001/* ImageObserver.java -- Java interface for asynchronous updates to an image
002   Copyright (C) 1999 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package java.awt.image;
040
041import java.awt.Image;
042
043/**
044 * An object implementing the <code>ImageObserver</code> interface can
045 * receive updates on image construction from an
046 * <code>ImageProducer</code> asynchronously.
047 *
048 * @see ImageProducer
049 * @author C. Brian Jones (cbj@gnu.org)
050 */
051public interface ImageObserver
052{
053    /**
054     * The width of the image has been provided as the
055     * <code>width</code> argument to <code>imageUpdate</code>.
056     *
057     * @see #imageUpdate
058     */
059    int WIDTH = 1;
060
061    /**
062     * The height of the image has been provided as the
063     * <code>height</code> argument to <code>imageUpdate</code>.
064     *
065     * @see #imageUpdate
066     */
067    int HEIGHT = 2;
068
069    /**
070     * The properties of the image have been provided.
071     *
072     * @see #imageUpdate
073     * @see java.awt.Image#getProperty (java.lang.String, java.awt.image.ImageObserver)
074     */
075    int PROPERTIES = 4;
076
077    /**
078     * More pixels are now available for drawing a scaled variation of
079     * the image.
080     *
081     * @see #imageUpdate
082     */
083    int SOMEBITS = 8;
084
085    /**
086     * All the pixels needed to draw a complete frame of a multi-frame
087     * image are available.
088     *
089     * @see #imageUpdate
090     */
091    int FRAMEBITS = 16;
092
093    /**
094     * An image with a single frame, a static image, is complete.
095     *
096     * @see #imageUpdate
097     */
098    int ALLBITS = 32;
099
100    /**
101     * An error was encountered while producing the image.
102     *
103     * @see #imageUpdate
104     */
105    int ERROR = 64;
106
107    /**
108     * Production of the image was aborted.
109     *
110     * @see #imageUpdate
111     */
112    int ABORT = 128;
113
114    /**
115     * This is a callback method for an asynchronous image producer to
116     * provide updates on the production of the image as it happens.
117     *
118     * @param image the image the update refers to
119     * @param flags a bit mask indicating what is provided with this update
120     * @param x the x coordinate of the image
121     * @param y the y coordinate of the image
122     * @param width the width of the image
123     * @param height the height of the image
124     *
125     * @see java.awt.Image
126     */
127    boolean imageUpdate(Image image, int flags, int x,
128                                        int y, int width, int height);
129}