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Modifier and Type |
Method and Description |
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flush |
void flush()
Flushes all reconstructable resources being used by this Image object.
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
method.
-
Image objects created by the Toolkit and Component classes which are
loaded from files, URLs or produced by an
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.
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|
getAccelerationPriority |
float getAccelerationPriority()
Returns the current value of the acceleration priority hint.
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
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|
getCapabilities |
Returns an ImageCapabilities object which can be
inquired as to the capabilities of this
Image on the specified GraphicsConfiguration.
-
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()
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|
getGraphics |
Creates a graphics context for drawing to an off-screen image.
-
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:
java.lang.UnsupportedOperationException - if called for a
non-off-screen image.- See Also:
Graphics ,
Component.createImage(int, int)
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|
getHeight |
abstract int getHeight(java.awt.image.ImageObserver observer)
Determines the height of the image.
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.
- 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) ,
ImageObserver
|
|
getProperty |
abstract java.lang.Object getProperty(java.lang.String name,
java.awt.image.ImageObserver observer)
Gets a property of this image by name.
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.
- Parameters:
name - a property name.observer - an object waiting for this image to be loaded.
- Returns:
- the value of the named property.
- Throws:
NullPointerException - if the property name is null.- See Also:
ImageObserver ,
UndefinedProperty
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|
getScaledInstance |
Image getScaledInstance(int width,
int height,
int hints)
Creates a scaled version of this image.
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.
- 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:
java.lang.IllegalArgumentException - if width
or height is zero.- Since:
- JDK1.1
- See Also:
SCALE_DEFAULT ,
SCALE_FAST ,
SCALE_SMOOTH ,
SCALE_REPLICATE ,
SCALE_AREA_AVERAGING
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|
getSource |
abstract java.awt.image.ImageProducer getSource()
Gets the object that produces the pixels for the image.
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.
- Returns:
- the image producer that produces the pixels
for this image.
- See Also:
ImageProducer
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|
getWidth |
abstract int getWidth(java.awt.image.ImageObserver observer)
Determines the width of the image.
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.
- 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) ,
ImageObserver
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|
setAccelerationPriority |
void setAccelerationPriority(float priority)
Sets a hint for this image about how important acceleration is.
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:
java.lang.IllegalArgumentException - if priority is less
than zero or greater than 1.- Since:
- 1.5
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