scroller - NicheInterests/mistfunk GitHub Wiki
SCROLLER adj./n. An ANSI artpiece that is longer than 23 or 25 lines that with critically rare exception is never animated. An ANSI of such length scrolls upwards when viewed on an IBM PC under DOS in its native 80x25 text mode from the command line or a terminal program connected to a BBS.
Elaborating a bit: prior to the release of ACiDDraw with its 1000-line length limit, it was rather difficult to draw canvases of more than the standard MS-DOS default terminal height of 25 rows. TheDraw only allowed 25 lines (50 lines only in 80x50 mode -- which would yield deformed proportions when viewed at 80x25) and ANSI screens longer than 25 lines needed to be made by concatenating 25-line files together and making sure none of them started with screen-clear/cursor-home commands. You can perceive the invisible seams when looking at early scrollers, starting with a 25-line header with the artist's initials and a logo for their crew, then 25 lines of rain, then 25 lines of lit, then a 25-line close-up portrait of a comic book character with no nose and a bad attitude, then a 25-line logo for the BBS being promoted, then 25 lines of the board's elite affiliations. Voila, a 150-line scroller!
It wasn't easy to draw scrollers (if the subject of your portrait was taller than 25 lines, good luck matching up the pieces to fit together properly!) and it wasn't always easy even to just view them, for BBS callers on slower modems, since at low baud rates an inactivity timer might kick a user offline while they waited for a long scroller to finish displaying and prompt them for input!
The terminal window typically would only display 25 lines at a time, so a scroller might allow an artist to get away with dodgy proportions in their showboating -- until ACiDdraw's "VGA preview" became a regular feature in ANSI viewer programs, your only reference to the contents of the screen that had just scrolled by was your memory. For long canvases BBS callers would only get to see a small window of the overall composition at a time, like viewing Duchamp's "Étant donnés" through a peephole.
As scrollers became more prevalent they were weighted as more valuable than single-screen illustrations or logos (though it's not like small-scale ANSI illustration is easy!), and ANSI artists might charge more for the commissioning of a 150-line piece than they would for a 100-liner or a 50-liner.