Class ImageReader
- java.lang.Object
-
- javax.imageio.ImageReader
public abstract class ImageReader extends Object
An abstract superclass for parsing and decoding of images. This class must be subclassed by classes that read in images in the context of the Java Image I/O framework.
ImageReader
objects are normally instantiated by the service provider interface (SPI) class for the specific format. Service provider classes (e.g., instances of ImageReaderSpi
) are registered with the IIORegistry
, which uses them for format recognition and presentation of available format readers and writers.
When an input source is set (using the setInput
method), it may be marked as "seek forward only". This setting means that images contained within the input source will only be read in order, possibly allowing the reader to avoid caching portions of the input containing data associated with images that have been read previously.
- See Also:
-
ImageWriter
,IIORegistry
,ImageReaderSpi
Field Summary
Modifier and Type | Field | Description |
---|---|---|
protected Locale[] | availableLocales | An array of |
protected boolean | ignoreMetadata |
|
protected Object | input | The |
protected Locale | locale | The current |
protected int | minIndex | The smallest valid index for reading, initially 0. |
protected ImageReaderSpi | originatingProvider | The |
protected List<IIOReadProgressListener> | progressListeners | A |
protected boolean | seekForwardOnly |
|
protected List<IIOReadUpdateListener> | updateListeners | A |
protected List<IIOReadWarningListener> | warningListeners | A |
protected List<Locale> | warningLocales | A |
Constructor Summary
Modifier | Constructor | Description |
---|---|---|
protected | ImageReader(ImageReaderSpi originatingProvider) | Constructs an |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
void | abort() | Requests that any current read operation be aborted. |
protected boolean | abortRequested() | Returns |
void | addIIOReadProgressListener(IIOReadProgressListener listener) | Adds an |
void | addIIOReadUpdateListener(IIOReadUpdateListener listener) | Adds an |
void | addIIOReadWarningListener(IIOReadWarningListener listener) | Adds an |
boolean | canReadRaster() | Returns |
protected static void | checkReadParamBandSettings(ImageReadParam param,
int numSrcBands,
int numDstBands) | A utility method that may be used by readers to test the validity of the source and destination band settings of an |
protected void | clearAbortRequest() | Clears any previous abort request. |
protected static void | computeRegions(ImageReadParam param,
int srcWidth,
int srcHeight,
BufferedImage image,
Rectangle srcRegion,
Rectangle destRegion) | Computes the source region of interest and the destination region of interest, taking the width and height of the source image, an optional destination image, and an optional |
void | dispose() | Allows any resources held by this object to be released. |
float | getAspectRatio(int imageIndex) | Returns the aspect ratio of the given image (that is, its width divided by its height) as a |
Locale[] | getAvailableLocales() | Returns an array of |
ImageReadParam | getDefaultReadParam() | Returns a default |
protected static BufferedImage | getDestination(ImageReadParam param,
Iterator<ImageTypeSpecifier> imageTypes,
int width,
int height) | Returns the |
String | getFormatName() | Returns a |
abstract int | getHeight(int imageIndex) | Returns the height in pixels of the given image within the input source. |
abstract IIOMetadata | getImageMetadata(int imageIndex) | Returns an |
IIOMetadata | getImageMetadata(int imageIndex,
String formatName,
Set<String> nodeNames) | Returns an |
abstract Iterator<ImageTypeSpecifier> | getImageTypes(int imageIndex) | Returns an |
Object | getInput() | Returns the |
Locale | getLocale() | Returns the currently set |
int | getMinIndex() | Returns the lowest valid index for reading an image, thumbnail, or image metadata. |
abstract int | getNumImages(boolean allowSearch) | Returns the number of images, not including thumbnails, available from the current input source. |
int | getNumThumbnails(int imageIndex) | Returns the number of thumbnail preview images associated with the given image. |
ImageReaderSpi | getOriginatingProvider() | Returns the |
ImageTypeSpecifier | getRawImageType(int imageIndex) | Returns an |
protected static Rectangle | getSourceRegion(ImageReadParam param,
int srcWidth,
int srcHeight) | A utility method that may be used by readers to compute the region of the source image that should be read, taking into account any source region and subsampling offset settings in the supplied |
abstract IIOMetadata | getStreamMetadata() | Returns an |
IIOMetadata | getStreamMetadata(String formatName,
Set<String> nodeNames) | Returns an |
int | getThumbnailHeight(int imageIndex,
int thumbnailIndex) | Returns the height of the thumbnail preview image indexed by |
int | getThumbnailWidth(int imageIndex,
int thumbnailIndex) | Returns the width of the thumbnail preview image indexed by |
int | getTileGridXOffset(int imageIndex) | Returns the X coordinate of the upper-left corner of tile (0, 0) in the given image. |
int | getTileGridYOffset(int imageIndex) | Returns the Y coordinate of the upper-left corner of tile (0, 0) in the given image. |
int | getTileHeight(int imageIndex) | Returns the height of a tile in the given image. |
int | getTileWidth(int imageIndex) | Returns the width of a tile in the given image. |
abstract int | getWidth(int imageIndex) | Returns the width in pixels of the given image within the input source. |
boolean | hasThumbnails(int imageIndex) | Returns |
boolean | isIgnoringMetadata() | Returns |
boolean | isImageTiled(int imageIndex) | Returns |
boolean | isRandomAccessEasy(int imageIndex) | Returns |
boolean | isSeekForwardOnly() | Returns |
protected void | processImageComplete() | Broadcasts the completion of an image read to all registered |
protected void | processImageProgress(float percentageDone) | Broadcasts the current percentage of image completion to all registered |
protected void | processImageStarted(int imageIndex) | Broadcasts the start of an image read to all registered |
protected void | processImageUpdate(BufferedImage theImage,
int minX,
int minY,
int width,
int height,
int periodX,
int periodY,
int[] bands) | Broadcasts the update of a set of samples to all registered |
protected void | processPassComplete(BufferedImage theImage) | Broadcasts the end of a progressive pass to all registered |
protected void | processPassStarted(BufferedImage theImage,
int pass,
int minPass,
int maxPass,
int minX,
int minY,
int periodX,
int periodY,
int[] bands) | Broadcasts the beginning of a progressive pass to all registered |
protected void | processReadAborted() | Broadcasts that the read has been aborted to all registered |
protected void | processSequenceComplete() | Broadcasts the completion of an sequence of image reads to all registered |
protected void | processSequenceStarted(int minIndex) | Broadcasts the start of an sequence of image reads to all registered |
protected void | processThumbnailComplete() | Broadcasts the completion of a thumbnail read to all registered |
protected void | processThumbnailPassComplete(BufferedImage theThumbnail) | Broadcasts the end of a thumbnail progressive pass to all registered |
protected void | processThumbnailPassStarted(BufferedImage theThumbnail,
int pass,
int minPass,
int maxPass,
int minX,
int minY,
int periodX,
int periodY,
int[] bands) | Broadcasts the beginning of a thumbnail progressive pass to all registered |
protected void | processThumbnailProgress(float percentageDone) | Broadcasts the current percentage of thumbnail completion to all registered |
protected void | processThumbnailStarted(int imageIndex,
int thumbnailIndex) | Broadcasts the start of a thumbnail read to all registered |
protected void | processThumbnailUpdate(BufferedImage theThumbnail,
int minX,
int minY,
int width,
int height,
int periodX,
int periodY,
int[] bands) | Broadcasts the update of a set of samples in a thumbnail image to all registered |
protected void | processWarningOccurred(String warning) | Broadcasts a warning message to all registered |
protected void | processWarningOccurred(String baseName,
String keyword) | Broadcasts a localized warning message to all registered |
BufferedImage | read(int imageIndex) | Reads the image indexed by |
abstract BufferedImage | read(int imageIndex,
ImageReadParam param) | Reads the image indexed by |
IIOImage | readAll(int imageIndex,
ImageReadParam param) | Reads the image indexed by |
Iterator<IIOImage> | readAll(Iterator<? extends ImageReadParam> params) | Returns an |
RenderedImage | readAsRenderedImage(int imageIndex,
ImageReadParam param) | Returns a |
boolean | readerSupportsThumbnails() | Returns |
Raster | readRaster(int imageIndex,
ImageReadParam param) | Returns a new |
BufferedImage | readThumbnail(int imageIndex,
int thumbnailIndex) | Returns the thumbnail preview image indexed by |
BufferedImage | readTile(int imageIndex,
int tileX,
int tileY) | Reads the tile indicated by the |
Raster | readTileRaster(int imageIndex,
int tileX,
int tileY) | Returns a new |
void | removeAllIIOReadProgressListeners() | Removes all currently registered |
void | removeAllIIOReadUpdateListeners() | Removes all currently registered |
void | removeAllIIOReadWarningListeners() | Removes all currently registered |
void | removeIIOReadProgressListener(IIOReadProgressListener listener) | Removes an |
void | removeIIOReadUpdateListener(IIOReadUpdateListener listener) | Removes an |
void | removeIIOReadWarningListener(IIOReadWarningListener listener) | Removes an |
void | reset() | Restores the |
void | setInput(Object input) | Sets the input source to use to the given |
void | setInput(Object input,
boolean seekForwardOnly) | Sets the input source to use to the given |
void | setInput(Object input,
boolean seekForwardOnly,
boolean ignoreMetadata) | Sets the input source to use to the given |
void | setLocale(Locale locale) | Sets the current |
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Field Detail
originatingProvider
protected ImageReaderSpi originatingProvider
The ImageReaderSpi
that instantiated this object, or null
if its identity is not known or none exists. By default it is initialized to null
.
input
protected Object input
The ImageInputStream
or other Object
by setInput
and retrieved by getInput
. By default it is initialized to null
.
seekForwardOnly
protected boolean seekForwardOnly
true
if the current input source has been marked as allowing only forward seeking by setInput
. By default, the value is false
.
ignoreMetadata
protected boolean ignoreMetadata
true
if the current input source has been marked as allowing metadata to be ignored by setInput
. By default, the value is false
.
minIndex
protected int minIndex
The smallest valid index for reading, initially 0. When seekForwardOnly
is true
, various methods may throw an IndexOutOfBoundsException
on an attempt to access data associate with an image having a lower index.
availableLocales
protected Locale[] availableLocales
An array of Locale
s which may be used to localize warning messages, or null
if localization is not supported.
locale
protected Locale locale
The current Locale
to be used for localization, or null
if none has been set.
warningListeners
protected List<IIOReadWarningListener> warningListeners
A List
of currently registered IIOReadWarningListener
s, initialized by default to null
, which is synonymous with an empty List
.
warningLocales
protected List<Locale> warningLocales
A List
of the Locale
s associated with each currently registered IIOReadWarningListener
, initialized by default to null
, which is synonymous with an empty List
.
progressListeners
protected List<IIOReadProgressListener> progressListeners
A List
of currently registered IIOReadProgressListener
s, initialized by default to null
, which is synonymous with an empty List
.
updateListeners
protected List<IIOReadUpdateListener> updateListeners
A List
of currently registered IIOReadUpdateListener
s, initialized by default to null
, which is synonymous with an empty List
.
Constructor Detail
ImageReader
protected ImageReader(ImageReaderSpi originatingProvider)
Constructs an ImageReader
and sets its originatingProvider
field to the supplied value.
Subclasses that make use of extensions should provide a constructor with signature (ImageReaderSpi,Object)
in order to retrieve the extension object. If the extension object is unsuitable, an IllegalArgumentException
should be thrown.
- Parameters:
-
originatingProvider
- theImageReaderSpi
that is invoking this constructor, ornull
.
Method Detail
getFormatName
public String getFormatName() throws IOException
Returns a String
identifying the format of the input source.
The default implementation returns originatingProvider.getFormatNames()[0]
. Implementations that may not have an originating service provider, or which desire a different naming policy should override this method.
- Returns:
- the format name, as a
String
. - Throws:
-
IOException
- if an error occurs reading the information from the input source.
getOriginatingProvider
public ImageReaderSpi getOriginatingProvider()
Returns the ImageReaderSpi
that was passed in on the constructor. Note that this value may be null
.
- Returns:
- an
ImageReaderSpi
, ornull
. - See Also:
ImageReaderSpi
setInput
public void setInput(Object input, boolean seekForwardOnly, boolean ignoreMetadata)
Sets the input source to use to the given ImageInputStream
or other Object
. The input source must be set before any of the query or read methods are used. If input
is null
, any currently set input source will be removed. In any case, the value of minIndex
will be initialized to 0.
The seekForwardOnly
parameter controls whether the value returned by getMinIndex
will be increased as each image (or thumbnail, or image metadata) is read. If seekForwardOnly
is true, then a call to read(index)
will throw an IndexOutOfBoundsException
if index < this.minIndex
; otherwise, the value of minIndex
will be set to index
. If seekForwardOnly
is false
, the value of minIndex
will remain 0 regardless of any read operations.
The ignoreMetadata
parameter, if set to true
, allows the reader to disregard any metadata encountered during the read. Subsequent calls to the getStreamMetadata
and getImageMetadata
methods may return null
, and an IIOImage
returned from readAll
may return null
from their getMetadata
method. Setting this parameter may allow the reader to work more efficiently. The reader may choose to disregard this setting and return metadata normally.
Subclasses should take care to remove any cached information based on the previous stream, such as header information or partially decoded image data.
Use of a general Object
other than an ImageInputStream
is intended for readers that interact directly with a capture device or imaging protocol. The set of legal classes is advertised by the reader's service provider's getInputTypes
method; most readers will return a single-element array containing only ImageInputStream.class
to indicate that they accept only an ImageInputStream
.
The default implementation checks the input
argument against the list returned by originatingProvider.getInputTypes()
and fails if the argument is not an instance of one of the classes in the list. If the originating provider is set to null
, the input is accepted only if it is an ImageInputStream
.
- Parameters:
-
input
- theImageInputStream
or otherObject
to use for future decoding. -
seekForwardOnly
- iftrue
, images and metadata may only be read in ascending order from this input source. -
ignoreMetadata
- iftrue
, metadata may be ignored during reads. - Throws:
-
IllegalArgumentException
- ifinput
is not an instance of one of the classes returned by the originating service provider'sgetInputTypes
method, or is not anImageInputStream
. - See Also:
-
ImageInputStream
,getInput()
,ImageReaderSpi.getInputTypes()
setInput
public void setInput(Object input, boolean seekForwardOnly)
Sets the input source to use to the given ImageInputStream
or other Object
. The input source must be set before any of the query or read methods are used. If input
is null
, any currently set input source will be removed. In any case, the value of minIndex
will be initialized to 0.
The seekForwardOnly
parameter controls whether the value returned by getMinIndex
will be increased as each image (or thumbnail, or image metadata) is read. If seekForwardOnly
is true, then a call to read(index)
will throw an IndexOutOfBoundsException
if index < this.minIndex
; otherwise, the value of minIndex
will be set to index
. If seekForwardOnly
is false
, the value of minIndex
will remain 0 regardless of any read operations.
This method is equivalent to setInput(input, seekForwardOnly, false)
.
- Parameters:
-
input
- theImageInputStream
or otherObject
to use for future decoding. -
seekForwardOnly
- iftrue
, images and metadata may only be read in ascending order from this input source. - Throws:
-
IllegalArgumentException
- ifinput
is not an instance of one of the classes returned by the originating service provider'sgetInputTypes
method, or is not anImageInputStream
. - See Also:
getInput()
setInput
public void setInput(Object input)
Sets the input source to use to the given ImageInputStream
or other Object
. The input source must be set before any of the query or read methods are used. If input
is null
, any currently set input source will be removed. In any case, the value of minIndex
will be initialized to 0.
This method is equivalent to setInput(input, false, false)
.
- Parameters:
-
input
- theImageInputStream
or otherObject
to use for future decoding. - Throws:
-
IllegalArgumentException
- ifinput
is not an instance of one of the classes returned by the originating service provider'sgetInputTypes
method, or is not anImageInputStream
. - See Also:
getInput()
getInput
public Object getInput()
Returns the ImageInputStream
or other Object
previously set as the input source. If the input source has not been set, null
is returned.
- Returns:
- the
Object
that will be used for future decoding, ornull
. - See Also:
-
ImageInputStream
,setInput(java.lang.Object, boolean, boolean)
isSeekForwardOnly
public boolean isSeekForwardOnly()
Returns true
if the current input source has been marked as seek forward only by passing true
as the seekForwardOnly
argument to the setInput
method.
- Returns:
-
true
if the input source is seek forward only. - See Also:
setInput(java.lang.Object, boolean, boolean)
isIgnoringMetadata
public boolean isIgnoringMetadata()
Returns true
if the current input source has been marked as allowing metadata to be ignored by passing true
as the ignoreMetadata
argument to the setInput
method.
- Returns:
-
true
if the metadata may be ignored. - See Also:
setInput(java.lang.Object, boolean, boolean)
getMinIndex
public int getMinIndex()
Returns the lowest valid index for reading an image, thumbnail, or image metadata. If seekForwardOnly()
is false
, this value will typically remain 0, indicating that random access is possible. Otherwise, it will contain the value of the most recently accessed index, and increase in a monotonic fashion.
- Returns:
- the minimum legal index for reading.
getAvailableLocales
public Locale[] getAvailableLocales()
Returns an array of Locale
s that may be used to localize warning listeners and compression settings. A return value of null
indicates that localization is not supported.
The default implementation returns a clone of the availableLocales
instance variable if it is non-null
, or else returns null
.
- Returns:
- an array of
Locale
s that may be used as arguments tosetLocale
, ornull
.
setLocale
public void setLocale(Locale locale)
Sets the current Locale
of this ImageReader
to the given value. A value of null
removes any previous setting, and indicates that the reader should localize as it sees fit.
- Parameters:
-
locale
- the desiredLocale
, ornull
. - Throws:
-
IllegalArgumentException
- iflocale
is non-null
but is not one of the values returned bygetAvailableLocales
. - See Also:
getLocale()
getLocale
public Locale getLocale()
Returns the currently set Locale
, or null
if none has been set.
- Returns:
- the current
Locale
, ornull
. - See Also:
setLocale(java.util.Locale)
getNumImages
public abstract int getNumImages(boolean allowSearch) throws IOException
Returns the number of images, not including thumbnails, available from the current input source.
Note that some image formats (such as animated GIF) do not specify how many images are present in the stream. Thus determining the number of images will require the entire stream to be scanned and may require memory for buffering. If images are to be processed in order, it may be more efficient to simply call read
with increasing indices until an IndexOutOfBoundsException
is thrown to indicate that no more images are available. The allowSearch
parameter may be set to false
to indicate that an exhaustive search is not desired; the return value will be -1
to indicate that a search is necessary. If the input has been specified with seekForwardOnly
set to true
, this method throws an IllegalStateException
if allowSearch
is set to true
.
- Parameters:
-
allowSearch
- iftrue
, the true number of images will be returned even if a search is required. Iffalse
, the reader may return-1
without performing the search. - Returns:
- the number of images, as an
int
, or-1
ifallowSearch
isfalse
and a search would be required. - Throws:
-
IllegalStateException
- if the input source has not been set, or if the input has been specified withseekForwardOnly
set totrue
. -
IOException
- if an error occurs reading the information from the input source. - See Also:
setInput(java.lang.Object, boolean, boolean)
getWidth
public abstract int getWidth(int imageIndex) throws IOException
Returns the width in pixels of the given image within the input source.
If the image can be rendered to a user-specified size, then this method returns the default width.
- Parameters:
-
imageIndex
- the index of the image to be queried. - Returns:
- the width of the image, as an
int
. - Throws:
-
IllegalStateException
- if the input source has not been set. -
IndexOutOfBoundsException
- if the supplied index is out of bounds. -
IOException
- if an error occurs reading the width information from the input source.
getHeight
public abstract int getHeight(int imageIndex) throws IOException
Returns the height in pixels of the given image within the input source.
If the image can be rendered to a user-specified size, then this method returns the default height.
- Parameters:
-
imageIndex
- the index of the image to be queried. - Returns:
- the height of the image, as an
int
. - Throws:
-
IllegalStateException
- if the input source has not been set. -
IndexOutOfBoundsException
- if the supplied index is out of bounds. -
IOException
- if an error occurs reading the height information from the input source.
isRandomAccessEasy
public boolean isRandomAccessEasy(int imageIndex) throws IOException
Returns true
if the storage format of the given image places no inherent impediment on random access to pixels. For most compressed formats, such as JPEG, this method should return false
, as a large section of the image in addition to the region of interest may need to be decoded.
This is merely a hint for programs that wish to be efficient; all readers must be able to read arbitrary regions as specified in an ImageReadParam
.
Note that formats that return false
from this method may nonetheless allow tiling (e.g. Restart Markers in JPEG), and random access will likely be reasonably efficient on tiles. See isImageTiled
.
A reader for which all images are guaranteed to support easy random access, or are guaranteed not to support easy random access, may return true
or false
respectively without accessing any image data. In such cases, it is not necessary to throw an exception even if no input source has been set or the image index is out of bounds.
The default implementation returns false
.
- Parameters:
-
imageIndex
- the index of the image to be queried. - Returns:
-
true
if reading a region of interest of the given image is likely to be efficient. - Throws:
-
IllegalStateException
- if an input source is required to determine the return value, but none has been set. -
IndexOutOfBoundsException
- if an image must be accessed to determine the return value, but the supplied index is out of bounds. -
IOException
- if an error occurs during reading.
getAspectRatio
public float getAspectRatio(int imageIndex) throws IOException
Returns the aspect ratio of the given image (that is, its width divided by its height) as a float
. For images that are inherently resizable, this method provides a way to determine the appropriate width given a desired height, or vice versa. For non-resizable images, the true width and height are used.
The default implementation simply returns (float)getWidth(imageIndex)/getHeight(imageIndex)
.
- Parameters:
-
imageIndex
- the index of the image to be queried. - Returns:
- a
float
indicating the aspect ratio of the given image. - Throws:
-
IllegalStateException
- if the input source has not been set. -
IndexOutOfBoundsException
- if the supplied index is out of bounds. -
IOException
- if an error occurs during reading.
getRawImageType
public ImageTypeSpecifier getRawImageType(int imageIndex) throws IOException
Returns an ImageTypeSpecifier
indicating the SampleModel
and ColorModel
which most closely represents the "raw" internal format of the image. If there is no close match then a type which preserves the most information from the image should be returned. The returned value should also be included in the list of values returned by getImageTypes
.
The default implementation simply returns the first entry from the list provided by getImageType
.
- Parameters:
-
imageIndex
- the index of the image to be queried. - Returns:
- an
ImageTypeSpecifier
. - Throws:
-
IllegalStateException
- if the input source has not been set. -
IndexOutOfBoundsException
- if the supplied index is out of bounds. -
IOException
- if an error occurs reading the format information from the input source.
getImageTypes
public abstract Iterator<ImageTypeSpecifier> getImageTypes(int imageIndex) throws IOException
Returns an Iterator
containing possible image types to which the given image may be decoded, in the form of ImageTypeSpecifiers
s. At least one legal image type will be returned.
The first element of the iterator should be the most "natural" type for decoding the image with as little loss as possible. For example, for a JPEG image the first entry should be an RGB image, even though the image data is stored internally in a YCbCr color space.
- Parameters:
-
imageIndex
- the index of the image to beretrieved
. - Returns:
- an
Iterator
containing at least oneImageTypeSpecifier
representing suggested image types for decoding the current given image. - Throws:
-
IllegalStateException
- if the input source has not been set. -
IndexOutOfBoundsException
- if the supplied index is out of bounds. -
IOException
- if an error occurs reading the format information from the input source. - See Also:
-
ImageReadParam.setDestination(BufferedImage)
,IIOParam.setDestinationType(ImageTypeSpecifier)
getDefaultReadParam
public ImageReadParam getDefaultReadParam()
Returns a default ImageReadParam
object appropriate for this format. All subclasses should define a set of default values for all parameters and return them with this call. This method may be called before the input source is set.
The default implementation constructs and returns a new ImageReadParam
object that does not allow source scaling (i.e., it returns new ImageReadParam()
.
- Returns:
- an
ImageReadParam
object which may be used to control the decoding process using a set of default settings.
getStreamMetadata
public abstract IIOMetadata getStreamMetadata() throws IOException
Returns an IIOMetadata
object representing the metadata associated with the input source as a whole (i.e., not associated with any particular image), or null
if the reader does not support reading metadata, is set to ignore metadata, or if no metadata is available.
- Returns:
- an
IIOMetadata
object, ornull
. - Throws:
-
IOException
- if an error occurs during reading.
getStreamMetadata
public IIOMetadata getStreamMetadata(String formatName, Set<String> nodeNames) throws IOException
Returns an IIOMetadata
object representing the metadata associated with the input source as a whole (i.e., not associated with any particular image). If no such data exists, null
is returned.
The resulting metadata object is only responsible for returning documents in the format named by formatName
. Within any documents that are returned, only nodes whose names are members of nodeNames
are required to be returned. In this way, the amount of metadata processing done by the reader may be kept to a minimum, based on what information is actually needed.
If formatName
is not the name of a supported metadata format, null
is returned.
In all cases, it is legal to return a more capable metadata object than strictly necessary. The format name and node names are merely hints that may be used to reduce the reader's workload.
The default implementation simply returns the result of calling getStreamMetadata()
, after checking that the format name is supported. If it is not, null
is returned.
- Parameters:
-
formatName
- a metadata format name that may be used to retrieve a document from the returnedIIOMetadata
object. -
nodeNames
- aSet
containing the names of nodes that may be contained in a retrieved document. - Returns:
- an
IIOMetadata
object, ornull
. - Throws:
-
IllegalArgumentException
- ifformatName
isnull
. -
IllegalArgumentException
- ifnodeNames
isnull
. -
IOException
- if an error occurs during reading.
getImageMetadata
public abstract IIOMetadata getImageMetadata(int imageIndex) throws IOException
Returns an IIOMetadata
object containing metadata associated with the given image, or null
if the reader does not support reading metadata, is set to ignore metadata, or if no metadata is available.
- Parameters:
-
imageIndex
- the index of the image whose metadata is to be retrieved. - Returns:
- an
IIOMetadata
object, ornull
. - Throws:
-
IllegalStateException
- if the input source has not been set. -
IndexOutOfBoundsException
- if the supplied index is out of bounds. -
IOException
- if an error occurs during reading.
getImageMetadata
public IIOMetadata getImageMetadata(int imageIndex, String formatName, Set<String> nodeNames) throws IOException
Returns an IIOMetadata
object representing the metadata associated with the given image, or null
if the reader does not support reading metadata or none is available.
The resulting metadata object is only responsible for returning documents in the format named by formatName
. Within any documents that are returned, only nodes whose names are members of nodeNames
are required to be returned. In this way, the amount of metadata processing done by the reader may be kept to a minimum, based on what information is actually needed.
If formatName
is not the name of a supported metadata format, null
may be returned.
In all cases, it is legal to return a more capable metadata object than strictly necessary. The format name and node names are merely hints that may be used to reduce the reader's workload.
The default implementation simply returns the result of calling getImageMetadata(imageIndex)
, after checking that the format name is supported. If it is not, null
is returned.
- Parameters:
-
imageIndex
- the index of the image whose metadata is to be retrieved. -
formatName
- a metadata format name that may be used to retrieve a document from the returnedIIOMetadata
object. -
nodeNames
- aSet
containing the names of nodes that may be contained in a retrieved document. - Returns:
- an
IIOMetadata
object, ornull
. - Throws:
-
IllegalStateException
- if the input source has not been set. -
IndexOutOfBoundsException
- if the supplied index is out of bounds. -
IllegalArgumentException
- ifformatName
isnull
. -
IllegalArgumentException
- ifnodeNames
isnull
. -
IOException
- if an error occurs during reading.
read
public BufferedImage read(int imageIndex) throws IOException
Reads the image indexed by imageIndex
and returns it as a complete BufferedImage
, using a default ImageReadParam
. This is a convenience method that calls read(imageIndex, null)
.
The image returned will be formatted according to the first ImageTypeSpecifier
returned from getImageTypes
.
Any registered IIOReadProgressListener
objects will be notified by calling their imageStarted
method, followed by calls to their imageProgress
method as the read progresses. Finally their imageComplete
method will be called. IIOReadUpdateListener
objects may be updated at other times during the read as pixels are decoded. Finally, IIOReadWarningListener
objects will receive notification of any non-fatal warnings that occur during decoding.
- Parameters:
-
imageIndex
- the index of the image to be retrieved. - Returns:
- the desired portion of the image as a
BufferedImage
. - Throws:
-
IllegalStateException
- if the input source has not been set. -
IndexOutOfBoundsException
- if the supplied index is out of bounds. -
IOException
- if an error occurs during reading.
read
public abstract BufferedImage read(int imageIndex, ImageReadParam param) throws IOException
Reads the image indexed by imageIndex
and returns it as a complete BufferedImage
, using a supplied ImageReadParam
.
The actual BufferedImage
returned will be chosen using the algorithm defined by the getDestination
method.
Any registered IIOReadProgressListener
objects will be notified by calling their imageStarted
method, followed by calls to their imageProgress
method as the read progresses. Finally their imageComplete
method will be called. IIOReadUpdateListener
objects may be updated at other times during the read as pixels are decoded. Finally, IIOReadWarningListener
objects will receive notification of any non-fatal warnings that occur during decoding.
The set of source bands to be read and destination bands to be written is determined by calling getSourceBands
and getDestinationBands
on the supplied ImageReadParam
. If the lengths of the arrays returned by these methods differ, the set of source bands contains an index larger that the largest available source index, or the set of destination bands contains an index larger than the largest legal destination index, an IllegalArgumentException
is thrown.
If the supplied ImageReadParam
contains optional setting values not supported by this reader (e.g. source render size or any format-specific settings), they will be ignored.
- Parameters:
-
imageIndex
- the index of the image to be retrieved. -
param
- anImageReadParam
used to control the reading process, ornull
. - Returns:
- the desired portion of the image as a
BufferedImage
. - Throws:
-
IllegalStateException
- if the input source has not been set. -
IndexOutOfBoundsException
- if the supplied index is out of bounds. -
IllegalArgumentException
- if the set of source and destination bands specified byparam.getSourceBands
andparam.getDestinationBands
differ in length or include indices that are out of bounds. -
IllegalArgumentException
- if the resulting image would have a width or height less than 1. -
IOException
- if an error occurs during reading.
readAll
public IIOImage readAll(int imageIndex, ImageReadParam param) throws IOException
Reads the image indexed by imageIndex
and returns an IIOImage
containing the image, thumbnails, and associated image metadata, using a supplied ImageReadParam
.
The actual BufferedImage
referenced by the returned IIOImage
will be chosen using the algorithm defined by the getDestination
method.
Any registered IIOReadProgressListener
objects will be notified by calling their imageStarted
method, followed by calls to their imageProgress
method as the read progresses. Finally their imageComplete
method will be called. IIOReadUpdateListener
objects may be updated at other times during the read as pixels are decoded. Finally, IIOReadWarningListener
objects will receive notification of any non-fatal warnings that occur during decoding.
The set of source bands to be read and destination bands to be written is determined by calling getSourceBands
and getDestinationBands
on the supplied ImageReadParam
. If the lengths of the arrays returned by these methods differ, the set of source bands contains an index larger that the largest available source index, or the set of destination bands contains an index larger than the largest legal destination index, an IllegalArgumentException
is thrown.
Thumbnails will be returned in their entirety regardless of the region settings.
If the supplied ImageReadParam
contains optional setting values not supported by this reader (e.g. source render size or any format-specific settings), those values will be ignored.
- Parameters:
-
imageIndex
- the index of the image to be retrieved. -
param
- anImageReadParam
used to control the reading process, ornull
. - Returns:
- an
IIOImage
containing the desired portion of the image, a set of thumbnails, and associated image metadata. - Throws:
-
IllegalStateException
- if the input source has not been set. -
IndexOutOfBoundsException
- if the supplied index is out of bounds. -
IllegalArgumentException
- if the set of source and destination bands specified byparam.getSourceBands
andparam.getDestinationBands
differ in length or include indices that are out of bounds. -
IllegalArgumentException
- if the resulting image would have a width or height less than 1. -
IOException
- if an error occurs during reading.
readAll
public Iterator<IIOImage> readAll(Iterator<? extends ImageReadParam> params) throws IOException
Returns an Iterator
containing all the images, thumbnails, and metadata, starting at the index given by getMinIndex
, from the input source in the form of IIOImage
objects. An Iterator
containing ImageReadParam
objects is supplied; one element is consumed for each image read from the input source until no more images are available. If the read param Iterator
runs out of elements, but there are still more images available from the input source, default read params are used for the remaining images.
If params
is null
, a default read param will be used for all images.
The actual BufferedImage
referenced by the returned IIOImage
will be chosen using the algorithm defined by the getDestination
method.
Any registered IIOReadProgressListener
objects will be notified by calling their sequenceStarted
method once. Then, for each image decoded, there will be a call to imageStarted
, followed by calls to imageProgress
as the read progresses, and finally to imageComplete
. The sequenceComplete
method will be called after the last image has been decoded. IIOReadUpdateListener
objects may be updated at other times during the read as pixels are decoded. Finally, IIOReadWarningListener
objects will receive notification of any non-fatal warnings that occur during decoding.
The set of source bands to be read and destination bands to be written is determined by calling getSourceBands
and getDestinationBands
on the supplied ImageReadParam
. If the lengths of the arrays returned by these methods differ, the set of source bands contains an index larger that the largest available source index, or the set of destination bands contains an index larger than the largest legal destination index, an IllegalArgumentException
is thrown.
Thumbnails will be returned in their entirety regardless of the region settings.
If any of the supplied ImageReadParam
s contain optional setting values not supported by this reader (e.g. source render size or any format-specific settings), they will be ignored.
- Parameters:
-
params
- anIterator
containingImageReadParam
objects. - Returns:
- an
Iterator
representing the contents of the input source asIIOImage
s. - Throws:
-
IllegalStateException
- if the input source has not been set. -
IllegalArgumentException
- if any non-null
element ofparams
is not anImageReadParam
. -
IllegalArgumentException
- if the set of source and destination bands specified byparam.getSourceBands
andparam.getDestinationBands
differ in length or include indices that are out of bounds. -
IllegalArgumentException
- if a resulting image would have a width or height less than 1. -
IOException
- if an error occurs during reading. - See Also:
-
ImageReadParam
,IIOImage
canReadRaster
public boolean canReadRaster()
Returns true
if this plug-in supports reading just a Raster
of pixel data. If this method returns false
, calls to readRaster
or readTileRaster
will throw an UnsupportedOperationException
.
The default implementation returns false
.
- Returns:
-
true
if this plug-in supports reading rawRaster
s. - See Also:
-
readRaster(int, javax.imageio.ImageReadParam)
,readTileRaster(int, int, int)
readRaster
public Raster readRaster(int imageIndex, ImageReadParam param) throws IOException
Returns a new Raster
object containing the raw pixel data from the image stream, without any color conversion applied. The application must determine how to interpret the pixel data by other means. Any destination or image-type parameters in the supplied ImageReadParam
object are ignored, but all other parameters are used exactly as in the read
method, except that any destination offset is used as a logical rather than a physical offset. The size of the returned Raster
will always be that of the source region clipped to the actual image. Logical offsets in the stream itself are ignored.
This method allows formats that normally apply a color conversion, such as JPEG, and formats that do not normally have an associated colorspace, such as remote sensing or medical imaging data, to provide access to raw pixel data.
Any registered readUpdateListener
s are ignored, as there is no BufferedImage
, but all other listeners are called exactly as they are for the read
method.
If canReadRaster()
returns false
, this method throws an UnsupportedOperationException
.
If the supplied ImageReadParam
contains optional setting values not supported by this reader (e.g. source render size or any format-specific settings), they will be ignored.
The default implementation throws an UnsupportedOperationException
.
- Parameters:
-
imageIndex
- the index of the image to be read. -
param
- anImageReadParam
used to control the reading process, ornull
. - Returns:
- the desired portion of the image as a
Raster
. - Throws:
-
UnsupportedOperationException
- if this plug-in does not support reading rawRaster
s. -
IllegalStateException
- if the input source has not been set. -
IndexOutOfBoundsException
- if the supplied index is out of bounds. -
IOException
- if an error occurs during reading. - See Also:
-
canReadRaster()
,read(int)
,Raster
isImageTiled
public boolean isImageTiled(int imageIndex) throws IOException
Returns true
if the image is organized into tiles, that is, equal-sized non-overlapping rectangles.
A reader plug-in may choose whether or not to expose tiling that is present in the image as it is stored. It may even choose to advertise tiling when none is explicitly present. In general, tiling should only be advertised if there is some advantage (in speed or space) to accessing individual tiles. Regardless of whether the reader advertises tiling, it must be capable of reading an arbitrary rectangular region specified in an ImageReadParam
.
A reader for which all images are guaranteed to be tiled, or are guaranteed not to be tiled, may return true
or false
respectively without accessing any image data. In such cases, it is not necessary to throw an exception even if no input source has been set or the image index is out of bounds.
The default implementation just returns false
.
- Parameters:
-
imageIndex
- the index of the image to be queried. - Returns:
-
true
if the image is tiled. - Throws:
-
IllegalStateException
- if an input source is required to determine the return value, but none has been set. -
IndexOutOfBoundsException
- if an image must be accessed to determine the return value, but the supplied index is out of bounds. -
IOException
- if an error occurs during reading.
getTileWidth
public int getTileWidth(int imageIndex) throws IOException
Returns the width of a tile in the given image.
The default implementation simply returns getWidth(imageIndex)
, which is correct for non-tiled images. Readers that support tiling should override this method.
- Parameters:
-
imageIndex
- the index of the image to be queried. - Returns:
- the width of a tile.
- Throws:
-
IllegalStateException
- if the input source has not been set. -
IndexOutOfBoundsException
- if the supplied index is out of bounds. -
IOException
- if an error occurs during reading.
getTileHeight
public int getTileHeight(int imageIndex) throws IOException
Returns the height of a tile in the given image.
The default implementation simply returns getHeight(imageIndex)
, which is correct for non-tiled images. Readers that support tiling should override this method.
- Parameters:
-
imageIndex
- the index of the image to be queried. - Returns:
- the height of a tile.
- Throws:
-
IllegalStateException
- if the input source has not been set. -
IndexOutOfBoundsException
- if the supplied index is out of bounds. -
IOException
- if an error occurs during reading.
getTileGridXOffset
public int getTileGridXOffset(int imageIndex) throws IOException
Returns the X coordinate of the upper-left corner of tile (0, 0) in the given image.
A reader for which the tile grid X offset always has the same value (usually 0), may return the value without accessing any image data. In such cases, it is not necessary to throw an exception even if no input source has been set or the image index is out of bounds.
The default implementation simply returns 0, which is correct for non-tiled images and tiled images in most formats. Readers that support tiling with non-(0, 0) offsets should override this method.
- Parameters:
-
imageIndex
- the index of the image to be queried. - Returns:
- the X offset of the tile grid.
- Throws:
-
IllegalStateException
- if an input source is required to determine the return value, but none has been set. -
IndexOutOfBoundsException
- if an image must be accessed to determine the return value, but the supplied index is out of bounds. -
IOException
- if an error occurs during reading.
getTileGridYOffset
public int getTileGridYOffset(int imageIndex) throws IOException
Returns the Y coordinate of the upper-left corner of tile (0, 0) in the given image.
A reader for which the tile grid Y offset always has the same value (usually 0), may return the value without accessing any image data. In such cases, it is not necessary to throw an exception even if no input source has been set or the image index is out of bounds.
The default implementation simply returns 0, which is correct for non-tiled images and tiled images in most formats. Readers that support tiling with non-(0, 0) offsets should override this method.
- Parameters:
-
imageIndex
- the index of the image to be queried. - Returns:
- the Y offset of the tile grid.
- Throws:
-
IllegalStateException
- if an input source is required to determine the return value, but none has been set. -
IndexOutOfBoundsException
- if an image must be accessed to determine the return value, but the supplied index is out of bounds. -
IOException
- if an error occurs during reading.
readTile
public BufferedImage readTile(int imageIndex, int tileX, int tileY) throws IOException
Reads the tile indicated by the tileX
and tileY
arguments, returning it as a BufferedImage
. If the arguments are out of range, an IllegalArgumentException
is thrown. If the image is not tiled, the values 0, 0 will return the entire image; any other values will cause an IllegalArgumentException
to be thrown.
This method is merely a convenience equivalent to calling read(int, ImageReadParam)
with a read param specifying a source region having offsets of tileX*getTileWidth(imageIndex)
, tileY*getTileHeight(imageIndex)
and width and height of getTileWidth(imageIndex)
, getTileHeight(imageIndex)
; and subsampling factors of 1 and offsets of 0. To subsample a tile, call read
with a read param specifying this region and different subsampling parameters.
The default implementation returns the entire image if tileX
and tileY
are 0, or throws an IllegalArgumentException
otherwise.
- Parameters:
-
imageIndex
- the index of the image to be retrieved. -
tileX
- the column index (starting with 0) of the tile to be retrieved. -
tileY
- the row index (starting with 0) of the tile to be retrieved. - Returns:
- the tile as a
BufferedImage
. - Throws:
-
IllegalStateException
- if the input source has not been set. -
IndexOutOfBoundsException
- ifimageIndex
is out of bounds. -
IllegalArgumentException
- if the tile indices are out of bounds. -
IOException
- if an error occurs during reading.
readTileRaster
public Raster readTileRaster(int imageIndex, int tileX, int tileY) throws IOException
Returns a new Raster
object containing the raw pixel data from the tile, without any color conversion applied. The application must determine how to interpret the pixel data by other means.
If canReadRaster()
returns false
, this method throws an UnsupportedOperationException
.
The default implementation checks if reading Raster
s is supported, and if so calls readRaster(imageIndex, null)
if tileX
and tileY
are 0, or throws an IllegalArgumentException
otherwise.
- Parameters:
-
imageIndex
- the index of the image to be retrieved. -
tileX
- the column index (starting with 0) of the tile to be retrieved. -
tileY
- the row index (starting with 0) of the tile to be retrieved. - Returns:
- the tile as a
Raster
. - Throws:
-
UnsupportedOperationException
- if this plug-in does not support reading rawRaster
s. -
IllegalArgumentException
- if the tile indices are out of bounds. -
IllegalStateException
- if the input source has not been set. -
IndexOutOfBoundsException
- ifimageIndex
is out of bounds. -
IOException
- if an error occurs during reading. - See Also:
-
readTile(int, int, int)
,readRaster(int, javax.imageio.ImageReadParam)
,Raster
readAsRenderedImage
public RenderedImage readAsRenderedImage(int imageIndex, ImageReadParam param) throws IOException
Returns a RenderedImage
object that contains the contents of the image indexed by imageIndex
. By default, the returned image is simply the BufferedImage
returned by read(imageIndex, param)
.
The semantics of this method may differ from those of the other read
methods in several ways. First, any destination image and/or image type set in the ImageReadParam
may be ignored. Second, the usual listener calls are not guaranteed to be made, or to be meaningful if they are. This is because the returned image may not be fully populated with pixel data at the time it is returned, or indeed at any time.
If the supplied ImageReadParam
contains optional setting values not supported by this reader (e.g. source render size or any format-specific settings), they will be ignored.
The default implementation just calls read(imageIndex, param)
.
- Parameters:
-
imageIndex
- the index of the image to be retrieved. -
param
- anImageReadParam
used to control the reading process, ornull
. - Returns:
- a
RenderedImage
object providing a view of the image. - Throws:
-
IllegalStateException
- if the input source has not been set. -
IndexOutOfBoundsException
- if the supplied index is out of bounds. -
IllegalArgumentException
- if the set of source and destination bands specified byparam.getSourceBands
andparam.getDestinationBands
differ in length or include indices that are out of bounds. -
IllegalArgumentException
- if the resulting image would have a width or height less than 1. -
IOException
- if an error occurs during reading.
readerSupportsThumbnails
public boolean readerSupportsThumbnails()
Returns true
if the image format understood by this reader supports thumbnail preview images associated with it. The default implementation returns false
.
If this method returns false
, hasThumbnails
and getNumThumbnails
will return false
and 0
, respectively, and readThumbnail
will throw an UnsupportedOperationException
, regardless of their arguments.
A reader that does not support thumbnails need not implement any of the thumbnail-related methods.
- Returns:
-
true
if thumbnails are supported.
hasThumbnails
public boolean hasThumbnails(int imageIndex) throws IOException
Returns true
if the given image has thumbnail preview images associated with it. If the format does not support thumbnails (readerSupportsThumbnails
returns false
), false
will be returned regardless of whether an input source has been set or whether imageIndex
is in bounds.
The default implementation returns true
if getNumThumbnails
returns a value greater than 0.
- Parameters:
-
imageIndex
- the index of the image being queried. - Returns:
-
true
if the given image has thumbnails. - Throws:
-
IllegalStateException
- if the reader supports thumbnails but the input source has not been set. -
IndexOutOfBoundsException
- if the reader supports thumbnails butimageIndex
is out of bounds. -
IOException
- if an error occurs during reading.
getNumThumbnails
public int getNumThumbnails(int imageIndex) throws IOException
Returns the number of thumbnail preview images associated with the given image. If the format does not support thumbnails, (readerSupportsThumbnails
returns false
), 0
will be returned regardless of whether an input source has been set or whether imageIndex
is in bounds.
The default implementation returns 0 without checking its argument.
- Parameters:
-
imageIndex
- the index of the image being queried. - Returns:
- the number of thumbnails associated with the given image.
- Throws:
-
IllegalStateException
- if the reader supports thumbnails but the input source has not been set. -
IndexOutOfBoundsException
- if the reader supports thumbnails butimageIndex
is out of bounds. -
IOException
- if an error occurs during reading.
getThumbnailWidth
public int getThumbnailWidth(int imageIndex, int thumbnailIndex) throws IOException
Returns the width of the thumbnail preview image indexed by thumbnailIndex
, associated with the image indexed by ImageIndex
.
If the reader does not support thumbnails, (readerSupportsThumbnails
returns false
), an UnsupportedOperationException
will be thrown.
The default implementation simply returns readThumbnail(imageindex, thumbnailIndex).getWidth()
. Subclasses should therefore override this method if possible in order to avoid forcing the thumbnail to be read.
- Parameters:
-
imageIndex
- the index of the image to be retrieved. -
thumbnailIndex
- the index of the thumbnail to be retrieved. - Returns:
- the width of the desired thumbnail as an
int
. - Throws:
-
UnsupportedOperationException
- if thumbnails are not supported. -
IllegalStateException
- if the input source has not been set. -
IndexOutOfBoundsException
- if either of the supplied indices are out of bounds. -
IOException
- if an error occurs during reading.
getThumbnailHeight
public int getThumbnailHeight(int imageIndex, int thumbnailIndex) throws IOException
Returns the height of the thumbnail preview image indexed by thumbnailIndex
, associated with the image indexed by ImageIndex
.
If the reader does not support thumbnails, (readerSupportsThumbnails
returns false
), an UnsupportedOperationException
will be thrown.
The default implementation simply returns readThumbnail(imageindex, thumbnailIndex).getHeight()
. Subclasses should therefore override this method if possible in order to avoid forcing the thumbnail to be read.
- Parameters:
-
imageIndex
- the index of the image to be retrieved. -
thumbnailIndex
- the index of the thumbnail to be retrieved. - Returns:
- the height of the desired thumbnail as an
int
. - Throws:
-
UnsupportedOperationException
- if thumbnails are not supported. -
IllegalStateException
- if the input source has not been set. -
IndexOutOfBoundsException
- if either of the supplied indices are out of bounds. -
IOException
- if an error occurs during reading.
readThumbnail
public BufferedImage readThumbnail(int imageIndex, int thumbnailIndex) throws IOException
Returns the thumbnail preview image indexed by thumbnailIndex
, associated with the image indexed by ImageIndex
as a BufferedImage
.
Any registered IIOReadProgressListener
objects will be notified by calling their thumbnailStarted
, thumbnailProgress
, and thumbnailComplete
methods.
If the reader does not support thumbnails, (readerSupportsThumbnails
returns false
), an UnsupportedOperationException
will be thrown regardless of whether an input source has been set or whether the indices are in bounds.
The default implementation throws an UnsupportedOperationException
.
- Parameters:
-
imageIndex
- the index of the image to be retrieved. -
thumbnailIndex
- the index of the thumbnail to be retrieved. - Returns:
- the desired thumbnail as a
BufferedImage
. - Throws:
-
UnsupportedOperationException
- if thumbnails are not supported. -
IllegalStateException
- if the input source has not been set. -
IndexOutOfBoundsException
- if either of the supplied indices are out of bounds. -
IOException
- if an error occurs during reading.
abort
public void abort()
Requests that any current read operation be aborted. The contents of the image following the abort will be undefined.
Readers should call clearAbortRequest
at the beginning of each read operation, and poll the value of abortRequested
regularly during the read.
abortRequested
protected boolean abortRequested()
Returns true
if a request to abort the current read operation has been made since the reader was instantiated or clearAbortRequest
was called.
- Returns:
-
true
if the current read operation should be aborted. - See Also:
-
abort()
,clearAbortRequest()
clearAbortRequest
protected void clearAbortRequest()
Clears any previous abort request. After this method has been called, abortRequested
will return false
.
- See Also:
-
abort()
,abortRequested()
addIIOReadWarningListener
public void addIIOReadWarningListener(IIOReadWarningListener listener)
Adds an IIOReadWarningListener
to the list of registered warning listeners. If listener
is null
, no exception will be thrown and no action will be taken. Messages sent to the given listener will be localized, if possible, to match the current Locale
. If no Locale
has been set, warning messages may be localized as the reader sees fit.
- Parameters:
-
listener
- anIIOReadWarningListener
to be registered. - See Also:
removeIIOReadWarningListener(javax.imageio.event.IIOReadWarningListener)
removeIIOReadWarningListener
public void removeIIOReadWarningListener(IIOReadWarningListener listener)
Removes an IIOReadWarningListener
from the list of registered error listeners. If the listener was not previously registered, or if listener
is null
, no exception will be thrown and no action will be taken.
- Parameters:
-
listener
- an IIOReadWarningListener to be unregistered. - See Also:
addIIOReadWarningListener(javax.imageio.event.IIOReadWarningListener)
removeAllIIOReadWarningListeners
public void removeAllIIOReadWarningListeners()
Removes all currently registered IIOReadWarningListener
objects.
The default implementation sets the warningListeners
and warningLocales
instance variables to null
.
addIIOReadProgressListener
public void addIIOReadProgressListener(IIOReadProgressListener listener)
Adds an IIOReadProgressListener
to the list of registered progress listeners. If listener
is null
, no exception will be thrown and no action will be taken.
- Parameters:
-
listener
- an IIOReadProgressListener to be registered. - See Also:
removeIIOReadProgressListener(javax.imageio.event.IIOReadProgressListener)
removeIIOReadProgressListener
public void removeIIOReadProgressListener(IIOReadProgressListener listener)
Removes an IIOReadProgressListener
from the list of registered progress listeners. If the listener was not previously registered, or if listener
is null
, no exception will be thrown and no action will be taken.
- Parameters:
-
listener
- an IIOReadProgressListener to be unregistered. - See Also:
addIIOReadProgressListener(javax.imageio.event.IIOReadProgressListener)
removeAllIIOReadProgressListeners
public void removeAllIIOReadProgressListeners()
Removes all currently registered IIOReadProgressListener
objects.
The default implementation sets the progressListeners
instance variable to null
.
addIIOReadUpdateListener
public void addIIOReadUpdateListener(IIOReadUpdateListener listener)
Adds an IIOReadUpdateListener
to the list of registered update listeners. If listener
is null
, no exception will be thrown and no action will be taken. The listener will receive notification of pixel updates as images and thumbnails are decoded, including the starts and ends of progressive passes.
If no update listeners are present, the reader may choose to perform fewer updates to the pixels of the destination images and/or thumbnails, which may result in more efficient decoding.
For example, in progressive JPEG decoding each pass contains updates to a set of coefficients, which would have to be transformed into pixel values and converted to an RGB color space for each pass if listeners are present. If no listeners are present, the coefficients may simply be accumulated and the final results transformed and color converted one time only.
The final results of decoding will be the same whether or not intermediate updates are performed. Thus if only the final image is desired it may be preferable not to register any IIOReadUpdateListener
s. In general, progressive updating is most effective when fetching images over a network connection that is very slow compared to local CPU processing; over a fast connection, progressive updates may actually slow down the presentation of the image.
- Parameters:
-
listener
- an IIOReadUpdateListener to be registered. - See Also:
removeIIOReadUpdateListener(javax.imageio.event.IIOReadUpdateListener)
removeIIOReadUpdateListener
public void removeIIOReadUpdateListener(IIOReadUpdateListener listener)
Removes an IIOReadUpdateListener
from the list of registered update listeners. If the listener was not previously registered, or if listener
is null
, no exception will be thrown and no action will be taken.
- Parameters:
-
listener
- an IIOReadUpdateListener to be unregistered. - See Also:
addIIOReadUpdateListener(javax.imageio.event.IIOReadUpdateListener)
removeAllIIOReadUpdateListeners
public void removeAllIIOReadUpdateListeners()
Removes all currently registered IIOReadUpdateListener
objects.
The default implementation sets the updateListeners
instance variable to null
.
processSequenceStarted
protected void processSequenceStarted(int minIndex)
Broadcasts the start of an sequence of image reads to all registered IIOReadProgressListener
s by calling their sequenceStarted
method. Subclasses may use this method as a convenience.
- Parameters:
-
minIndex
- the lowest index being read.
processSequenceComplete
protected void processSequenceComplete()
Broadcasts the completion of an sequence of image reads to all registered IIOReadProgressListener
s by calling their sequenceComplete
method. Subclasses may use this method as a convenience.
processImageStarted
protected void processImageStarted(int imageIndex)
Broadcasts the start of an image read to all registered IIOReadProgressListener
s by calling their imageStarted
method. Subclasses may use this method as a convenience.
- Parameters:
-
imageIndex
- the index of the image about to be read.
processImageProgress
protected void processImageProgress(float percentageDone)
Broadcasts the current percentage of image completion to all registered IIOReadProgressListener
s by calling their imageProgress
method. Subclasses may use this method as a convenience.
- Parameters:
-
percentageDone
- the current percentage of completion, as afloat
.
processImageComplete
protected void processImageComplete()
Broadcasts the completion of an image read to all registered IIOReadProgressListener
s by calling their imageComplete
method. Subclasses may use this method as a convenience.
processThumbnailStarted
protected void processThumbnailStarted(int imageIndex, int thumbnailIndex)
Broadcasts the start of a thumbnail read to all registered IIOReadProgressListener
s by calling their thumbnailStarted
method. Subclasses may use this method as a convenience.
- Parameters:
-
imageIndex
- the index of the image associated with the thumbnail. -
thumbnailIndex
- the index of the thumbnail.
processThumbnailProgress
protected void processThumbnailProgress(float percentageDone)
Broadcasts the current percentage of thumbnail completion to all registered IIOReadProgressListener
s by calling their thumbnailProgress
method. Subclasses may use this method as a convenience.
- Parameters:
-
percentageDone
- the current percentage of completion, as afloat
.
processThumbnailComplete
protected void processThumbnailComplete()
Broadcasts the completion of a thumbnail read to all registered IIOReadProgressListener
s by calling their thumbnailComplete
method. Subclasses may use this method as a convenience.
processReadAborted
protected void processReadAborted()
Broadcasts that the read has been aborted to all registered IIOReadProgressListener
s by calling their readAborted
method. Subclasses may use this method as a convenience.
processPassStarted
protected void processPassStarted(BufferedImage theImage, int pass, int minPass, int maxPass, int minX, int minY, int periodX, int periodY, int[] bands)
Broadcasts the beginning of a progressive pass to all registered IIOReadUpdateListener
s by calling their passStarted
method. Subclasses may use this method as a convenience.
- Parameters:
-
theImage
- theBufferedImage
being updated. -
pass
- the index of the current pass, starting with 0. -
minPass
- the index of the first pass that will be decoded. -
maxPass
- the index of the last pass that will be decoded. -
minX
- the X coordinate of the upper-left pixel included in the pass. -
minY
- the X coordinate of the upper-left pixel included in the pass. -
periodX
- the horizontal separation between pixels. -
periodY
- the vertical separation between pixels. -
bands
- an array ofint
s indicating the set of affected bands of the destination.
processImageUpdate
protected void processImageUpdate(BufferedImage theImage, int minX, int minY, int width, int height, int periodX, int periodY, int[] bands)
Broadcasts the update of a set of samples to all registered IIOReadUpdateListener
s by calling their imageUpdate
method. Subclasses may use this method as a convenience.
- Parameters:
-
theImage
- theBufferedImage
being updated. -
minX
- the X coordinate of the upper-left pixel included in the pass. -
minY
- the X coordinate of the upper-left pixel included in the pass. -
width
- the total width of the area being updated, including pixels being skipped ifperiodX > 1
. -
height
- the total height of the area being updated, including pixels being skipped ifperiodY > 1
. -
periodX
- the horizontal separation between pixels. -
periodY
- the vertical separation between pixels. -
bands
- an array ofint
s indicating the set of affected bands of the destination.
processPassComplete
protected void processPassComplete(BufferedImage theImage)
Broadcasts the end of a progressive pass to all registered IIOReadUpdateListener
s by calling their passComplete
method. Subclasses may use this method as a convenience.
- Parameters:
-
theImage
- theBufferedImage
being updated.
processThumbnailPassStarted
protected void processThumbnailPassStarted(BufferedImage theThumbnail, int pass, int minPass, int maxPass, int minX, int minY, int periodX, int periodY, int[] bands)
Broadcasts the beginning of a thumbnail progressive pass to all registered IIOReadUpdateListener
s by calling their thumbnailPassStarted
method. Subclasses may use this method as a convenience.
- Parameters:
-
theThumbnail
- theBufferedImage
thumbnail being updated. -
pass
- the index of the current pass, starting with 0. -
minPass
- the index of the first pass that will be decoded. -
maxPass
- the index of the last pass that will be decoded. -
minX
- the X coordinate of the upper-left pixel included in the pass. -
minY
- the X coordinate of the upper-left pixel included in the pass. -
periodX
- the horizontal separation between pixels. -
periodY
- the vertical separation between pixels. -
bands
- an array ofint
s indicating the set of affected bands of the destination.
processThumbnailUpdate
protected void processThumbnailUpdate(BufferedImage theThumbnail, int minX, int minY, int width, int height, int periodX, int periodY, int[] bands)
Broadcasts the update of a set of samples in a thumbnail image to all registered IIOReadUpdateListener
s by calling their thumbnailUpdate
method. Subclasses may use this method as a convenience.
- Parameters:
-
theThumbnail
- theBufferedImage
thumbnail being updated. -
minX
- the X coordinate of the upper-left pixel included in the pass. -
minY
- the X coordinate of the upper-left pixel included in the pass. -
width
- the total width of the area being updated, including pixels being skipped ifperiodX > 1
. -
height
- the total height of the area being updated, including pixels being skipped ifperiodY > 1
. -
periodX
- the horizontal separation between pixels. -
periodY
- the vertical separation between pixels. -
bands
- an array ofint
s indicating the set of affected bands of the destination.
processThumbnailPassComplete
protected void processThumbnailPassComplete(BufferedImage theThumbnail)
Broadcasts the end of a thumbnail progressive pass to all registered IIOReadUpdateListener
s by calling their thumbnailPassComplete
method. Subclasses may use this method as a convenience.
- Parameters:
-
theThumbnail
- theBufferedImage
thumbnail being updated.
processWarningOccurred
protected void processWarningOccurred(String warning)
Broadcasts a warning message to all registered IIOReadWarningListener
s by calling their warningOccurred
method. Subclasses may use this method as a convenience.
- Parameters:
-
warning
- the warning message to send. - Throws:
-
IllegalArgumentException
- ifwarning
isnull
.
processWarningOccurred
protected void processWarningOccurred(String baseName, String keyword)
Broadcasts a localized warning message to all registered IIOReadWarningListener
s by calling their warningOccurred
method with a string taken from a ResourceBundle
. Subclasses may use this method as a convenience.
- Parameters:
-
baseName
- the base name of a set ofResourceBundle
s containing localized warning messages. -
keyword
- the keyword used to index the warning message within the set ofResourceBundle
s. - Throws:
-
IllegalArgumentException
- ifbaseName
isnull
. -
IllegalArgumentException
- ifkeyword
isnull
. -
IllegalArgumentException
- if no appropriateResourceBundle
may be located. -
IllegalArgumentException
- if the named resource is not found in the locatedResourceBundle
. -
IllegalArgumentException
- if the object retrieved from theResourceBundle
is not aString
.
reset
public void reset()
Restores the ImageReader
to its initial state.
The default implementation calls setInput(null, false)
, setLocale(null)
, removeAllIIOReadUpdateListeners()
, removeAllIIOReadWarningListeners()
, removeAllIIOReadProgressListeners()
, and clearAbortRequest
.
dispose
public void dispose()
Allows any resources held by this object to be released. The result of calling any other method (other than finalize
) subsequent to a call to this method is undefined.
It is important for applications to call this method when they know they will no longer be using this ImageReader
. Otherwise, the reader may continue to hold on to resources indefinitely.
The default implementation of this method in the superclass does nothing. Subclass implementations should ensure that all resources, especially native resources, are released.
getSourceRegion
protected static Rectangle getSourceRegion(ImageReadParam param, int srcWidth, int srcHeight)
A utility method that may be used by readers to compute the region of the source image that should be read, taking into account any source region and subsampling offset settings in the supplied ImageReadParam
. The actual subsampling factors, destination size, and destination offset are not taken into consideration, thus further clipping must take place. The computeRegions
method performs all necessary clipping.
- Parameters:
-
param
- theImageReadParam
being used, ornull
. -
srcWidth
- the width of the source image. -
srcHeight
- the height of the source image. - Returns:
- the source region as a
Rectangle
.
computeRegions
protected static void computeRegions(ImageReadParam param, int srcWidth, int srcHeight, BufferedImage image, Rectangle srcRegion, Rectangle destRegion)
Computes the source region of interest and the destination region of interest, taking the width and height of the source image, an optional destination image, and an optional ImageReadParam
into account. The source region begins with the entire source image. Then that is clipped to the source region specified in the ImageReadParam
, if one is specified.
If either of the destination offsets are negative, the source region is clipped so that its top left will coincide with the top left of the destination image, taking subsampling into account. Then the result is clipped to the destination image on the right and bottom, if one is specified, taking subsampling and destination offsets into account.
Similarly, the destination region begins with the source image, is translated to the destination offset given in the ImageReadParam
if there is one, and finally is clipped to the destination image, if there is one.
If either the source or destination regions end up having a width or height of 0, an IllegalArgumentException
is thrown.
The getSourceRegion>
method may be used if only source clipping is desired.
- Parameters:
-
param
- anImageReadParam
, ornull
. -
srcWidth
- the width of the source image. -
srcHeight
- the height of the source image. -
image
- aBufferedImage
that will be the destination image, ornull
. -
srcRegion
- aRectangle
that will be filled with the source region of interest. -
destRegion
- aRectangle
that will be filled with the destination region of interest. - Throws:
-
IllegalArgumentException
- ifsrcRegion
isnull
. -
IllegalArgumentException
- ifdstRegion
isnull
. -
IllegalArgumentException
- if the resulting source or destination region is empty.
checkReadParamBandSettings
protected static void checkReadParamBandSettings(ImageReadParam param, int numSrcBands, int numDstBands)
A utility method that may be used by readers to test the validity of the source and destination band settings of an ImageReadParam
. This method may be called as soon as the reader knows both the number of bands of the source image as it exists in the input stream, and the number of bands of the destination image that being written.
The method retrieves the source and destination band setting arrays from param using the getSourceBands
and getDestinationBands
methods (or considers them to be null
if param
is null
). If the source band setting array is null
, it is considered to be equal to the array { 0, 1, ..., numSrcBands - 1 }
, and similarly for the destination band setting array.
The method then tests that both arrays are equal in length, and that neither array contains a value larger than the largest available band index.
Any failure results in an IllegalArgumentException
being thrown; success results in the method returning silently.
- Parameters:
-
param
- theImageReadParam
being used to read the image. -
numSrcBands
- the number of bands of the image as it exists int the input source. -
numDstBands
- the number of bands in the destination image being written. - Throws:
-
IllegalArgumentException
- ifparam
contains an invalid specification of a source and/or destination band subset.
getDestination
protected static BufferedImage getDestination(ImageReadParam param, Iterator<ImageTypeSpecifier> imageTypes, int width, int height) throws IIOException
Returns the BufferedImage
to which decoded pixel data should be written. The image is determined by inspecting the supplied ImageReadParam
if it is non-null
; if its getDestination
method returns a non-null
value, that image is simply returned. Otherwise, param.getDestinationType
method is called to determine if a particular image type has been specified. If so, the returned ImageTypeSpecifier
is used after checking that it is equal to one of those included in imageTypes
.
If param
is null
or the above steps have not yielded an image or an ImageTypeSpecifier
, the first value obtained from the imageTypes
parameter is used. Typically, the caller will set imageTypes
to the value of getImageTypes(imageIndex)
.
Next, the dimensions of the image are determined by a call to computeRegions
. The actual width and height of the image being decoded are passed in as the width
and height
parameters.
- Parameters:
-
param
- anImageReadParam
to be used to get the destination image or image type, ornull
. -
imageTypes
- anIterator
ofImageTypeSpecifier
s indicating the legal image types, with the default first. -
width
- the true width of the image or tile being decoded. -
height
- the true width of the image or tile being decoded. - Returns:
- the
BufferedImage
to which decoded pixel data should be written. - Throws:
-
IIOException
- if theImageTypeSpecifier
specified byparam
does not match any of the legal ones fromimageTypes
. -
IllegalArgumentException
- ifimageTypes
isnull
or empty, or if an object not of typeImageTypeSpecifier
is retrieved from it. -
IllegalArgumentException
- if the resulting image would have a width or height less than 1. -
IllegalArgumentException
- if the product ofwidth
andheight
is greater thanInteger.MAX_VALUE
.