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| 1 | /* | ||
| 2 | * Copyright (c) 2000, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 9 | * by Oracle in the LICENSE file that accompanied this code. | ||
| 10 | * | ||
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT | ||
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
| 14 | * version 2 for more details (a copy is included in the LICENSE file that | ||
| 15 | * accompanied this code). | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU General Public License version | ||
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, | ||
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 20 | * | ||
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 22 | * or visit www.oracle.com if you need additional information or have any | ||
| 23 | * questions. | ||
| 24 | */ | ||
| 25 | |||
| 26 | package javax.imageio; | ||
| 27 | |||
| 28 | import javax.imageio.metadata.IIOMetadata; | ||
| 29 | |||
| 30 | /** | ||
| 31 | * An interface providing metadata transcoding capability. | ||
| 32 | * | ||
| 33 | * <p> Any image may be transcoded (written to a different format | ||
| 34 | * than the one it was originally stored in) simply by performing | ||
| 35 | * a read operation followed by a write operation. However, loss | ||
| 36 | * of data may occur in this process due to format differences. | ||
| 37 | * | ||
| 38 | * <p> In general, the best results will be achieved when | ||
| 39 | * format-specific metadata objects can be created to encapsulate as | ||
| 40 | * much information about the image and its associated metadata as | ||
| 41 | * possible, in terms that are understood by the specific | ||
| 42 | * <code>ImageWriter</code> used to perform the encoding. | ||
| 43 | * | ||
| 44 | * <p> An <code>ImageTranscoder</code> may be used to convert the | ||
| 45 | * <code>IIOMetadata</code> objects supplied by the | ||
| 46 | * <code>ImageReader</code> (representing per-stream and per-image | ||
| 47 | * metadata) into corresponding objects suitable for encoding by a | ||
| 48 | * particular <code>ImageWriter</code>. In the case where the methods | ||
| 49 | * of this interface are being called directly on an | ||
| 50 | * <code>ImageWriter</code>, the output will be suitable for that | ||
| 51 | * writer. | ||
| 52 | * | ||
| 53 | * <p> The internal details of converting an <code>IIOMetadata</code> | ||
| 54 | * object into a writer-specific format will vary according to the | ||
| 55 | * context of the operation. Typically, an <code>ImageWriter</code> | ||
| 56 | * will inspect the incoming object to see if it implements additional | ||
| 57 | * interfaces with which the writer is familiar. This might be the | ||
| 58 | * case, for example, if the object was obtained by means of a read | ||
| 59 | * operation on a reader plug-in written by the same vendor as the | ||
| 60 | * writer. In this case, the writer may access the incoming object by | ||
| 61 | * means of its plug-in specific interfaces. In this case, the | ||
| 62 | * re-encoding may be close to lossless if the image file format is | ||
| 63 | * kept constant. If the format is changing, the writer may still | ||
| 64 | * attempt to preserve as much information as possible. | ||
| 65 | * | ||
| 66 | * <p> If the incoming object does not implement any additional | ||
| 67 | * interfaces known to the writer, the writer has no choice but to | ||
| 68 | * access it via the standard <code>IIOMetadata</code> interfaces such | ||
| 69 | * as the tree view provided by <code>IIOMetadata.getAsTree</code>. | ||
| 70 | * In this case, there is likely to be significant loss of | ||
| 71 | * information. | ||
| 72 | * | ||
| 73 | * <p> An independent <code>ImageTranscoder</code> essentially takes | ||
| 74 | * on the same role as the writer plug-in in the above examples. It | ||
| 75 | * must be familiar with the private interfaces used by both the | ||
| 76 | * reader and writer plug-ins, and manually instantiate an object that | ||
| 77 | * will be usable by the writer. The resulting metadata objects may | ||
| 78 | * be used by the writer directly. | ||
| 79 | * | ||
| 80 | * <p> No independent implementations of <code>ImageTranscoder</code> | ||
| 81 | * are provided as part of the standard API. Instead, the intention | ||
| 82 | * of this interface is to provide a way for implementations to be | ||
| 83 | * created and discovered by applications as the need arises. | ||
| 84 | * | ||
| 85 | */ | ||
| 86 | public interface ImageTranscoder { | ||
| 87 | |||
| 88 | /** | ||
| 89 | * Returns an <code>IIOMetadata</code> object that may be used for | ||
| 90 | * encoding and optionally modified using its document interfaces | ||
| 91 | * or other interfaces specific to the writer plug-in that will be | ||
| 92 | * used for encoding. | ||
| 93 | * | ||
| 94 | * <p> An optional <code>ImageWriteParam</code> may be supplied | ||
| 95 | * for cases where it may affect the structure of the stream | ||
| 96 | * metadata. | ||
| 97 | * | ||
| 98 | * <p> If the supplied <code>ImageWriteParam</code> contains | ||
| 99 | * optional setting values not understood by this writer or | ||
| 100 | * transcoder, they will be ignored. | ||
| 101 | * | ||
| 102 | * @param inData an <code>IIOMetadata</code> object representing | ||
| 103 | * stream metadata, used to initialize the state of the returned | ||
| 104 | * object. | ||
| 105 | * @param param an <code>ImageWriteParam</code> that will be used to | ||
| 106 | * encode the image, or <code>null</code>. | ||
| 107 | * | ||
| 108 | * @return an <code>IIOMetadata</code> object, or | ||
| 109 | * <code>null</code> if the plug-in does not provide metadata | ||
| 110 | * encoding capabilities. | ||
| 111 | * | ||
| 112 | * @exception IllegalArgumentException if <code>inData</code> is | ||
| 113 | * <code>null</code>. | ||
| 114 | */ | ||
| 115 | IIOMetadata convertStreamMetadata(IIOMetadata inData, | ||
| 116 | ImageWriteParam param); | ||
| 117 | |||
| 118 | /** | ||
| 119 | * Returns an <code>IIOMetadata</code> object that may be used for | ||
| 120 | * encoding and optionally modified using its document interfaces | ||
| 121 | * or other interfaces specific to the writer plug-in that will be | ||
| 122 | * used for encoding. | ||
| 123 | * | ||
| 124 | * <p> An optional <code>ImageWriteParam</code> may be supplied | ||
| 125 | * for cases where it may affect the structure of the image | ||
| 126 | * metadata. | ||
| 127 | * | ||
| 128 | * <p> If the supplied <code>ImageWriteParam</code> contains | ||
| 129 | * optional setting values not understood by this writer or | ||
| 130 | * transcoder, they will be ignored. | ||
| 131 | * | ||
| 132 | * @param inData an <code>IIOMetadata</code> object representing | ||
| 133 | * image metadata, used to initialize the state of the returned | ||
| 134 | * object. | ||
| 135 | * @param imageType an <code>ImageTypeSpecifier</code> indicating | ||
| 136 | * the layout and color information of the image with which the | ||
| 137 | * metadata will be associated. | ||
| 138 | * @param param an <code>ImageWriteParam</code> that will be used to | ||
| 139 | * encode the image, or <code>null</code>. | ||
| 140 | * | ||
| 141 | * @return an <code>IIOMetadata</code> object, | ||
| 142 | * or <code>null</code> if the plug-in does not provide | ||
| 143 | * metadata encoding capabilities. | ||
| 144 | * | ||
| 145 | * @exception IllegalArgumentException if either of | ||
| 146 | * <code>inData</code> or <code>imageType</code> is | ||
| 147 | * <code>null</code>. | ||
| 148 | */ | ||
| 149 | IIOMetadata convertImageMetadata(IIOMetadata inData, | ||
| 150 | ImageTypeSpecifier imageType, | ||
| 151 | ImageWriteParam param); | ||
| 152 | } | ||