Struct SimpleLayouter 

pub struct SimpleLayouter {
    pub flow_direction: FlowDirection,
}

Simple layouter that supports both horizontal (LTR) and vertical flow.

For horizontal flow, advances a cursor left-to-right, emitting a PositionedGlyph for each input glyph and wrapping when the cursor exceeds max_width.

For vertical flow, advances the cursor top-to-bottom using each glyph’s y_advance (falling back to x_advance when y_advance is zero), and wraps into a new column when max_width (treated as max column height) is exceeded.

This is the M1 cursor-advance layouter. For word-aware wrapping with UAX #14 line breaking, alignment, and structured per-line metrics, use LayoutEngine instead (see its crate::engine module docs).

Example

use oxitext_core::{LayoutConstraints, ShapedGlyph, ShapedRun};
use oxitext_layout::SimpleLayouter;
use std::sync::Arc;

// A run of 5 glyphs, each advancing the cursor by 10px (a real shaper
// would produce this from actual text + a font).
let glyphs: Vec<ShapedGlyph> = (0u32..5)
    .map(|i| ShapedGlyph {
        gid: (i + 1) as u16,
        x_advance: 10.0,
        cluster: i,
        ..Default::default()
    })
    .collect();
let run = ShapedRun {
    glyphs: glyphs.into(),
    font_data: Arc::from(&[][..]),
};

let constraints = LayoutConstraints {
    max_width: 800.0,
    font_size: 16.0,
};
let positioned = SimpleLayouter::new()
    .layout(&[run], &constraints)
    .expect("layout is currently infallible");

assert_eq!(positioned.len(), 5);
// Cursor advances left-to-right within the (wide) max_width.
for pair in positioned.windows(2) {
    assert!(pair[1].pos.0 > pair[0].pos.0);
}

Fields

flow_direction: FlowDirection

Text flow direction for this layouter instance.

Implementations

impl SimpleLayouter

pub fn new() -> Self

Creates a new layouter with horizontal flow (the default).

pub fn with_flow_direction(self, dir: FlowDirection) -> Self

Returns a copy of this layouter with the given flow direction.

pub fn layout( &self, runs: &[ShapedRun], constraints: &LayoutConstraints, ) -> Result<Vec<PositionedGlyph>, OxiTextError>

Positions glyphs from the shaped runs according to constraints.

Dispatches to Self::layout_horizontal or Self::layout_vertical based on Self::flow_direction.

Errors

Currently infallible; returns Err only for forward compatibility.

Trait Implementations

impl Default for SimpleLayouter

fn default() -> Self

Returns the “default value” for a type.