java.awt
Class Image

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

public abstract class Image
extends Object

This is the abstract superclass of all image objects in Java.

Since:
1.0

Field Summary
protected  float accelerationPriority
          The acceleration priority of the image
static int SCALE_AREA_AVERAGING
          Constant indicating that the area averaging scaling algorithm should be used.
static int SCALE_DEFAULT
          Constant indicating that the default scaling algorithm should be used.
static int SCALE_FAST
          Constant indicating that a fast scaling algorithm should be used.
static int SCALE_REPLICATE
          Constant indicating that the ReplicateScaleFilter class algorithm should be used for scaling.
static int SCALE_SMOOTH
          Constant indicating that a smooth scaling algorithm should be used.
static Object UndefinedProperty
          This variable is returned whenever a property that is not defined is requested.
 
Constructor Summary
Image()
          A default constructor for subclasses.
 
Method Summary
abstract  void flush()
          Flushes (that is, destroys) any resources used for this image.
 float getAccelerationPriority()
          Returns the acceleration priority of the image.
abstract  Graphics getGraphics()
          Returns a graphics context object for drawing an off-screen object.
abstract  int getHeight(ImageObserver observer)
          Returns the height of the image, or -1 if it is unknown.
abstract  Object getProperty(String name, ImageObserver observer)
          This method requests a named property for an object.
 Image getScaledInstance(int width, int height, int flags)
          Scales the image to the requested dimension.
abstract  ImageProducer getSource()
          Returns the image producer object for this object.
abstract  int getWidth(ImageObserver observer)
          Returns the width of the image, or -1 if it is unknown.
 void setAccelerationPriority(float priority)
          Sets the acceleration priority of the image.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

UndefinedProperty

public static final Object UndefinedProperty
This variable is returned whenever a property that is not defined is requested.


SCALE_DEFAULT

public static final int SCALE_DEFAULT
Constant indicating that the default scaling algorithm should be used.

Since:
1.1
See Also:
Constant Field Values

SCALE_FAST

public static final int SCALE_FAST
Constant indicating that a fast scaling algorithm should be used.

Since:
1.1
See Also:
Constant Field Values

SCALE_SMOOTH

public static final int SCALE_SMOOTH
Constant indicating that a smooth scaling algorithm should be used.

Since:
1.1
See Also:
Constant Field Values

SCALE_REPLICATE

public static final int SCALE_REPLICATE
Constant indicating that the ReplicateScaleFilter class algorithm should be used for scaling.

Since:
1.1
See Also:
ReplicateScaleFilter, Constant Field Values

SCALE_AREA_AVERAGING

public static final int SCALE_AREA_AVERAGING
Constant indicating that the area averaging scaling algorithm should be used.

Since:
1.1
See Also:
AreaAveragingScaleFilter, Constant Field Values

accelerationPriority

protected float accelerationPriority
The acceleration priority of the image

Since:
1.5
Constructor Detail

Image

public Image()
A default constructor for subclasses.

Method Detail

getWidth

public abstract int getWidth(ImageObserver observer)
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.

Parameters:
observer - the image observer for this object
Returns:
the width in pixels
See Also:
getHeight(ImageObserver)

getHeight

public abstract int getHeight(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.

Parameters:
observer - the image observer for this object
Returns:
the height in pixels
See Also:
getWidth(ImageObserver)

getSource

public abstract ImageProducer getSource()
Returns the image producer object for this object. The producer is the object which generates pixels for this image.

Returns:
the image producer for this object

getGraphics

public abstract Graphics getGraphics()
Returns a graphics context object for drawing an off-screen object. This method is only valid for off-screen objects.

Returns:
a graphics context object for an off-screen object

getProperty

public abstract Object getProperty(String name,
                                   ImageObserver observer)
This method requests a named property for an object. The value of the property is returned. The value UndefinedProperty is returned if there is no property with the specified name. The value null 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.

Parameters:
name - the requested property name
observer - the image observer for this object
Returns:
the named property, if available
See Also:
UndefinedProperty

getScaledInstance

public Image getScaledInstance(int width,
                               int height,
                               int flags)
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. If an illegal value of flags is passed, the default algorithm is used.

Parameters:
width - the width of the scaled image
height - the height of the scaled image
flags - a value indicating the algorithm to use
Returns:
the scaled Image object
Since:
1.1
See Also:
SCALE_DEFAULT, SCALE_FAST, SCALE_SMOOTH, SCALE_REPLICATE, SCALE_AREA_AVERAGING

flush

public abstract void flush()
Flushes (that is, destroys) any resources used for this image. This includes the actual image data.


setAccelerationPriority

public void setAccelerationPriority(float priority)
Sets the acceleration priority of the image. This is a value from 0 (lowest) to 1 (highest), which may be used as a hint for image acceleration. E.g. higher priority images may be stored in video memory.

Parameters:
priority - - the priority
Throws:
IllegalArgumentException - if priority is not >= 0 and <= 1.
Since:
1.5

getAccelerationPriority

public float getAccelerationPriority()
Returns the acceleration priority of the image.

Since:
1.5
See Also:
setAccelerationPriority(float)