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| java.lang.Object
 javax.imageio.ImageIO
| ImageIO | | final public class ImageIO (Code) | | A class containing static convenience methods for locating
ImageReaders and ImageWriters, and
performing simple encoding and decoding.
version:
0.5 |
| Inner Class :static class CacheInfo | |
| Method Summary | |
| public static ImageInputStream | createImageInputStream(Object input)
Returns an ImageInputStream that will take its
input from the given Object. | | public static ImageOutputStream | createImageOutputStream(Object output)
Returns an ImageOutputStream that will send its
output to the given Object. | | public static File | getCacheDirectory()
Returns the current value set by
setCacheDirectory, or null if no
explicit setting has been made. | | public static ImageReader | getImageReader(ImageWriter writer)
Returns an ImageReadercorresponding to the given
ImageWriter, if there is one, or null
if the plug-in for this ImageWriter does not
specify a corresponding ImageReader, or if the
given ImageWriter is not registered. | | public static Iterator<ImageReader> | getImageReaders(Object input)
Returns an Iterator containing all currently
registered ImageReaders that claim to be able to
decode the supplied Object, typically an
ImageInputStream.
The stream position is left at its prior position upon
exit from this method.
Parameters:
input - an ImageInputStream or otherObject containing encoded image data. | | public static Iterator<ImageReader> | getImageReadersByFormatName(String formatName)
Returns an Iterator containing all currently
registered ImageReaders that claim to be able to
decode the named format.
Parameters:
formatName - a String containing the informalname of a format (e.g., "jpeg" or "tiff". | | public static Iterator<ImageReader> | getImageReadersByMIMEType(String MIMEType)
Returns an Iterator containing all currently
registered ImageReaders that claim to be able to
decode files with the given MIME type.
Parameters:
MIMEType - a String containing a filesuffix (e.g., "image/jpeg" or "image/x-bmp"). | | public static Iterator<ImageReader> | getImageReadersBySuffix(String fileSuffix)
Returns an Iterator containing all currently
registered ImageReaders that claim to be able to
decode files with the given suffix.
Parameters:
fileSuffix - a String containing a filesuffix (e.g., "jpg" or "tiff"). | | public static Iterator<ImageTranscoder> | getImageTranscoders(ImageReader reader, ImageWriter writer)
Returns an Iterator containing all currently
registered ImageTranscoders that claim to be
able to transcode between the metadata of the given
ImageReader and ImageWriter.
Parameters:
reader - an ImageReader.
Parameters:
writer - an ImageWriter. | | public static ImageWriter | getImageWriter(ImageReader reader)
Returns an ImageWritercorresponding to the given
ImageReader, if there is one, or null
if the plug-in for this ImageReader does not
specify a corresponding ImageWriter, or if the
given ImageReader is not registered. | | public static Iterator<ImageWriter> | getImageWriters(ImageTypeSpecifier type, String formatName)
Returns an Iterator containing all currently
registered ImageWriters that claim to be able to
encode images of the given layout (specified using an
ImageTypeSpecifier) in the given format.
Parameters:
type - an ImageTypeSpecifier indicating thelayout of the image to be written.
Parameters:
formatName - the informal name of the format. | | public static Iterator<ImageWriter> | getImageWritersByFormatName(String formatName)
Returns an Iterator containing all currently
registered ImageWriters that claim to be able to
encode the named format.
Parameters:
formatName - a String containing the informalname of a format (e.g., "jpeg" or "tiff". | | public static Iterator<ImageWriter> | getImageWritersByMIMEType(String MIMEType)
Returns an Iterator containing all currently
registered ImageWriters that claim to be able to
encode files with the given MIME type.
Parameters:
MIMEType - a String containing a filesuffix (e.g., "image/jpeg" or "image/x-bmp"). | | public static Iterator<ImageWriter> | getImageWritersBySuffix(String fileSuffix)
Returns an Iterator containing all currently
registered ImageWriters that claim to be able to
encode files with the given suffix.
Parameters:
fileSuffix - a String containing a filesuffix (e.g., "jpg" or "tiff"). | | public static String[] | getReaderFileSuffixes()
Returns an array of Strings listing all of the
file suffixes associated with the formats understood
by the current set of registered readers. | | public static String[] | getReaderFormatNames()
Returns an array of Strings listing all of the
informal format names understood by the current set of registered
readers. | | public static String[] | getReaderMIMETypes()
Returns an array of Strings listing all of the
MIME types understood by the current set of registered
readers. | | public static boolean | getUseCache()
Returns the current value set by setUseCache, or
true if no explicit setting has been made. | | public static String[] | getWriterFileSuffixes()
Returns an array of Strings listing all of the
file suffixes associated with the formats understood
by the current set of registered writers. | | public static String[] | getWriterFormatNames()
Returns an array of Strings listing all of the
informal format names understood by the current set of registered
writers. | | public static String[] | getWriterMIMETypes()
Returns an array of Strings listing all of the
MIME types understood by the current set of registered
writers. | | public static BufferedImage | read(File input)
Returns a BufferedImage as the result of decoding
a supplied File with an ImageReader
chosen automatically from among those currently registered.
The File is wrapped in an
ImageInputStream. | | public static BufferedImage | read(InputStream input)
Returns a BufferedImage as the result of decoding
a supplied InputStream with an ImageReader
chosen automatically from among those currently registered.
The InputStream is wrapped in an
ImageInputStream. | | public static BufferedImage | read(URL input)
Returns a BufferedImage as the result of decoding
a supplied URL with an ImageReader
chosen automatically from among those currently registered. | | public static BufferedImage | read(ImageInputStream stream)
Returns a BufferedImage as the result of decoding
a supplied ImageInputStream with an
ImageReader chosen automatically from among those
currently registered. | | public static void | scanForPlugins()
Scans for plug-ins on the application class path,
loads their service provider classes, and registers a service
provider instance for each one found with the
IIORegistry.
This method is needed because the application class path can
theoretically change, or additional plug-ins may become available.
Rather than re-scanning the classpath on every invocation of the
API, the class path is scanned automatically only on the first
invocation. | | public static void | setCacheDirectory(File cacheDirectory)
Sets the directory where cache files are to be created. | | public static void | setUseCache(boolean useCache)
Sets a flag indicating whether a disk-based cache file should
be used when creating ImageInputStreams and
ImageOutputStreams.
When reading from a standard InputStream>, it
may be necessary to save previously read information in a cache
since the underlying stream does not allow data to be re-read.
Similarly, when writing to a standard
OutputStream, a cache may be used to allow a
previously written value to be changed before flushing it to
the final destination.
The cache may reside in main memory or on disk. | | public static boolean | write(RenderedImage im, String formatName, ImageOutputStream output)
Writes an image using the an arbitrary ImageWriter
that supports the given format to an
ImageOutputStream. | | public static boolean | write(RenderedImage im, String formatName, File output)
Writes an image using an arbitrary ImageWriter
that supports the given format to a File. | | public static boolean | write(RenderedImage im, String formatName, OutputStream output)
Writes an image using an arbitrary ImageWriter
that supports the given format to an OutputStream.
This method does not close the provided
OutputStream after the write operation has completed;
it is the responsibility of the caller to close the stream, if desired.
The current cache settings from getUseCacheand
getCacheDirectory will be used to control caching.
Parameters:
im - a RenderedImage to be written.
Parameters:
formatName - a String containg the informalname of the format.
Parameters:
output - an OutputStream to be written to. |
| createImageInputStream | | public static ImageInputStream createImageInputStream(Object input) throws IOException(Code) | | Returns an ImageInputStream that will take its
input from the given Object. The set of
ImageInputStreamSpis registered with the
IIORegistry class is queried and the first one
that is able to take input from the supplied object is used to
create the returned ImageInputStream. If no
suitable ImageInputStreamSpi exists,
null is returned.
The current cache settings from getUseCacheand
getCacheDirectory will be used to control caching.
Parameters:
input - an Object to be used as an inputsource, such as a File, readableRandomAccessFile, or InputStream. an ImageInputStream, or null.
exception:
IllegalArgumentException - if inputis null.
exception:
IOException - if a cache file is needed but cannot becreated.
See Also: javax.imageio.spi.ImageInputStreamSpi |
| createImageOutputStream | | public static ImageOutputStream createImageOutputStream(Object output) throws IOException(Code) | | Returns an ImageOutputStream that will send its
output to the given Object. The set of
ImageOutputStreamSpis registered with the
IIORegistry class is queried and the first one
that is able to send output from the supplied object is used to
create the returned ImageOutputStream. If no
suitable ImageOutputStreamSpi exists,
null is returned.
The current cache settings from getUseCacheand
getCacheDirectory will be used to control caching.
Parameters:
output - an Object to be used as an outputdestination, such as a File, writableRandomAccessFile, or OutputStream. an ImageOutputStream, ornull.
exception:
IllegalArgumentException - if output isnull.
exception:
IOException - if a cache file is needed but cannot becreated.
See Also: javax.imageio.spi.ImageOutputStreamSpi |
| getCacheDirectory | | public static File getCacheDirectory()(Code) | | Returns the current value set by
setCacheDirectory, or null if no
explicit setting has been made.
a File indicating the directory wherecache files will be created, or null to indicatethe system-dependent default temporary-file directory.
See Also: ImageIO.setCacheDirectory |
| getImageReader | | public static ImageReader getImageReader(ImageWriter writer)(Code) | | Returns an ImageReadercorresponding to the given
ImageWriter, if there is one, or null
if the plug-in for this ImageWriter does not
specify a corresponding ImageReader, or if the
given ImageWriter is not registered. This method
is provided principally for symmetry with
getImageWriter(ImageReader). Note that this
method returns the "preferred" reader, which is the first in
the list returned by
javax.imageio.spi.ImageWriterSpi.getImageReaderSpiNames().
Parameters:
writer - an instance of a registered ImageWriter. an ImageReader, or null.
exception:
IllegalArgumentException - if writer isnull.
See Also: ImageIO.getImageWriter(ImageReader)
See Also: javax.imageio.spi.ImageWriterSpi.getImageReaderSpiNames |
| getImageReaders | | public static Iterator<ImageReader> getImageReaders(Object input)(Code) | | Returns an Iterator containing all currently
registered ImageReaders that claim to be able to
decode the supplied Object, typically an
ImageInputStream.
The stream position is left at its prior position upon
exit from this method.
Parameters:
input - an ImageInputStream or otherObject containing encoded image data. an Iterator containing ImageReaders.
exception:
IllegalArgumentException - if input isnull.
See Also: javax.imageio.spi.ImageReaderSpi.canDecodeInput |
| getImageTranscoders | | public static Iterator<ImageTranscoder> getImageTranscoders(ImageReader reader, ImageWriter writer)(Code) | | Returns an Iterator containing all currently
registered ImageTranscoders that claim to be
able to transcode between the metadata of the given
ImageReader and ImageWriter.
Parameters:
reader - an ImageReader.
Parameters:
writer - an ImageWriter. an Iterator containingImageTranscoders.
exception:
IllegalArgumentException - if reader orwriter is null. |
| getImageWriter | | public static ImageWriter getImageWriter(ImageReader reader)(Code) | | Returns an ImageWritercorresponding to the given
ImageReader, if there is one, or null
if the plug-in for this ImageReader does not
specify a corresponding ImageWriter, or if the
given ImageReader is not registered. This
mechanism may be used to obtain an ImageWriter
that will understand the internal structure of non-pixel
metadata (as encoded by IIOMetadata objects)
generated by the ImageReader. By obtaining this
data from the ImageReader and passing it on to the
ImageWriter obtained with this method, a client
program can read an image, modify it in some way, and write it
back out preserving all metadata, without having to understand
anything about the structure of the metadata, or even about
the image format. Note that this method returns the
"preferred" writer, which is the first in the list returned by
javax.imageio.spi.ImageReaderSpi.getImageWriterSpiNames().
Parameters:
reader - an instance of a registered ImageReader. an ImageWriter, or null.
exception:
IllegalArgumentException - if reader isnull.
See Also: ImageIO.getImageReader(ImageWriter)
See Also: javax.imageio.spi.ImageReaderSpi.getImageWriterSpiNames |
| getReaderFileSuffixes | | public static String[] getReaderFileSuffixes()(Code) | | Returns an array of Strings listing all of the
file suffixes associated with the formats understood
by the current set of registered readers.
an array of Strings.
since:
1.6 |
| getReaderFormatNames | | public static String[] getReaderFormatNames()(Code) | | Returns an array of Strings listing all of the
informal format names understood by the current set of registered
readers.
an array of Strings. |
| getReaderMIMETypes | | public static String[] getReaderMIMETypes()(Code) | | Returns an array of Strings listing all of the
MIME types understood by the current set of registered
readers.
an array of Strings. |
| getUseCache | | public static boolean getUseCache()(Code) | | Returns the current value set by setUseCache, or
true if no explicit setting has been made.
true if a disk-based cache may be used forImageInputStreams andImageOutputStreams.
See Also: ImageIO.setUseCache |
| getWriterFileSuffixes | | public static String[] getWriterFileSuffixes()(Code) | | Returns an array of Strings listing all of the
file suffixes associated with the formats understood
by the current set of registered writers.
an array of Strings.
since:
1.6 |
| getWriterFormatNames | | public static String[] getWriterFormatNames()(Code) | | Returns an array of Strings listing all of the
informal format names understood by the current set of registered
writers.
an array of Strings. |
| getWriterMIMETypes | | public static String[] getWriterMIMETypes()(Code) | | Returns an array of Strings listing all of the
MIME types understood by the current set of registered
writers.
an array of Strings. |
| read | | public static BufferedImage read(File input) throws IOException(Code) | | Returns a BufferedImage as the result of decoding
a supplied File with an ImageReader
chosen automatically from among those currently registered.
The File is wrapped in an
ImageInputStream. If no registered
ImageReader claims to be able to read the
resulting stream, null is returned.
The current cache settings from getUseCacheand
getCacheDirectory will be used to control caching in the
ImageInputStream that is created.
Note that there is no read method that takes a
filename as a String; use this method instead after
creating a File from the filename.
This method does not attempt to locate
ImageReaders that can read directly from a
File; that may be accomplished using
IIORegistry and ImageReaderSpi.
Parameters:
input - a File to read from. a BufferedImage containing the decodedcontents of the input, or null.
exception:
IllegalArgumentException - if input is null.
exception:
IOException - if an error occurs during reading. |
| read | | public static BufferedImage read(InputStream input) throws IOException(Code) | | Returns a BufferedImage as the result of decoding
a supplied InputStream with an ImageReader
chosen automatically from among those currently registered.
The InputStream is wrapped in an
ImageInputStream. If no registered
ImageReader claims to be able to read the
resulting stream, null is returned.
The current cache settings from getUseCacheand
getCacheDirectory will be used to control caching in the
ImageInputStream that is created.
This method does not attempt to locate
ImageReaders that can read directly from an
InputStream; that may be accomplished using
IIORegistry and ImageReaderSpi.
This method does not close the provided
InputStream after the read operation has completed;
it is the responsibility of the caller to close the stream, if desired.
Parameters:
input - an InputStream to read from. a BufferedImage containing the decodedcontents of the input, or null.
exception:
IllegalArgumentException - if input is null.
exception:
IOException - if an error occurs during reading. |
| read | | public static BufferedImage read(URL input) throws IOException(Code) | | Returns a BufferedImage as the result of decoding
a supplied URL with an ImageReader
chosen automatically from among those currently registered. An
InputStream is obtained from the URL,
which is wrapped in an ImageInputStream. If no
registered ImageReader claims to be able to read
the resulting stream, null is returned.
The current cache settings from getUseCacheand
getCacheDirectory will be used to control caching in the
ImageInputStream that is created.
This method does not attempt to locate
ImageReaders that can read directly from a
URL; that may be accomplished using
IIORegistry and ImageReaderSpi.
Parameters:
input - a URL to read from. a BufferedImage containing the decodedcontents of the input, or null.
exception:
IllegalArgumentException - if input is null.
exception:
IOException - if an error occurs during reading. |
| read | | public static BufferedImage read(ImageInputStream stream) throws IOException(Code) | | Returns a BufferedImage as the result of decoding
a supplied ImageInputStream with an
ImageReader chosen automatically from among those
currently registered. If no registered
ImageReader claims to be able to read the stream,
null is returned.
Unlike most other methods in this class, this method does
close the provided ImageInputStream after the read
operation has completed, unless null is returned,
in which case this method does not close the stream.
Parameters:
stream - an ImageInputStream to read from. a BufferedImage containing the decodedcontents of the input, or null.
exception:
IllegalArgumentException - if stream is null.
exception:
IOException - if an error occurs during reading. |
| scanForPlugins | | public static void scanForPlugins()(Code) | | Scans for plug-ins on the application class path,
loads their service provider classes, and registers a service
provider instance for each one found with the
IIORegistry.
This method is needed because the application class path can
theoretically change, or additional plug-ins may become available.
Rather than re-scanning the classpath on every invocation of the
API, the class path is scanned automatically only on the first
invocation. Clients can call this method to prompt a re-scan.
Thus this method need only be invoked by sophisticated applications
which dynamically make new plug-ins available at runtime.
The getResources method of the context
ClassLoader is used locate JAR files containing
files named
META-INF/services/javax.imageio.spi.classname,
where classname is one of ImageReaderSpi,
ImageWriterSpi, ImageTranscoderSpi,
ImageInputStreamSpi, or
ImageOutputStreamSpi, along the application class
path.
The contents of the located files indicate the names of
actual implementation classes which implement the
aforementioned service provider interfaces; the default class
loader is then used to load each of these classes and to
instantiate an instance of each class, which is then placed
into the registry for later retrieval.
The exact set of locations searched depends on the
implementation of the Java runtime enviroment.
See Also: ClassLoader.getResources |
| setCacheDirectory | | public static void setCacheDirectory(File cacheDirectory)(Code) | | Sets the directory where cache files are to be created. A
value of null indicates that the system-dependent
default temporary-file directory is to be used. If
getUseCache returns false, this value is ignored.
Parameters:
cacheDirectory - a File specifying a directory.
See Also: File.createTempFile(StringStringFile)
exception:
SecurityException - if the security manager deniesaccess to the directory.
exception:
IllegalArgumentException - if cacheDir isnon-null but is not a directory.
See Also: ImageIO.getCacheDirectory |
| setUseCache | | public static void setUseCache(boolean useCache)(Code) | | Sets a flag indicating whether a disk-based cache file should
be used when creating ImageInputStreams and
ImageOutputStreams.
When reading from a standard InputStream>, it
may be necessary to save previously read information in a cache
since the underlying stream does not allow data to be re-read.
Similarly, when writing to a standard
OutputStream, a cache may be used to allow a
previously written value to be changed before flushing it to
the final destination.
The cache may reside in main memory or on disk. Setting
this flag to false disallows the use of disk for
future streams, which may be advantageous when working with
small images, as the overhead of creating and destroying files
is removed.
On startup, the value is set to true.
Parameters:
useCache - a boolean indicating whether acache file should be used, in cases where it is optional.
See Also: ImageIO.getUseCache |
| write | | public static boolean write(RenderedImage im, String formatName, ImageOutputStream output) throws IOException(Code) | | Writes an image using the an arbitrary ImageWriter
that supports the given format to an
ImageOutputStream. The image is written to the
ImageOutputStream starting at the current stream
pointer, overwriting existing stream data from that point
forward, if present.
This method does not close the provided
ImageOutputStream after the write operation has completed;
it is the responsibility of the caller to close the stream, if desired.
Parameters:
im - a RenderedImage to be written.
Parameters:
formatName - a String containg the informalname of the format.
Parameters:
output - an ImageOutputStream to be written to. false if no appropriate writer is found.
exception:
IllegalArgumentException - if any parameter isnull.
exception:
IOException - if an error occurs during writing. |
| write | | public static boolean write(RenderedImage im, String formatName, File output) throws IOException(Code) | | Writes an image using an arbitrary ImageWriter
that supports the given format to a File. If
there is already a File present, its contents are
discarded.
Parameters:
im - a RenderedImage to be written.
Parameters:
formatName - a String containg the informalname of the format.
Parameters:
output - a File to be written to. false if no appropriate writer is found.
exception:
IllegalArgumentException - if any parameter isnull.
exception:
IOException - if an error occurs during writing. |
| write | | public static boolean write(RenderedImage im, String formatName, OutputStream output) throws IOException(Code) | | Writes an image using an arbitrary ImageWriter
that supports the given format to an OutputStream.
This method does not close the provided
OutputStream after the write operation has completed;
it is the responsibility of the caller to close the stream, if desired.
The current cache settings from getUseCacheand
getCacheDirectory will be used to control caching.
Parameters:
im - a RenderedImage to be written.
Parameters:
formatName - a String containg the informalname of the format.
Parameters:
output - an OutputStream to be written to. false if no appropriate writer is found.
exception:
IllegalArgumentException - if any parameter isnull.
exception:
IOException - if an error occurs during writing. |
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