Struct PolylineSampler 

pub struct PolylineSampler { /* private fields */ }

Pre-flattened polyline with a cumulative segment-length table. Build once, then sample at arbitrary arc-length distances in O(N) per query.

Used when the caller needs irregular sampling — e.g. LineGeom walking a linetype pattern where Dash / Gap / Marker steps consume different amounts of arc length per step, or Phase D’s TextPathGeom placing each glyph at the next-glyph-width along the path. For regular fixed-step sampling use ArcLengthWalker instead.

Implementations

impl PolylineSampler

pub fn from_polyline(points: &[Point]) -> Self

Build a sampler from a piecewise-linear point list. Zero-length segments are dropped from the segment table but their start point still anchors the sampler’s total_length == 0 case behaviour.

pub fn from_path(path: &Path, tolerance: f64) -> Vec<Self>

Build one sampler per subpath of path, flattening curves with tolerance.

pub fn from_closed_path(path: &Path, tolerance: f64) -> Vec<Self>

Build one sampler per subpath of path, treating each subpath as closed — the segment from the last vertex back to the first is included in the total arc length. Use this for walking the perimeter of a closed shape (Polygon / Rect / Ellipse / Wedge) where the pattern should wrap continuously around the boundary.

pub fn total_length(&self) -> f64

Total arc length of the polyline.

pub fn subpath(&self) -> usize

0-based subpath index this sampler was built from.

pub fn segment_boundaries_between(&self, start: f64, end: f64) -> Vec<f64>

Cumulative distances at every interior original-segment boundary strictly between start and end (exclusive on both ends, with a small epsilon to avoid duplicates). Iterates in arc-length order. Empty when end <= start or when no interior boundary falls in the interval.

Useful for clients that need to draw a sub-polyline of the sampler spanning [start, end] while preserving the original polyline’s vertex set inside the interval (so collinear runs remain a single segment).

pub fn sample_at(&self, distance: f64) -> Option<ArcSample>

Sample at arbitrary distance. Clamped to [0, total_length]. Returns None only when the polyline has no non-degenerate segments.

Trait Implementations

impl Clone for PolylineSampler

fn clone(&self) -> PolylineSampler

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for PolylineSampler

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

Formats the value using the given formatter.