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	<id>https://mediawiki.zeropage.org/index.php?action=history&amp;feed=atom&amp;title=PNGFileFormat%2FFileStructure</id>
	<title>PNGFileFormat/FileStructure - Revision history</title>
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	<updated>2026-05-14T23:44:56Z</updated>
	<subtitle>Revision history for this page on the wiki</subtitle>
	<generator>MediaWiki 1.39.8</generator>
	<entry>
		<id>https://mediawiki.zeropage.org/index.php?title=PNGFileFormat/FileStructure&amp;diff=84761&amp;oldid=prev</id>
		<title>Maintenance script: Repair batch-0003 pages from live compare</title>
		<link rel="alternate" type="text/html" href="https://mediawiki.zeropage.org/index.php?title=PNGFileFormat/FileStructure&amp;diff=84761&amp;oldid=prev"/>
		<updated>2026-03-27T00:29:03Z</updated>

		<summary type="html">&lt;p&gt;Repair batch-0003 pages from live compare&lt;/p&gt;
&lt;table style=&quot;background-color: #fff; color: #202122;&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
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				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;Revision as of 00:29, 27 March 2026&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l80&quot;&gt;Line 80:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 80:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;----&lt;/div&gt;&lt;/td&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;----&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;[[PNGFileFormat]]&lt;/div&gt;&lt;/td&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;[[PNGFileFormat]]&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class=&quot;diff-marker&quot; data-marker=&quot;−&quot;&gt;&lt;/td&gt;&lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;del style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;&lt;/del&gt;&lt;/div&gt;&lt;/td&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-side-added&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Maintenance script</name></author>
	</entry>
	<entry>
		<id>https://mediawiki.zeropage.org/index.php?title=PNGFileFormat/FileStructure&amp;diff=37430&amp;oldid=prev</id>
		<title>imported&gt;Unknown at 05:23, 7 February 2021</title>
		<link rel="alternate" type="text/html" href="https://mediawiki.zeropage.org/index.php?title=PNGFileFormat/FileStructure&amp;diff=37430&amp;oldid=prev"/>
		<updated>2021-02-07T05:23:58Z</updated>

		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;p&gt;&lt;b&gt;New page&lt;/b&gt;&lt;/p&gt;&lt;div&gt;== 파일 구조 ==&lt;br /&gt;
 PNG 파일은 PNG 시그너처와 여러개의 chunk로 이루어짐.&lt;br /&gt;
&lt;br /&gt;
=== 1. PNG file 시그너처 ===&lt;br /&gt;
* PNG파일의 처음 8바이트는 다음의 십진 값들로 시작.&lt;br /&gt;
 137 80 78 71 13 10 26 10&lt;br /&gt;
   &lt;br /&gt;
&lt;br /&gt;
=== 2. Chunk Layout ===&lt;br /&gt;
* 각 chunk는 네 부분으로 나뉘어진다.&lt;br /&gt;
** Length : 4바이트. Length, Chunk Type, CRC 길이는 포함되지 않은 값이다.&lt;br /&gt;
** Chunk Type : 4바이트. 반드시 알파벳이어야 함(편리함. 가독성을 위해). 엔코더, 디코더는 이 값을 이진 값으로 인지.&lt;br /&gt;
** Chunk Data : Type 에 따른 데이터. 길이가 0일수 있음.&lt;br /&gt;
** CRC : Chunk Type + Chunk Data 에 대한 4 바이트 CRC 값.&lt;br /&gt;
&lt;br /&gt;
=== 3. Chunk 이름짓기 규칙 ===&lt;br /&gt;
=== 4. CRC 알고리즘 ===&lt;br /&gt;
=== 5. Chunk Spec. ===&lt;br /&gt;
* 제일 처음에는 IHDR chunk가 오는데, 다음의 요소로 이루어져 있다.&lt;br /&gt;
** Width : 픽셀단위의 이미지 너비&lt;br /&gt;
** Height : 픽셀단위의 이미지 높이&lt;br /&gt;
** Bit depth : 하나의 샘플(픽셀과는 다른개념)당 또는 파레트 인덱스당 쓰이는 비트의 수&lt;br /&gt;
** Compression method : 이미지 데이터를 압축하는데 쓰는 방법&lt;br /&gt;
** Filter method : 이미지 데이터에 대한 전처리 방법. Compression과 관련.&lt;br /&gt;
** Interlace method : 이미지에 대한 비트오더.&lt;br /&gt;
{| class=&amp;quot;wikitable&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
| Color Type&lt;br /&gt;
| Allowed Bit Depths&lt;br /&gt;
| Interpretation&lt;br /&gt;
|-&lt;br /&gt;
| 0&lt;br /&gt;
| 1,2,4,8,16&lt;br /&gt;
| Each pixel is a grayscale sample.&lt;br /&gt;
|-&lt;br /&gt;
| 2&lt;br /&gt;
| 8, 16&lt;br /&gt;
| Each pixel is an R, G, B triple.&lt;br /&gt;
|-&lt;br /&gt;
| 3&lt;br /&gt;
| 1, 2, 4, 8&lt;br /&gt;
| Each pixel is a palette index; a PLTE chunk must appear.&lt;br /&gt;
|-&lt;br /&gt;
| 4&lt;br /&gt;
| 8, 16&lt;br /&gt;
| Each pixel is a grayscle sample, followed by an alpha sample.&lt;br /&gt;
|-&lt;br /&gt;
| 6&lt;br /&gt;
| 8, 16&lt;br /&gt;
| Each pixel is an R, G, B triple, followed by an alpha sample.&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
* PLTE chunk : 256개의 엔트리를 갖음. R, G, B 색상)&lt;br /&gt;
* IDAT chunk : 실제 픽셀값. IDAT는 여러개가 올 수 있다. (see also [[PNGFileFormat/ImageData]])&lt;br /&gt;
* IEND chunk : 반드시 이 chunk 로 끝나야 함. Data 길이는 0.&lt;br /&gt;
&lt;br /&gt;
=== Summary ===&lt;br /&gt;
{| class=&amp;quot;wikitable&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
| Name&lt;br /&gt;
| 여러개 허용?&lt;br /&gt;
| 파일상의 위치 제약&lt;br /&gt;
|-&lt;br /&gt;
| IHDR&lt;br /&gt;
| x&lt;br /&gt;
| 반드시 제일 앞에 와야함 (처음의 8비트 제외)&lt;br /&gt;
|-&lt;br /&gt;
| PLTE&lt;br /&gt;
| x&lt;br /&gt;
| IDAT전에 와야함&lt;br /&gt;
|-&lt;br /&gt;
| IDAT&lt;br /&gt;
| o&lt;br /&gt;
| 여러개가 사용된다면 반드시 연속적이어야 함&lt;br /&gt;
|-&lt;br /&gt;
| IEND&lt;br /&gt;
| x&lt;br /&gt;
| 반드시 제일 끝에 와야 함&lt;br /&gt;
|}&lt;br /&gt;
----&lt;br /&gt;
[[PNGFileFormat]]&lt;br /&gt;
&lt;/div&gt;</summary>
		<author><name>imported&gt;Unknown</name></author>
	</entry>
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