Struct AdaptiveLayoutParams 

pub struct AdaptiveLayoutParams {
    pub xy_cut_min_gap_ratio: f32,
    pub word_gap_threshold: f32,
    pub line_gap_threshold: f32,
    pub column_gap_threshold: f32,
    pub xy_cut_max_depth: u32,
    pub xy_cut_min_region_size: f32,
    pub gaussian_sigma: f32,
}

Adaptive layout parameters computed from document properties.

These parameters are used by layout algorithms (XY-Cut, clustering, etc.) and are computed as ratios/multiples of measured document properties rather than fixed absolute values.

Fields

xy_cut_min_gap_ratio: f32

Minimum gap for XY-Cut split (as ratio of page dimension).

Typical: 0.05 (5% of page width/height)

word_gap_threshold: f32

Word clustering threshold (horizontal gap between characters).

Gaps larger than this likely indicate word boundaries. Computed as multiple of median character width.

line_gap_threshold: f32

Line clustering threshold (vertical gap between characters).

Gaps larger than this likely indicate line boundaries. Computed as multiple of median line spacing.

column_gap_threshold: f32

Column gap threshold (minimum gap between columns).

Computed as multiple of median font size.

xy_cut_max_depth: u32

Maximum recursion depth for XY-Cut.

xy_cut_min_region_size: f32

Minimum region size for XY-Cut split (in PDF units).

Regions smaller than this won’t be split further.

gaussian_sigma: f32

Gaussian smoothing sigma for projection profiles.

Controls noise reduction in XY-Cut valley detection. Adaptive based on layout density:

• Dense layouts (short lines): Low sigma (0.5) for sharp peaks
• Medium layouts: Medium sigma (1.5) balances noise vs detail
• Sparse layouts (long lines): High sigma (2.5) for broad valleys

Meunier (ICDAR 2005) recommends σ=2.0 as baseline.

Implementations

impl AdaptiveLayoutParams

pub fn from_properties(props: &DocumentProperties) -> Self

Compute adaptive parameters from document properties.

Arguments

• props - Analyzed document properties

Returns

Adaptive parameters tuned for the specific document.

Examples

let page_bbox = Rect::new(0.0, 0.0, 612.0, 792.0);
let props = DocumentProperties::analyze(&chars, page_bbox)?;
let params = AdaptiveLayoutParams::from_properties(&props);

println!("Word gap threshold: {:.1}", params.word_gap_threshold);
println!("Column gap threshold: {:.1}", params.column_gap_threshold);

pub fn default_for_letter_pdf() -> Self

Create default parameters for when document analysis is unavailable.

These are reasonable defaults for typical Letter-sized PDFs with 10-12pt text.

Trait Implementations

impl Clone for AdaptiveLayoutParams

fn clone(&self) -> AdaptiveLayoutParams

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for AdaptiveLayoutParams

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

Formats the value using the given formatter.