1 files changed, 126 insertions, 0 deletions
diff --git a/packages/math/ellipse.test.ts b/packages/math/ellipse.test.ts
new file mode 100644
index 0000000..507cc5a
--- /dev/null
+++ b/packages/math/ellipse.test.ts
@@ -0,0 +1,126 @@
+import {
+  ellipse,
+  ellipseSegmentInterceptPoints,
+  ellipseIncludesPoint,
+  ellipseTouchesPoint,
+  ellipseLineIntersectionPoints,
+} from "./ellipse";
+import { line } from "./line";
+import { pointFrom } from "./point";
+import { lineSegment } from "./segment";
+import type { Ellipse, GlobalPoint } from "./types";
+
+describe("point and ellipse", () => {
+  it("point on ellipse", () => {
+    const target: Ellipse<GlobalPoint> = ellipse(pointFrom(1, 2), 2, 1);
+    [
+      pointFrom(1, 3),
+      pointFrom(1, 1),
+      pointFrom(3, 2),
+      pointFrom(-1, 2),
+    ].forEach((p) => {
+      expect(ellipseTouchesPoint(p, target)).toBe(true);
+    });
+    expect(ellipseTouchesPoint(pointFrom(-0.4, 2.7), target, 0.1)).toBe(true);
+    expect(ellipseTouchesPoint(pointFrom(-0.4, 2.71), target, 0.01)).toBe(true);
+
+    expect(ellipseTouchesPoint(pointFrom(2.4, 2.7), target, 0.1)).toBe(true);
+    expect(ellipseTouchesPoint(pointFrom(2.4, 2.71), target, 0.01)).toBe(true);
+
+    expect(ellipseTouchesPoint(pointFrom(2, 1.14), target, 0.1)).toBe(true);
+    expect(ellipseTouchesPoint(pointFrom(2, 1.14), target, 0.01)).toBe(true);
+
+    expect(ellipseTouchesPoint(pointFrom(0, 1.14), target, 0.1)).toBe(true);
+    expect(ellipseTouchesPoint(pointFrom(0, 1.14), target, 0.01)).toBe(true);
+
+    expect(ellipseTouchesPoint(pointFrom(0, 2.8), target)).toBe(false);
+    expect(ellipseTouchesPoint(pointFrom(2, 1.2), target)).toBe(false);
+  });
+
+  it("point in ellipse", () => {
+    const target: Ellipse<GlobalPoint> = ellipse(pointFrom(0, 0), 2, 1);
+    [
+      pointFrom(0, 1),
+      pointFrom(0, -1),
+      pointFrom(2, 0),
+      pointFrom(-2, 0),
+    ].forEach((p) => {
+      expect(ellipseIncludesPoint(p, target)).toBe(true);
+    });
+
+    expect(ellipseIncludesPoint(pointFrom(-1, 0.8), target)).toBe(true);
+    expect(ellipseIncludesPoint(pointFrom(1, -0.8), target)).toBe(true);
+
+    // Point on outline
+    expect(ellipseIncludesPoint(pointFrom(2, 0), target)).toBe(true);
+
+    expect(ellipseIncludesPoint(pointFrom(-1, 1), target)).toBe(false);
+    expect(ellipseIncludesPoint(pointFrom(-1.4, 0.8), target)).toBe(false);
+  });
+});
+
+describe("segment and ellipse", () => {
+  it("detects outside segment", () => {
+    const e = ellipse(pointFrom(0, 0), 2, 2);
+
+    expect(
+      ellipseSegmentInterceptPoints(
+        e,
+        lineSegment<GlobalPoint>(pointFrom(-100, 0), pointFrom(-10, 0)),
+      ),
+    ).toEqual([]);
+    expect(
+      ellipseSegmentInterceptPoints(
+        e,
+        lineSegment<GlobalPoint>(pointFrom(-10, 0), pointFrom(10, 0)),
+      ),
+    ).toEqual([pointFrom(-2, 0), pointFrom(2, 0)]);
+    expect(
+      ellipseSegmentInterceptPoints(
+        e,
+        lineSegment<GlobalPoint>(pointFrom(-10, -2), pointFrom(10, -2)),
+      ),
+    ).toEqual([pointFrom(0, -2)]);
+    expect(
+      ellipseSegmentInterceptPoints(
+        e,
+        lineSegment<GlobalPoint>(pointFrom(0, -1), pointFrom(0, 1)),
+      ),
+    ).toEqual([]);
+  });
+});
+
+describe("line and ellipse", () => {
+  const e = ellipse(pointFrom(0, 0), 2, 2);
+
+  it("detects outside line", () => {
+    expect(
+      ellipseLineIntersectionPoints(
+        e,
+        line<GlobalPoint>(pointFrom(-10, -10), pointFrom(10, -10)),
+      ),
+    ).toEqual([]);
+  });
+  it("detects line intersecting ellipse", () => {
+    expect(
+      ellipseLineIntersectionPoints(
+        e,
+        line<GlobalPoint>(pointFrom(0, -1), pointFrom(0, 1)),
+      ),
+    ).toEqual([pointFrom(0, 2), pointFrom(0, -2)]);
+    expect(
+      ellipseLineIntersectionPoints(
+        e,
+        line<GlobalPoint>(pointFrom(-100, 0), pointFrom(-10, 0)),
+      ).map(([x, y]) => pointFrom(Math.round(x), Math.round(y))),
+    ).toEqual([pointFrom(2, 0), pointFrom(-2, 0)]);
+  });
+  it("detects line touching ellipse", () => {
+    expect(
+      ellipseLineIntersectionPoints(
+        e,
+        line<GlobalPoint>(pointFrom(-2, -2), pointFrom(2, -2)),
+      ),
+    ).toEqual([pointFrom(0, -2)]);
+  });
+});