    001/* ===========================================================
    002 * JFreeChart : a free chart library for the Java(tm) platform
    003 * ===========================================================
    004 *
    005 * (C) Copyright 2000-2011, 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 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
    025 * Other names may be trademarks of their respective owners.]
    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}