PackBits - Revision history

Jsummers at 17:40, 23 June 2024

2024-06-23T17:40:00Z

Jsummers at 15:10, 9 May 2024

2024-05-09T15:10:34Z

Jsummers: /* Specifications */

2017-02-12T19:59:54Z

‎Specifications

Jsummers at 21:47, 11 November 2015

2015-11-11T21:47:36Z

Jsummers: /* Related formats */

2015-10-26T20:44:09Z

‎Related formats

Jsummers: Format details

2015-09-22T22:06:17Z

Format details

Jsummers at 01:14, 22 April 2015

2015-04-22T01:14:32Z

Jsummers: /* Overview */

2013-04-28T14:33:28Z

‎Overview

Jsummers: /* Overview */

2013-04-28T14:32:33Z

‎Overview

Jsummers: Created page with "{{FormatInfo |formattype=electronic |subcat=Graphics }} == Overview == '''PackBits''', or '''Apple Macintosh PackBits''', is a simple lossless image compression scheme that us..."

2013-04-15T14:31:31Z

Created page with "{{FormatInfo |formattype=electronic |subcat=Graphics }} == Overview == '''PackBits''', or '''Apple Macintosh PackBits''', is a simple lossless image compression scheme that us..."

New page

{{FormatInfo
|formattype=electronic
|subcat=Graphics
}}
== Overview ==
'''PackBits''', or '''Apple Macintosh PackBits''', is a simple lossless image compression scheme that uses [[run-length encoding]].

It is byte-oriented (as opposed to pixel-oriented), so depending on how the image data is organized, it may be ineffective for images that use more than one byte per pixel.

== Related formats ==
PackBits compression is used by [[MacPaint]] files, and some [[TIFF]] files.

== Specifications ==
* [http://partners.adobe.com/public/developer/en/tiff/TIFF6.pdf TIFF 6.0 Specification], Section 9: PackBits Compression
* [http://web.archive.org/web/20080705155158/http://developer.apple.com/technotes/tn/tn1023.html Technical Note TN1023]: Understanding PackBits

== Resources ==
* [[Wikipedia:PackBits|Wikipedia article]]

[[Category:Compression]]
[[Category:Macintosh]]

@@ Line 4: / Line 4: @@
 }}
 '''PackBits''' (or '''Apple Macintosh PackBits''', or '''Macintosh RLE''') is a form of [[run-length encoding]] often used to compress image data.
 == Format details ==
@@ Line 34: / Line 32: @@
 == Variants ==
-PackBits can easily be modified such that a unit of decompressed data is some fixed number of bytes greater than one. Formats that may use such variants include [[PICT]], [[Palm bitmap]], and [[IFF-DEEP]].
+PackBits compresses a sequence of bytes, but variants exist in which a unit of decompressed data is more than one byte (e.g. some [[PICT]], [[Palm bitmap]], and [[IFF-DEEP]] compression schemes), or even less than one byte (e.g. [[GlowIcons]]).
 == Related formats ==

@@ Line 7: / Line 7: @@
 It is byte-oriented (as opposed to pixel-oriented), so depending on how the image data is organized, it may be ineffective for images that use more than one byte per pixel.
-== Format ==
+== Format details ==
 The compressed data stream consists of a code byte, followed by zero or more data bytes, followed by another code byte, and so on.
@@ Line 32: / Line 32: @@
 The reserved code byte (128 or −128) should be ignored, unless a format specification says otherwise. A few formats use it to mark the end of the compressed data.
 == Related formats ==

@@ Line 34: / Line 34: @@
 == Related formats ==
-Formats that may use PackBits compression include [[MacPaint]], [[TIFF]], [[ILBM]], and [[Prism Paint]].
+Formats that may use PackBits compression include [[MacPaint]], [[PICT]], [[TIFF]], [[ILBM]], and [[DEGAS image|DEGAS]].
 == Specifications ==

@@ Line 4: / Line 4: @@
 }}
 == Overview ==
-'''PackBits''' (or '''Apple Macintosh PackBits''', or '''Macintosh RLE'''), is a simple lossless image compression scheme that uses [[run-length encoding]].
+'''PackBits''' (or '''Apple Macintosh PackBits''', or '''Macintosh RLE''') is a simple lossless image compression scheme that uses [[run-length encoding]].
 It is byte-oriented (as opposed to pixel-oriented), so depending on how the image data is organized, it may be ineffective for images that use more than one byte per pixel.

@@ Line 39: / Line 39: @@
 * [http://partners.adobe.com/public/developer/en/tiff/TIFF6.pdf TIFF 6.0 Specification], Section 9: PackBits Compression
 * [http://web.archive.org/web/20080705155158/http://developer.apple.com/technotes/tn/tn1023.html Technical Note TN1023]: Understanding PackBits
-* [http://www.atari-wiki.com/?title=ST_Picture_Formats ST Picture Formats]
+* {{AtariForumWiki|PackBits_Compression_Algorithm|AtariForumWiki: PackBits Compression Algorithm}}
 == Resources ==

@@ Line 1: / Line 1: @@
 {{FormatInfo
 |formattype=electronic
-|subcat=Graphics
+|subcat=Compression
 }}
 '''PackBits''' (or '''Apple Macintosh PackBits''', or '''Macintosh RLE''') is a form of [[run-length encoding]] often used to compress image data.
@@ Line 44: / Line 44: @@
 * [[Wikipedia:PackBits|Wikipedia article]]
-[[Category:Compression]]
+[[Category:Graphics]]
 [[Category:Macintosh]]