/* * Copyright (c) 1995, 1999, Oracle and/or its affiliates. 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. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.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. * * @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). * *

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. *

* The infoflags argument should be the bitwise inclusive * OR of the following flags: WIDTH, * HEIGHT, PROPERTIES, SOMEBITS, * FRAMEBITS, ALLBITS, ERROR, * ABORT. * * @param img the image being observed. * @param infoflags the bitwise inclusive OR of the following * flags: WIDTH, HEIGHT, * PROPERTIES, SOMEBITS, * FRAMEBITS, ALLBITS, * ERROR, ABORT. * @param x the x coordinate. * @param y the y coordinate. * @param width the width. * @param height the height. * @return false if the infoflags indicate that the * image is completely loaded; true otherwise. * * @see #WIDTH * @see #HEIGHT * @see #PROPERTIES * @see #SOMEBITS * @see #FRAMEBITS * @see #ALLBITS * @see #ERROR * @see #ABORT * @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); /** * This flag in the infoflags argument to imageUpdate indicates that * 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; /** * This flag in the infoflags argument to imageUpdate indicates that * 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; /** * This flag in the infoflags argument to imageUpdate indicates that * the properties of the image are now available. * @see Image#getProperty * @see #imageUpdate */ public static final int PROPERTIES = 4; /** * This flag in the infoflags argument to imageUpdate indicates that * 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; /** * This flag in the infoflags argument to imageUpdate indicates that * 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; /** * This flag in the infoflags argument to imageUpdate indicates that * 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; /** * This flag in the infoflags argument to imageUpdate indicates that * 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; /** * This flag in the infoflags argument to imageUpdate indicates that * 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; }