BitmapRegionDecoder
public
final
class
BitmapRegionDecoder
extends Object
java.lang.Object | |
↳ | android.graphics.BitmapRegionDecoder |
BitmapRegionDecoder can be used to decode a rectangle region from an image. BitmapRegionDecoder is particularly useful when an original image is large and you only need parts of the image.
To create a BitmapRegionDecoder, call newInstance(...). Given a BitmapRegionDecoder, users can call decodeRegion() repeatedly to get a decoded Bitmap of the specified region.
Summary
Public methods | |
---|---|
Bitmap
|
decodeRegion(Rect rect, BitmapFactory.Options options)
Decodes a rectangle region in the image specified by rect. |
int
|
getHeight()
Returns the original image's height |
int
|
getWidth()
Returns the original image's width |
boolean
|
isRecycled()
Returns true if this region decoder has been recycled. |
static
BitmapRegionDecoder
|
newInstance(byte[] data, int offset, int length)
Create a BitmapRegionDecoder from the specified byte array. |
static
BitmapRegionDecoder
|
newInstance(String pathName, boolean isShareable)
This method was deprecated
in API level 31.
In favor of |
static
BitmapRegionDecoder
|
newInstance(byte[] data, int offset, int length, boolean isShareable)
This method was deprecated
in API level 31.
In favor of |
static
BitmapRegionDecoder
|
newInstance(ParcelFileDescriptor pfd)
Create a BitmapRegionDecoder from the file descriptor. |
static
BitmapRegionDecoder
|
newInstance(InputStream is)
Create a BitmapRegionDecoder from an input stream. |
static
BitmapRegionDecoder
|
newInstance(InputStream is, boolean isShareable)
This method was deprecated
in API level 31.
In favor of Prior to |
static
BitmapRegionDecoder
|
newInstance(FileDescriptor fd, boolean isShareable)
This method was deprecated
in API level 31.
In favor of |
static
BitmapRegionDecoder
|
newInstance(String pathName)
Create a BitmapRegionDecoder from a file path. |
void
|
recycle()
Frees up the memory associated with this region decoder, and mark the region decoder as "dead", meaning it will throw an exception if decodeRegion(), getWidth() or getHeight() is called. |
Protected methods | |
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void
|
finalize()
Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. |
Inherited methods | |
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Public methods
decodeRegion
public Bitmap decodeRegion (Rect rect, BitmapFactory.Options options)
Decodes a rectangle region in the image specified by rect.
Parameters | |
---|---|
rect |
Rect : The rectangle that specified the region to be decode. |
options |
BitmapFactory.Options : null-ok; Options that control downsampling.
inPurgeable is not supported. |
Returns | |
---|---|
Bitmap |
The decoded bitmap, or null if the image data could not be decoded. |
Throws | |
---|---|
IllegalArgumentException |
if BitmapFactory.Options.inPreferredConfig
is Bitmap.Config.HARDWARE
and BitmapFactory.Options.inMutable is set, if the specified color space
is not RGB , or if the specified color space's transfer
function is not an ICC parametric curve |
getHeight
public int getHeight ()
Returns the original image's height
Returns | |
---|---|
int |
getWidth
public int getWidth ()
Returns the original image's width
Returns | |
---|---|
int |
isRecycled
public boolean isRecycled ()
Returns true if this region decoder has been recycled. If so, then it is an error to try use its method.
Returns | |
---|---|
boolean |
true if the region decoder has been recycled |
newInstance
public static BitmapRegionDecoder newInstance (byte[] data, int offset, int length)
Create a BitmapRegionDecoder from the specified byte array. Currently only the JPEG, PNG, WebP and HEIF formats are supported.
Parameters | |
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data |
byte : byte array of compressed image data.
This value cannot be null . |
offset |
int : offset into data for where the decoder should begin
parsing. |
length |
int : the number of bytes, beginning at offset, to parse |
Returns | |
---|---|
BitmapRegionDecoder |
This value cannot be null . |
Throws | |
---|---|
IOException |
if the image format is not supported or can not be decoded. |
newInstance
public static BitmapRegionDecoder newInstance (String pathName, boolean isShareable)
This method was deprecated
in API level 31.
In favor of newInstance(java.lang.String)
Create a BitmapRegionDecoder from a file path. Currently only the JPEG, PNG, WebP and HEIF formats are supported.
Parameters | |
---|---|
pathName |
String : complete path name for the file to be decoded.
This value cannot be null . |
isShareable |
boolean : This field has always been ignored. |
Returns | |
---|---|
BitmapRegionDecoder |
This value cannot be null . |
Throws | |
---|---|
IOException |
if the image format is not supported or can not be decoded. |
newInstance
public static BitmapRegionDecoder newInstance (byte[] data, int offset, int length, boolean isShareable)
This method was deprecated
in API level 31.
In favor of newInstance(byte[], int, int)
Create a BitmapRegionDecoder from the specified byte array. Currently only the JPEG, PNG, WebP and HEIF formats are supported.
Parameters | |
---|---|
data |
byte : byte array of compressed image data.
This value cannot be null . |
offset |
int : offset into data for where the decoder should begin
parsing. |
length |
int : the number of bytes, beginning at offset, to parse |
isShareable |
boolean : This field has been ignored since
Build.VERSION_CODES.GINGERBREAD . |
Returns | |
---|---|
BitmapRegionDecoder |
This value cannot be null . |
Throws | |
---|---|
IOException |
if the image format is not supported or can not be decoded. |
newInstance
public static BitmapRegionDecoder newInstance (ParcelFileDescriptor pfd)
Create a BitmapRegionDecoder from the file descriptor. The position within the descriptor will not be changed when this returns, so the descriptor can be used again as is. Currently only the JPEG, PNG, WebP and HEIF formats are supported.
Parameters | |
---|---|
pfd |
ParcelFileDescriptor : The parcel file descriptor containing the data to decode
This value cannot be null . |
Returns | |
---|---|
BitmapRegionDecoder |
This value cannot be null . |
Throws | |
---|---|
IOException |
if the image format is not supported or can not be decoded. |
newInstance
public static BitmapRegionDecoder newInstance (InputStream is)
Create a BitmapRegionDecoder from an input stream. The stream's position will be where ever it was after the encoded data was read. Currently only the JPEG, PNG, WebP and HEIF formats are supported.
Parameters | |
---|---|
is |
InputStream : The input stream that holds the raw data to be decoded into a
BitmapRegionDecoder.
This value cannot be null . |
Returns | |
---|---|
BitmapRegionDecoder |
A new BitmapRegionDecoder, or null if is is null . |
Throws | |
---|---|
IOException |
if the image format is not supported or can not be decoded. |
newInstance
public static BitmapRegionDecoder newInstance (InputStream is, boolean isShareable)
This method was deprecated
in API level 31.
In favor of newInstance(java.io.InputStream)
Prior to Build.VERSION_CODES.KITKAT
,
if is.markSupported()
returns true,
is.mark(1024)
would be called. As of
Build.VERSION_CODES.KITKAT
, this is no longer the case.
Create a BitmapRegionDecoder from an input stream. The stream's position will be where ever it was after the encoded data was read. Currently only the JPEG, PNG, WebP and HEIF formats are supported.
Parameters | |
---|---|
is |
InputStream : The input stream that holds the raw data to be decoded into a
BitmapRegionDecoder.
This value cannot be null . |
isShareable |
boolean : This field has always been ignored. |
Returns | |
---|---|
BitmapRegionDecoder |
A new BitmapRegionDecoder, or null if is is null . |
Throws | |
---|---|
IOException |
if the image format is not supported or can not be decoded. |
newInstance
public static BitmapRegionDecoder newInstance (FileDescriptor fd, boolean isShareable)
This method was deprecated
in API level 31.
In favor of newInstance(android.os.ParcelFileDescriptor)
Create a BitmapRegionDecoder from the file descriptor. The position within the descriptor will not be changed when this returns, so the descriptor can be used again as is. Currently only the JPEG, PNG, WebP and HEIF formats are supported.
Parameters | |
---|---|
fd |
FileDescriptor : The file descriptor containing the data to decode
This value cannot be null . |
isShareable |
boolean : This field has been ignored since
Build.VERSION_CODES.KITKAT . |
Returns | |
---|---|
BitmapRegionDecoder |
This value cannot be null . |
Throws | |
---|---|
IOException |
if the image format is not supported or can not be decoded. |
newInstance
public static BitmapRegionDecoder newInstance (String pathName)
Create a BitmapRegionDecoder from a file path. Currently only the JPEG, PNG, WebP and HEIF formats are supported.
Parameters | |
---|---|
pathName |
String : complete path name for the file to be decoded.
This value cannot be null . |
Returns | |
---|---|
BitmapRegionDecoder |
This value cannot be null . |
Throws | |
---|---|
IOException |
if the image format is not supported or can not be decoded. |
recycle
public void recycle ()
Frees up the memory associated with this region decoder, and mark the region decoder as "dead", meaning it will throw an exception if decodeRegion(), getWidth() or getHeight() is called.
This operation cannot be reversed, so it should only be called if you are sure there are no further uses for the region decoder. This is an advanced call, and normally need not be called, since the normal GC process will free up this memory when there are no more references to this region decoder.
Protected methods
finalize
protected void finalize ()
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.
Throws | |
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Throwable |