Files
homelable/frontend/src/utils/__tests__/alignment.test.ts
T
Pouzor 004a8f19c1 feat(canvas): alignment guides + snap while dragging nodes
Draw.io / Figma style: while dragging a node, show dashed cyan guide
lines when its edges (left / center / right / top / middle / bottom)
align with another node's, and snap the position to the matched line
within a configurable threshold.

- utils/alignment.ts: pure snap math, returns delta + guide segments.
  Same-size boxes show all aligned guides simultaneously.
- canvas/AlignmentGuides.tsx: SVG overlay locked to the React Flow
  viewport (panned/zoomed correctly).
- hooks/useAlignmentGuides.ts: wires onNodeDrag/onNodeDragStop, applies
  snap via setNodes, listens for Alt to temporarily disable.
- utils/alignmentSettings.ts: localStorage-backed prefs (enabled,
  threshold 2-16px) with a tiny CustomEvent pub-sub so the SettingsPanel
  and the drag hook stay in sync without a global store.
- Sidebar settings panel: toggle + threshold slider.

Multi-selection drag uses the union bounding box. Children with
parentId are skipped for v1 to avoid mixing absolute and parent-relative
coordinates. Hold Alt to escape snap.
2026-05-11 00:35:50 +02:00

111 lines
4.2 KiB
TypeScript

import { describe, it, expect } from 'vitest'
import { computeSnap, unionBox, type Box } from '../alignment'
const box = (id: string, x: number, y: number, width = 100, height = 50): Box => ({ id, x, y, width, height })
describe('computeSnap', () => {
it('returns zero deltas with no candidates', () => {
const r = computeSnap(box('a', 0, 0), [], 6)
expect(r).toEqual({ deltaX: 0, deltaY: 0, guides: [] })
})
it('snaps left edges when within threshold (same-size boxes show all aligned guides)', () => {
const dragged = box('a', 102, 200) // left=102
const other = box('b', 100, 0) // left=100 → delta -2 → all three edges tie
const r = computeSnap(dragged, [other], 6)
expect(r.deltaX).toBe(-2)
expect(r.deltaY).toBe(0)
// Same width: left/center/right all tie at delta -2. Draw all three guides.
expect(r.guides.map((g) => g.position).sort((a, b) => a - b)).toEqual([100, 150, 200])
expect(r.guides.every((g) => g.axis === 'x')).toBe(true)
})
it('shows a single guide when only one edge aligns', () => {
const dragged = box('a', 102, 200, 80, 50) // left=102, center=142, right=182
const other = box('b', 100, 0, 100, 50) // left=100, center=150, right=200
const r = computeSnap(dragged, [other], 6)
expect(r.deltaX).toBe(-2) // left↔left wins
expect(r.guides).toHaveLength(1)
expect(r.guides[0].position).toBe(100)
})
it('does not snap when outside threshold', () => {
const dragged = box('a', 110, 200)
const other = box('b', 100, 0)
const r = computeSnap(dragged, [other], 6)
expect(r.deltaX).toBe(0)
expect(r.guides).toHaveLength(0)
})
it('snaps centerX to centerX', () => {
const dragged = box('a', 51, 300, 100, 50) // center=101
const other = box('b', 75, 0, 50, 50) // center=100 → delta -1
const r = computeSnap(dragged, [other], 6)
expect(r.deltaX).toBe(-1)
expect(r.guides).toHaveLength(1)
expect(r.guides[0].position).toBe(100)
})
it('snaps right edge of dragged to left edge of candidate', () => {
const dragged = box('a', 0, 200) // right=100
const other = box('b', 102, 0) // left=102 → delta +2
const r = computeSnap(dragged, [other], 6)
expect(r.deltaX).toBe(2)
})
it('snaps both axes simultaneously', () => {
const dragged = box('a', 102, 53, 80, 30)
const other = box('b', 100, 50, 100, 50)
const r = computeSnap(dragged, [other], 6)
expect(r.deltaX).toBe(-2)
expect(r.deltaY).toBe(-3)
// Distinct sizes → exactly one X guide and one Y guide.
expect(r.guides.filter((g) => g.axis === 'x')).toHaveLength(1)
expect(r.guides.filter((g) => g.axis === 'y')).toHaveLength(1)
})
it('picks the closest match when multiple candidates compete', () => {
const dragged = box('a', 103, 0)
const closer = box('b', 100, 0) // delta -3
const farther = box('c', 109, 0) // delta +6 — also within threshold but worse
const r = computeSnap(dragged, [closer, farther], 6)
expect(r.deltaX).toBe(-3)
})
it('ignores the dragged box itself when present in candidates', () => {
const dragged = box('a', 102, 0)
const r = computeSnap(dragged, [dragged, box('b', 100, 0)], 6)
expect(r.deltaX).toBe(-2)
})
it('returns no snap with non-positive threshold', () => {
const r = computeSnap(box('a', 100, 0), [box('b', 100, 0)], 0)
expect(r.guides).toEqual([])
})
it('guide span covers both involved boxes', () => {
const dragged = box('a', 102, 200, 100, 50) // y range 200..250
const other = box('b', 100, 0, 100, 50) // y range 0..50
const r = computeSnap(dragged, [other], 6)
const g = r.guides[0]
expect(g.start).toBeLessThanOrEqual(0)
expect(g.end).toBeGreaterThanOrEqual(250)
})
})
describe('unionBox', () => {
it('returns null for empty input', () => {
expect(unionBox([])).toBeNull()
})
it('returns the box itself for one input', () => {
const b = box('a', 10, 20, 30, 40)
expect(unionBox([b])).toMatchObject({ x: 10, y: 20, width: 30, height: 40 })
})
it('computes union of multiple boxes', () => {
const u = unionBox([box('a', 0, 0, 50, 50), box('b', 100, 100, 50, 50)])
expect(u).toMatchObject({ x: 0, y: 0, width: 150, height: 150 })
})
})