java/12 : java.desktop/javax/imageio/spi/ImageWriterSpi.java

ImageWriterSpi
https://openjdk.java.net/
GPLv2 + Classpath Exception
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package javax.imageio.spi;

import java.awt.image.RenderedImage;
import java.io.IOException;
import javax.imageio.ImageTypeSpecifier;
import javax.imageio.ImageWriter;
import javax.imageio.stream.ImageOutputStream;

The service provider interface (SPI) for ImageWriters. For more information on service provider classes, see the class comment for the IIORegistry class.  Each ImageWriterSpi provides several types of information about the ImageWriter class with which it is associated. 
 The name of the vendor who defined the SPI class and a brief description of the class are available via the getVendorName, getDescription, and getVersion methods. These methods may be internationalized to provide locale-specific output. These methods are intended mainly to provide short, human-writable information that might be used to organize a pop-up menu or other list. 
 Lists of format names, file suffixes, and MIME types associated with the service may be obtained by means of the getFormatNames, getFileSuffixes, and getMIMEType methods. These methods may be used to identify candidate ImageWriters for writing a particular file or stream based on manual format selection, file naming, or MIME associations. 
 A more reliable way to determine which ImageWriters are likely to be able to parse a particular data stream is provided by the canEncodeImage method. This methods allows the service provider to inspect the actual image contents. 
 Finally, an instance of the ImageWriter class associated with this service provider may be obtained by calling the createWriterInstance method. Any heavyweight initialization, such as the loading of native libraries or creation of large tables, should be deferred at least until the first invocation of this method. 
See Also: IIORegistry
ImageTypeSpecifier
ImageWriter/**
 * The service provider interface (SPI) for {@code ImageWriter}s.
 * For more information on service provider classes, see the class comment
 * for the {@code IIORegistry} class.
 *
 * <p> Each {@code ImageWriterSpi} provides several types of information
 * about the {@code ImageWriter} class with which it is associated.
 *
 * <p> The name of the vendor who defined the SPI class and a
 * brief description of the class are available via the
 * {@code getVendorName}, {@code getDescription},
 * and {@code getVersion} methods.
 * These methods may be internationalized to provide locale-specific
 * output.  These methods are intended mainly to provide short,
 * human-writable information that might be used to organize a pop-up
 * menu or other list.
 *
 * <p> Lists of format names, file suffixes, and MIME types associated
 * with the service may be obtained by means of the
 * {@code getFormatNames}, {@code getFileSuffixes}, and
 * {@code getMIMEType} methods.  These methods may be used to
 * identify candidate {@code ImageWriter}s for writing a
 * particular file or stream based on manual format selection, file
 * naming, or MIME associations.
 *
 * <p> A more reliable way to determine which {@code ImageWriter}s
 * are likely to be able to parse a particular data stream is provided
 * by the {@code canEncodeImage} method.  This methods allows the
 * service provider to inspect the actual image contents.
 *
 * <p> Finally, an instance of the {@code ImageWriter} class
 * associated with this service provider may be obtained by calling
 * the {@code createWriterInstance} method.  Any heavyweight
 * initialization, such as the loading of native libraries or creation
 * of large tables, should be deferred at least until the first
 * invocation of this method.
 *
 * @see IIORegistry
 * @see javax.imageio.ImageTypeSpecifier
 * @see javax.imageio.ImageWriter
 *
 */
public abstract class ImageWriterSpi extends ImageReaderWriterSpi {

    A single-element array, initially containing ImageOutputStream.class, to be returned from getOutputTypes. 
Deprecated: Instead of using this field, directly create the equivalent array { ImageOutputStream.class }./**
     * A single-element array, initially containing
     * {@code ImageOutputStream.class}, to be returned from
     * {@code getOutputTypes}.
     * @deprecated Instead of using this field, directly create
     * the equivalent array {@code { ImageOutputStream.class }}.
     */
    @Deprecated
    public static final Class<?>[] STANDARD_OUTPUT_TYPE =
        { ImageOutputStream.class };

    An array of Class objects to be returned from getOutputTypes, initially null. /**
     * An array of {@code Class} objects to be returned from
     * {@code getOutputTypes}, initially {@code null}.
     */
    protected Class<?>[] outputTypes = null;

    An array of strings to be returned from getImageReaderSpiNames, initially null. /**
     * An array of strings to be returned from
     * {@code getImageReaderSpiNames}, initially
     * {@code null}.
     */
    protected String[] readerSpiNames = null;

    The Class of the writer, initially null. /**
     * The {@code Class} of the writer, initially
     * {@code null}.
     */
    private Class<?> writerClass = null;

    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. /**
     * Constructs a blank {@code 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.
     */
    protected ImageWriterSpi() {
    }

    Constructs an ImageWriterSpi with a given set of values. 
Params: vendorName – the vendor name, as a non-null String.
version – a version identifier, as a non-null String.
names – a non-null array of Strings indicating the format names. At least one entry must be present.
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.
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.
writerClassName – the fully-qualified name of the associated ImageWriterSpi class, as a non-null String.
outputTypes – an array of Class objects of length at least 1 indicating the legal output types.
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.
supportsStandardStreamMetadataFormat – a boolean that indicates whether a stream metadata object can use trees described by the standard metadata format.
nativeStreamMetadataFormatName – a String, or null, to be returned from getNativeStreamMetadataFormatName.
nativeStreamMetadataFormatClassName – a String, or null, to be used to instantiate a metadata format object to be returned from getNativeStreamMetadataFormat.
extraStreamMetadataFormatNames – an array of Strings, or null, to be returned from getExtraStreamMetadataFormatNames. An array of length 0 is normalized to null.
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.
supportsStandardImageMetadataFormat – a boolean that indicates whether an image metadata object can use trees described by the standard metadata format.
nativeImageMetadataFormatName – a String, or null, to be returned from getNativeImageMetadataFormatName.
nativeImageMetadataFormatClassName – a String, or null, to be used to instantiate a metadata format object to be returned from getNativeImageMetadataFormat.
extraImageMetadataFormatNames – an array of Strings to be returned from getExtraImageMetadataFormatNames. An array of length 0 is normalized to null.
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.
Throws: IllegalArgumentException – if vendorName is null.
IllegalArgumentException – if version is null.
IllegalArgumentException – if names is null or has length 0.
IllegalArgumentException – if writerClassName is null.
IllegalArgumentException – if outputTypes is null or has length 0./**
     * Constructs an {@code ImageWriterSpi} with a given
     * set of values.
     *
     * @param vendorName the vendor name, as a non-{@code null}
     * {@code String}.
     * @param version a version identifier, as a non-{@code null}
     * {@code String}.
     * @param names a non-{@code null} array of
     * {@code String}s indicating the format names.  At least one
     * entry must be present.
     * @param suffixes an array of {@code String}s indicating the
     * common file suffixes.  If no suffixes are defined,
     * {@code null} should be supplied.  An array of length 0
     * will be normalized to {@code null}.
     * @param MIMETypes an array of {@code String}s indicating
     * the format's MIME types.  If no suffixes are defined,
     * {@code null} should be supplied.  An array of length 0
     * will be normalized to {@code null}.
     * @param writerClassName the fully-qualified name of the
     * associated {@code ImageWriterSpi} class, as a
     * non-{@code null String}.
     * @param outputTypes an array of {@code Class} objects of
     * length at least 1 indicating the legal output types.
     * @param readerSpiNames an array {@code String}s of length
     * at least 1 naming the classes of all associated
     * {@code ImageReader}s, or {@code null}.  An array of
     * length 0 is normalized to {@code null}.
     * @param supportsStandardStreamMetadataFormat a
     * {@code boolean} that indicates whether a stream metadata
     * object can use trees described by the standard metadata format.
     * @param nativeStreamMetadataFormatName a
     * {@code String}, or {@code null}, to be returned from
     * {@code getNativeStreamMetadataFormatName}.
     * @param nativeStreamMetadataFormatClassName a
     * {@code String}, or {@code null}, to be used to instantiate
     * a metadata format object to be returned from
     * {@code getNativeStreamMetadataFormat}.
     * @param extraStreamMetadataFormatNames an array of
     * {@code String}s, or {@code null}, to be returned from
     * {@code getExtraStreamMetadataFormatNames}.  An array of length
     * 0 is normalized to {@code null}.
     * @param extraStreamMetadataFormatClassNames an array of
     * {@code String}s, or {@code null}, to be used to instantiate
     * a metadata format object to be returned from
     * {@code getStreamMetadataFormat}.  An array of length
     * 0 is normalized to {@code null}.
     * @param supportsStandardImageMetadataFormat a
     * {@code boolean} that indicates whether an image metadata
     * object can use trees described by the standard metadata format.
     * @param nativeImageMetadataFormatName a
     * {@code String}, or {@code null}, to be returned from
     * {@code getNativeImageMetadataFormatName}.
     * @param nativeImageMetadataFormatClassName a
     * {@code String}, or {@code null}, to be used to instantiate
     * a metadata format object to be returned from
     * {@code getNativeImageMetadataFormat}.
     * @param extraImageMetadataFormatNames an array of
     * {@code String}s to be returned from
     * {@code getExtraImageMetadataFormatNames}.  An array of length 0
     * is normalized to {@code null}.
     * @param extraImageMetadataFormatClassNames an array of
     * {@code String}s, or {@code null}, to be used to instantiate
     * a metadata format object to be returned from
     * {@code getImageMetadataFormat}.  An array of length
     * 0 is normalized to {@code null}.
     *
     * @exception IllegalArgumentException if {@code vendorName}
     * is {@code null}.
     * @exception IllegalArgumentException if {@code version}
     * is {@code null}.
     * @exception IllegalArgumentException if {@code names}
     * is {@code null} or has length 0.
     * @exception IllegalArgumentException if {@code writerClassName}
     * is {@code null}.
     * @exception IllegalArgumentException if {@code outputTypes}
     * is {@code null} or has length 0.
     */
    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) {
        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 = (outputTypes == STANDARD_OUTPUT_TYPE) ?
            new Class<?>[] { ImageOutputStream.class } :
            outputTypes.clone();

        // If length == 0, leave it null
        if (readerSpiNames != null && readerSpiNames.length > 0) {
            this.readerSpiNames = readerSpiNames.clone();
        }
    }

    Returns true if the format that this writer outputs preserves pixel data bit-accurately. The default implementation returns true. 
Returns: true if the format preserves full pixel accuracy./**
     * Returns {@code true} if the format that this writer
     * outputs preserves pixel data bit-accurately.  The default
     * implementation returns {@code true}.
     *
     * @return {@code true} if the format preserves full pixel
     * accuracy.
     */
    public boolean isFormatLossless() {
        return true;
    }

    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. 
Returns: a non-null array of Class objects of length at least 1./**
     * Returns an array of {@code Class} objects indicating what
     * types of objects may be used as arguments to the writer's
     * {@code setOutput} method.
     *
     * <p> For most writers, which only output to an
     * {@code ImageOutputStream}, a single-element array
     * containing {@code ImageOutputStream.class} should be
     * returned.
     *
     * @return a non-{@code null} array of
     * {@code Class} objects of length at least 1.
     */
    public Class<?>[] getOutputTypes() {
        return outputTypes.clone();
    }

    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. 
Params: type – an ImageTypeSpecifier specifying the layout of the image to be written.
Throws: IllegalArgumentException – if type is null.
Returns: true if this writer is likely to be able to encode images with the given layout./**
     * Returns {@code true} if the {@code ImageWriter}
     * implementation associated with this service provider is able to
     * encode an image with the given layout.  The layout
     * (<i>i.e.</i>, the image's {@code SampleModel} and
     * {@code ColorModel}) is described by an
     * {@code ImageTypeSpecifier} object.
     *
     * <p> A return value of {@code 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
     * {@code false} if handed an RGB {@code 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.
     *
     * <p> Different {@code ImageWriter}s, 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 {@code ImageTypeSpecifier} specifying the
     * layout of the image to be written.
     *
     * @return {@code true} if this writer is likely to be able
     * to encode images with the given layout.
     *
     * @exception IllegalArgumentException if {@code type}
     * is {@code null}.
     */
    public abstract boolean canEncodeImage(ImageTypeSpecifier type);

    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. 
Params: im – an instance of RenderedImage to be encoded.
Throws: IllegalArgumentException – if im is null.
Returns: true if this writer is likely to be able to encode this image./**
     * Returns {@code true} if the {@code ImageWriter}
     * implementation associated with this service provider is able to
     * encode the given {@code RenderedImage} instance.  Note
     * that this includes instances of
     * {@code java.awt.image.BufferedImage}.
     *
     * <p> See the discussion for
     * {@code canEncodeImage(ImageTypeSpecifier)} for information
     * on the semantics of this method.
     *
     * @param im an instance of {@code RenderedImage} to be encoded.
     *
     * @return {@code true} if this writer is likely to be able
     * to encode this image.
     *
     * @exception IllegalArgumentException if {@code im}
     * is {@code null}.
     */
    public boolean canEncodeImage(RenderedImage im) {
        return canEncodeImage(ImageTypeSpecifier.createFromRenderedImage(im));
    }

    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). 
Throws: IOException – if an error occurs during loading,
or initialization of the writer class, or during instantiation
or initialization of the writer object.
Returns: an ImageWriter instance./**
     * Returns an instance of the {@code ImageWriter}
     * implementation associated with this service provider.
     * The returned object will initially be in an initial state as if
     * its {@code reset} method had been called.
     *
     * <p> The default implementation simply returns
     * {@code createWriterInstance(null)}.
     *
     * @return an {@code 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.
     */
    public ImageWriter createWriterInstance() throws IOException {
        return createWriterInstance(null);
    }

    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). 
Params: extension – a plug-in specific extension object, which may be null.
Throws: IOException – if the attempt to instantiate
the writer fails.
IllegalArgumentException – if the ImageWriter's constructor throws an IllegalArgumentException to indicate that the extension object is unsuitable.
Returns: an ImageWriter instance./**
     * Returns an instance of the {@code ImageWriter}
     * implementation associated with this service provider.
     * The returned object will initially be in an initial state
     * as if its {@code reset} method had been called.
     *
     * <p> An {@code Object} may be supplied to the plug-in at
     * construction time.  The nature of the object is entirely
     * plug-in specific.
     *
     * <p> Typically, a plug-in will implement this method using code
     * such as {@code return new MyImageWriter(this)}.
     *
     * @param extension a plug-in specific extension object, which may
     * be {@code null}.
     *
     * @return an {@code ImageWriter} instance.
     *
     * @exception IOException if the attempt to instantiate
     * the writer fails.
     * @exception IllegalArgumentException if the
     * {@code ImageWriter}'s constructor throws an
     * {@code IllegalArgumentException} to indicate that the
     * extension object is unsuitable.
     */
    public abstract ImageWriter createWriterInstance(Object extension)
        throws IOException;

    Returns true if the ImageWriter object passed in is an instance of the ImageWriter associated with this service provider. 
Params: writer – an ImageWriter instance.
Throws: IllegalArgumentException – if writer is null.
Returns: true if writer is recognized/**
     * Returns {@code true} if the {@code ImageWriter} object
     * passed in is an instance of the {@code ImageWriter}
     * associated with this service provider.
     *
     * @param writer an {@code ImageWriter} instance.
     *
     * @return {@code true} if {@code writer} is recognized
     *
     * @exception IllegalArgumentException if {@code writer} is
     * {@code null}.
     */
    public boolean isOwnWriter(ImageWriter writer) {
        if (writer == null) {
            throw new IllegalArgumentException("writer == null!");
        }
        String name = writer.getClass().getName();
        return name.equals(pluginClassName);
    }

    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. 
See Also: ImageIO.getImageReader(ImageWriter)
ImageReaderSpi.getImageWriterSpiNames()
Returns: an array of Strings of length at least 1 containing names of ImageReaderSpis, or null./**
     * Returns an array of {@code String}s containing all the
     * fully qualified names of all the {@code ImageReaderSpi}
     * classes that can understand the internal metadata
     * representation used by the {@code ImageWriter} associated
     * with this service provider, or {@code null} if there are
     * no such {@code ImageReaders} specified.  If a
     * non-{@code null} value is returned, it must have non-zero
     * length.
     *
     * <p> 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 {@code ImageReader} returned by
     * {@code ImageIO.getImageReader(ImageWriter)}.
     *
     * <p> This mechanism may be used to obtain
     * {@code ImageReaders} that will generated non-pixel
     * meta-data (see {@code IIOExtraDataInfo}) in a structure
     * understood by an {@code ImageWriter}.  By reading the
     * image and obtaining this data from one of the
     * {@code ImageReaders} obtained with this method and passing
     * it on to the {@code 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 {@code String}s of length at least 1
     * containing names of {@code ImageReaderSpi}s, or
     * {@code null}.
     *
     * @see javax.imageio.ImageIO#getImageReader(ImageWriter)
     * @see ImageReaderSpi#getImageWriterSpiNames()
     */
    public String[] getImageReaderSpiNames() {
        return readerSpiNames == null ?
            null : readerSpiNames.clone();
    }
}
Params:	type – an `ImageTypeSpecifier` specifying the layout of the image to be written.
Throws:	IllegalArgumentException – if `type` is `null`.
Returns:	`true` if this writer is likely to be able to encode images with the given layout.
Params:	im – an instance of `RenderedImage` to be encoded.
Throws:	IllegalArgumentException – if `im` is `null`.
Returns:	`true` if this writer is likely to be able to encode this image.
Throws:	IOException – if an error occurs during loading, or initialization of the writer class, or during instantiation or initialization of the writer object.
Returns:	an `ImageWriter` instance.
Params:	extension – a plug-in specific extension object, which may be `null`.
Throws:	IOException – if the attempt to instantiate the writer fails. IllegalArgumentException – if the `ImageWriter`'s constructor throws an `IllegalArgumentException` to indicate that the extension object is unsuitable.
Returns:	an `ImageWriter` instance.
Params:	writer – an `ImageWriter` instance.
Throws:	IllegalArgumentException – if `writer` is `null`.
Returns:	`true` if `writer` is recognized
See Also:	ImageIO.getImageReader(ImageWriter) ImageReaderSpi.getImageWriterSpiNames()
Returns:	an array of `String`s of length at least 1 containing names of `ImageReaderSpi`s, or `null`.
/

java/ 12/ java.desktop/javax/imageio/spi/ImageWriterSpi.java
