- All Implemented Interfaces:
RegisterableService
ImageWriter
s.
For more information on service provider classes, see the class comment
for the IIORegistry
class.
Each ImageWriterSpi
provides several types of information
about the ImageWriter
class with which it is associated.
The name of the vendor who defined the SPI class and a
brief description of the class are available via the
getVendorName
, getDescription
,
and getVersion
methods.
These methods may be internationalized to provide locale-specific
output. These methods are intended mainly to provide short,
human-writable information that might be used to organize a pop-up
menu or other list.
Lists of format names, file suffixes, and MIME types associated
with the service may be obtained by means of the
getFormatNames
, getFileSuffixes
, and
getMIMEType
methods. These methods may be used to
identify candidate ImageWriter
s for writing a
particular file or stream based on manual format selection, file
naming, or MIME associations.
A more reliable way to determine which ImageWriter
s
are likely to be able to parse a particular data stream is provided
by the canEncodeImage
method. This methods allows the
service provider to inspect the actual image contents.
Finally, an instance of the ImageWriter
class
associated with this service provider may be obtained by calling
the createWriterInstance
method. Any heavyweight
initialization, such as the loading of native libraries or creation
of large tables, should be deferred at least until the first
invocation of this method.
- See Also:
-
Field Summary
Modifier and TypeFieldDescriptionprotected Class<?>[]
An array ofClass
objects to be returned fromgetOutputTypes
, initiallynull
.protected String[]
An array of strings to be returned fromgetImageReaderSpiNames
, initiallynull
.static final Class<?>[]
Deprecated.Fields declared in class javax.imageio.spi.ImageReaderWriterSpi
extraImageMetadataFormatClassNames, extraImageMetadataFormatNames, extraStreamMetadataFormatClassNames, extraStreamMetadataFormatNames, MIMETypes, names, nativeImageMetadataFormatClassName, nativeImageMetadataFormatName, nativeStreamMetadataFormatClassName, nativeStreamMetadataFormatName, pluginClassName, suffixes, supportsStandardImageMetadataFormat, supportsStandardStreamMetadataFormat
Fields declared in class javax.imageio.spi.IIOServiceProvider
vendorName, version
-
Constructor Summary
ModifierConstructorDescriptionprotected
Constructs a blankImageWriterSpi
.ImageWriterSpi
(String vendorName, String version, String[] names, String[] suffixes, String[] MIMETypes, String writerClassName, Class<?>[] outputTypes, String[] readerSpiNames, boolean supportsStandardStreamMetadataFormat, String nativeStreamMetadataFormatName, String nativeStreamMetadataFormatClassName, String[] extraStreamMetadataFormatNames, String[] extraStreamMetadataFormatClassNames, boolean supportsStandardImageMetadataFormat, String nativeImageMetadataFormatName, String nativeImageMetadataFormatClassName, String[] extraImageMetadataFormatNames, String[] extraImageMetadataFormatClassNames) Constructs anImageWriterSpi
with a given set of values. -
Method Summary
Modifier and TypeMethodDescriptionboolean
Returnstrue
if theImageWriter
implementation associated with this service provider is able to encode the givenRenderedImage
instance.abstract boolean
Returnstrue
if theImageWriter
implementation associated with this service provider is able to encode an image with the given layout.Returns an instance of theImageWriter
implementation associated with this service provider.abstract ImageWriter
createWriterInstance
(Object extension) Returns an instance of theImageWriter
implementation associated with this service provider.String[]
Returns an array ofString
s containing all the fully qualified names of all theImageReaderSpi
classes that can understand the internal metadata representation used by theImageWriter
associated with this service provider, ornull
if there are no suchImageReaders
specified.Class<?>[]
Returns an array ofClass
objects indicating what types of objects may be used as arguments to the writer'ssetOutput
method.boolean
Returnstrue
if the format that this writer outputs preserves pixel data bit-accurately.boolean
isOwnWriter
(ImageWriter writer) Returnstrue
if theImageWriter
object passed in is an instance of theImageWriter
associated with this service provider.Methods declared in class javax.imageio.spi.ImageReaderWriterSpi
getExtraImageMetadataFormatNames, getExtraStreamMetadataFormatNames, getFileSuffixes, getFormatNames, getImageMetadataFormat, getMIMETypes, getNativeImageMetadataFormatName, getNativeStreamMetadataFormatName, getPluginClassName, getStreamMetadataFormat, isStandardImageMetadataFormatSupported, isStandardStreamMetadataFormatSupported
Methods declared in class javax.imageio.spi.IIOServiceProvider
getDescription, getVendorName, getVersion, onDeregistration, onRegistration
-
Field Details
-
STANDARD_OUTPUT_TYPE
Deprecated.Instead of using this field, directly create the equivalent array{ ImageOutputStream.class }
.A single-element array, initially containingImageOutputStream.class
, to be returned fromgetOutputTypes
. -
outputTypes
An array ofClass
objects to be returned fromgetOutputTypes
, initiallynull
. -
readerSpiNames
An array of strings to be returned fromgetImageReaderSpiNames
, initiallynull
.
-
-
Constructor Details
-
ImageWriterSpi
protected ImageWriterSpi()Constructs a blankImageWriterSpi
. It is up to the subclass to initialize instance variables and/or override method implementations in order to provide working versions of all methods. -
ImageWriterSpi
public ImageWriterSpi(String vendorName, String version, String[] names, String[] suffixes, String[] MIMETypes, String writerClassName, Class<?>[] outputTypes, String[] readerSpiNames, boolean supportsStandardStreamMetadataFormat, String nativeStreamMetadataFormatName, String nativeStreamMetadataFormatClassName, String[] extraStreamMetadataFormatNames, String[] extraStreamMetadataFormatClassNames, boolean supportsStandardImageMetadataFormat, String nativeImageMetadataFormatName, String nativeImageMetadataFormatClassName, String[] extraImageMetadataFormatNames, String[] extraImageMetadataFormatClassNames) Constructs anImageWriterSpi
with a given set of values.- Parameters:
vendorName
- the vendor name, as a non-null
String
.version
- a version identifier, as a non-null
String
.names
- a non-null
array ofString
s indicating the format names. At least one entry must be present.suffixes
- an array ofString
s indicating the common file suffixes. If no suffixes are defined,null
should be supplied. An array of length 0 will be normalized tonull
.MIMETypes
- an array ofString
s indicating the format's MIME types. If no suffixes are defined,null
should be supplied. An array of length 0 will be normalized tonull
.writerClassName
- the fully-qualified name of the associatedImageWriterSpi
class, as a non-null String
.outputTypes
- an array ofClass
objects of length at least 1 indicating the legal output types.readerSpiNames
- an arrayString
s of length at least 1 naming the classes of all associatedImageReader
s, ornull
. An array of length 0 is normalized tonull
.supportsStandardStreamMetadataFormat
- aboolean
that indicates whether a stream metadata object can use trees described by the standard metadata format.nativeStreamMetadataFormatName
- aString
, ornull
, to be returned fromgetNativeStreamMetadataFormatName
.nativeStreamMetadataFormatClassName
- aString
, ornull
, to be used to instantiate a metadata format object to be returned fromgetNativeStreamMetadataFormat
.extraStreamMetadataFormatNames
- an array ofString
s, ornull
, to be returned fromgetExtraStreamMetadataFormatNames
. An array of length 0 is normalized tonull
.extraStreamMetadataFormatClassNames
- an array ofString
s, ornull
, to be used to instantiate a metadata format object to be returned fromgetStreamMetadataFormat
. An array of length 0 is normalized tonull
.supportsStandardImageMetadataFormat
- aboolean
that indicates whether an image metadata object can use trees described by the standard metadata format.nativeImageMetadataFormatName
- aString
, ornull
, to be returned fromgetNativeImageMetadataFormatName
.nativeImageMetadataFormatClassName
- aString
, ornull
, to be used to instantiate a metadata format object to be returned fromgetNativeImageMetadataFormat
.extraImageMetadataFormatNames
- an array ofString
s to be returned fromgetExtraImageMetadataFormatNames
. An array of length 0 is normalized tonull
.extraImageMetadataFormatClassNames
- an array ofString
s, ornull
, to be used to instantiate a metadata format object to be returned fromgetImageMetadataFormat
. An array of length 0 is normalized tonull
.- Throws:
IllegalArgumentException
- ifvendorName
isnull
.IllegalArgumentException
- ifversion
isnull
.IllegalArgumentException
- ifnames
isnull
or has length 0.IllegalArgumentException
- ifwriterClassName
isnull
.IllegalArgumentException
- ifoutputTypes
isnull
or has length 0.
-
-
Method Details
-
isFormatLossless
public boolean isFormatLossless()Returnstrue
if the format that this writer outputs preserves pixel data bit-accurately. The default implementation returnstrue
.- Returns:
true
if the format preserves full pixel accuracy.
-
getOutputTypes
Returns an array ofClass
objects indicating what types of objects may be used as arguments to the writer'ssetOutput
method.For most writers, which only output to an
ImageOutputStream
, a single-element array containingImageOutputStream.class
should be returned.- Returns:
- a non-
null
array ofClass
objects of length at least 1.
-
canEncodeImage
Returnstrue
if theImageWriter
implementation associated with this service provider is able to encode an image with the given layout. The layout (i.e., the image'sSampleModel
andColorModel
) is described by anImageTypeSpecifier
object.A return value of
true
is not an absolute guarantee of successful encoding; the encoding process may still produce errors due to factors such as I/O errors, inconsistent or malformed data structures, etc. The intent is that a reasonable inspection of the basic structure of the image be performed in order to determine if it is within the scope of the encoding format. For example, a service provider for a format that can only encode greyscale would returnfalse
if handed an RGBBufferedImage
. Similarly, a service provider for a format that can encode 8-bit RGB imagery might refuse to encode an image with an associated alpha channel.Different
ImageWriter
s, and thus service providers, may choose to be more or less strict. For example, they might accept an image with premultiplied alpha even though it will have to be divided out of each pixel, at some loss of precision, in order to be stored.- Parameters:
type
- anImageTypeSpecifier
specifying the layout of the image to be written.- Returns:
true
if this writer is likely to be able to encode images with the given layout.- Throws:
IllegalArgumentException
- iftype
isnull
.
-
canEncodeImage
Returnstrue
if theImageWriter
implementation associated with this service provider is able to encode the givenRenderedImage
instance. Note that this includes instances ofjava.awt.image.BufferedImage
.See the discussion for
canEncodeImage(ImageTypeSpecifier)
for information on the semantics of this method.- Parameters:
im
- an instance ofRenderedImage
to be encoded.- Returns:
true
if this writer is likely to be able to encode this image.- Throws:
IllegalArgumentException
- ifim
isnull
.
-
createWriterInstance
Returns an instance of theImageWriter
implementation associated with this service provider. The returned object will initially be in an initial state as if itsreset
method had been called.The default implementation simply returns
createWriterInstance(null)
.- Returns:
- an
ImageWriter
instance. - Throws:
IOException
- if an error occurs during loading, or initialization of the writer class, or during instantiation or initialization of the writer object.
-
createWriterInstance
Returns an instance of theImageWriter
implementation associated with this service provider. The returned object will initially be in an initial state as if itsreset
method had been called.An
Object
may be supplied to the plug-in at construction time. The nature of the object is entirely plug-in specific.Typically, a plug-in will implement this method using code such as
return new MyImageWriter(this)
.- Parameters:
extension
- a plug-in specific extension object, which may benull
.- Returns:
- an
ImageWriter
instance. - Throws:
IOException
- if the attempt to instantiate the writer fails.IllegalArgumentException
- if theImageWriter
's constructor throws anIllegalArgumentException
to indicate that the extension object is unsuitable.
-
isOwnWriter
Returnstrue
if theImageWriter
object passed in is an instance of theImageWriter
associated with this service provider.- Parameters:
writer
- anImageWriter
instance.- Returns:
true
ifwriter
is recognized- Throws:
IllegalArgumentException
- ifwriter
isnull
.
-
getImageReaderSpiNames
Returns an array ofString
s containing all the fully qualified names of all theImageReaderSpi
classes that can understand the internal metadata representation used by theImageWriter
associated with this service provider, ornull
if there are no suchImageReaders
specified. If a non-null
value is returned, it must have non-zero length.The first item in the array must be the name of the service provider for the "preferred" reader, as it will be used to instantiate the
ImageReader
returned byImageIO.getImageReader(ImageWriter)
.This mechanism may be used to obtain
ImageReaders
that will generated non-pixel meta-data (seeIIOExtraDataInfo
) in a structure understood by anImageWriter
. By reading the image and obtaining this data from one of theImageReaders
obtained with this method and passing it on to theImageWriter
, a client program can read an image, modify it in some way, and write it back out preserving all meta-data, without having to understand anything about the internal structure of the meta-data, or even about the image format.- Returns:
- an array of
String
s of length at least 1 containing names ofImageReaderSpi
s, ornull
. - See Also:
-
{ ImageOutputStream.class }
.