ImageTranscoder.java revision 2362
2362N/A * Copyright (c) 2000, Oracle and/or its affiliates. All rights reserved. 0N/A * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 0N/A * This code is free software; you can redistribute it and/or modify it 0N/A * under the terms of the GNU General Public License version 2 only, as 2362N/A * published by the Free Software Foundation. Oracle designates this 0N/A * particular file as subject to the "Classpath" exception as provided 2362N/A * by Oracle in the LICENSE file that accompanied this code. 0N/A * This code is distributed in the hope that it will be useful, but WITHOUT 0N/A * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 0N/A * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 0N/A * version 2 for more details (a copy is included in the LICENSE file that 0N/A * accompanied this code). 0N/A * You should have received a copy of the GNU General Public License version 0N/A * 2 along with this work; if not, write to the Free Software Foundation, 0N/A * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 2362N/A * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 2362N/A * or visit www.oracle.com if you need additional information or have any 0N/A * An interface providing metadata transcoding capability. 0N/A * <p> Any image may be transcoded (written to a different format 0N/A * than the one it was originally stored in) simply by performing 0N/A * a read operation followed by a write operation. However, loss 0N/A * of data may occur in this process due to format differences. 0N/A * <p> In general, the best results will be achieved when 0N/A * format-specific metadata objects can be created to encapsulate as 0N/A * much information about the image and its associated metadata as 0N/A * possible, in terms that are understood by the specific 0N/A * <code>ImageWriter</code> used to perform the encoding. 0N/A * <p> An <code>ImageTranscoder</code> may be used to convert the 0N/A * <code>IIOMetadata</code> objects supplied by the 0N/A * <code>ImageReader</code> (representing per-stream and per-image 0N/A * metadata) into corresponding objects suitable for encoding by a 0N/A * particular <code>ImageWriter</code>. In the case where the methods 0N/A * of this interface are being called directly on an 0N/A * <code>ImageWriter</code>, the output will be suitable for that 0N/A * <p> The internal details of converting an <code>IIOMetadata</code> 0N/A * object into a writer-specific format will vary according to the 0N/A * context of the operation. Typically, an <code>ImageWriter</code> 0N/A * will inspect the incoming object to see if it implements additional 0N/A * interfaces with which the writer is familiar. This might be the 0N/A * case, for example, if the object was obtained by means of a read 0N/A * operation on a reader plug-in written by the same vendor as the 0N/A * writer. In this case, the writer may access the incoming object by 0N/A * means of its plug-in specific interfaces. In this case, the 0N/A * re-encoding may be close to lossless if the image file format is 0N/A * kept constant. If the format is changing, the writer may still 0N/A * attempt to preserve as much information as possible. 0N/A * <p> If the incoming object does not implement any additional 0N/A * interfaces known to the writer, the writer has no choice but to 0N/A * access it via the standard <code>IIOMetadata</code> interfaces such 0N/A * as the tree view provided by <code>IIOMetadata.getAsTree</code>. 0N/A * In this case, there is likely to be significant loss of 0N/A * <p> An independent <code>ImageTranscoder</code> essentially takes 0N/A * on the same role as the writer plug-in in the above examples. It 0N/A * must be familiar with the private interfaces used by both the 0N/A * reader and writer plug-ins, and manually instantiate an object that 0N/A * will be usable by the writer. The resulting metadata objects may 0N/A * be used by the writer directly. 0N/A * <p> No independent implementations of <code>ImageTranscoder</code> 0N/A * are provided as part of the standard API. Instead, the intention 0N/A * of this interface is to provide a way for implementations to be 0N/A * created and discovered by applications as the need arises. 0N/A * Returns an <code>IIOMetadata</code> object that may be used for 0N/A * encoding and optionally modified using its document interfaces 0N/A * or other interfaces specific to the writer plug-in that will be 0N/A * used for encoding. 0N/A * <p> An optional <code>ImageWriteParam</code> may be supplied 0N/A * for cases where it may affect the structure of the stream 0N/A * <p> If the supplied <code>ImageWriteParam</code> contains 0N/A * optional setting values not understood by this writer or 0N/A * transcoder, they will be ignored. 0N/A * @param inData an <code>IIOMetadata</code> object representing 0N/A * stream metadata, used to initialize the state of the returned 0N/A * @param param an <code>ImageWriteParam</code> that will be used to 0N/A * encode the image, or <code>null</code>. 0N/A * @return an <code>IIOMetadata</code> object, or 0N/A * <code>null</code> if the plug-in does not provide metadata 0N/A * encoding capabilities. 0N/A * @exception IllegalArgumentException if <code>inData</code> is 0N/A * <code>null</code>. 0N/A * Returns an <code>IIOMetadata</code> object that may be used for 0N/A * encoding and optionally modified using its document interfaces 0N/A * or other interfaces specific to the writer plug-in that will be 0N/A * used for encoding. 0N/A * <p> An optional <code>ImageWriteParam</code> may be supplied 0N/A * for cases where it may affect the structure of the image 0N/A * <p> If the supplied <code>ImageWriteParam</code> contains 0N/A * optional setting values not understood by this writer or 0N/A * transcoder, they will be ignored. 0N/A * @param inData an <code>IIOMetadata</code> object representing 0N/A * image metadata, used to initialize the state of the returned 0N/A * @param imageType an <code>ImageTypeSpecifier</code> indicating 0N/A * the layout and color information of the image with which the 0N/A * metadata will be associated. 0N/A * @param param an <code>ImageWriteParam</code> that will be used to 0N/A * encode the image, or <code>null</code>. 0N/A * @return an <code>IIOMetadata</code> object, 0N/A * or <code>null</code> if the plug-in does not provide 0N/A * metadata encoding capabilities. 0N/A * @exception IllegalArgumentException if either of 0N/A * <code>inData</code> or <code>imageType</code> is 0N/A * <code>null</code>.