File	Doc	Category	Size	Date	Package
Image.java	API Doc	Java SE 5 API	12082	Fri Aug 26 14:56:46 BST 2005	java.awt

Image

• java.lang.Object

Fields Summary
private static ImageCapabilities	defaultImageCaps convenience object; we can use this single static object for all images that do not create their own image caps; it holds the default (unaccelerated) properties.
protected float	accelerationPriority Priority for accelerating this image. Subclasses are free to set different default priorities and applications are free to set the priority for specific images via the setAccelerationPriority(float) method.
public static final Object	UndefinedProperty The UndefinedProperty object should be returned whenever a property which was not defined for a particular image is fetched.
public static final int	SCALE_DEFAULT Use the default image-scaling algorithm.
public static final int	SCALE_FAST Choose an image-scaling algorithm that gives higher priority to scaling speed than smoothness of the scaled image.
public static final int	SCALE_SMOOTH Choose an image-scaling algorithm that gives higher priority to image smoothness than scaling speed.
public static final int	SCALE_REPLICATE Use the image scaling algorithm embodied in the ReplicateScaleFilter class. The Image 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.
public static final int	SCALE_AREA_AVERAGING 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.

Constructors Summary

Methods Summary
public abstract void	flush() 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. This method always leaves the image in a state such that it can be reconstructed. This means the method applies only to cached or other secondary representations of images such as those that have been generated from an ImageProducer (read from a file, for example). It does nothing for off-screen images that have only one copy of their data.
public float	getAccelerationPriority() Returns the current value of the acceleration priority hint. see #setAccelerationPriority(float priority) setAccelerationPriority return value between 0 and 1, inclusive, which represents the current priority value since 1.5 return accelerationPriority;
public java.awt.ImageCapabilities	getCapabilities(java.awt.GraphicsConfiguration gc) Returns an ImageCapabilities object which can be inquired as to the capabilities of this Image on the specified GraphicsConfiguration. This allows programmers to find out more runtime information on the specific Image object that they have created. For example, the user might create a BufferedImage but the system may have no video memory left for creating an image of that size on the given GraphicsConfiguration, so although the object may be acceleratable in general, it is does not have that capability on this GraphicsConfiguration. param gc a GraphicsConfiguration object. A value of null for this parameter will result in getting the image capabilities for the default GraphicsConfiguration. return an ImageCapabilities object that contains the capabilities of this Image on the specified GraphicsConfiguration. see #java.awt.image.VolatileImage.getCapabilities() VolatileImage.getCapabilities() since 1.5 // Note: this is just a default object that gets returned by the // base Image object. Subclasses of Image should override this // method and return an ImageCapabilities object that is appropriate // for a given instance of that subclass. return defaultImageCaps;
public abstract java.awt.Graphics	getGraphics() 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. exception UnsupportedOperationException if called for a non-off-screen image. see java.awt.Graphics see java.awt.Component#createImage(int, int)
public abstract int	getHeight(java.awt.image.ImageObserver observer) Determines the height of the image. If the height is not yet known, this method returns -1 and the specified ImageObserver object is notified later. param observer an object waiting for the image to be loaded. return the height of this image, or -1 if the height is not yet known. see java.awt.Image#getWidth see java.awt.image.ImageObserver
public abstract java.lang.Object	getProperty(java.lang.String name, java.awt.image.ImageObserver observer) Gets a property of this image by name. Individual property names are defined by the various image formats. If a property is not defined for a particular image, this method returns the UndefinedProperty object. If the properties for this image are not yet known, this method returns null, and the ImageObserver object is notified later. The property name "comment" 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. throws NullPointerException if the property name is null. see java.awt.image.ImageObserver see java.awt.Image#UndefinedProperty
public java.awt.Image	getScaledInstance(int width, int height, int hints) Creates a scaled version of this image. A new Image object is returned which will render the image at the specified width and height by default. The new Image object may be loaded asynchronously even if the original source image has already been loaded completely. If either width or height is a negative number then a value is substituted to maintain the aspect ratio of the original image dimensions. If both width and height are negative, then the original image dimensions are used. 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. exception IllegalArgumentException if width or height is zero. 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 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);
public abstract java.awt.image.ImageProducer	getSource() 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 int	getWidth(java.awt.image.ImageObserver observer) Determines the width of the image. If the width is not yet known, this method returns -1 and the specified ImageObserver object is notified later. param observer an object waiting for the image to be loaded. return the width of this image, or -1 if the width is not yet known. see java.awt.Image#getHeight see java.awt.image.ImageObserver
public void	setAccelerationPriority(float priority) Sets a hint for this image about how important acceleration is. This priority hint is used to compare to the priorities of other Image objects when determining how to use scarce acceleration resources such as video memory. When and if it is possible to accelerate this Image, if there are not enough resources available to provide that acceleration but enough can be freed up by de-acceleration some other image of lower priority, then that other Image may be de-accelerated in deference to this one. Images that have the same priority take up resources on a first-come, first-served basis. param priority a value between 0 and 1, inclusive, where higher values indicate more importance for acceleration. A value of 0 means that this Image should never be accelerated. Other values are used simply to determine acceleration priority relative to other Images. throws IllegalArgumentException if priority is less than zero or greater than 1. since 1.5 if (priority < 0 || priority > 1) { throw new IllegalArgumentException("Priority must be a value " + "between 0 and 1, inclusive"); } accelerationPriority = priority;