Instant Graphics and Sound (IGS)

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A screenshot from the "XNET_LST.IG" demo for Instant Graphics and Sound.

Instant Graphics and Sound, also known as IGS or IG, is a graphics language created by Larry Mears for the Atari ST computer to transmit vector graphics, sound effects, and animation from text-based bulletin board systems.

Introduced in 1988, IGS provided a way to encode vector graphics, sound effects, and animation effects as ASCII text. The IGS specification also allowed for the creation of graphical user interfaces with menus and clickable buttons. These IGS menus could replace the ASCII or VT-52 text menus that were common on Atari ST BBSes. To view these graphics, a user needed to install the IGS desk accessory. Once installed, GEM-based terminal programs like FLASH could properly translate the text sequences. Mears also wrote an .EMU plugin for Interlink.

Anthony Rau and Kevin Moody developed an editor utility to make it easier for users to create IGS graphics and animations, releasing several versions between 1990 and 1993.


An IGS drawing of the Federation Cruiser from the game FTL, drawn in 2023 using the new v2.18 editor.
A screenshot from the "BLITZ.IG" demo for Instant Graphics and Sound.

In the 1980s, Atari ST BBSes were entirely text-based. While the ST's VT-52 terminal emulation allowed for cursor movement, most BBSes ran in 80-column medium resolution, which was limited to four colors.

Mears was disappointed with the limitations of VT-52[1], and developed Instant Graphics and Sound to enable sysops to create more immersive bulletin board systems.

IGS uses the Atari ST's built-in VDI graphics routines to generate colored lines, shapes, and text with various sizes and effects. The format also supports looping, sound effects and music, flood fills, pattern fills, bit blitting, color cycling, and resolution changes.

A writer for Atari Interface magazine in 1990 praised IGS as "the future of the ST telecommunications," saying it enabled "dazzling visual effects."[2]

The earliest extant version of IGS, v2.14, was released in May 1990. The included changelog indicates that v2.10 was released on October 1989 — several years before the better-remembered Remote Imaging Protocol was introduced for DOS.

As the ST declined in popularity, Mears began developing a similar system for the PC, which he called Blue Instant Graphics, or BIG. This later morphed into a driver, which he called Condor.

Mears stopped working on IGS for the Atari ST in 1992, releasing the final contemporary version, v2.17, in January. He released the source code several months later.

But 30 years later, Mears published an unexpected new version of IGS — v2.18 — along with a new editor program. This version adds many new features, including robust support for the ST's 16-color low-resolution mode.

See also



  1. Stewart, David (March 1990). "ST World On-line". ST World. Gollner Publishing Ltd. Because the graphics are not transmitted as a block-map or bit-map, IGS is impressively fast ... The possibilities for this system are quite broad. 
  2. Bailey, Jon (October 1990). "Instant Graphics and Sound: An OnLine Odyssey". Atari Interface. Unicorn Publications. I have seen the future of ST telecommunications and this is it. The new Instant Graphics and Sound (IGS) program, from shareware author Larry Mears, not only provides dazzling visual effects, but also beeps, bells, hoots, whistles and a varied assortment of other goodies! 

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