程序包 ohos.media.image

类 ImageReceiver

java.lang.Object

ohos.media.image.ImageReceiver

public class ImageReceiver
extends Object

Describes an image receiver that connects to an image output device and provides a buffer queue to receive image data.

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SystemCapability

SystemCapability.Multimedia#IMAGE

嵌套类概要

嵌套类

限定符和类型	类	说明
static interface	ImageReceiver.IImageArrivalListener	Callback interface used when new image data is received.

方法概要

限定符和类型	方法	说明
static ImageReceiver	create(int width, int height, int format, int capacity)	Creates an ImageReceiver instance based on a specified image width, height, format, and the buffer queue capacity.
protected void	finalize()	Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
int	getCapacity()	Obtains the maximum buffer capacity of the image receiver.
int	getImageFormat()	Obtains the image format.
Size	getImageSize()	Obtains the image size.
Surface	getRecevingSurface()	Obtains the receiver surface of the image receiver.
Image	readLatestImage()	Reads the latest image data from the buffer queue and clears earlier images from the queue.
Image	readNextImage()	Reads the next image from the buffer queue.
void	release()	Releases native resources associated with the image receiver, including the surface and obtained images.
void	setImageArrivalListener(ImageReceiver.IImageArrivalListener listener)	Sets the image listener which will be called when new image data is received.

从类继承的方法 java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

方法详细资料

create

public static ImageReceiver create(int width,
                                   int height,
                                   int format,
                                   int capacity)

Creates an ImageReceiver instance based on a specified image width, height, format, and the buffer queue capacity.

参数:

width - Indicates the image width.

height - Indicates the image height.

format - Indicates the image format, which is defined by ImageFormat.

capacity - Indicates the maximum buffer capacity of the image receiver. The value must be greater than 0.

返回:

Returns the ImageReceiver object.

抛出:

IllegalArgumentException - Throws this exception if a parameter is incorrect.

IllegalStateException - Throws this exception if the operation is not supported in the current state, for example, if native resources fail to be applied for the receiver.

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getRecevingSurface

public Surface getRecevingSurface()

Obtains the receiver surface of the image receiver.

返回:

Returns a Surface object of the image receiver.

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getImageSize

public Size getImageSize()

Obtains the image size.

返回:

Returns the image size specified in a Size object.

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getCapacity

public int getCapacity()

Obtains the maximum buffer capacity of the image receiver.

返回:

Returns the buffer size of the image receiver.

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getImageFormat

public int getImageFormat()

Obtains the image format.

返回:

Returns the image format, which is defined by ImageFormat.

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readLatestImage

public Image readLatestImage()

Reads the latest image data from the buffer queue and clears earlier images from the queue.

返回:

Returns the latest image data if obtained; returns null otherwise.

抛出:

IllegalStateException - Throws this exception if the operation is not supported in the current state, for example, if native resources associated with the receiver are released.

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readNextImage

public Image readNextImage()

Reads the next image from the buffer queue.

返回:

Returns next image data if obtained; returns null otherwise.

抛出:

IllegalStateException - Throws this exception if the operation is not supported in the current state, for example, if native resources associated with the receiver are released.

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release

public void release()

Releases native resources associated with the image receiver, including the surface and obtained images.

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finalize

protected void finalize()
                 throws Throwable

从类复制的说明: Object

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. A subclass overrides the finalize method to dispose of system resources or to perform other cleanup.

The general contract of finalize is that it is invoked if and when the Java™ virtual machine has determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, except as a result of an action taken by the finalization of some other object or class which is ready to be finalized. The finalize method may take any action, including making this object available again to other threads; the usual purpose of finalize, however, is to perform cleanup actions before the object is irrevocably discarded. For example, the finalize method for an object that represents an input/output connection might perform explicit I/O transactions to break the connection before the object is permanently discarded.

The finalize method of class Object performs no special action; it simply returns normally. Subclasses of Object may override this definition.

The Java programming language does not guarantee which thread will invoke the finalize method for any given object. It is guaranteed, however, that the thread that invokes finalize will not be holding any user-visible synchronization locks when finalize is invoked. If an uncaught exception is thrown by the finalize method, the exception is ignored and finalization of that object terminates.

After the finalize method has been invoked for an object, no further action is taken until the Java virtual machine has again determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, including possible actions by other objects or classes which are ready to be finalized, at which point the object may be discarded.

The finalize method is never invoked more than once by a Java virtual machine for any given object.

Any exception thrown by the finalize method causes the finalization of this object to be halted, but is otherwise ignored.

覆盖:

finalize 在类中 Object

抛出:

Throwable - the Exception raised by this method

另请参阅:

WeakReference, PhantomReference

setImageArrivalListener

public void setImageArrivalListener(ImageReceiver.IImageArrivalListener listener)

Sets the image listener which will be called when new image data is received.

参数:

listener - Indicates the image listener, which is defined by IImageArrivalListener.

从以下版本开始:

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