Add SurfaceGeom2::origin

crates/fj-core/src/geometry/curve.rs

@@ -1,6 +1,6 @@
 use std::collections::BTreeMap;
 
-use fj_math::{Circle, Line};
+use fj_math::{Circle, Line, Point};
 
 use crate::{storage::Handle, topology::Surface};
 
@@ -65,12 +65,27 @@ pub struct LocalCurveGeom {
 /// We'll have a much clearer image of the situation then. Hopefully, by then it
 /// will be clearer what specific role this trait will play in relation to other
 /// curve geometry types, and a better name will reveal itself.
-pub trait CurveGeom2<const D: usize> {}
+pub trait CurveGeom2<const D: usize> {
+    /// # Access the origin of the curve
+    fn origin(&self) -> Point<D>;
+}
 
-impl<const D: usize> CurveGeom2<D> for Circle<D> {}
+impl<const D: usize> CurveGeom2<D> for Circle<D> {
+    fn origin(&self) -> Point<D> {
+        self.center() + self.a()
+    }
+}
 
-impl<const D: usize> CurveGeom2<D> for Line<D> {}
+impl<const D: usize> CurveGeom2<D> for Line<D> {
+    fn origin(&self) -> Point<D> {
+        self.origin()
+    }
+}
 
 // This implementation is temporary, to ease the transition towards a curve
 // geometry trait. Eventually, `CurveGeom2` is expected to replace `Path`.
-impl<const D: usize> CurveGeom2<D> for Path<D> {}
+impl<const D: usize> CurveGeom2<D> for Path<D> {
+    fn origin(&self) -> Point<D> {
+        self.origin()
+    }
+}