Struct VisualLine 

pub struct VisualLine {
    pub visual: Vec<char>,
    pub logical_to_visual: Vec<usize>,
    pub visual_to_logical: Vec<usize>,
    pub base_level: u8,
}

The visual-order result of driving the full UAX #9 §3 + §3.4 bidirectional pipeline over one display line.

A renderer that wants correct bidirectional text walks VisualLine::visual left-to-right (the natural rendering direction of the output device), feeding each character to the shaper / cmap and laying the glyphs out in increasing x. The per-character permutation VisualLine::logical_to_visual and its inverse VisualLine::visual_to_logical let the caller map a visual glyph back to its source character (cursor hit-testing, selection-rectangle building) and vice versa.

visual already has rule L4 mirroring applied — every character whose resolved level is odd (right-to-left) and that has a Bidi_Mirroring_Glyph pair (a bracket, an angle quotation mark, a mathematical relation, …) is the mirrored code point, not the logical one — so the renderer must not mirror again.

Fields

visual: Vec<char>

The line’s characters in left-to-right visual order, with L4 mirroring applied. visual.len() equals the line’s character count.

logical_to_visual: Vec<usize>

Permutation entry k is the logical index of the character that belongs at visual position k (the UAX #9 §3.4 L2 output). visual[k] is the L4-mirrored form of the logical character at index logical_to_visual[k].

visual_to_logical: Vec<usize>

The inverse permutation: entry i is the visual position of the character whose logical index is i. Equivalent to inverting Self::logical_to_visual; precomputed for O(1) logical-to-visual hit-testing.

base_level: u8

The paragraph embedding level resolved by P2 / P3 (or supplied by the caller as the HL1 override). 0 for an LTR line, 1 for an RTL line.

Implementations

impl VisualLine

pub fn to_visual_string(&self) -> String

Collect Self::visual into a String — the line in the order a left-to-right renderer paints it.

pub fn len(&self) -> usize

Number of characters in the line.

pub fn is_empty(&self) -> bool

Whether the line is empty.

Trait Implementations

impl Clone for VisualLine

fn clone(&self) -> VisualLine

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for VisualLine

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for VisualLine

impl PartialEq for VisualLine

fn eq(&self, other: &VisualLine) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for VisualLine