simplify_polyline

Removes the points of a polyline that change its shape by less than tolerance, with the Ramer–Douglas–Peucker algorithm: each removed point is at most tolerance away from the simplified line. It shrinks map outlines or traced paths by orders of magnitude while keeping their look.

The first and last points are always kept. With a tolerance of 0.0, only points exactly on a straight line are removed. It is iterative, so very long polylines cannot overflow the stack.

Import

use helpers4::geometry::simplify_polyline;

Cargo feature geometry (enabled by default). To compile only this module:

cargo add helpers4 --no-default-features --features geometry

or in Cargo.toml:

[dependencies]
helpers4 = { version = "0.0.9", default-features = false, features = ["geometry"] }

Signature

pub fn simplify_polyline(points: &[Point], tolerance: f64) -> Option<Vec<Point>>

Parameters

Parameter	Type	Description
points	&[Point]	The polyline.
tolerance	f64	The maximum distance between a removed point and the result, in the units of the points.

Returns

Option<Vec<Point>> — The kept points in their original order, or None when tolerance is negative or NaN.

Examples

use helpers4::geometry::{simplify_polyline, Point};

let line = [Point::new(0.0, 0.0), Point::new(1.0, 0.1), Point::new(2.0, 0.0)];
assert_eq!(
    simplify_polyline(&line, 0.5),
    Some(vec![Point::new(0.0, 0.0), Point::new(2.0, 0.0)])
);
assert_eq!(simplify_polyline(&line, -1.0), None);

Source

src/geometry/simplify_polyline.rs