A Rust implementation of the Polylabel algorithm for finding optimum polygon label positions, with Python binding.
Project description
Pylylabel
A Rust implementation of the Polylabel algorithm.
This is a fork of polylabel-rs. Pylylabel's polylabel
function also
returns the distance from the label position to the polygon. Python binding is provided using PyO3.
The orange dot is the polygon centroid. The teal dot is the ideal label position. Red boxes show the search space.
How to Use
extern crate pylylabel;
use pylylabel::polylabel;
extern crate geo;
use geo::{Point, Polygon};
let coords = vec![
(0.0, 0.0),
(4.0, 0.0),
(4.0, 1.0),
(1.0, 1.0),
(1.0, 4.0),
(0.0, 4.0),
(0.0, 0.0)
];
let poly = Polygon::new(coords.into(), vec![]);
let label_pos, distance = polylabel(&poly, &0.10);
// Point(0.5625, 0.5625), 0.5625
Documentation
Performance vs Accuracy
Using a 4-core 2.3 GHz Intel Core i5, finding a label position on a ~9k-vertex polygon (representing the Norwegian mainland) using a tolerance of 1.0
takes around 9 ms. Depending upon the dimensions of your polygon(s), you may require a higher tolerance (i.e. a smaller number). See here for some guidance on the accuracy provided by each decimal place.
Build
Requirements:
- Python 3.5+
- Rust stable
- maturin
maturin build --release