Module text 

Text utilities for terminal rendering.

This module intentionally focuses on terminal cell concepts (columns/rows), not on rich text editing. The editor crate can own the higher-level buffer, undo/redo, and modal behavior.

The helpers here are aimed at:

• status bars / command lines
• horizontal clipping / truncation
• “fit this string into N terminal columns”

Width and clipping use complete grapheme clusters and Unicode width tables, including emoji sequences, combining marks, and wide CJK characters.

Enums

TabPolicy

How to handle tab characters ('\t') when measuring/clipping text.

TextWrapMode

Where to break text that exceeds the available terminal cells.

Functions

byte_index_for_char_index

Converts a character index into a byte index for s.

byte_index_for_grapheme_index

Converts a grapheme index into a byte index for s.

cell_column_for_char_index

Returns the terminal cell column for a character index in s.

cell_column_for_grapheme_index

Returns the terminal cell column for a grapheme index in s.

cell_width

Returns the terminal width of complete grapheme clusters, ignoring controls.

cell_width_char

Returns the width of a Unicode scalar. Use cell_width for grapheme clusters.

char_index_from_cell_column

Maps a terminal column to the start of its grapheme, in character indices.

clip_to_cells

Clips s to at most max_cells terminal cells.

clip_to_cells_cow

Clips s to at most max_cells terminal cells, borrowing s when no clipping or character normalization is required.

clip_to_cells_ellipsis

Clips s to max_cells like clip_to_cells, but appends an ellipsis if clipped.

clip_to_cells_into

Clips s into an existing string buffer, reusing the allocation.

fit_to_cells

Pads or truncates s to exactly target_cells cells.

grapheme_count

Returns the number of grapheme clusters in s.

grapheme_index_from_cell_column

Best-effort mapping from terminal cell column to grapheme index.

wrap_ranges_to_cells

Returns source byte ranges for lines wrapped to max_cells terminal columns.

wrap_to_cells

Wraps plain text into renderable lines, expanding tabs and removing controls.