Image (Java Platform SE 8 ) (original) (raw)

java.lang.Object
- java.awt.Image
Direct Known Subclasses:
BufferedImage, VolatileImage

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.
Since:
JDK1.0

Field Summary

Fields

Modifier and Type	Field	Description
protected float	accelerationPriority	Priority for accelerating this image.
static int	SCALE_AREA_AVERAGING	Use the Area Averaging image scaling algorithm.
static int	SCALE_DEFAULT	Use the default image-scaling algorithm.
static int	SCALE_FAST	Choose an image-scaling algorithm that gives higher priority to scaling speed than smoothness of the scaled image.
static int	SCALE_REPLICATE	Use the image scaling algorithm embodied in theReplicateScaleFilter class.
static int	SCALE_SMOOTH	Choose an image-scaling algorithm that gives higher priority to image smoothness than scaling speed.
static Object	UndefinedProperty	The UndefinedProperty object should be returned whenever a property which was not defined for a particular image is fetched.

Constructor Summary

Constructors

Constructor	Description
Image()

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods

Modifier and Type	Method	Description
void	flush()	Flushes all reconstructable resources being used by this Image object.
float	getAccelerationPriority()	Returns the current value of the acceleration priority hint.
ImageCapabilities	getCapabilities(GraphicsConfiguration gc)	Returns an ImageCapabilities object which can be inquired as to the capabilities of this Image on the specified GraphicsConfiguration.
abstract Graphics	getGraphics()	Creates a graphics context for drawing to an off-screen image.
abstract int	getHeight(ImageObserver observer)	Determines the height of the image.
abstract Object	getProperty(String name,ImageObserver observer)	Gets a property of this image by name.
Image	getScaledInstance(int width, int height, int hints)	Creates a scaled version of this image.
abstract ImageProducer	getSource()	Gets the object that produces the pixels for the image.
abstract int	getWidth(ImageObserver observer)	Determines the width of the image.
void	setAccelerationPriority(float priority)	Sets a hint for this image about how important acceleration is.

   * ### Methods inherited from class java.lang.[Object](../../java/lang/Object.html "class in java.lang")  
   `[clone](../../java/lang/Object.html#clone--), [equals](../../java/lang/Object.html#equals-java.lang.Object-), [finalize](../../java/lang/Object.html#finalize--), [getClass](../../java/lang/Object.html#getClass--), [hashCode](../../java/lang/Object.html#hashCode--), [notify](../../java/lang/Object.html#notify--), [notifyAll](../../java/lang/Object.html#notifyAll--), [toString](../../java/lang/Object.html#toString--), [wait](../../java/lang/Object.html#wait--), [wait](../../java/lang/Object.html#wait-long-), [wait](../../java/lang/Object.html#wait-long-int-)`

Field Detail

 * #### accelerationPriority  
 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.  
 Since:  
 1.5  
 * #### UndefinedProperty  
 public static final [Object](../../java/lang/Object.html "class in java.lang") UndefinedProperty  
 The `UndefinedProperty` object should be returned whenever a property which was not defined for a particular image is fetched.  
 * #### SCALE\_DEFAULT  
 public static final int SCALE_DEFAULT  
 Use the default image-scaling algorithm.  
 Since:  
 JDK1.1  
 See Also:  
 [Constant Field Values](../../constant-values.html#java.awt.Image.SCALE%5FDEFAULT)  
 * #### SCALE\_FAST  
 public static final int SCALE_FAST  
 Choose an image-scaling algorithm that gives higher priority to scaling speed than smoothness of the scaled image.  
 Since:  
 JDK1.1  
 See Also:  
 [Constant Field Values](../../constant-values.html#java.awt.Image.SCALE%5FFAST)  
 * #### SCALE\_SMOOTH  
 public static final int SCALE_SMOOTH  
 Choose an image-scaling algorithm that gives higher priority to image smoothness than scaling speed.  
 Since:  
 JDK1.1  
 See Also:  
 [Constant Field Values](../../constant-values.html#java.awt.Image.SCALE%5FSMOOTH)  
 * #### SCALE\_REPLICATE  
 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.  
 Since:  
 JDK1.1  
 See Also:  
 [ReplicateScaleFilter](../../java/awt/image/ReplicateScaleFilter.html "class in java.awt.image"), [Constant Field Values](../../constant-values.html#java.awt.Image.SCALE%5FREPLICATE)  
 * #### SCALE\_AREA\_AVERAGING  
 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.  
 Since:  
 JDK1.1  
 See Also:  
 [AreaAveragingScaleFilter](../../java/awt/image/AreaAveragingScaleFilter.html "class in java.awt.image"), [Constant Field Values](../../constant-values.html#java.awt.Image.SCALE%5FAREA%5FAVERAGING)

Constructor Detail
```
* #### Image  
public Image()  
```

Method Detail

* #### getWidth  
public abstract int getWidth([ImageObserver](../../java/awt/image/ImageObserver.html "interface in java.awt.image") 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.  
Parameters:  
`observer` \- an object waiting for the image to be loaded.  
Returns:  
the width of this image, or `-1` if the width is not yet known.  
See Also:  
[getHeight(java.awt.image.ImageObserver)](../../java/awt/Image.html#getHeight-java.awt.image.ImageObserver-), [ImageObserver](../../java/awt/image/ImageObserver.html "interface in java.awt.image")  
* #### getHeight  
public abstract int getHeight([ImageObserver](../../java/awt/image/ImageObserver.html "interface in java.awt.image") 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.  
Parameters:  
`observer` \- an object waiting for the image to be loaded.  
Returns:  
the height of this image, or `-1` if the height is not yet known.  
See Also:  
[getWidth(java.awt.image.ImageObserver)](../../java/awt/Image.html#getWidth-java.awt.image.ImageObserver-), [ImageObserver](../../java/awt/image/ImageObserver.html "interface in java.awt.image")  
* #### getSource  
public abstract [ImageProducer](../../java/awt/image/ImageProducer.html "interface in java.awt.image") 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.  
Returns:  
the image producer that produces the pixels for this image.  
See Also:  
[ImageProducer](../../java/awt/image/ImageProducer.html "interface in java.awt.image")  
* #### getGraphics  
public abstract [Graphics](../../java/awt/Graphics.html "class in java.awt") getGraphics()  
Creates a graphics context for drawing to an off-screen image. This method can only be called for off-screen images.  
Returns:  
a graphics context to draw to the off-screen image.  
Throws:  
`[UnsupportedOperationException](../../java/lang/UnsupportedOperationException.html "class in java.lang")` \- if called for a non-off-screen image.  
See Also:  
[Graphics](../../java/awt/Graphics.html "class in java.awt"), [Component.createImage(int, int)](../../java/awt/Component.html#createImage-int-int-)  
* #### getProperty  
public abstract [Object](../../java/lang/Object.html "class in java.lang") getProperty([String](../../java/lang/String.html "class in java.lang") name,  
                                   [ImageObserver](../../java/awt/image/ImageObserver.html "interface in java.awt.image") 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.  
Parameters:  
`name` \- a property name.  
`observer` \- an object waiting for this image to be loaded.  
Returns:  
the value of the named property.  
Throws:  
`[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if the property name is null.  
See Also:  
[ImageObserver](../../java/awt/image/ImageObserver.html "interface in java.awt.image"), [UndefinedProperty](../../java/awt/Image.html#UndefinedProperty)  
* #### getScaledInstance  
public [Image](../../java/awt/Image.html "class in java.awt") 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.  
Parameters:  
`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.  
Returns:  
a scaled version of the image.  
Throws:  
`[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang")` \- if `width` or `height` is zero.  
Since:  
JDK1.1  
See Also:  
[SCALE\_DEFAULT](../../java/awt/Image.html#SCALE%5FDEFAULT), [SCALE\_FAST](../../java/awt/Image.html#SCALE%5FFAST), [SCALE\_SMOOTH](../../java/awt/Image.html#SCALE%5FSMOOTH), [SCALE\_REPLICATE](../../java/awt/Image.html#SCALE%5FREPLICATE), [SCALE\_AREA\_AVERAGING](../../java/awt/Image.html#SCALE%5FAREA%5FAVERAGING)  
* #### flush  
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:  
         * BufferedImage objects leave the primary Raster which stores their pixels untouched, but flush any information cached about those pixels such as copies uploaded to the display hardware for accelerated blits.  
         * Image objects created by the Component methods which take a width and height leave their primary buffer of pixels untouched, but have all cached information released much like is done for BufferedImage objects.  
         * VolatileImage objects release all of their pixel resources including their primary copy which is typically stored on the display hardware where resources are scarce. These objects can later be restored using their[validate](../../java/awt/image/VolatileImage.html#validate-java.awt.GraphicsConfiguration-) method.  
         * Image objects created by the Toolkit and Component classes which are loaded from files, URLs or produced by an [ImageProducer](../../java/awt/image/ImageProducer.html "interface in java.awt.image") 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.  
* #### getCapabilities  
public [ImageCapabilities](../../java/awt/ImageCapabilities.html "class in java.awt") getCapabilities([GraphicsConfiguration](../../java/awt/GraphicsConfiguration.html "class in java.awt") 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.  
Parameters:  
`gc` \- a `GraphicsConfiguration` object. A value of null for this parameter will result in getting the image capabilities for the default `GraphicsConfiguration`.  
Returns:  
an `ImageCapabilities` object that contains the capabilities of this `Image` on the specified GraphicsConfiguration.  
Since:  
1.5  
See Also:  
[VolatileImage.getCapabilities()](../../java/awt/image/VolatileImage.html#getCapabilities--)  
* #### setAccelerationPriority  
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.  
Parameters:  
`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](../../java/lang/IllegalArgumentException.html "class in java.lang")` \- if `priority` is less than zero or greater than 1.  
Since:  
1.5  
* #### getAccelerationPriority  
public float getAccelerationPriority()  
Returns the current value of the acceleration priority hint.  
Returns:  
value between 0 and 1, inclusive, which represents the current priority value  
Since:  
1.5  
See Also:  
[setAccelerationPriority](../../java/awt/Image.html#setAccelerationPriority-float-)

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Image (Java Platform SE 8 ) (original) (raw)

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail