程序包 ohos.media.image

类 ImagePacker

java.lang.Object

ohos.media.image.ImagePacker

public class ImagePacker
extends Object

Represents the image packer that packs compressed images into files or other objects.

You can call create to create an image packer, initializePacking to set packing options, addImage to add image data to be packed, and finalizePacking to complete packing and output the target object.

从以下版本开始:

3

SystemCapability

SystemCapability.Multimedia#IMAGE

嵌套类概要

嵌套类

限定符和类型	类	说明
static class	ImagePacker.PackingOptions	Describes options for compressing and packing.

方法概要

限定符和类型	方法	说明
boolean	addImage(ImageSource source)	Adds the image in an ImageSource to the image packer.
boolean	addImage(ImageSource source, int index)	Adds a specified image in an ImageSource to the image packer.
boolean	addImage(PixelMap pixelmap)	Adds a PixelMap to the image packer.
static ImagePacker	create()	Creates an ImagePacker instance.
protected void	finalize()	Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
long	finalizePacking()	Completes the image packing.
static HashSet<String>	getSupportedFormats()	Obtains the supported output image formats for packing.
boolean	initializePacking(byte[] data, int offset, ImagePacker.PackingOptions opts)	Initializes the packing task that outputs the result to a byte array at a specific offset.
boolean	initializePacking(byte[] data, ImagePacker.PackingOptions opts)	Initializes the packing task that outputs the result to a byte array.
boolean	initializePacking(OutputStream outputStream, ImagePacker.PackingOptions opts)	Initializes the packing task that outputs the result to a OutputStream object.
void	release()	Releases native resources associated with the ImagePacker object.

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 ImagePacker create()

Creates an ImagePacker instance.

返回:

Returns the ImagePacker instance if created; returns null if an exception occurs.

从以下版本开始:

3

getSupportedFormats

public static HashSet<String> getSupportedFormats()

Obtains the supported output image formats for packing.

返回:

Returns the set of supported output image formats, which are represented by MIME type strings, for example, image/jpeg. Currently, only the JPEG format is supported.

从以下版本开始:

3

initializePacking

public boolean initializePacking(byte[] data,
                                 ImagePacker.PackingOptions opts)

Initializes the packing task that outputs the result to a byte array.

参数:

data - Indicates the byte array containing the packed images.

opts - Indicates the packing options.

返回:

Returns true if the packing task is successfully initialized; returns false otherwise.

抛出:

IllegalArgumentException - Throws this exception if the input parameter is invalid.

从以下版本开始:

3

initializePacking

public boolean initializePacking(byte[] data,
                                 int offset,
                                 ImagePacker.PackingOptions opts)

Initializes the packing task that outputs the result to a byte array at a specific offset.

参数:

data - Indicates the byte array containing the packed images.

offset - Indicates the data array offset into which the compressed image data will be written.

opts - Indicates the packing options.

返回:

Returns true if the packing task is successfully initialized; returns false otherwise.

抛出:

IllegalArgumentException - Throws this exception if the input parameter is invalid.

从以下版本开始:

3

initializePacking

public boolean initializePacking(OutputStream outputStream,
                                 ImagePacker.PackingOptions opts)

Initializes the packing task that outputs the result to a OutputStream object.

参数:

outputStream - Indicates the output stream of the packed images.

opts - Indicates the packing options.

返回:

Returns true if the packing task is successfully initialized; returns false otherwise.

抛出:

IllegalArgumentException - Throws this exception if the input parameter is invalid.

从以下版本开始:

3

addImage

public boolean addImage(PixelMap pixelmap)

Adds a PixelMap to the image packer.

This method adds only one PixelMap object at a time.

参数:

pixelmap - Indicates the PixelMap to be packed.

返回:

Returns true if the pixel map is added; returns false otherwise.

抛出:

IllegalArgumentException - Throws this exception if the input parameter is invalid.

从以下版本开始:

3

addImage

public boolean addImage(ImageSource source)

Adds the image in an ImageSource to the image packer.

If the ImageSource contains multiple images, only the first image will be added.

参数:

source - Indicates the ImageSource.

返回:

Returns true if the image is added; returns false otherwise.

抛出:

IllegalArgumentException - Throws this exception if the input parameter is invalid.

从以下版本开始:

3

addImage

public boolean addImage(ImageSource source,
                        int index)

Adds a specified image in an ImageSource to the image packer.

You can use an index to specify the image to be added.

参数:

source - Indicates the ImageSource.

index - Indicates the index of the target image in the ImageSource. The value starts from 0.

返回:

Returns true if the specified image is added; returns false otherwise.

抛出:

IllegalArgumentException - Throws this exception if the input parameter is invalid.

从以下版本开始:

3

finalizePacking

public long finalizePacking()

Completes the image packing.

Calling this method will inform the ImagePacker that all the required image data has been added for packing and the ImagePacker will pack the data into the specified object.

返回:

Returns the output data size (in bytes) if the operation is successful; returns -1 otherwise.

从以下版本开始:

3

release

public void release()

Releases native resources associated with the ImagePacker object.

从以下版本开始:

3

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