JPEGImageDecoder.java :  » 6.0-JDK-Modules-sun » awt » sun » awt » image » Java Open Source

Java Open Source » 6.0 JDK Modules sun » awt 
awt » sun » awt » image » JPEGImageDecoder.java
/*
 * Copyright 1995-2003 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */
/*-
 *  Reads JPEG images from an InputStream and reports the
 *  image data to an InputStreamImageSource object.
 *
 * The native implementation of the JPEG image decoder was adapted from
 * release 6 of the free JPEG software from the Independent JPEG Group.
 */
package sun.awt.image;

import java.util.Vector;
import java.util.Hashtable;
import java.io.InputStream;
import java.io.IOException;
import java.awt.image.*;

/**
 * JPEG Image converter
 *
 * @version 1.29 05/05/07
 * @author Jim Graham
 */
public class JPEGImageDecoder extends ImageDecoder {
    private static ColorModel RGBcolormodel;
    private static ColorModel ARGBcolormodel;
    private static ColorModel Graycolormodel;

    private static final Class InputStreamClass = InputStream.class;
    private static native void initIDs(Class InputStreamClass);

    private ColorModel colormodel;

    static {
        java.security.AccessController.doPrivileged(
      new sun.security.action.LoadLibraryAction("jpeg"));
  initIDs(InputStreamClass);
  RGBcolormodel = new DirectColorModel(24, 0xff0000, 0xff00, 0xff);
        ARGBcolormodel = ColorModel.getRGBdefault();
  byte g[] = new byte[256];
  for (int i = 0; i < 256; i++) {
      g[i] = (byte) i;
  }
  Graycolormodel = new IndexColorModel(8, 256, g, g, g);
    }

    private native void readImage(InputStream is, byte buf[])
  throws ImageFormatException, IOException;

    Hashtable props = new Hashtable();

    public JPEGImageDecoder(InputStreamImageSource src, InputStream is) {
  super(src, is);
    }

    /**
     * An error has occurred. Throw an exception.
     */
    private static void error(String s1) throws ImageFormatException {
  throw new ImageFormatException(s1);
    }

    public boolean sendHeaderInfo(int width, int height,
          boolean gray, boolean hasalpha,
                                  boolean multipass) 
    {
  setDimensions(width, height);

  setProperties(props);
        if (gray) {
            colormodel = Graycolormodel;
        } else {
            if (hasalpha) {
                colormodel = ARGBcolormodel;
            } else {
                colormodel = RGBcolormodel;
            }
        }

  setColorModel(colormodel);

  int flags = hintflags;
  if (!multipass) {
      flags |= ImageConsumer.SINGLEPASS;
  }
  setHints(hintflags);
  headerComplete();

  return true;
    }

    public boolean sendPixels(int pixels[], int y) {
  int count = setPixels(0, y, pixels.length, 1, colormodel,
            pixels, 0, pixels.length);
  if (count <= 0) {
      aborted = true;
  }
  return !aborted;
    }

    public boolean sendPixels(byte pixels[], int y) {
  int count = setPixels(0, y, pixels.length, 1, colormodel,
            pixels, 0, pixels.length);
  if (count <= 0) {
      aborted = true;
  }
  return !aborted;
    }

    /**
     * produce an image from the stream.
     */
    public void produceImage() throws IOException, ImageFormatException {
  try {
      readImage(input, new byte[1024]);
      if (!aborted) {
    imageComplete(ImageConsumer.STATICIMAGEDONE, true);
      }
  } catch (IOException e) {
      if (!aborted) {
    throw e;
      }
  } finally {
      close();
  }
    }

    /**
     * The ImageConsumer hints flag for a JPEG image.
     */
    private static final int hintflags =
  ImageConsumer.TOPDOWNLEFTRIGHT | ImageConsumer.COMPLETESCANLINES |
  ImageConsumer.SINGLEFRAME;
}
java2s.com  | Contact Us | Privacy Policy
Copyright 2009 - 12 Demo Source and Support. All rights reserved.
All other trademarks are property of their respective owners.