One of the interesting modes of the Coco1 was the semigraphics group. One version of this still exists in the Coco3, block characters on the low res text screen. However, semigraphics-24 was the mode that presented some unique possibilities to the older unit. Unfortunately Tandy never provided a tool for users to access this mode.
What is semigraphics? The
highest
graphics resolution on the Coco1 in normal use is 256x192 in two
colors.
The pixels are 1x1 in size. Semigraphics is displayed on the text
screen
where a single character block is split into sections, each of which
can
be changed. S-24 takes the standard 8x12 character and gives you a 2x12
matrix where each slice can be altered. The pixel size in this mode is
thus 4x1. This presents some artistic problems but they can be overcome
as shown below.
The colors on this screen are true not artifacts and it is easy to mix text and graphics. This mode may still be of interest because there is renewed interest in the Coco via the Coco2 emulator. The emulator supports the S-24 mode and will run my S-24 software available below.