1 <!doctype html>
2 <html lang="en">
3 <head>
4 <meta charset="utf-8"/>
5 <title>PNG Metadata Format Specification</title>
6 </head>
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8 Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
9 DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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11 This code is free software; you can redistribute it and/or modify it
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13 published by the Free Software Foundation. Oracle designates this
14 particular file as subject to the "Classpath" exception as provided
15 by Oracle in the LICENSE file that accompanied this code.
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17 This code is distributed in the hope that it will be useful, but WITHOUT
18 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
19 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
20 version 2 for more details (a copy is included in the LICENSE file that
21 accompanied this code).
22
23 You should have received a copy of the GNU General Public License version
24 2 along with this work; if not, write to the Free Software Foundation,
25 Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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28 or visit www.oracle.com if you need additional information or have any
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30 -->
31
32 <body>
33 <main role="main">
34 <h1>PNG Metadata Format Specification</h1>
35
36 <p>
37
38 The PNG native format encodes the complete contents of a PNG file
39 chunk by chunk, except for the IDAT chunks that contain the actual
40 image data. Chunks that are not defined in the PNG 1.2 specification
41 are stored under the <code>UnknownChunks</code> element. Note that it
42 is the responsibility of application software to implement the rules
43 for PNG readers, writers, and editors (<i>e.g.</i>, the rules
44 concerning unsafe-to-copy chunks) described in the PNG specification.
45 The Image I/O library is not, in and of itself, a PNG reader, writer,
46 or editor in the sense of the specification. Rather, it is a tool
47 that may be used to build PNG readers, writers, and editors.
48
49 <p>
50
51 The image's actual width, height, bit depth, and color type will
52 override any values passed to the writer via metadata, with one
53 exception. If the image has an <code>IndexColorModel</code>, the
544 <!-- Data type: String -->
545 <!ATTLIST "zTXtEntry" "compressionMethod" ("deflate")
546 #REQUIRED>
547 <!-- The compressed text -->
548
549 <!ELEMENT "UnknownChunks" (UnknownChunk)*>
550 <!-- A set of unknown chunks -->
551 <!-- Min children: 1 -->
552 <!-- Max children: 2147483647 -->
553
554 <!ELEMENT "UnknownChunk" EMPTY>
555 <!-- Unknown chunk data stored as a byte array -->
556 <!-- User object: array of byte -->
557 <!-- Min length: 0 -->
558 <!-- Max length: 2147483647 -->
559 <!ATTLIST "UnknownChunk" "type" #CDATA #REQUIRED>
560 <!-- The 4-character type of the unknown chunk -->
561 <!-- Data type: String -->
562 ]>
563 </pre>
564 </main>
565 </body>
566 </html>
|
1 <!doctype html>
2 <html lang="en">
3 <head>
4 <meta charset="utf-8"/>
5 <title>PNG Metadata Format Specification</title>
6 </head>
7 <!--
8 Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
9 DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
10
11 This code is free software; you can redistribute it and/or modify it
12 under the terms of the GNU General Public License version 2 only, as
13 published by the Free Software Foundation. Oracle designates this
14 particular file as subject to the "Classpath" exception as provided
15 by Oracle in the LICENSE file that accompanied this code.
16
17 This code is distributed in the hope that it will be useful, but WITHOUT
18 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
19 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
20 version 2 for more details (a copy is included in the LICENSE file that
21 accompanied this code).
22
23 You should have received a copy of the GNU General Public License version
24 2 along with this work; if not, write to the Free Software Foundation,
25 Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
26
27 Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
28 or visit www.oracle.com if you need additional information or have any
29 questions.
30 -->
31
32 <body>
33 <main role="main">
34 <div class="contentContainer">
35 <h1>PNG Metadata Format Specification</h1>
36
37 <p>
38
39 The PNG native format encodes the complete contents of a PNG file
40 chunk by chunk, except for the IDAT chunks that contain the actual
41 image data. Chunks that are not defined in the PNG 1.2 specification
42 are stored under the <code>UnknownChunks</code> element. Note that it
43 is the responsibility of application software to implement the rules
44 for PNG readers, writers, and editors (<i>e.g.</i>, the rules
45 concerning unsafe-to-copy chunks) described in the PNG specification.
46 The Image I/O library is not, in and of itself, a PNG reader, writer,
47 or editor in the sense of the specification. Rather, it is a tool
48 that may be used to build PNG readers, writers, and editors.
49
50 <p>
51
52 The image's actual width, height, bit depth, and color type will
53 override any values passed to the writer via metadata, with one
54 exception. If the image has an <code>IndexColorModel</code>, the
545 <!-- Data type: String -->
546 <!ATTLIST "zTXtEntry" "compressionMethod" ("deflate")
547 #REQUIRED>
548 <!-- The compressed text -->
549
550 <!ELEMENT "UnknownChunks" (UnknownChunk)*>
551 <!-- A set of unknown chunks -->
552 <!-- Min children: 1 -->
553 <!-- Max children: 2147483647 -->
554
555 <!ELEMENT "UnknownChunk" EMPTY>
556 <!-- Unknown chunk data stored as a byte array -->
557 <!-- User object: array of byte -->
558 <!-- Min length: 0 -->
559 <!-- Max length: 2147483647 -->
560 <!ATTLIST "UnknownChunk" "type" #CDATA #REQUIRED>
561 <!-- The 4-character type of the unknown chunk -->
562 <!-- Data type: String -->
563 ]>
564 </pre>
565 </div>
566 </main>
567 </body>
568 </html>
|