Add adapter to stream any geo_traits geometry into GeomProcessor #261
Description
Motivation
geozero can stream many concrete geometry types, and has helpers for geo-types. A small adapter would let any geo-traits implementor be processed by geozero without first converting to geo-types. This would help anyone defining their own geometry types that implement geo-traits, not just existing libraries.
Proposal
Provide a lightweight newtype wrapper that implements GeozeroGeometry for any G: geo_traits::GeometryTrait.
This could be gated behind an optional cargo feature.
Example sketch (This is AI-generated and intended for demonstration purposes only, not as a final implementation):
use geozero::{GeomProcessor, GeozeroGeometry, error::Result as GzResult, CoordDimensions};
use geo_traits::{GeometryTrait, GeometryType};
pub struct AsGeozero<G>(pub G);
impl<G> GeozeroGeometry for AsGeozero<G>
where
G: GeometryTrait<T = f64>,
{
fn process_geom<P: GeomProcessor>(&self, p: &mut P) -> GzResult<()> {
match self.0.as_type() {
GeometryType::Point(pt) => {
p.point_begin(0)?;
let c = pt.coord();
p.xy(c.x(), c.y(), 0)?;
p.point_end(0)?;
}
GeometryType::LineString(ls) => {
p.linestring_begin(0, ls.num_coords() as usize, false, 0)?;
for c in ls.coords_iter() { p.xy(c.x(), c.y(), 0)?; }
p.linestring_end(0, false, 0)?;
}
// ...Polygon, Multi*, GeometryCollection, Rect, etc.
}
Ok(())
}
fn dims(&self) -> CoordDimensions { CoordDimensions::xy() }
fn srid(&self) -> Option<i32> { None }
}