- /*
- * @(#)ImageTranscoder.java 1.19 03/12/19
- *
- * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
- * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
- */
-
- package javax.imageio;
-
- import javax.imageio.metadata.IIOMetadata;
-
- /**
- * An interface providing metadata transcoding capability.
- *
- * <p> Any image may be transcoded (written to a different format
- * than the one it was originally stored in) simply by performing
- * a read operation followed by a write operation. However, loss
- * of data may occur in this process due to format differences.
- *
- * <p> In general, the best results will be achieved when
- * format-specific metadata objects can be created to encapsulate as
- * much information about the image and its associated metadata as
- * possible, in terms that are understood by the specific
- * <code>ImageWriter</code> used to perform the encoding.
- *
- * <p> An <code>ImageTranscoder</code> may be used to convert the
- * <code>IIOMetadata</code> objects supplied by the
- * <code>ImageReader</code> (representing per-stream and per-image
- * metadata) into corresponding objects suitable for encoding by a
- * particular <code>ImageWriter</code>. In the case where the methods
- * of this interface are being called directly on an
- * <code>ImageWriter</code>, the output will be suitable for that
- * writer.
- *
- * <p> The internal details of converting an <code>IIOMetadata</code>
- * object into a writer-specific format will vary according to the
- * context of the operation. Typically, an <code>ImageWriter</code>
- * will inspect the incoming object to see if it implements additional
- * interfaces with which the writer is familiar. This might be the
- * case, for example, if the object was obtained by means of a read
- * operation on a reader plug-in written by the same vendor as the
- * writer. In this case, the writer may access the incoming object by
- * means of its plug-in specific interfaces. In this case, the
- * re-encoding may be close to lossless if the image file format is
- * kept constant. If the format is changing, the writer may still
- * attempt to preserve as much information as possible.
- *
- * <p> If the incoming object does not implement any additional
- * interfaces known to the writer, the writer has no choice but to
- * access it via the standard <code>IIOMetadata</code> interfaces such
- * as the tree view provided by <code>IIOMetadata.getAsTree</code>.
- * In this case, there is likely to be significant loss of
- * information.
- *
- * <p> An independent <code>ImageTranscoder</code> essentially takes
- * on the same role as the writer plug-in in the above examples. It
- * must be familiar with the private interfaces used by both the
- * reader and writer plug-ins, and manually instantiate an object that
- * will be usable by the writer. The resulting metadata objects may
- * be used by the writer directly.
- *
- * <p> No independent implementations of <code>ImageTranscoder</code>
- * are provided as part of the standard API. Instead, the intention
- * of this interface is to provide a way for implementations to be
- * created and discovered by applications as the need arises.
- *
- * @version 0.5
- */
- public interface ImageTranscoder {
-
- /**
- * Returns an <code>IIOMetadata</code> object that may be used for
- * encoding and optionally modified using its document interfaces
- * or other interfaces specific to the writer plug-in that will be
- * used for encoding.
- *
- * <p> An optional <code>ImageWriteParam</code> may be supplied
- * for cases where it may affect the structure of the stream
- * metadata.
- *
- * <p> If the supplied <code>ImageWriteParam</code> contains
- * optional setting values not understood by this writer or
- * transcoder, they will be ignored.
- *
- * @param inData an <code>IIOMetadata</code> object representing
- * stream metadata, used to initialize the state of the returned
- * object.
- * @param param an <code>ImageWriteParam</code> that will be used to
- * encode the image, or <code>null</code>.
- *
- * @return an <code>IIOMetadata</code> object, or
- * <code>null</code> if the plug-in does not provide metadata
- * encoding capabilities.
- *
- * @exception IllegalArgumentException if <code>inData</code> is
- * <code>null</code>.
- */
- IIOMetadata convertStreamMetadata(IIOMetadata inData,
- ImageWriteParam param);
-
- /**
- * Returns an <code>IIOMetadata</code> object that may be used for
- * encoding and optionally modified using its document interfaces
- * or other interfaces specific to the writer plug-in that will be
- * used for encoding.
- *
- * <p> An optional <code>ImageWriteParam</code> may be supplied
- * for cases where it may affect the structure of the image
- * metadata.
- *
- * <p> If the supplied <code>ImageWriteParam</code> contains
- * optional setting values not understood by this writer or
- * transcoder, they will be ignored.
- *
- * @param inData an <code>IIOMetadata</code> object representing
- * image metadata, used to initialize the state of the returned
- * object.
- * @param imageType an <code>ImageTypeSpecifier</code> indicating
- * the layout and color information of the image with which the
- * metadata will be associated.
- * @param param an <code>ImageWriteParam</code> that will be used to
- * encode the image, or <code>null</code>.
- *
- * @return an <code>IIOMetadata</code> object,
- * or <code>null</code> if the plug-in does not provide
- * metadata encoding capabilities.
- *
- * @exception IllegalArgumentException if either of
- * <code>inData</code> or <code>imageType</code> is
- * <code>null</code>.
- */
- IIOMetadata convertImageMetadata(IIOMetadata inData,
- ImageTypeSpecifier imageType,
- ImageWriteParam param);
- }