sunpngencoderadapter.java

来自「JfreeChart 常用图表例子」· Java 代码 · 共 131 行

/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 *
 * This library is free software; you can redistribute it and/or modify it 
 * under the terms of the GNU Lesser General Public License as published by 
 * the Free Software Foundation; either version 2.1 of the License, or 
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License 
 * along with this library; if not, write to the Free Software Foundation, 
 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 *
 * -------------------
 * SunPNGEncoderAdapter.java
 * -------------------
 * (C) Copyright 2004, by Richard Atkinson and Contributors.
 *
 * Original Author:  Richard Atkinson;
 * Contributor(s):   -;
 *
 * $Id: SunPNGEncoderAdapter.java,v 1.3 2005/03/28 19:38:57 mungady Exp $
 *
 * Changes
 * -------
 * 01-Aug-2004 : Initial version (RA);
 *
 */
package org.jfree.chart.encoders;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.OutputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

/**
 * Adapter class for the Sun PNG Encoder.  The ImageEncoderFactory will only 
 * return a reference to this class by default if the library has been compiled 
 * under a JDK 1.4+ and is being run using a JDK 1.4+.
 *
 * @author Richard Atkinson
 */
public class SunPNGEncoderAdapter implements ImageEncoder {

    /**
     * Get the quality of the image encoding (always 0.0).
     *
     * @return A float representing the quality.
     */
    public float getQuality() {
        return 0.0f;
    }

    /**
     * Set the quality of the image encoding (not supported in this 
     * ImageEncoder).
     *
     * @param quality  A float representing the quality.
     */
    public void setQuality(float quality) {
        //  No op
    }

    /**
     * Get whether the encoder should encode alpha transparency (always false).
     *
     * @return Whether the encoder is encoding alpha transparency.
     */
    public boolean isEncodingAlpha() {
        return false;
    }

    /**
     * Set whether the encoder should encode alpha transparency (not 
     * supported in this ImageEncoder).
     *
     * @param encodingAlpha  Whether the encoder should encode alpha 
     *                       transparency.
     */
    public void setEncodingAlpha(boolean encodingAlpha) {
        //  No op
    }

    /**
     * Encodes an image in PNG format.
     *
     * @param bufferedImage  The image to be encoded.
     * 
     * @return The byte[] that is the encoded image.
     * 
     * @throws IOException
     */
    public byte[] encode(BufferedImage bufferedImage) throws IOException {
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        encode(bufferedImage, outputStream);
        return outputStream.toByteArray();
    }

    /**
     * Encodes an image in PNG format and writes it to an OutputStream.
     *
     * @param bufferedImage  The image to be encoded.
     * @param outputStream  The OutputStream to write the encoded image to.
     * @throws IOException
     */
    public void encode(BufferedImage bufferedImage, OutputStream outputStream) 
        throws IOException {
        if (bufferedImage == null) {
            throw new IllegalArgumentException("Null 'image' argument.");
        }
        if (outputStream == null) {
            throw new IllegalArgumentException("Null 'outputStream' argument.");
        }
        ImageIO.write(bufferedImage, ImageFormat.PNG, outputStream);
    }

}