Module width 

How many terminal columns a glyph occupies.

Every renderer measures cells through this one function, so a hidden cell reserves exactly as many columns as the glyph will need once it appears. That is what keeps a row from shifting sideways as the reveal crosses a wide glyph.

Functions

glyph_cols

Display columns a glyph occupies: 0 for zero-width and combining marks, 2 for wide glyphs (CJK and many emoji), 1 otherwise.

sanitize

Replace control characters with spaces.

str_cols

Total display columns of a string.

truncate_to_cols

Truncate s to at most max display columns, dropping whole glyphs so a wide glyph is never split across the edge.