public abstract class Image extends Object
The abstract class Image is the superclass of all classes that represent graphical images. The image must be obtained in a platform-specific manner.
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.
ReplicateScaleFilter, Constant Field Valuespublic 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.
AreaAveragingScaleFilter, Constant Field Valuespublic Image()
public abstract int getWidth(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.
observer - an object waiting for the image to be loaded.-1 if the width is not yet known.getHeight(java.awt.image.ImageObserver), ImageObserver
public abstract int getHeight(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.
observer - an object waiting for the image to be loaded.-1 if the height is not yet known.getWidth(java.awt.image.ImageObserver), ImageObserver
public abstract 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.
ImageProducerpublic abstract Graphics getGraphics()
Creates a graphics context for drawing to an off-screen image. This method can only be called for off-screen images.
UnsupportedOperationException - if called for a non-off-screen image.Graphics, Component.createImage(int, int)
public abstract Object getProperty(String name,
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.
name - a property name.observer - an object waiting for this image to be loaded.NullPointerException - if the property name is null.ImageObserver, UndefinedProperty
public 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.
width - the width to which to scale the image.height - the height to which to scale the image.hints - flags to indicate the type of algorithm to use for image resampling.IllegalArgumentException - if width or height is zero.SCALE_DEFAULT, SCALE_FAST, SCALE_SMOOTH, SCALE_REPLICATE, SCALE_AREA_AVERAGING
public void flush()
Flushes all reconstructable 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 if they can be recreated. 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.
Examples of how this method affects specific types of Image object:
validate method. ImageProducer are unloaded and all local resources are released. These objects can later be reloaded from their original source as needed when they are rendered, just as when they were first created. public ImageCapabilities getCapabilities(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 does not have that capability on this GraphicsConfiguration.
gc - a GraphicsConfiguration object. A value of null for this parameter will result in getting the image capabilities for the default GraphicsConfiguration.ImageCapabilities object that contains the capabilities of this Image on the specified GraphicsConfiguration.VolatileImage.getCapabilities()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-accelerating 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.
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.IllegalArgumentException - if priority is less than zero or greater than 1.public float getAccelerationPriority()
Returns the current value of the acceleration priority hint.
setAccelerationPriority
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