refactor: separate elements logic into a standalone package (#9285)

packages/math/tests/curve.test.ts

@@ -0,0 +1,102 @@
+import "@excalidraw/utils/test-utils";
+
+import {
+  curve,
+  curveClosestPoint,
+  curveIntersectLineSegment,
+  curvePointDistance,
+} from "../src/curve";
+import { pointFrom } from "../src/point";
+import { lineSegment } from "../src/segment";
+
+describe("Math curve", () => {
+  describe("line segment intersection", () => {
+    it("point is found when control points are the same", () => {
+      const c = curve(
+        pointFrom(100, 0),
+        pointFrom(100, 100),
+        pointFrom(100, 100),
+        pointFrom(0, 100),
+      );
+      const l = lineSegment(pointFrom(0, 0), pointFrom(200, 200));
+
+      expect(curveIntersectLineSegment(c, l)).toCloselyEqualPoints([
+        [87.5, 87.5],
+      ]);
+    });
+
+    it("point is found when control points aren't the same", () => {
+      const c = curve(
+        pointFrom(100, 0),
+        pointFrom(100, 60),
+        pointFrom(60, 100),
+        pointFrom(0, 100),
+      );
+      const l = lineSegment(pointFrom(0, 0), pointFrom(200, 200));
+
+      expect(curveIntersectLineSegment(c, l)).toCloselyEqualPoints([
+        [72.5, 72.5],
+      ]);
+    });
+
+    it("points are found when curve is sliced at 3 points", () => {
+      const c = curve(
+        pointFrom(-50, -50),
+        pointFrom(10, -50),
+        pointFrom(10, 50),
+        pointFrom(50, 50),
+      );
+      const l = lineSegment(pointFrom(0, 112.5), pointFrom(90, 0));
+
+      expect(curveIntersectLineSegment(c, l)).toCloselyEqualPoints([[50, 50]]);
+    });
+
+    it("can be detected where the determinant is overly precise", () => {
+      const c = curve(
+        pointFrom(41.028864759926016, 12.226249068355052),
+        pointFrom(41.028864759926016, 33.55958240168839),
+        pointFrom(30.362198093259348, 44.22624906835505),
+        pointFrom(9.028864759926016, 44.22624906835505),
+      );
+      const l = lineSegment(
+        pointFrom(-82.30963544324186, -41.19949363038283),
+
+        pointFrom(188.2149592542487, 134.75505940984908),
+      );
+
+      expect(curveIntersectLineSegment(c, l)).toCloselyEqualPoints([
+        [34.4, 34.71],
+      ]);
+    });
+  });
+
+  describe("point closest to other", () => {
+    it("point can be found", () => {
+      const c = curve(
+        pointFrom(-50, -50),
+        pointFrom(10, -50),
+        pointFrom(10, 50),
+        pointFrom(50, 50),
+      );
+      const p = pointFrom(0, 0);
+
+      expect([curveClosestPoint(c, p)]).toCloselyEqualPoints([
+        [5.965462100367372, -3.04104878946646],
+      ]);
+    });
+  });
+
+  describe("point shortest distance", () => {
+    it("can be determined", () => {
+      const c = curve(
+        pointFrom(-50, -50),
+        pointFrom(10, -50),
+        pointFrom(10, 50),
+        pointFrom(50, 50),
+      );
+      const p = pointFrom(0, 0);
+
+      expect(curvePointDistance(c, p)).toBeCloseTo(6.695873043213627);
+    });
+  });
+});