| /* Image.java -- superclass for images |
| Copyright (C) 1999, 2002, 2004, 2005 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package java.awt; |
| |
| import java.awt.image.FilteredImageSource; |
| import java.awt.image.ImageObserver; |
| import java.awt.image.ImageProducer; |
| import java.awt.image.ReplicateScaleFilter; |
| |
| /** |
| * This is the abstract superclass of all image objects in Java. |
| * |
| * @author Aaron M. Renn (arenn@urbanophile.com) |
| * @since 1.0 |
| * @status updated to 1.4 |
| */ |
| public abstract class Image |
| { |
| /** |
| * This variable is returned whenever a property that is not defined |
| * is requested. |
| */ |
| // For debug purposes, this might as well be a unique string. |
| public static final Object UndefinedProperty |
| = new String("undefined property"); |
| |
| /** |
| * Constant indicating that the default scaling algorithm should be used. |
| * |
| * @since 1.1 |
| */ |
| public static final int SCALE_DEFAULT = 1; |
| |
| /** |
| * Constant indicating that a fast scaling algorithm should be used. |
| * |
| * @since 1.1 |
| */ |
| public static final int SCALE_FAST = 2; |
| |
| /** |
| * Constant indicating that a smooth scaling algorithm should be used. |
| * |
| * @since 1.1 |
| */ |
| public static final int SCALE_SMOOTH = 4; |
| |
| /** |
| * Constant indicating that the <code>ReplicateScaleFilter</code> class |
| * algorithm should be used for scaling. |
| * |
| * @see ReplicateScaleFilter |
| * @since 1.1 |
| */ |
| public static final int SCALE_REPLICATE = 8; |
| |
| /** |
| * Constant indicating that the area averaging scaling algorithm should be |
| * used. |
| * |
| * @see AreaAveragingScaleFilter |
| * @since 1.1 |
| */ |
| public static final int SCALE_AREA_AVERAGING = 16; |
| |
| /** |
| * A default constructor for subclasses. |
| */ |
| public Image() |
| { |
| } |
| |
| /** |
| * Returns the width of the image, or -1 if it is unknown. If the |
| * image width is unknown, the observer object will be notified when |
| * the value is known. |
| * |
| * @param observer the image observer for this object |
| * @return the width in pixels |
| * @see #getHeight(ImageObserver) |
| */ |
| public abstract int getWidth(ImageObserver observer); |
| |
| /** |
| * Returns the height of the image, or -1 if it is unknown. If the |
| * image height is unknown, the observer object will be notified when |
| * the value is known. |
| * |
| * @param observer the image observer for this object |
| * @return the height in pixels |
| * @see #getWidth(ImageObserver) |
| */ |
| public abstract int getHeight(ImageObserver observer); |
| |
| /** |
| * Returns the image producer object for this object. The producer is the |
| * object which generates pixels for this image. |
| * |
| * @return the image producer for this object |
| */ |
| public abstract ImageProducer getSource(); |
| |
| /** |
| * Returns a graphics context object for drawing an off-screen object. |
| * This method is only valid for off-screen objects. |
| * |
| * @return a graphics context object for an off-screen object |
| * @see Graphics#createImage(int, int) |
| */ |
| public abstract Graphics getGraphics(); |
| |
| /** |
| * This method requests a named property for an object. The value of the |
| * property is returned. The value <code>UndefinedProperty</code> is |
| * returned if there is no property with the specified name. The value |
| * <code>null</code> is returned if the properties for the object are |
| * not yet known. In this case, the specified image observer is notified |
| * when the properties are known. |
| * |
| * @param name the requested property name |
| * @param observer the image observer for this object |
| * @return the named property, if available |
| * @see #UndefinedProperty |
| */ |
| public abstract Object getProperty(String name, ImageObserver observer); |
| |
| /** |
| * Scales the image to the requested dimension. A new Image with asynchronous |
| * loading will be produced according to the hints of the algorithm |
| * requested. If either the width or height is non-positive, it is adjusted |
| * to preserve the original aspect ratio. |
| * |
| * @param width the width of the scaled image |
| * @param height the height of the scaled image |
| * @param flags a value indicating the algorithm to use |
| * @return the scaled <code>Image</code> object |
| * @see #SCALE_DEFAULT |
| * @see #SCALE_FAST |
| * @see #SCALE_SMOOTH |
| * @see #SCALE_REPLICATE |
| * @see #SCALE_AREA_AVERAGING |
| * @since 1.1 |
| */ |
| public Image getScaledInstance(int width, int height, int flags) |
| { |
| switch (flags) |
| { |
| case SCALE_DEFAULT: |
| case SCALE_FAST: |
| case SCALE_REPLICATE: |
| ImageProducer producer = |
| new FilteredImageSource(this.getSource(), |
| new ReplicateScaleFilter(width, height)); |
| return Toolkit.getDefaultToolkit().createImage(producer); |
| case SCALE_SMOOTH: |
| case SCALE_AREA_AVERAGING: |
| default: |
| throw new Error("not implemented"); |
| } |
| } |
| |
| /** |
| * Flushes (that is, destroys) any resources used for this image. This |
| * includes the actual image data. |
| */ |
| public abstract void flush(); |
| } // class Image |