Class ImageIO

public static ImageInputStream createImageInputStream(Object input)
            throws IOException

Create an image input stream from the given object. The collection of ImageInputStreamSpis registered with the IIORegistry is searched for an image input stream that can take input from the given object. null is returned if no such SPI is registered. The image data will be cached in the current cache directory if caching is enabled.

Parameters:

input - an object from which to read image data

Returns:

an ImageInputStream that can read data from input, or null

Throws:

IllegalArgumentException - if input is null

IOException - if caching is required but not enabled

public static ImageOutputStream createImageOutputStream(Object output)
            throws IOException

Create an image output stream from the given object. The collection of ImageOutputStreamSpis registered with the IIORegistry is searched for an image output stream that can send output to the given object. null is returned if no such SPI is registered. The image data will be cached in the current cache directory if caching is enabled.

Parameters:

output - an object to which to write image data

Returns:

an ImageOutputStream that can send data to output, or null

Throws:

IllegalArgumentException - if output is null

IOException - if caching is required but not enabled

public static File getCacheDirectory()

Retrieve the current cache directory.

Returns:

the current cache directory or null if none is set.

public static ImageReader getImageReader(ImageWriter writer)

Retrieve an image reader corresponding to an image writer, or null if writer is not registered or if no corresponding reader is registered.

Parameters:

writer - a registered image writer

Returns:

an image reader corresponding to writer, or null

Throws:

IllegalArgumentException - if writer is null

public static Iterator getImageReaders(Object input)

Retrieve an iterator over the collection of registered image readers that support reading data from the given object.

Parameters:

input - the object for which to retrieve image readers

Returns:

an iterator over a collection of image readers

public static Iterator getImageReadersByFormatName(String formatName)

Retrieve an iterator over all registered readers for the given format.

Parameters:

formatName - an infomal format name (e.g. "jpeg" or "bmp")

Returns:

an iterator over a collection of image readers

Throws:

IllegalArgumentException - if formatName is null

public static Iterator getImageReadersByMIMEType(String MIMEType)

Retrieve an iterator over all registered readers for the given MIME type.

Parameters:

MIMEType - a MIME specification for an image type (e.g. "image/jpeg" or "image/x-bmp")

Returns:

an iterator over a collection of image readers

Throws:

IllegalArgumentException - if MIMEType is null

public static Iterator getImageReadersBySuffix(String fileSuffix)

Retrieve an iterator over all registered readers for the given file suffix.

Parameters:

fileSuffix - an image file suffix (e.g. "jpg" or "bmp")

Returns:

an iterator over a collection of image readers

Throws:

IllegalArgumentException - if fileSuffix is null

public static Iterator getImageTranscoders(ImageReader reader,
                                                            ImageWriter writer)

Retrieve an iterator over a collection of image transcoders that support transcoding from the given image reader's metadata format to the given writer's metadata format.

Parameters:

reader - an image reader

writer - an image writer

Returns:

an iterator over a collection of image transcoders

Throws:

IllegalArgumentException - if either reader or writer is null

public static ImageWriter getImageWriter(ImageReader reader)

Retrieve an image writer corresponding to an image reader, or null if reader is not registered or if no corresponding writer is registered. This method is useful for preserving metadata without needing to understand its format, since the returned writer will be able to write, unchanged, the metadata passed to it by the reader.

Parameters:

reader - a registered image reader

Returns:

an image writer corresponding to reader, or null

Throws:

IllegalArgumentException - if reader is null

public static Iterator getImageWriters(ImageTypeSpecifier type,
                                                    String formatName)

Retrieve an iterator over the collection of registered image writers that support writing images of the given type and in the given format.

Parameters:

type - the output image's colour and sample models

formatName - the output image format

Returns:

an iterator over a collection of image writers

public static Iterator getImageWritersByFormatName(String formatName)

Retrieve an iterator over all registered writers for the given format.

Parameters:

formatName - an infomal format name (e.g. "jpeg" or "bmp")

Returns:

an iterator over a collection of image writers

Throws:

IllegalArgumentException - if formatName is null

public static Iterator getImageWritersByMIMEType(String MIMEType)

Retrieve an iterator over all registered writers for the given MIME type.

Parameters:

MIMEType - a MIME specification for an image type (e.g. "image/jpeg" or "image/x-bmp")

Returns:

an iterator over a collection of image writers

Throws:

IllegalArgumentException - if MIMEType is null

public static Iterator getImageWritersBySuffix(String fileSuffix)

Retrieve an iterator over all registered writers for the given file suffix.

Parameters:

fileSuffix - an image file suffix (e.g. "jpg" or "bmp")

Returns:

an iterator over a collection of image writers

Throws:

IllegalArgumentException - if fileSuffix is null

public static String[] getReaderFormatNames()

Retrieve all the informal format names supported by the collection of registered image readers.

Returns:

an array of format names

public static String[] getReaderMIMETypes()

Retrieve all the MIME types supported by the collection of registered image readers.

Returns:

an array of MIME types

public static boolean getUseCache()

Check whether or not an on-disk cache is used for image input and output streams.

Returns:

true if an on-disk cache is available, false otherwise

public static String[] getWriterFormatNames()

Retrieve all the informal format names supported by the collection of registered image writers.

Returns:

an array of format names

public static String[] getWriterMIMETypes()

Retrieve all the MIME types supported by the collection of registered image writers.

Returns:

an array of MIME types

public static BufferedImage read(File input)
            throws IOException

Create a buffered image from a file. An image reader that supports the given image data is automatically selected from the collection of registered readers. If no registered reader can handle the input format, null is returned. The image data will be cached in the current cache directory if caching is enabled. This method does not locate readers that read data directly from a file. To locate such readers manually, use IIORegistry and ImageReaderSpi.

Parameters:

input - the file from which to read image data

Returns:

a new buffered image created from the given image file, or null

Throws:

IllegalArgumentException - if input is null

IOException - if a reading error occurs

public static BufferedImage read(InputStream input)
            throws IOException

Create a buffered image from an input stream. An image reader that supports the given image data is automatically selected from the collection of registered readers. If no registered reader can handle the input format, null is returned. The image data will be cached in the current cache directory if caching is enabled. This method does not locate readers that read data directly from an input stream. To locate such readers manually, use IIORegistry and ImageReaderSpi.

Parameters:

input - the input stream from which to read the image data

Returns:

a new buffered image created from the given input stream, or null

Throws:

IllegalArgumentException - if input is null

IOException - if a reading error occurs

public static BufferedImage read(URL input)
            throws IOException

Create a buffered image from a URL. An image reader that supports the given image data is automatically selected from the collection of registered readers. If no registered reader can handle the input format, null is returned. The image data will be cached in the current cache directory if caching is enabled. This method does not locate readers that read data directly from a URL. To locate such readers manually, use IIORegistry and ImageReaderSpi.

Parameters:

input - the URL from which to retrieve the image file

Returns:

a new buffered image created from the given image URL, or null

Throws:

IllegalArgumentException - if input is null

IOException - if a reading error occurs

public static BufferedImage read(ImageInputStream stream)
            throws IOException

Create a buffered image from an image input stream. An image reader that supports the given image data is automatically selected from the collection of registered readers. If no registered reader can handle the input format, null is returned.

Parameters:

stream - the image input stream from which to read image data

Returns:

a new buffered image created from the given image data, or null

Throws:

IllegalArgumentException - if stream is null

IOException - if a reading error occurs

public static void scanForPlugins()

Rescans the application classpath for ImageIO service providers and registers them.

public static void setCacheDirectory(File cacheDirectory)

Set the directory to be used for caching image data. A null argument means to use the default system temporary directory. This cache directory is only used if getUseCache returns true.

Parameters:

cacheDirectory - the directory where image data should be cached

Throws:

IllegalArgumentException - if cacheDirectory is not a directory

public static void setUseCache(boolean useCache)

Control whether or not an on-disk cache is used. This cache is used to store input or output data from an image data stream when data in the stream needs to be re-processed. If useCache is false the cache will be stored in memory. Doing so eliminates file creation and deletion overhead. The default is to use an on-disk cache.

Parameters:

useCache - true to use an on-disk cache, false otherwise

public static boolean write(RenderedImage im,
                            String formatName,
                            File output)
            throws IOException

Write an image to a file using a registered writer that supports the given format, overwriting the file if it already exists.

Parameters:

im - the image data to write

formatName - an informal description of the output format

output - the file to which the image will be written

Returns:

false if no registered writer supports the given format, true otherwise

Throws:

IllegalArgumentException - if any argument is null

IOException - if a writing error occurs

public static boolean write(RenderedImage im,
                            String formatName,
                            OutputStream output)
            throws IOException

Write an image to an output stream using a registered writer that supports the given format.

Parameters:

im - the image data to write

formatName - an informal description of the output format

output - the output stream to which the image will be written

Returns:

false if no registered writer supports the given format, true otherwise

Throws:

IllegalArgumentException - if any argument is null

IOException - if a writing error occurs

public static boolean write(RenderedImage im,
                            String formatName,
                            ImageOutputStream output)
            throws IOException

Write an image to an ImageOutputStream using a registered writer that supports the given format. Image data is written starting at the ImageOutputStream's current stream pointer, overwriting any existing data.

Parameters:

im - the image data to write

formatName - an informal description of the output format

output - the image output stream to which the image will be written

Returns:

false if no registered writer supports the given format, true otherwise

Throws:

IllegalArgumentException - if any argument is null

IOException - if a writing error occurs