Extended DEGAS image

Extended DEGAS image is the name we're using for a collection of raster graphics formats associated with Atari TT and Atari Falcon computers, characterized by file extensions .PI4 through .PI9. This file extension pattern is presumably inspired by the original DEGAS image formats, and some of the formats are clearly based on the DEGAS formats.

''[Ed. note: This article maybe ought to be divided into two or more separate articles, but we don't have enough information about these formats to do that very well.]''

Formats
PI4 and PI5 formats come from a program named View ST/TT (a.k.a. ViewST/TT).

PI9 and a different PI4 format originated with a paint program unfortunately named Fuckpaint.

The origin of the other formats, and the total number of formats, is unknown.

Compression
No internal data compression is known to be used for any of the formats (the logical .PC4 through .PC9 file extensions have not been observed). But sometimes the entire file is compressed, for example with Pack-Ice.

Sample files

 * RECOIL's examples.zip → *.PI4, *.PI9
 * http://cd.textfiles.com/atarilibrary/atari_cd07/DISKMAGS/ONLINE/ONLINE_2/
 * http://cd.textfiles.com/atarilibrary/atari_cd07/DISKMAGS/DBAMAG/DBAMAG12/PICTURES/
 * menu2.pi4

Links

 * ST Picture Formats
 * View ST/TT
 * viewttst.txt - Defines PI4, PI5. (Also refers to "PI0" format, but that might be a clerical error that should be "PI1".)
 * Fuckpaint
 * The Atari A to Z format list - Confirms that PI5, PI7, PI8 exist.