Module position 

Position newtypes and the conversions between them.

This is the only module that knows about tab stops, grapheme clusters and display widths. The canonical position everywhere else is ByteOffset.

Structs

ByteOffset

Byte offset into the document’s UTF-8 text, always on a char boundary.

CharIdx

Char index; only used at the boundary with Ropey 1.x.

LineCol

A line and a byte column within that line.

VisualCol

On-screen cell column, after tab expansion and wide-glyph widths.

Wrapped

How one line wraps into display rows.

Constants

MIN_WRAP_WIDTH

The narrowest wrap width, in cells.

Functions

byte_to_line_col

byte_to_visual_col

cells

(byte, visual column, width in cells) of each grapheme of one line’s text.

grapheme_width

Display width of one grapheme starting at visual column col. Tabs expand to the next tab stop; every other grapheme takes at least one cell so that distinct boundaries always have distinct visual columns.

line_col_to_byte

Clamps the column to the end of the line. The column must land on a char boundary; out-of-range lines clamp to the end of the document.

line_visual_width

Width of the whole line in visual columns.

next_grapheme_boundary

The next grapheme boundary after pos (or the end of the document).

prev_grapheme_boundary

The previous grapheme boundary before pos (or 0).

visual_col_to_byte

The last grapheme boundary on line whose visual column is <= col, or the line end if the line is shorter (no virtual space).

visual_col_to_byte_ceil

The first grapheme boundary on line whose visual column is >= col, or the line end. Used for the left edge of a rectangle so that a tab or wide glyph straddling the edge stays outside it.

wrap_line

Wraps text (one line, without its line break) to rows of width cells. Rows break after a run of whitespace when there is one in the row, otherwise before the grapheme that does not fit; a grapheme is never split, and one wider than a row gets a row of its own. Tab stops count from the start of the line, so wrapping never changes a grapheme’s visual column. Rows after the first are indented like the line, by at most half the width.