New nodes: Resample Points, Spline from Points (#1226)

* Create node (no implementation)

* Resampling - WIP

* use bezier::from_linear_dvec2

* Use from anchors instead of Bezier

* Tidy up anchor collection & subpath creation

* Add Spline from Points node (not implemented)

* Add spline from points node implementation

* Update resampling

* Update minimum density 0.01 -> 1.0

* Add a way to create a custom vector network

* Add spline from points node to spline tool

* Fix crash when no points

* Add anchor method to subpath

* Exact start and end point

* Fix compile errors from rebase

* Fix spline tool

* Rename 'Density' to 'Spacing'

* Fix transforms

* Only close subpaths with >1 anchor

* Fix compile

* Fix compile error

* Fix from points with many subpaths

* Fix new_cubic_spline crash with one point

* Rename to resample as polyline

* Fix div zero

* Fix missing file

* Fix resample

* Rename to resample points

---------

Co-authored-by: hypercube <0hypercube@gmail.com>
Co-authored-by: Keavon Chambers <keavon@keavon.com>

libraries/bezier-rs/src/subpath/core.rs

@@ -112,6 +112,11 @@ impl<ManipulatorGroupId: crate::Identifier> Subpath<ManipulatorGroupId> {
 		&self.manipulator_groups
 	}
 
+	/// Returns a vector of all the anchors (DVec2) for this `Subpath`.
+	pub fn anchors(&self) -> Vec<DVec2> {
+		self.manipulator_groups().iter().map(|group| group.anchor).collect()
+	}
+
 	/// Returns if the Subpath is equivalent to a single point.
 	pub fn is_point(&self) -> bool {
 		if self.is_empty() {
@@ -254,7 +259,7 @@ impl<ManipulatorGroupId: crate::Identifier> Subpath<ManipulatorGroupId> {
 	/// Construct a cubic spline from a list of points.
 	/// Based on <https://mathworld.wolfram.com/CubicSpline.html>.
 	pub fn new_cubic_spline(points: Vec<DVec2>) -> Self {
-		if points.is_empty() {
+		if points.len() < 2 {
 			return Self::new(Vec::new(), false);
 		}
 

libraries/bezier-rs/src/subpath/lookup.rs

@@ -252,4 +252,16 @@ mod tests {
 		assert_eq!(closed_subpath.t_value_to_parametric(SubpathTValue::GlobalParametric(0.)), (0, 0.));
 		assert_eq!(closed_subpath.t_value_to_parametric(SubpathTValue::GlobalParametric(1.)), (4, 1.));
 	}
+
+	#[test]
+	fn exact_start_end() {
+		let start = DVec2::new(20., 30.);
+		let end = DVec2::new(60., 45.);
+		let handle = DVec2::new(75., 85.);
+
+		let subpath: Subpath<EmptyId> = Subpath::from_bezier(&Bezier::from_quadratic_dvec2(start, handle, end));
+
+		assert_eq!(subpath.evaluate(SubpathTValue::GlobalEuclidean(0.0)), start);
+		assert_eq!(subpath.evaluate(SubpathTValue::GlobalEuclidean(1.0)), end);
+	}
 }