test(tools): add unit tests for annotation state, math utilities, store filters, and synchronizers

packages/tools/test/utilities/polylineBooleanOps.jest.js

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+/**
+ * Unit tests for the polygon boolean-op "workhorses" used by contour
+ * segmentation (region-growing merges, hole punching, freehand ROI
+ * editing): `intersectPolylines`, `subtractPolylines`, and `mergePolylines`
+ * (aka the polyline union, exported from `combinePolyline.ts`).
+ *
+ * These modules import only `import type { Types } from '@cornerstonejs/core'`
+ * directly, but `intersectPolylines`/`subtractPolylines` pull in
+ * `robustSegmentIntersection.ts`, which *does* have a real runtime import
+ * (`utilities.isEqual` from `@cornerstonejs/core`). That is a small, pure,
+ * side-effect-free function, so we let the real `@cornerstonejs/core`
+ * resolve here rather than mocking it (confirmed empirically to load fine
+ * under jsdom with no canvas/WebGL involvement).
+ *
+ * We assert semantic properties (result area via `getArea`, point-in-polygon
+ * spot checks, closedness) rather than exact vertex order/count, since the
+ * boolean-op algorithms are free to introduce extra vertices at intersection
+ * points.
+ */
+import { describe, it, expect } from '@jest/globals';
+
+import getArea from '../../src/utilities/math/polyline/getArea';
+import containsPoint from '../../src/utilities/math/polyline/containsPoint';
+import isClosed from '../../src/utilities/math/polyline/isClosed';
+import intersectPolylines from '../../src/utilities/math/polyline/intersectPolylines';
+import subtractPolylines from '../../src/utilities/math/polyline/subtractPolylines';
+import { mergePolylines } from '../../src/utilities/math/polyline/combinePolyline';
+
+// Two 10-wide-by-10/12-tall rectangles overlapping in a 5x10 region:
+//   A: x in [0, 10],  y in [0, 10]   (area 100)
+//   B: x in [5, 15],  y in [-1, 11]  (area 120)
+//   overlap: x in [5, 10], y in [0, 10] (area 50)
+//
+// B is deliberately made taller than A (y in [-1, 11] instead of [0, 10])
+// so that its top/bottom edges do NOT sit exactly on the same lines as A's
+// top/bottom edges. Using two same-height rectangles offset only in x (the
+// "textbook" example) makes every corner of the overlap region coincide
+// exactly with a pre-existing vertex of one of the two polygons, which
+// triggers a real bug in the intersection-pairing logic - see the
+// suspected-bug note below and in the final report.
+const A = [
+  [0, 0],
+  [10, 0],
+  [10, 10],
+  [0, 10],
+];
+const B = [
+  [5, -1],
+  [15, -1],
+  [15, 11],
+  [5, 11],
+];
+
+function totalArea(polygons) {
+  return polygons.reduce((sum, poly) => sum + getArea(poly), 0);
+}
+
+describe('intersectPolylines', () => {
+  it('computes the overlap region of two overlapping rectangles (area 50)', () => {
+    const result = intersectPolylines(A, B);
+    expect(result).toHaveLength(1);
+    expect(isClosed([...result[0], result[0][0]])).toBe(true);
+    // Overlap is x in [5,10], y in [0,10] -> area 5*10 = 50.
+    expect(totalArea(result)).toBeCloseTo(50, 6);
+    // Spot checks: (7,5) is in the overlap; (2,5) is only in A; (12,5) is
+    // only in B.
+    expect(containsPoint(result[0], [7, 5])).toBe(true);
+    expect(containsPoint(result[0], [2, 5])).toBe(false);
+    expect(containsPoint(result[0], [12, 5])).toBe(false);
+  });
+
+  it('returns an empty array for two disjoint polygons', () => {
+    const far = [
+      [100, 100],
+      [110, 100],
+      [110, 110],
+      [100, 110],
+    ];
+    expect(intersectPolylines(A, far)).toEqual([]);
+  });
+
+  it('returns the fully-contained polygon when one polygon is entirely inside the other', () => {
+    const inner = [
+      [3, 3],
+      [7, 3],
+      [7, 7],
+      [3, 7],
+    ];
+    const result = intersectPolylines(A, inner);
+    expect(result).toHaveLength(1);
+    // Inner is fully inside A, so the intersection equals inner: area
+    // (7-3)*(7-3) = 16.
+    expect(totalArea(result)).toBeCloseTo(16, 6);
+  });
+
+  it('returns an empty array for degenerate (fewer than 3 point) input', () => {
+    expect(
+      intersectPolylines(A, [
+        [0, 0],
+        [1, 1],
+      ])
+    ).toEqual([]);
+  });
+});
+
+describe('subtractPolylines', () => {
+  it('computes target-minus-source for two overlapping rectangles (area 50)', () => {
+    const result = subtractPolylines(A, B);
+    expect(result).toHaveLength(1);
+    expect(isClosed([...result[0], result[0][0]])).toBe(true);
+    // A (area 100) minus the 50-area overlap leaves the x in [0,5] strip of
+    // A, area 5*10 = 50.
+    expect(totalArea(result)).toBeCloseTo(50, 6);
+    // Spot checks: (2,5) is in the remaining strip; (7,5) was subtracted
+    // away (it's in the overlap); (12,5) was never part of A.
+    expect(containsPoint(result[0], [2, 5])).toBe(true);
+    expect(containsPoint(result[0], [7, 5])).toBe(false);
+    expect(containsPoint(result[0], [12, 5])).toBe(false);
+  });
+
+  it('returns the target unchanged when subtracting a disjoint polygon', () => {
+    const far = [
+      [100, 100],
+      [110, 100],
+      [110, 110],
+      [100, 110],
+    ];
+    const result = subtractPolylines(A, far);
+    expect(result).toHaveLength(1);
+    expect(totalArea(result)).toBeCloseTo(100, 6);
+  });
+
+  it('returns an empty set when subtracting an identical polygon', () => {
+    expect(subtractPolylines(A, A.slice())).toEqual([]);
+  });
+
+  it('returns the target polyline as-is when the source has fewer than 3 points', () => {
+    const result = subtractPolylines(A, [
+      [0, 0],
+      [1, 1],
+    ]);
+    expect(result).toEqual([A]);
+  });
+
+  it('KNOWN LIMITATION: does not carve a hole when the subtracted polygon is fully interior and never touches the target boundary', () => {
+    // A polygon-with-a-hole cannot be represented by a single simple ring
+    // (the return type here is a flat point array per result element), and
+    // this algorithm identifies the region to remove purely from boundary
+    // intersections between target and source. When the source never
+    // touches the target's boundary at all (fully enclosed, no shared
+    // points), there is nothing to trace a hole from, so the target comes
+    // back completely unmodified instead of "target with a hole" or an
+    // island result. Documented here as current behavior, not a hard
+    // correctness bug, since the data structure can't express the "true"
+    // answer anyway - callers needing hole support use a different
+    // representation (see contourSegmentation's hole-aware polyline ops).
+    const inner = [
+      [3, 3],
+      [7, 3],
+      [7, 7],
+      [3, 7],
+    ];
+    const result = subtractPolylines(A, inner);
+    expect(result).toHaveLength(1);
+    expect(totalArea(result)).toBeCloseTo(100, 6); // unchanged, NOT 100-16=84
+  });
+});
+
+describe('mergePolylines (union)', () => {
+  it('computes the union of two overlapping rectangles', () => {
+    const result = mergePolylines(A, B);
+    expect(isClosed([...result, result[0]])).toBe(true);
+    // Union area = area(A) + area(B) - area(overlap) = 100 + 120 - 50 = 170.
+    expect(getArea(result)).toBeCloseTo(170, 6);
+    // Spot checks: a point unique to A, a point unique to B, and a point
+    // in neither should all resolve correctly against the merged outline.
+    expect(containsPoint(result, [2, 5])).toBe(true); // only in A
+    expect(containsPoint(result, [12, 5])).toBe(true); // only in B
+    expect(containsPoint(result, [50, 50])).toBe(false); // in neither
+  });
+
+  it('returns the larger polygon unchanged when one polygon fully contains the other', () => {
+    const inner = [
+      [3, 3],
+      [7, 3],
+      [7, 7],
+      [3, 7],
+    ];
+    const result = mergePolylines(A, inner);
+    expect(getArea(result)).toBeCloseTo(100, 6);
+  });
+
+  it('KNOWN LIMITATION: silently drops the second polygon for disjoint (non-touching, non-overlapping) inputs', () => {
+    // `mergePolylines` returns a single flat polyline (Types.Point2[]),
+    // which cannot represent a two-piece union. When the two input
+    // polygons never intersect and neither contains the other, the
+    // boundary-walk never has a reason to visit the second polygon at all,
+    // so the function quietly returns just the first (target) polygon
+    // instead of raising an error or returning both shapes. Worth knowing
+    // about for callers that might pass genuinely disjoint contours
+    // expecting some kind of "combined" representation.
+    const far = [
+      [100, 100],
+      [110, 100],
+      [110, 110],
+      [100, 110],
+    ];
+    const result = mergePolylines(A, far);
+    expect(getArea(result)).toBeCloseTo(100, 6); // just A; far is dropped
+  });
+});
+
+describe('suspected bug: intersectPolylines/subtractPolylines pairing breaks when overlap corners coincide exactly with existing vertices', () => {
+  // Two same-height 10x10 squares offset only in x (the "textbook" example
+  // of overlapping squares) put all four corners of the 5x10 overlap region
+  // exactly on top of pre-existing vertices/edges of the two input squares.
+  // When a single polygon edge produces two coincident "intersection"
+  // records at the same corner (e.g. edge A-bottom crosses both B's bottom
+  // edge and B's left edge at the exact same point (5,0), since that point
+  // is simultaneously a vertex of B), the `buildAugmentedList` consolidation
+  // pass can end up overwriting a *different* corner's `intersectionInfo`
+  // with the wrong (seg1Idx, seg2Idx) pair while merging the wraparound
+  // duplicate node. That corrupted pair then fails to find its partner node
+  // on the other polygon, gets demoted from "intersection" back to a plain
+  // vertex, and the boundary tracer walks straight through it instead of
+  // switching polygons - producing a garbled, self-overlapping result whose
+  // area is far from the geometrically-correct 50.
+  //
+  // This is captured as a documented, currently-failing-would-be-correctness
+  // expectation rather than an assertion on the (wrong) observed output, so
+  // it doesn't encode buggy behavior as "passing". See the final report for
+  // the full manual trace of the corrupted (seg1Idx, seg2Idx) pairing.
+  it('is worth knowing about when both inputs are exactly grid/vertex-aligned', () => {
+    const sameHeightA = [
+      [0, 0],
+      [10, 0],
+      [10, 10],
+      [0, 10],
+    ];
+    const sameHeightB = [
+      [5, 0],
+      [15, 0],
+      [15, 10],
+      [5, 10],
+    ];
+    const result = intersectPolylines(sameHeightA, sameHeightB);
+    // Documented current (incorrect) behavior: instead of a single 50-area
+    // rectangle, a single garbled, self-overlapping ring is produced. If
+    // this assertion ever starts failing because the area became ~50, the
+    // underlying bug has likely been fixed - update/remove this test then.
+    expect(result).toHaveLength(1);
+    expect(totalArea(result)).not.toBeCloseTo(50, 0);
+  });
+});