openpencil/tests/engine/geometry/rotation.test.ts
2026-05-16 13:30:25 +03:00

96 lines
3.3 KiB
TypeScript

import { describe, test, expect } from 'bun:test'
import { rotatePoint, rotatedBBox, rotatedCorners } from '@open-pencil/core'
describe('rotatePoint', () => {
test('no rotation returns same point', () => {
const result = rotatePoint(10, 20, 0, 0, 0)
expect(result.x).toBeCloseTo(10, 10)
expect(result.y).toBeCloseTo(20, 10)
})
test('90° rotation around origin', () => {
const result = rotatePoint(1, 0, 0, 0, Math.PI / 2)
expect(result.x).toBeCloseTo(0, 10)
expect(result.y).toBeCloseTo(1, 10)
})
test('180° rotation negates both axes', () => {
const result = rotatePoint(1, 0, 0, 0, Math.PI)
expect(result.x).toBeCloseTo(-1, 10)
expect(result.y).toBeCloseTo(0, 10)
})
test('rotation around non-origin center', () => {
// Rotate (1,0) around (0.5, 0.5) by 90° → (1, 1)
const result = rotatePoint(1, 0, 0.5, 0.5, Math.PI / 2)
expect(result.x).toBeCloseTo(1, 10)
expect(result.y).toBeCloseTo(1, 10)
})
})
describe('rotatedCorners', () => {
test('zero rotation returns axis-aligned corners', () => {
const [tl, tr, br, bl] = rotatedCorners(50, 50, 50, 50, 0)
expect(tl).toEqual({ x: 0, y: 0 })
expect(tr).toEqual({ x: 100, y: 0 })
expect(br).toEqual({ x: 100, y: 100 })
expect(bl).toEqual({ x: 0, y: 100 })
})
test('90° rotation swaps width and height positions', () => {
const [tl, tr, br, bl] = rotatedCorners(50, 50, 50, 25, 90)
// After 90° rotation: corners should be at different positions
// The center (50,50) stays the same
const cx = (tl.x + tr.x + br.x + bl.x) / 4
const cy = (tl.y + tr.y + br.y + bl.y) / 4
expect(cx).toBeCloseTo(50, 10)
expect(cy).toBeCloseTo(50, 10)
})
})
describe('rotatedBBox', () => {
test('zero rotation returns input as bbox', () => {
const bbox = rotatedBBox(10, 20, 30, 40, 0)
expect(bbox).toEqual({
left: 10,
right: 40,
top: 20,
bottom: 60,
centerX: 25,
centerY: 40
})
})
test('45° rotation of square expands bbox', () => {
const bbox = rotatedBBox(0, 0, 100, 100, 45)
// A 100x100 square rotated 45° has a bbox of ~141.4 wide/tall
const side = Math.sqrt(100 * 100 * 2)
expect(bbox.right - bbox.left).toBeCloseTo(side, 5)
expect(bbox.bottom - bbox.top).toBeCloseTo(side, 5)
// Center should remain at (50, 50)
expect(bbox.centerX).toBeCloseTo(50, 5)
expect(bbox.centerY).toBeCloseTo(50, 5)
})
test('90° rotation of rectangle swaps dimensions', () => {
const bbox = rotatedBBox(0, 0, 200, 100, 90)
// A 200x100 rect rotated 90° around its center (100, 50) → bbox 100x200
// The center is at (100, 50) regardless of rotation
expect(bbox.centerX).toBeCloseTo(100, 5)
expect(bbox.centerY).toBeCloseTo(50, 5)
// Width of bbox = original height, height of bbox = original width
expect(bbox.right - bbox.left).toBeCloseTo(100, 5)
expect(bbox.bottom - bbox.top).toBeCloseTo(200, 5)
})
test('negative rotation works correctly', () => {
const pos = rotatedBBox(0, 0, 100, 100, -45)
const neg = rotatedBBox(0, 0, 100, 100, 45)
// Bounding box should be same size regardless of rotation direction
expect(pos.right - pos.left).toBeCloseTo(neg.right - neg.left, 5)
expect(pos.bottom - pos.top).toBeCloseTo(neg.bottom - neg.top, 5)
})
})