/*
* @(#)ImageObserver.java 1.26 06/10/10
*
* Copyright 1990-2008 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program 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.
*
* 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 version 2 for more details (a copy is
* included at /legal/license.txt).
*
* 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 or visit www.sun.com if you need additional
* information or have any questions.
*
*/
package java.awt.image;
import java.awt.Image;
/**
* An asynchronous update interface for receiving notifications about
* Image information as the Image is constructed.
*
* @version 1.22 08/19/02
* @author Jim Graham
*/
public interface ImageObserver {
/**
* This method is called when information about an image which was
* previously requested using an asynchronous interface becomes
* available. Asynchronous interfaces are method calls such as
* getWidth(ImageObserver) and drawImage(img, x, y, ImageObserver)
* which take an ImageObserver object as an argument. Those methods
* register the caller as interested either in information about
* the overall image itself (in the case of getWidth(ImageObserver))
* or about an output version of an image (in the case of the
* drawImage(img, x, y, [w, h,] ImageObserver) call).
* <p>This method
* should return true if further updates are needed or false if the
* required information has been acquired. The image which was being
* tracked is passed in using the img argument. Various constants
* are combined to form the infoflags argument which indicates what
* information about the image is now available. The interpretation
* of the x, y, width, and height arguments depends on the contents
* of the infoflags argument.
* @see Image#getWidth
* @see Image#getHeight
* @see java.awt.Graphics#drawImage
*/
public boolean imageUpdate(Image img, int infoflags,
int x, int y, int width, int height);
/**
* The width of the base image is now available and can be taken
* from the width argument to the imageUpdate callback method.
* @see Image#getWidth
* @see #imageUpdate
*/
public static final int WIDTH = 1;
/**
* The height of the base image is now available and can be taken
* from the height argument to the imageUpdate callback method.
* @see Image#getHeight
* @see #imageUpdate
*/
public static final int HEIGHT = 2;
/**
* The properties of the image are now available.
* @see Image#getProperty
* @see #imageUpdate
*/
public static final int PROPERTIES = 4;
/**
* More pixels needed for drawing a scaled variation of the image
* are available. The bounding box of the new pixels can be taken
* from the x, y, width, and height arguments to the imageUpdate
* callback method.
* @see java.awt.Graphics#drawImage
* @see #imageUpdate
*/
public static final int SOMEBITS = 8;
/**
* Another complete frame of a multi-frame image which was previously
* drawn is now available to be drawn again. The x, y, width, and height
* arguments to the imageUpdate callback method should be ignored.
* @see java.awt.Graphics#drawImage
* @see #imageUpdate
*/
public static final int FRAMEBITS = 16;
/**
* A static image which was previously drawn is now complete and can
* be drawn again in its final form. The x, y, width, and height
* arguments to the imageUpdate callback method should be ignored.
* @see java.awt.Graphics#drawImage
* @see #imageUpdate
*/
public static final int ALLBITS = 32;
/**
* An image which was being tracked asynchronously has encountered
* an error. No further information will become available and
* drawing the image will fail.
* As a convenience, the ABORT flag will be indicated at the same
* time to indicate that the image production was aborted.
* @see #imageUpdate
*/
public static final int ERROR = 64;
/**
* An image which was being tracked asynchronously was aborted before
* production was complete. No more information will become available
* without further action to trigger another image production sequence.
* If the ERROR flag was not also set in this image update, then
* accessing any of the data in the image will restart the production
* again, probably from the beginning.
* @see #imageUpdate
*/
public static final int ABORT = 128;
}