feat(geom): avoid recursive application of __samples attrib

- add internal __copyAttribsNoSamples() helper
- update implementations for:
  - asPolygon()
  - asPolyline()
  - edges()
  - resample()
  - splitArcLength()
- update Group ctor to make attribs optional

packages/geom/src/api/group.ts

@@ -5,7 +5,7 @@ import { __copyAttribs } from "../internal/copy.js";
 
 export class Group implements IHiccupShape {
 	constructor(
-		public attribs: Attribs,
+		public attribs?: Attribs,
 		public children: IHiccupShape[] = []
 	) {}
 

packages/geom/src/as-polygon.ts

@@ -2,7 +2,7 @@ import type { MultiFn1O } from "@thi.ng/defmulti";
 import { defmulti } from "@thi.ng/defmulti/defmulti";
 import type { IShape, SamplingOpts } from "@thi.ng/geom-api";
 import { Polygon } from "./api/polygon.js";
-import { __copyAttribs } from "./internal/copy.js";
+import { __copyAttribsNoSamples as __attribs } from "./internal/copy.js";
 import { __dispatch } from "./internal/dispatch.js";
 import { vertices } from "./vertices.js";
 
@@ -12,6 +12,9 @@ import { vertices } from "./vertices.js";
  * or number of target vertices.
  *
  * @remarks
+ * If the shape has a `__samples` attribute, it will be removed in the result to
+ * avoid recursive application.
+ *
  * Currently implemented for:
  *
  * - {@link Circle}
@@ -45,6 +48,6 @@ export const asPolygon: MultiFn1O<
 		tri: "points",
 	},
 	{
-		points: ($, opts) => new Polygon(vertices($, opts), __copyAttribs($)),
+		points: ($, opts) => new Polygon(vertices($, opts), __attribs($)),
 	}
 );

packages/geom/src/as-polyline.ts

@@ -4,7 +4,7 @@ import type { IShape, SamplingOpts } from "@thi.ng/geom-api";
 import { set } from "@thi.ng/vectors/set";
 import type { Path } from "./api/path.js";
 import { Polyline } from "./api/polyline.js";
-import { __copyAttribs } from "./internal/copy.js";
+import { __copyAttribsNoSamples as __attribs } from "./internal/copy.js";
 import { __dispatch } from "./internal/dispatch.js";
 import { vertices } from "./vertices.js";
 
@@ -14,6 +14,9 @@ import { vertices } from "./vertices.js";
  * or number of target vertices.
  *
  * @remarks
+ * If the shape has a `__samples` attribute, it will be removed in the result to
+ * avoid recursive application.
+ *
  * Currently implemented for:
  *
  * - {@link Arc}
@@ -51,18 +54,18 @@ export const asPolyline: MultiFn1O<
 		tri: "poly",
 	},
 	{
-		points: ($, opts) => new Polyline(vertices($, opts), __copyAttribs($)),
+		points: ($, opts) => new Polyline(vertices($, opts), __attribs($)),
 
 		path: ($: Path, opts) => {
 			const pts = vertices($, opts);
 			$.closed && pts.push(set([], pts[0]));
-			return new Polyline(pts, __copyAttribs($));
+			return new Polyline(pts, __attribs($));
 		},
 
 		poly: ($, opts) => {
 			const pts = vertices($, opts);
 			pts.push(set([], pts[0]));
-			return new Polyline(pts, __copyAttribs($));
+			return new Polyline(pts, __attribs($));
 		},
 	}
 );

packages/geom/src/edges.ts

@@ -1,11 +1,13 @@
 import type { MultiFn1O } from "@thi.ng/defmulti";
 import { defmulti } from "@thi.ng/defmulti/defmulti";
 import type { IShape, SamplingOpts } from "@thi.ng/geom-api";
+import { mapcat } from "@thi.ng/transducers/mapcat";
 import type { VecPair } from "@thi.ng/vectors";
 import type { AABB } from "./api/aabb.js";
 import type { Arc } from "./api/arc.js";
 import type { BPatch } from "./api/bpatch.js";
 import type { Circle } from "./api/circle.js";
+import type { Group } from "./api/group.js";
 import type { Path } from "./api/path.js";
 import type { Polygon } from "./api/polygon.js";
 import type { Polyline } from "./api/polyline.js";
@@ -18,10 +20,12 @@ import { vertices } from "./vertices.js";
 
 /**
  * Extracts the edges of given shape's boundary and returns them as an iterable
- * of vector pairs. Some shapes also support
- * [`SamplingOpts`](https://docs.thi.ng/umbrella/geom-api/interfaces/SamplingOpts.html).
+ * of vector pairs.
  *
  * @remarks
+ * If the shape has a `__samples` attribute, it will be removed in the result to
+ * avoid recursive application.
+ *
  * Currently implemented for:
  *
  * - {@link AABB}
@@ -30,6 +34,7 @@ import { vertices } from "./vertices.js";
  * - {@link Circle}
  * - {@link Cubic}
  * - {@link Ellipse}
+ * - {@link Group}
  * - {@link Line}
  * - {@link Path}
  * - {@link Polygon}
@@ -39,6 +44,17 @@ import { vertices } from "./vertices.js";
  * - {@link Rect}
  * - {@link Triangle}
  *
+ * The implementations for the following shapes **do not** support
+ * [`SamplingOpts`](https://docs.thi.ng/umbrella/geom-api/interfaces/SamplingOpts.html)
+ * (all others do):
+ *
+ * - {@link Line}
+ * - {@link Polygon}
+ * - {@link Polyline}
+ * - {@link Quad}
+ * - {@link Rect}
+ * - {@link Triangle}
+ *
  * @param shape
  * @param opts
  */
@@ -85,6 +101,8 @@ export const edges: MultiFn1O<
 
 		circle: ($: Circle, opts) => __edges(asPolygon($, opts).points, true),
 
+		group: ($: Group, opts) => mapcat((c) => edges(c, opts), $.children),
+
 		path: ($: Path, opts) => __edges(asPolygon($, opts).points, $.closed),
 
 		poly: ($: Polygon) => __edges($.points, true),

packages/geom/src/internal/copy.ts

@@ -1,14 +1,35 @@
 // thing:export
-import { copyVectors } from "@thi.ng/vectors/copy";
+import { withoutKeysObj } from "@thi.ng/associative/without-keys";
 import type {
 	Attribs,
 	IShape,
 	PCLike,
 	PCLikeConstructor,
 } from "@thi.ng/geom-api";
+import { copyVectors } from "@thi.ng/vectors/copy";
 
-/** @internal */
-export const __copyAttribs = ($: IShape) => <Attribs>{ ...$.attribs };
+/**
+ * Creates a shallow copy of shape's attribs. Any `exclude` keys will be removed
+ * from result attribs.
+ *
+ * @internal
+ */
+export const __copyAttribs = ($: IShape, ...exclude: string[]) => {
+	if (!$.attribs) return;
+	const attribs = <Attribs>{ ...$.attribs };
+	return exclude.length ? <Attribs>withoutKeysObj(attribs, exclude) : attribs;
+};
+
+/**
+ * Syntax sugar for {@link __copyAttribs}, also removing `__samples` key from
+ * result.
+ *
+ * @param x
+ *
+ * @internal
+ */
+export const __copyAttribsNoSamples = (x: IShape) =>
+	__copyAttribs(x, "__samples");
 
 /** @internal */
 export const __copyShape = <T extends PCLike>(

packages/geom/src/resample.ts

@@ -5,14 +5,17 @@ import { resample as _resample } from "@thi.ng/geom-resample/resample";
 import { Polygon } from "./api/polygon.js";
 import { Polyline } from "./api/polyline.js";
 import { asPolygon } from "./as-polygon.js";
-import { __copyAttribs } from "./internal/copy.js";
+import { __copyAttribsNoSamples as __attribs } from "./internal/copy.js";
 import { __dispatch } from "./internal/dispatch.js";
 
 /**
  * Resamples given 2D shape with given options and returns result as polygon (if
  * closed) or polyline (if open).
  *
  * @remarks
+ * If the shape has a `__samples` attribute, it will be removed in the result to
+ * avoid recursive application.
+ *
  * Currently implemented for:
  *
  * - {@link Circle}
@@ -44,15 +47,9 @@ export const resample: MultiFn2<
 		circle: ($: IShape, opts) => asPolygon($, opts),
 
 		poly: ($: PCLike, opts) =>
-			new Polygon(
-				_resample($.points, opts, true, true),
-				__copyAttribs($)
-			),
+			new Polygon(_resample($.points, opts, true, true), __attribs($)),
 
 		polyline: ($: PCLike, opts) =>
-			new Polyline(
-				_resample($.points, opts, false, true),
-				__copyAttribs($)
-			),
+			new Polyline(_resample($.points, opts, false, true), __attribs($)),
 	}
 );

packages/geom/src/split-arclength.ts

@@ -7,7 +7,7 @@ import type { Vec } from "@thi.ng/vectors";
 import { Group } from "./api/group.js";
 import { Polyline } from "./api/polyline.js";
 import { asPolyline } from "./as-polyline.js";
-import { __copyAttribs } from "./internal/copy.js";
+import { __copyAttribsNoSamples as __attribs } from "./internal/copy.js";
 import { __dispatch } from "./internal/dispatch.js";
 import { __pointArraysAsShapes } from "./internal/points-as-shape.js";
 
@@ -16,6 +16,9 @@ import { __pointArraysAsShapes } from "./internal/points-as-shape.js";
  * Returns array of new shapes/polylines.
  *
  * @remarks
+ * If the shape has a `__samples` attribute, it will be removed in the result to
+ * avoid recursive application.
+ *
  * Currently only implemented for:
  *
  * - {@link Group}
@@ -24,23 +27,28 @@ import { __pointArraysAsShapes } from "./internal/points-as-shape.js";
  * Other shape types will be attempted to be auto-converted via
  * {@link asPolyline} first.
  *
+ * Groups will be recursively processed (i.e. by calling {@link splitArcLength}
+ * for each child). Any nested groups will be retained, but each group might
+ * have a greater resulting number of children (depending on number of splits
+ * performed).
+ *
  * @param shape
  * @param dist
  */
-export const splitArclength: MultiFn2<IShape, number, IShape[]> = defmulti<
+export const splitArcLength: MultiFn2<IShape, number, IShape[]> = defmulti<
 	any,
 	number,
 	IShape[]
 >(
 	__dispatch,
 	{},
 	{
-		[DEFAULT]: ($: IShape, d: number) => splitArclength(asPolyline($), d),
+		[DEFAULT]: ($: IShape, d: number) => splitArcLength(asPolyline($), d),
 
 		group: ($, d) => [
-			new Group(__copyAttribs($.attribs), [
+			new Group(__attribs($), [
 				...mapcat(
-					(c: IShape) => <IHiccupShape[]>splitArclength(c, d),
+					(c: IShape) => <IHiccupShape[]>splitArcLength(c, d),
 					$.children
 				),
 			]),
@@ -62,7 +70,7 @@ export const splitArclength: MultiFn2<IShape, number, IShape[]> = defmulti<
 					break;
 				}
 			}
-			return __pointArraysAsShapes(Polyline, chunks, $.attribs)!;
+			return __pointArraysAsShapes(Polyline, chunks, __attribs($))!;
 		},
 	}
 );