/*
* @(#)Image.java 1.35 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;
import java.awt.image.ImageProducer;
import java.awt.image.ImageObserver;
import java.awt.image.ImageFilter;
import java.awt.image.FilteredImageSource;
import java.awt.image.AreaAveragingScaleFilter;
import java.awt.image.ReplicateScaleFilter;
/**
* The abstract class <code>Image</code> is the superclass of all
* classes that represent graphical images. The image must be
* obtained in a platform-specific manner.
* <h3>Compatibility</h3>
* The Image class in Personal Java supported GIF(CompuServ 89a),
* JPEG(JFIF), and XBM(X Bitmap). In addition to these, Personal
* Profile supports the PNG image file format. Images are created using
* the <code>Toolkit.createImage()</code> method or by an imageProducer.
*
* @version 1.31, 08/19/02
* @author Sami Shaio
* @author Arthur van Hoff
* @see java.awt.Toolkit#createImage
* @since JDK1.0
*/
public abstract class Image {
/**
* Determines the width of the image. If the width is not yet known,
* this method returns <code>-1</code> and the specified
* <code>ImageObserver</code> object is notified later.
* @param observer an object waiting for the image to be loaded.
* @return the width of this image, or <code>-1</code>
* if the width is not yet known.
* @see java.awt.Image#getHeight
* @see java.awt.image.ImageObserver
* @since JDK1.0
*/
public abstract int getWidth(ImageObserver observer);
/**
* Determines the height of the image. If the height is not yet known,
* this method returns <code>-1</code> and the specified
* <code>ImageObserver</code> object is notified later.
* @param observer an object waiting for the image to be loaded.
* @return the height of this image, or <code>-1</code>
* if the height is not yet known.
* @see java.awt.Image#getWidth
* @see java.awt.image.ImageObserver
* @since JDK1.0
*/
public abstract int getHeight(ImageObserver observer);
/**
* Gets the object that produces the pixels for the image.
* This method is called by the image filtering classes and by
* methods that perform image conversion and scaling.
* @return the image producer that produces the pixels
* for this image.
* @see java.awt.image.ImageProducer
*/
public abstract ImageProducer getSource();
/**
* Creates a graphics context for drawing to an off-screen image.
* This method can only be called for off-screen images.
* @return a graphics context to draw to the off-screen image.
* @see java.awt.Graphics
* @see java.awt.Component#createImage(int, int)
* @since JDK1.0
*/
public abstract Graphics getGraphics();
/**
* Gets a property of this image by name.
* <p>
* Individual property names are defined by the various image
* formats. If a property is not defined for a particular image, this
* method returns the <code>UndefinedProperty</code> object.
* <p>
* If the properties for this image are not yet known, this method
* returns <code>null</code>, and the <code>ImageObserver</code>
* object is notified later.
* <p>
* The property name <code>"comment"</code> should be used to store
* an optional comment which can be presented to the application as a
* description of the image, its source, or its author.
* @param name a property name.
* @param observer an object waiting for this image to be loaded.
* @return the value of the named property.
* @see java.awt.image.ImageObserver
* @see java.awt.Image#UndefinedProperty
* @since JDK1.0
*/
public abstract Object getProperty(String name, ImageObserver observer);
/**
* The <code>UndefinedProperty</code> object should be returned whenever a
* property which was not defined for a particular image is fetched.
* @since JDK1.0
*/
public static final Object UndefinedProperty = new Object();
/**
* Creates a scaled version of this image.
* A new <code>Image</code> object is returned which will render
* the image at the specified <code>width</code> and
* <code>height</code> by default. The new <code>Image</code> object
* may be loaded asynchronously even if the original source image
* has already been loaded completely. If either the <code>width</code>
* or <code>height</code> is a negative number then a value is
* substituted to maintain the aspect ratio of the original image
* dimensions.
* @param width the width to which to scale the image.
* @param height the height to which to scale the image.
* @param hints flags to indicate the type of algorithm to use
* for image resampling.
* @return a scaled version of the image.
* @see java.awt.Image#SCALE_DEFAULT
* @see java.awt.Image#SCALE_FAST
* @see java.awt.Image#SCALE_SMOOTH
* @see java.awt.Image#SCALE_REPLICATE
* @see java.awt.Image#SCALE_AREA_AVERAGING
* @since JDK1.1
*/
public Image getScaledInstance(int width, int height, int hints) {
ImageFilter filter;
if ((hints & (SCALE_SMOOTH | SCALE_AREA_AVERAGING)) != 0) {
filter = new AreaAveragingScaleFilter(width, height);
} else {
filter = new ReplicateScaleFilter(width, height);
}
ImageProducer prod;
prod = new FilteredImageSource(getSource(), filter);
return Toolkit.getDefaultToolkit().createImage(prod);
}
/**
* Use the default image-scaling algorithm.
* @since JDK1.1
*/
public static final int SCALE_DEFAULT = 1;
/**
* Choose an image-scaling algorithm that gives higher priority
* to scaling speed than smoothness of the scaled image.
* @since JDK1.1
*/
public static final int SCALE_FAST = 2;
/**
* Choose an image-scaling algorithm that gives higher priority
* to image smoothness than scaling speed.
* @since JDK1.1
*/
public static final int SCALE_SMOOTH = 4;
/**
* Use the image scaling algorithm embodied in the
* <code>ReplicateScaleFilter</code> class.
* The <code>Image</code> object is free to substitute a different filter
* that performs the same algorithm yet integrates more efficiently
* into the imaging infrastructure supplied by the toolkit.
* @see java.awt.image.ReplicateScaleFilter
* @since JDK1.1
*/
public static final int SCALE_REPLICATE = 8;
/**
* Use the Area Averaging image scaling algorithm. The
* image object is free to substitute a different filter that
* performs the same algorithm yet integrates more efficiently
* into the image infrastructure supplied by the toolkit.
* @see java.awt.image.AreaAveragingScaleFilter
* @since JDK1.1
*/
public static final int SCALE_AREA_AVERAGING = 16;
/**
* Flushes all resources being used by this Image object. This
* includes any pixel data that is being cached for rendering to
* the screen as well as any system resources that are being used
* to store data or pixels for the image. The image is reset to
* a state similar to when it was first created so that if it is
* again rendered, the image data will have to be recreated or
* fetched again from its source.
* @since JDK1.0
*/
public abstract void flush();
}