ColoRIX

Latest revision as of 04:21, 28 December 2023

ColoRIX, or RIX, is a raster image file format associated with the EGA Paint and ColoRIX VGA Paint applications for MS-DOS, developed by RIX SoftWorks. There are at least two versions of it.

[edit] Format details

The "new" format (with "RIX3" signature) has a 10-byte header, then an optional and rare "extension block", then a color palette, then the image data. If the image is compressed, the high bit of the byte at offset 9 is set.

The "old" format lacks the header. If the image is compressed, the high bit of the first byte of the file is set. The low 6 bits of the first 16 bytes are an EGA-style color palette. The image data starts at offset 16.

Both old and new ColoRIX files may optionally be compressed, using a fairly complex compression scheme. The compression scheme starts by splitting the image data into one or more segments. For 256-color images only, an XOR filter is applied. Then comes run-length encoding, followed by Huffman coding. It is vaguely similar to Squeeze, though the details are different.

[edit] Identifiers

Many filename extensions have been reported or observed. Most are listed below. Extensions beginning with "SC" are generally used for full-screen images, with the third letter a code for the screen mode.

[edit] Identification

New (VGA Paint) format: Files begin with ASCII characters "RIX3".

Note that the VGA Paint distribution includes other files, in other formats, that also begin with "RIX", but have a different fourth byte.

Uncompressed old format: There's no robust way to identify the format, though you could check the file size (exactly 112016 bytes for SCR format), and validate the palette.

Compressed old format: There's no easy way to identify the format, though it is possible to identify it by reading the file and checking for errors.

[edit] Specifications

• RIX File Format Summary, from the Encyclopedia of Graphics File Formats
• RIX image File Format
• Picture format docs (of a number of formats including this one)
• Fallout 2 RIX File Format

[edit] Software

• ColoRIX VGA Paint 1.36 (at Internet Archive)
• ColoRIX VGA Paint - Various versions at old-dos.ru
• RIXLATE.EXE - Format conversion utility for DOS, included with, e.g., ColoRIX VGA Paint 1.36
• Konvertor
• XnView
• GrafX2
• Deark

[edit] Sample files

• VGARIX.ZIP → *.SCI
• dexvert samples — image/rix
• SCF Samples
• SDN¹ Plus → demos/colorix.zip → *.SCF
• Shareware Grab Bag → 008/egaslide.arc - EGA Slide, a component of EGA Paint (?). Includes some .SCR files in an old version of the format.

[edit] The Rolex demo

Apparently, RIX SoftWorks released a "Rolex" clock demo app that loads and displays an included (old-format) RIX file.

• MS-DOS Shareware: ROLEX
• rolex.zip

And some people modified it to display a custom image. A few of these mods may be found by searching the Internet Archive Software Collection for "rix softworks" (some may be NSFW).

• Other examples (compressed): micky.zip, tiggs.zip, GARFY.ZIP, SMURF.ZIP, MEGCLOCK.ZIP
• Other examples (uncompressed): buny.zip, pinkp.zip, TWEET.ZIP, USA_1.ZIP, EMIKO1.ZIP

[edit] Links

• EGA Paint ad in PC Magazine, Mar 10, 1987, p. 287