pub const NINE_LEVELS: [char; 9];Expand description
The nine bar levels from empty to full, indexed 0..=8: a blank cell, then
ONE_EIGHTH through FULL in order.
Indexing this directly by round(fraction * 8.0) as usize turns a 0.0..=1.0 magnitude
into the right glyph for one bar column. Six of these eight are outside CP437 (only ’ ’ and
FULL are covered); a pixel backend resolving glyphs through a CP437 table draws the other
six as its fallback solid block, which erases the ramp’s granularity. For a bar that has to
stay legible on a CP437-only tileset/sprite path, use SHADE_LEVELS instead.