Module text 

Text measurement, padding and word wrapping.

Everything here works on visible columns: ANSI escape sequences count as zero width and characters are measured with unicode_width, so Czech diacritics, box-drawing characters and emoji line up. ⚠️ (an emoji presentation sequence of two code points) is the one case where terminals disagree with the standard, so text that goes into a box is normalised to the bare ⚠ first, see normalize_emoji.

Two layers live in this module:

• the public helpers (visible_width, pad_to, center, wrap_plain, …) that the screens use directly, and
• a small styled-text layout engine (crate-private) shared by wrap_plain and the markdown renderer. Words are laid out before any escape sequence is written and every styled run of a line is closed on that same line, so a line never carries a style over to the next one, wherever it is wrapped.

Constants

TAB_WIDTH

Tab stop distance used when tabs are expanded.

Functions

center

Centers line in width columns.

expand_tabs

Expands tab characters to spaces, with tab stops every tab_width columns.

fold_ansi

Cuts a possibly styled line into rows of at most width visible columns.

is_self_contained

True when line leaves no colour or attribute switched on at its end.

normalize_emoji

Removes the emoji variation selector U+FE0F after a one-column character.

pad_start

Pads line on the left so it ends at column width (right alignment).

pad_to

Pads line on the right with spaces up to width visible columns.

sanitize

Prepares text for display inside a box: control characters (except \n and \t) become U+FFFD and emoji are normalised with normalize_emoji.

strip_ansi

Removes ANSI escape sequences from s.

truncate

Shortens line to at most width visible columns, ending it with … when something was cut.

visible_width

Number of terminal columns s occupies, ignoring ANSI escape sequences.

with_base_style

Wraps text in base, keeping base active after any style reset inside the text.

wrap_plain

Wraps plain text to width columns without interpreting it in any way.