Writes an image to an output stream as a JPEG file. The JPEG quality can be specified in percent. : JPEG « 2D Graphics GUI « Java

1. Java
2. 2D Graphics GUI
3. JPEG

Writes an image to an output stream as a JPEG file. The JPEG quality can be specified in percent.

 
/*
 * JSwiff is an open source Java API for Macromedia Flash file generation
 * and manipulation
 *
 * Copyright (C) 2004-2006 Ralf Terdic (contact@jswiff.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

//package com.jswiff.util;

import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Iterator;
import java.util.Locale;

import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageReader;
import javax.imageio.ImageWriteParam;
import javax.imageio.ImageWriter;
import javax.imageio.plugins.jpeg.JPEGImageWriteParam;
import javax.imageio.stream.ImageInputStream;
import javax.imageio.stream.ImageOutputStream;

/**
 * Provides utility methods for image processing.
 * 
 * @author <a href="mailto:ralf@terdic.de">Ralf Terdic</a>
 */
public class ImageUtilities {
  /**
   * Returns the format of an image (as string).
   * 
   * @param stream
   *            image source stream
   * 
   * @return format stream (e.g. "JPEG")
   * 
   * @throws IOException
   *             if an I/O error occured
   */
  public static String getFormat(InputStream stream) throws IOException {
    ImageInputStream iis = ImageIO.createImageInputStream(stream);
    Iterator iter = ImageIO.getImageReaders(iis);
    if (!iter.hasNext()) {
      throw new IOException("Unsupported image format!");
    }
    ImageReader reader = (ImageReader) iter.next();
    iis.close();
    return reader.getFormatName();
  }

  /**
   * Loads an image from a stream.
   * 
   * @param stream
   *            input stream
   * 
   * @return the loaded image
   * 
   * @throws IOException
   *             if the image could not be loaded
   */
  public static BufferedImage loadImage(InputStream stream)
      throws IOException {
    return ImageIO.read(stream);
  }

  /**
   * Writes an image to an output stream as a JPEG file.
   * 
   * @param image
   *            image to be written
   * @param stream
   *            target stream
   * 
   * @throws IOException
   *             if an I/O error occured
   */
  public static void saveImageAsJPEG(BufferedImage image, OutputStream stream)
      throws IOException {
    ImageIO.write(image, "jpg", stream);
  }

  /**
   * Writes an image to an output stream as a JPEG file. The JPEG quality can
   * be specified in percent.
   * 
   * @param image
   *            image to be written
   * @param stream
   *            target stream
   * @param qualityPercent
   *            JPEG quality in percent
   * 
   * @throws IOException
   *             if an I/O error occured
   * @throws IllegalArgumentException
   *             if qualityPercent not between 0 and 100
   */
  public static void saveImageAsJPEG(BufferedImage image,
      OutputStream stream, int qualityPercent) throws IOException {
    if ((qualityPercent < 0) || (qualityPercent > 100)) {
      throw new IllegalArgumentException("Quality out of bounds!");
    }
    float quality = qualityPercent / 100f;
    ImageWriter writer = null;
    Iterator iter = ImageIO.getImageWritersByFormatName("jpg");
    if (iter.hasNext()) {
      writer = (ImageWriter) iter.next();
    }
    ImageOutputStream ios = ImageIO.createImageOutputStream(stream);
    writer.setOutput(ios);
    ImageWriteParam iwparam = new JPEGImageWriteParam(Locale.getDefault());
    iwparam.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
    iwparam.setCompressionQuality(quality);
    writer.write(null, new IIOImage(image, null, null), iwparam);
    ios.flush();
    writer.dispose();
    ios.close();
  }

  /**
   * Writes an image to an output stream as a PNG file.
   * 
   * @param image
   *            image to be written
   * @param stream
   *            target stream
   * 
   * @throws IOException
   *             if an I/O error occured
   */
  public static void saveImageAsPNG(BufferedImage image, OutputStream stream)
      throws IOException {
    ImageIO.write(image, "png", stream);
  }

  private static BufferedImage convertToARGB(BufferedImage srcImage) {
    BufferedImage newImage = new BufferedImage(srcImage.getWidth(null),
        srcImage.getHeight(null), BufferedImage.TYPE_INT_ARGB);
    Graphics bg = newImage.getGraphics();
    bg.drawImage(srcImage, 0, 0, null);
    bg.dispose();
    return newImage;
  }
}

   
  

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