required.
138     * @param encodingAlpha  Sets whether alpha transparency should be encoded.
139     *
140     * @return The ImageEncoder or <code>null</code> if none available.
141     */
142    public static ImageEncoder newInstance(String format,
143                                           boolean encodingAlpha) {
144        ImageEncoder imageEncoder = newInstance(format);
145        imageEncoder.setEncodingAlpha(encodingAlpha);
146        return imageEncoder;
147    }
148
149    /**
150     * Used to retrieve an ImageEncoder for a specific image format.
151     *
152     * @param format  The image format required.
153     * @param quality  The quality to be set before returning.
154     * @param encodingAlpha  Sets whether alpha transparency should be encoded.
155     *
156     * @return The ImageEncoder or <code>null</code> if none available.
157     */
158    public static ImageEncoder newInstance(String format, float quality,
159                                           boolean encodingAlpha) {
160        ImageEncoder imageEncoder = newInstance(format);
161        imageEncoder.setQuality(quality);
162        imageEncoder.setEncodingAlpha(encodingAlpha);
163        return imageEncoder;
164    }
165
166}