getNumHeaderBytes() method, which returns 0 if
arbitrary access to the stream is required, and otherwise returns the number
of header bytes required to recognize the format. Each subclass of ImageCodec
needs to implement only one of the two variants.
This class is not a committed part of the JAI API. It may be removed or
changed in future releases of JAI.
|
Constructor Summary |
protected |
ImageCodec()
Allow only subclasses to instantiate this class. |
|
Method Summary |
abstract boolean |
canEncodeImage(java.awt.image.RenderedImage im,
ImageEncodeParam param)
Returns true if the given image and encoder param object are
suitable for encoding by this ImageCodec. |
static java.awt.image.ColorModel |
createComponentColorModel(java.awt.image.SampleModel sm)
A convenience method to create an instance of ComponentColorModel
suitable for use with the given SampleModel. |
static java.awt.image.ColorModel |
createGrayIndexColorModel(java.awt.image.SampleModel sm,
boolean blackIsZero)
A convenience methods to create an instance of IndexColorModel
suitable for the given 1-banded SampleModel. |
protected ImageDecoder |
createImageDecoder(java.io.File src,
ImageDecodeParam param)
Returns an implementation of the ImageDecoder interface
appropriate for that codec. |
protected ImageDecoder |
createImageDecoder(java.io.InputStream src,
ImageDecodeParam param)
Returns an implementation of the ImageDecoder interface
appropriate for that codec. |
protected abstract ImageDecoder |
createImageDecoder(SeekableStream src,
ImageDecodeParam param)
In a concrete subclass of ImageCodec, returns an
implementation of the ImageDecoder interface appropriate for
that codec. |
static ImageDecoder |
createImageDecoder(java.lang.String name,
java.io.File src,
ImageDecodeParam param)
Returns an ImageDecoder object suitable for decoding from the
supplied File, using the supplied ImageDecodeParam
object. |
static ImageDecoder |
createImageDecoder(java.lang.String name,
java.io.InputStream src,
ImageDecodeParam param)
Returns an ImageDecoder object suitable for decoding from the
supplied InputStream, using the supplied ImageDecodeParam
object. |
static ImageDecoder |
createImageDecoder(java.lang.String name,
SeekableStream src,
ImageDecodeParam param)
Returns an ImageDecoder object suitable for decoding from the
supplied SeekableStream, using the supplied ImageDecodeParam
object. |
protected abstract ImageEncoder |
createImageEncoder(java.io.OutputStream dst,
ImageEncodeParam param)
In a concrete subclass of ImageCodec, returns an
implementation of the ImageEncoder interface appropriate for
that codec. |
static ImageEncoder |
createImageEncoder(java.lang.String name,
java.io.OutputStream dst,
ImageEncodeParam param)
Returns an ImageEncoder object suitable for encoding to the
supplied OutputStream, using the supplied ImageEncoderParam
object. |
static ImageCodec |
getCodec(java.lang.String name)
Returns the ImageCodec associated with the given name. |
static java.util.Enumeration |
getCodecs()
Returns an Enumeration of all regstered ImageCodec
objects. |
protected abstract java.lang.Class |
getDecodeParamClass()
Returns a Class object indicating the proper subclass of
ImageDecodeParam to be used with this ImageCodec
. |
static java.lang.String[] |
getDecoderNames(SeekableStream src)
Returns an array of Strings indicating the names of
registered ImageCodecs that may be appropriate for reading
the given SeekableStream. |
protected abstract java.lang.Class |
getEncodeParamClass()
Returns a Class object indicating the proper subclass of
ImageEncodeParam to be used with this ImageCodec
. |
static java.lang.String[] |
getEncoderNames(java.awt.image.RenderedImage im,
ImageEncodeParam param)
Returns an array of Strings indicating the names of
registered ImageCodecs that may be appropriate for writing
the given RenderedImage, using the optional ImageEncodeParam
, which may be null. |
abstract java.lang.String |
getFormatName()
Returns the name of this image format. |
int |
getNumHeaderBytes()
Returns the number of bytes of header needed to recognize the format, or 0
if an arbitrary number of bytes may be needed. |
boolean |
isFormatRecognized(byte[] header)
Returns true if the format is recognized in the initial
portion of a stream. |
boolean |
isFormatRecognized(SeekableStream src)
Returns true if the format is recognized in the input data
stream. |
static void |
registerCodec(ImageCodec codec)
Associates an ImageCodec with its format name, as determined
by its getFormatName() method. |
static void |
unregisterCodec(java.lang.String name)
Unregisters the ImageCodec object currently responsible for
handling the named format. |
private static java.lang.String[] |
vectorToStrings(java.util.Vector nameVec)
|
| Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
codecs
private static java.util.Hashtable codecs
grayIndexCmaps
private static final byte[][] grayIndexCmaps
GrayBits8
private static final int[] GrayBits8
colorModelGray8
private static final java.awt.image.ComponentColorModel colorModelGray8
GrayAlphaBits8
private static final int[] GrayAlphaBits8
colorModelGrayAlpha8
private static final java.awt.image.ComponentColorModel colorModelGrayAlpha8
GrayBits16
private static final int[] GrayBits16
colorModelGray16
private static final java.awt.image.ComponentColorModel colorModelGray16
GrayAlphaBits16
private static final int[] GrayAlphaBits16
colorModelGrayAlpha16
private static final java.awt.image.ComponentColorModel colorModelGrayAlpha16
GrayBits32
private static final int[] GrayBits32
colorModelGray32
private static final java.awt.image.ComponentColorModel colorModelGray32
GrayAlphaBits32
private static final int[] GrayAlphaBits32
colorModelGrayAlpha32
private static final java.awt.image.ComponentColorModel colorModelGrayAlpha32
RGBBits8
private static final int[] RGBBits8
colorModelRGB8
private static final java.awt.image.ComponentColorModel colorModelRGB8
RGBABits8
private static final int[] RGBABits8
colorModelRGBA8
private static final java.awt.image.ComponentColorModel colorModelRGBA8
RGBBits16
private static final int[] RGBBits16
colorModelRGB16
private static final java.awt.image.ComponentColorModel colorModelRGB16
RGBABits16
private static final int[] RGBABits16
colorModelRGBA16
private static final java.awt.image.ComponentColorModel colorModelRGBA16
RGBBits32
private static final int[] RGBBits32
colorModelRGB32
private static final java.awt.image.ComponentColorModel colorModelRGB32
RGBABits32
private static final int[] RGBABits32
colorModelRGBA32
private static final java.awt.image.ComponentColorModel colorModelRGBA32
ImageCodec
protected ImageCodec()
- Allow only subclasses to instantiate this class.
getCodec
public static ImageCodec getCodec(java.lang.String name)
- Returns the
ImageCodec associated with the given name. null
is returned if no codec is registered with the given name. Case is not
significant.
getCodecs
public static java.util.Enumeration getCodecs()
- Returns an
Enumeration of all regstered ImageCodec
objects.
getDecoderNames
public static java.lang.String[] getDecoderNames(SeekableStream src)
- Returns an array of
Strings indicating the names of
registered ImageCodecs that may be appropriate for reading
the given SeekableStream.
If the src SeekableStream does not support
seeking backwards (that is, its canSeekBackwards() method
returns false) then only FormatRecognizers that
require only a fixed-length header will be checked.
If the src stream does not support seeking backwards, it must
support marking, as determined by its markSupported() method.
getEncoderNames
public static java.lang.String[] getEncoderNames(java.awt.image.RenderedImage im,
ImageEncodeParam param)
- Returns an array of
Strings indicating the names of
registered ImageCodecs that may be appropriate for writing
the given RenderedImage, using the optional ImageEncodeParam
, which may be null.
registerCodec
public static void registerCodec(ImageCodec codec)
- Associates an
ImageCodec with its format name, as determined
by its getFormatName() method. Case is not significant. Any
codec previously associated with the name is discarded.
unregisterCodec
public static void unregisterCodec(java.lang.String name)
- Unregisters the
ImageCodec object currently responsible for
handling the named format. Case is not significant.
createImageEncoder
public static ImageEncoder createImageEncoder(java.lang.String name,
java.io.OutputStream dst,
ImageEncodeParam param)
- Returns an
ImageEncoder object suitable for encoding to the
supplied OutputStream, using the supplied ImageEncoderParam
object.
createImageDecoder
public static ImageDecoder createImageDecoder(java.lang.String name,
java.io.InputStream src,
ImageDecodeParam param)
- Returns an
ImageDecoder object suitable for decoding from the
supplied InputStream, using the supplied ImageDecodeParam
object.
createImageDecoder
public static ImageDecoder createImageDecoder(java.lang.String name,
java.io.File src,
ImageDecodeParam param)
throws java.io.IOException
- Returns an
ImageDecoder object suitable for decoding from the
supplied File, using the supplied ImageDecodeParam
object.
createImageDecoder
public static ImageDecoder createImageDecoder(java.lang.String name,
SeekableStream src,
ImageDecodeParam param)
- Returns an
ImageDecoder object suitable for decoding from the
supplied SeekableStream, using the supplied ImageDecodeParam
object.
createGrayIndexColorModel
public static java.awt.image.ColorModel createGrayIndexColorModel(java.awt.image.SampleModel sm,
boolean blackIsZero)
- A convenience methods to create an instance of
IndexColorModel
suitable for the given 1-banded SampleModel.
createComponentColorModel
public static java.awt.image.ColorModel createComponentColorModel(java.awt.image.SampleModel sm)
- A convenience method to create an instance of
ComponentColorModel
suitable for use with the given SampleModel. The SampleModel
should have a data type of DataBuffer.TYPE_BYTE, TYPE_USHORT
, or TYPE_INT and between 1 and 4 bands. Depending on the
number of bands of the SampleModel, either a gray,
gray+alpha, rgb, or rgb+alpha ColorModel is returned.
vectorToStrings
private static java.lang.String[] vectorToStrings(java.util.Vector nameVec)
getFormatName
public abstract java.lang.String getFormatName()
- Returns the name of this image format.
getNumHeaderBytes
public int getNumHeaderBytes()
- Returns the number of bytes of header needed to recognize the format, or 0
if an arbitrary number of bytes may be needed. The default implementation
returns 0.
The return value must be a constant for all instances of each particular
subclass of ImageCodec.
Although it is legal to always return 0, in some cases processing may be
more efficient if the number of bytes needed is known in advance.
isFormatRecognized
public boolean isFormatRecognized(byte[] header)
- Returns
true if the format is recognized in the initial
portion of a stream. The header will be passed in as a byte
array of length getNumHeaderBytes(). This method should be
called only if getNumHeaderBytes() returns a value greater
than 0.
The default implementation throws an exception to indicate that it should
never be called.
isFormatRecognized
public boolean isFormatRecognized(SeekableStream src)
throws java.io.IOException
- Returns
true if the format is recognized in the input data
stream. This method should be called only if getNumHeaderBytesNeeded()
returns 0.
The source SeekableStream is guaranteed to support seeking
backwards, and should be seeked to 0 prior to calling this method.
The default implementation throws an exception to indicate that it should
never be called.
canEncodeImage
public abstract boolean canEncodeImage(java.awt.image.RenderedImage im,
ImageEncodeParam param)
- Returns
true if the given image and encoder param object are
suitable for encoding by this ImageCodec. For example, some
codecs may only deal with images with a certain number of bands; an
attempt to encode an image with an unsupported number of bands will fail.
getEncodeParamClass
protected abstract java.lang.Class getEncodeParamClass()
- Returns a
Class object indicating the proper subclass of
ImageEncodeParam to be used with this ImageCodec
. If encoding is not supported by this codec, null is
returned. If encoding is supported, but a parameter object is not used
during encoding, Object.class is returned to signal this fact.
getDecodeParamClass
protected abstract java.lang.Class getDecodeParamClass()
- Returns a
Class object indicating the proper subclass of
ImageDecodeParam to be used with this ImageCodec
. If encoding is not supported by this codec, null is
returned. If decoding is supported, but a parameter object is not used
during decoding, Object.class is returned to signal this fact.
createImageEncoder
protected abstract ImageEncoder createImageEncoder(java.io.OutputStream dst,
ImageEncodeParam param)
- In a concrete subclass of
ImageCodec, returns an
implementation of the ImageEncoder interface appropriate for
that codec.
createImageDecoder
protected ImageDecoder createImageDecoder(java.io.InputStream src,
ImageDecodeParam param)
- Returns an implementation of the
ImageDecoder interface
appropriate for that codec. Subclasses of ImageCodec may
override this method if they wish to accept data directly from an InputStream
; otherwise, this method will convert the source into a backwards-seekable
SeekableStream and call the appropriate version of createImageDecoder
for that data type.
Instances of ImageCodec that do not require the ability to
seek backwards in their source SeekableStream should override
this method in order to avoid the default call to SeekableStream.wrapInputStream(src, true)
.
createImageDecoder
protected ImageDecoder createImageDecoder(java.io.File src,
ImageDecodeParam param)
throws java.io.IOException
- Returns an implementation of the
ImageDecoder interface
appropriate for that codec. Subclasses of ImageCodec may
override this method if they wish to accept data directly from a File
; otherwise, this method will convert the source into a SeekableStream
and call the appropriate version of createImageDecoder for
that data type.
createImageDecoder
protected abstract ImageDecoder createImageDecoder(SeekableStream src,
ImageDecodeParam param)
- In a concrete subclass of
ImageCodec, returns an
implementation of the ImageDecoder interface appropriate for
that codec.
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