feat: add interactive edge waypoints with smooth path editing

- Drag waypoints to reshape edges; double-click a waypoint to remove it - + handles at segment midpoints to insert new waypoints - Bezier style: catmull-rom smooth curves through waypoints - Smooth style: rounded-corner polyline with soft 45° snap (snaps within 15px) - First + handle biased to source axis for perpendicular node exit - snap45both: ray-intersection solver ensures both adjacent segments snap to 45° simultaneously - Clear path button in EdgeModal when waypoints exist - Waypoints serialised/deserialised with canvas state
2026-04-08 22:42:18 +02:00
parent 9d9fdd61e9
commit 9e8bab5dec
9 changed files with 687 additions and 11 deletions
@@ -0,0 +1,175 @@
+import { describe, it, expect } from 'vitest'
+import { buildWaypointPath, distToSegment, findInsertIndex, snap45, snap45both } from '../waypointUtils'
+
+describe('buildWaypointPath — bezier (default)', () => {
+  it('builds a catmull-rom curve with no waypoints (start = end clamp)', () => {
+    // With only 2 pts (src + target), catmull-rom = cubic bezier
+    const path = buildWaypointPath(0, 0, [], 100, 100)
+    expect(path).toMatch(/^M 0 0 C/)
+  })
+
+  it('routes through a single waypoint with smooth curve', () => {
+    const path = buildWaypointPath(0, 0, [{ x: 50, y: 0 }], 100, 100)
+    expect(path).toMatch(/^M 0 0 C/)
+    // Should not be a straight polyline
+    expect(path).not.toContain(' L ')
+  })
+
+  it('routes through multiple waypoints', () => {
+    const path = buildWaypointPath(0, 0, [{ x: 50, y: 0 }, { x: 50, y: 100 }], 100, 100)
+    expect(path).toMatch(/^M 0 0 C/)
+  })
+})
+
+describe('buildWaypointPath — smooth style', () => {
+  it('builds a direct straight line with no waypoints (no bend)', () => {
+    // Only 2 points → no intermediate vertex → no rounding needed
+    expect(buildWaypointPath(0, 0, [], 100, 100, 'smooth')).toBe('M 0 0 L 100 100')
+  })
+
+  it('routes through a single waypoint with straight lines (no intermediate bend)', () => {
+    // 3 pts: src → wp → target — only 1 intermediate → rounded corners at wp
+    const path = buildWaypointPath(0, 0, [{ x: 50, y: 0 }], 100, 100, 'smooth')
+    // Should start at source and end at target
+    expect(path).toMatch(/^M 0 0/)
+    expect(path).toMatch(/100 100$/)
+    // Should contain a quadratic bezier at the waypoint corner
+    expect(path).toContain('Q')
+  })
+
+  it('routes through multiple waypoints with rounded corners', () => {
+    const path = buildWaypointPath(0, 0, [{ x: 50, y: 0 }, { x: 50, y: 100 }], 100, 100, 'smooth')
+    expect(path).toMatch(/^M 0 0/)
+    expect(path).toMatch(/100 100$/)
+    expect(path).toContain('Q')
+  })
+
+  it('does not round corners when segment is too short (r clamped to 0)', () => {
+    // Adjacent waypoints very close together — r → 0, falls back to L
+    const path = buildWaypointPath(0, 0, [{ x: 1, y: 0 }, { x: 2, y: 0 }], 100, 0, 'smooth')
+    expect(path).toMatch(/^M 0 0/)
+  })
+})
+
+describe('snap45', () => {
+  // Use positions very close to a 45° angle so deviation < SNAP_THRESHOLD (15px)
+  it('snaps horizontal direction when close (deviation < threshold)', () => {
+    // (100, 3) — nearly horizontal, deviation from 0° ≈ 3px → snaps
+    const r = snap45({ x: 0, y: 0 }, { x: 100, y: 3 })
+    expect(r.y).toBe(0)
+    expect(r.x).toBeGreaterThan(0)
+  })
+
+  it('snaps vertical direction when close', () => {
+    const r = snap45({ x: 0, y: 0 }, { x: 3, y: 100 })
+    expect(r.x).toBe(0)
+    expect(r.y).toBeGreaterThan(0)
+  })
+
+  it('snaps 45° diagonal when close', () => {
+    // (80, 83) — nearly 45°, deviation ≈ 2px → snaps
+    const r = snap45({ x: 0, y: 0 }, { x: 80, y: 83 })
+    expect(r.x).toBe(r.y)
+  })
+
+  it('does NOT snap when deviation exceeds threshold', () => {
+    // (100, 40) — deviation from 0° is ~40px > 15 → no snap
+    const pos = { x: 100, y: 40 }
+    const r = snap45({ x: 0, y: 0 }, pos)
+    expect(r).toEqual(pos)
+  })
+
+  it('returns pos unchanged when distance < 1', () => {
+    const pos = { x: 5, y: 5 }
+    expect(snap45({ x: 5, y: 5 }, pos)).toBe(pos)
+  })
+
+  it('preserves distance from origin when snapping', () => {
+    const from = { x: 0, y: 0 }
+    const pos = { x: 100, y: 3 }  // close to horizontal
+    const r = snap45(from, pos)
+    const origDist = Math.hypot(pos.x - from.x, pos.y - from.y)
+    const snapDist = Math.hypot(r.x - from.x, r.y - from.y)
+    expect(snapDist).toBeCloseTo(origDist, 0)
+  })
+})
+
+describe('snap45both', () => {
+  it('finds intersection satisfying 45° from both adjacent points (axis-aligned)', () => {
+    // prev=(0,0), next=(100,100): diagonal — midpoint (50,50) should satisfy both
+    const r = snap45both({ x: 0, y: 0 }, { x: 100, y: 100 }, { x: 50, y: 50 })
+    // Result must be on a 45°-ray from (0,0)
+    const a1 = Math.atan2(r.y - 0, r.x - 0) / (Math.PI / 4)
+    expect(Math.abs(a1 - Math.round(a1))).toBeLessThan(0.05)
+    // Result must be on a 45°-ray from (100,100)
+    const a2 = Math.atan2(r.y - 100, r.x - 100) / (Math.PI / 4)
+    expect(Math.abs(a2 - Math.round(a2))).toBeLessThan(0.05)
+  })
+
+  it('snaps so both incoming and outgoing segments are at 45° when within threshold', () => {
+    // prev=(0,0), next=(200,0) — valid intersection at (100,100) (45° from each)
+    // pos=(100,93) is 7px away → within 15px threshold → should snap to (100,100)
+    const r = snap45both({ x: 0, y: 0 }, { x: 200, y: 0 }, { x: 100, y: 93 })
+    const a1 = Math.atan2(r.y - 0, r.x - 0) / (Math.PI / 4)
+    expect(Math.abs(a1 - Math.round(a1))).toBeLessThan(0.05)
+    const a2 = Math.atan2(r.y - 0, r.x - 200) / (Math.PI / 4)
+    expect(Math.abs(a2 - Math.round(a2))).toBeLessThan(0.05)
+  })
+
+  it('returns raw pos when beyond threshold', () => {
+    // pos=(100,80) is 20px from nearest intersection (100,100) → no snap
+    const pos = { x: 100, y: 80 }
+    const r = snap45both({ x: 0, y: 0 }, { x: 200, y: 0 }, pos)
+    expect(r).toEqual(pos)
+  })
+
+  it('falls back gracefully when prev === next', () => {
+    // No valid intersection → fallback to snap45
+    const r = snap45both({ x: 50, y: 50 }, { x: 50, y: 50 }, { x: 100, y: 90 })
+    expect(r).toBeDefined()
+  })
+})
+
+describe('distToSegment', () => {
+  it('returns 0 when point is on the segment', () => {
+    expect(distToSegment({ x: 50, y: 0 }, { x: 0, y: 0 }, { x: 100, y: 0 })).toBeCloseTo(0)
+  })
+
+  it('returns perpendicular distance when point is beside segment', () => {
+    expect(distToSegment({ x: 50, y: 10 }, { x: 0, y: 0 }, { x: 100, y: 0 })).toBeCloseTo(10)
+  })
+
+  it('returns distance to nearest endpoint when point is past the segment', () => {
+    expect(distToSegment({ x: 200, y: 0 }, { x: 0, y: 0 }, { x: 100, y: 0 })).toBeCloseTo(100)
+  })
+
+  it('handles zero-length segment (a === b)', () => {
+    expect(distToSegment({ x: 3, y: 4 }, { x: 0, y: 0 }, { x: 0, y: 0 })).toBeCloseTo(5)
+  })
+})
+
+describe('findInsertIndex', () => {
+  it('returns 0 when there are no waypoints (only one segment)', () => {
+    expect(findInsertIndex(0, 0, [], 100, 0, { x: 50, y: 5 })).toBe(0)
+  })
+
+  it('inserts before first waypoint when click is on first segment', () => {
+    const idx = findInsertIndex(0, 0, [{ x: 100, y: 0 }], 200, 0, { x: 30, y: 5 })
+    expect(idx).toBe(0)
+  })
+
+  it('inserts after first waypoint when click is on second segment', () => {
+    const idx = findInsertIndex(0, 0, [{ x: 100, y: 0 }], 200, 0, { x: 160, y: 5 })
+    expect(idx).toBe(1)
+  })
+
+  it('picks the closest segment among multiple', () => {
+    const idx = findInsertIndex(
+      0, 0,
+      [{ x: 100, y: 0 }, { x: 100, y: 100 }],
+      200, 100,
+      { x: 150, y: 105 },
+    )
+    expect(idx).toBe(2)
+  })
+})