#polygon #geometry #multipolygon #geo #graphics #ocg

geo-normalized

A trait for producing a normalized Polygon/Multipolygon according to OCG winding rules

2 releases

0.1.1 Apr 15, 2020
0.1.0 Apr 15, 2020

#712 in Graphics APIs


Used in geo-svg-io

MIT license

11KB
226 lines

rust-geo-normalized

Creates a new instance of the rust geo/geo-types Polygon/Multipolygon that follows the OGC winding rules.

The rust geo and geo-types crates are not as strict as the OGC guidelines, and allow for polygons with inner and outer rings in any winding order. This trait returns a Polygon/Multipolygon where all outer rings are clockwise, and all inner rings are anti-clockwise.

Examples

// Anti-clockwise winding order for outer ring
let bad = polygon![
        (x: 1.0, y: 1.0),
        (x: 4.0, y: 1.0),
        (x: 4.0, y: 4.0),
        (x: 1.0, y: 4.0),
        (x: 1.0, y: 1.0),
        ];

// Clockwise winding order for outer ring
let good = polygon![
        (x: 1.0, y: 1.0),
        (x: 1.0, y: 4.0),
        (x: 4.0, y: 4.0),
        (x: 4.0, y: 1.0),
        (x: 1.0, y: 1.0),
        ];

let norm = bad.normalized();
// norm should have the same points and shape as `bad` but in the valid winding order
assert_eq!(norm, good);

Dependencies

~2MB
~38K SLoC