File	Doc	Category	Size	Date	Package
ImageWriterSpi.java	API Doc	Java SE 5 API	18096	Fri Aug 26 14:57:30 BST 2005	javax.imageio.spi

ImageWriterSpi

• java.lang.Object
  • javax.imageio.spi.IIOServiceProvider
    • javax.imageio.spi.ImageReaderWriterSpi

Fields Summary
public static final Class[]	STANDARD_OUTPUT_TYPE A single-element array, initially containing ImageInputStream.class, to be returned from getInputTypes.
protected Class[]	outputTypes An array of Class objects to be returned from getOutputTypes, initially null.
protected String[]	readerSpiNames An array of strings to be returned from getImageReaderSpiNames, initially null.
private Class	writerClass The Class of the writer, initially null.

Constructors Summary
protected ImageWriterSpi() Constructs a blank ImageWriterSpi. It is up to the subclass to initialize instance variables and/or override method implementations in order to provide working versions of all methods.
public ImageWriterSpi(String vendorName, String version, String[] names, String[] suffixes, String[] MIMETypes, String writerClassName, Class[] outputTypes, String[] readerSpiNames, boolean supportsStandardStreamMetadataFormat, String nativeStreamMetadataFormatName, String nativeStreamMetadataFormatClassName, String[] extraStreamMetadataFormatNames, String[] extraStreamMetadataFormatClassNames, boolean supportsStandardImageMetadataFormat, String nativeImageMetadataFormatName, String nativeImageMetadataFormatClassName, String[] extraImageMetadataFormatNames, String[] extraImageMetadataFormatClassNames) Constructs an ImageWriterSpi with a given set of values. param vendorName the vendor name, as a non-null String. param version a version identifier, as a non-null String. param names a non-null array of Strings indicating the format names. At least one entry must be present. param suffixes an array of Strings indicating the common file suffixes. If no suffixes are defined, null should be supplied. An array of length 0 will be normalized to null. param MIMETypes an array of Strings indicating the format's MIME types. If no suffixes are defined, null should be supplied. An array of length 0 will be normalized to null. param writerClassName the fully-qualified name of the associated ImageWriterSpi class, as a non-null String. param outputTypes an array of Class objects of length at least 1 indicating the legal output types. param readerSpiNames an array Strings of length at least 1 naming the classes of all associated ImageReaders, or null. An array of length 0 is normalized to null. param supportsStandardStreamMetadataFormat a boolean that indicates whether a stream metadata object can use trees described by the standard metadata format. param nativeStreamMetadataFormatName a String, or null, to be returned from getNativeStreamMetadataFormatName. param nativeStreamMetadataFormatClassName a String, or null, to be used to instantiate a metadata format object to be returned from getNativeStreamMetadataFormat. param extraStreamMetadataFormatNames an array of Strings, or null, to be returned from getExtraStreamMetadataFormatNames. An array of length 0 is normalized to null. param extraStreamMetadataFormatClassNames an array of Strings, or null, to be used to instantiate a metadata format object to be returned from getStreamMetadataFormat. An array of length 0 is normalized to null. param supportsStandardImageMetadataFormat a boolean that indicates whether an image metadata object can use trees described by the standard metadata format. param nativeImageMetadataFormatName a String, or null, to be returned from getNativeImageMetadataFormatName. param nativeImageMetadataFormatClassName a String, or null, to be used to instantiate a metadata format object to be returned from getNativeImageMetadataFormat. param extraImageMetadataFormatNames an array of Strings to be returned from getExtraImageMetadataFormatNames. An array of length 0 is normalized to null. param extraImageMetadataFormatClassNames an array of Strings, or null, to be used to instantiate a metadata format object to be returned from getImageMetadataFormat. An array of length 0 is normalized to null. exception IllegalArgumentException if vendorName is null. exception IllegalArgumentException if version is null. exception IllegalArgumentException if names is null or has length 0. exception IllegalArgumentException if writerClassName is null. exception IllegalArgumentException if outputTypes is null or has length 0. super(vendorName, version, names, suffixes, MIMETypes, writerClassName, supportsStandardStreamMetadataFormat, nativeStreamMetadataFormatName, nativeStreamMetadataFormatClassName, extraStreamMetadataFormatNames, extraStreamMetadataFormatClassNames, supportsStandardImageMetadataFormat, nativeImageMetadataFormatName, nativeImageMetadataFormatClassName, extraImageMetadataFormatNames, extraImageMetadataFormatClassNames); if (outputTypes == null) { throw new IllegalArgumentException ("outputTypes == null!"); } if (outputTypes.length == 0) { throw new IllegalArgumentException ("outputTypes.length == 0!"); } this.outputTypes = (Class[])outputTypes.clone(); // If length == 0, leave it null if (readerSpiNames != null && readerSpiNames.length > 0) { this.readerSpiNames = (String[])readerSpiNames.clone(); }

Methods Summary
public abstract boolean	canEncodeImage(javax.imageio.ImageTypeSpecifier type) Returns true if the ImageWriter implementation associated with this service provider is able to encode an image with the given layout. The layout (i.e., the image's SampleModel and ColorModel) is described by an ImageTypeSpecifier object. A return value of true is not an absolute guarantee of successful encoding; the encoding process may still produce errors due to factors such as I/O errors, inconsistent or malformed data structures, etc. The intent is that a reasonable inspection of the basic structure of the image be performed in order to determine if it is within the scope of the encoding format. For example, a service provider for a format that can only encode greyscale would return false if handed an RGB BufferedImage. Similarly, a service provider for a format that can encode 8-bit RGB imagery might refuse to encode an image with an associated alpha channel. Different ImageWriters, and thus service providers, may choose to be more or less strict. For example, they might accept an image with premultiplied alpha even though it will have to be divided out of each pixel, at some loss of precision, in order to be stored. param type an ImageTypeSpecifier specifying the layout of the image to be written. return true if this writer is likely to be able to encode images with the given layout. exception IllegalArgumentException if type is null.
public boolean	canEncodeImage(java.awt.image.RenderedImage im) Returns true if the ImageWriter implementation associated with this service provider is able to encode the given RenderedImage instance. Note that this includes instances of java.awt.image.BufferedImage. See the discussion for canEncodeImage(ImageTypeSpecifier) for information on the semantics of this method. param im an instance of RenderedImage to be encoded. return true if this writer is likely to be able to encode this image. exception IllegalArgumentException if im is null. return canEncodeImage(ImageTypeSpecifier.createFromRenderedImage(im));
public javax.imageio.ImageWriter	createWriterInstance() Returns an instance of the ImageWriter implementation associated with this service provider. The returned object will initially be in an initial state as if its reset method had been called. The default implementation simply returns createWriterInstance(null). return an ImageWriter instance. exception IOException if an error occurs during loading, or initialization of the writer class, or during instantiation or initialization of the writer object. return createWriterInstance(null);
public abstract javax.imageio.ImageWriter	createWriterInstance(java.lang.Object extension) Returns an instance of the ImageWriter implementation associated with this service provider. The returned object will initially be in an initial state as if its reset method had been called. An Object may be supplied to the plug-in at construction time. The nature of the object is entirely plug-in specific. Typically, a plug-in will implement this method using code such as return new MyImageWriter(this). param extension a plug-in specific extension object, which may be null. return an ImageWriter instance. exception IOException if the attempt to instantiate the writer fails. exception IllegalArgumentException if the ImageWriter's constructor throws an IllegalArgumentException to indicate that the extension object is unsuitable.
public java.lang.String[]	getImageReaderSpiNames() Returns an array of Strings containing all the fully qualified names of all the ImageReaderSpi classes that can understand the internal metadata representation used by the ImageWriter associated with this service provider, or null if there are no such ImageReaders specified. If a non-null value is returned, it must have non-zero length. The first item in the array must be the name of the service provider for the "preferred" reader, as it will be used to instantiate the ImageReader returned by ImageIO.getImageReader(ImageWriter). This mechanism may be used to obtain ImageReaders that will generated non-pixel meta-data (see IIOExtraDataInfo) in a structure understood by an ImageWriter. By reading the image and obtaining this data from one of the ImageReaders obtained with this method and passing it on to the ImageWriter, a client program can read an image, modify it in some way, and write it back out preserving all meta-data, without having to understand anything about the internal structure of the meta-data, or even about the image format. return an array of Strings of length at least 1 containing names of ImageReaderSpis, or null. see javax.imageio.ImageIO#getImageReader(ImageWriter) see ImageReaderSpi#getImageWriterSpiNames() return readerSpiNames == null ? null : (String[])readerSpiNames.clone();
public java.lang.Class[]	getOutputTypes() Returns an array of Class objects indicating what types of objects may be used as arguments to the writer's setOutput method. For most writers, which only output to an ImageOutputStream, a single-element array containing ImageOutputStream.class should be returned. return a non-null array of Classobjects of length at least 1. return (Class[])outputTypes.clone();
public boolean	isFormatLossless() Returns true if the format that this writer outputs preserves pixel data bit-accurately. The default implementation returns true. return true if the format preserves full pixel accuracy. return true;
public boolean	isOwnWriter(javax.imageio.ImageWriter writer) Returns true if the ImageWriter object passed in is an instance of the ImageWriter associated with this service provider. param writer an ImageWriter instance. return true if writer is recognized exception IllegalArgumentException if writer is null. if (writer == null) { throw new IllegalArgumentException("writer == null!"); } String name = writer.getClass().getName(); return name.equals(pluginClassName);