Merge pull request #204 from VisActor/feat/cartesian-to-polar

feat: add `cartesianToPolar` util function

common/changes/@visactor/vutils/feat-cartesian-to-polar_2024-09-19-07-49.json

@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@visactor/vutils",
+      "comment": "feat: add `cartesianToPolar` util",
+      "type": "none"
+    }
+  ],
+  "packageName": "@visactor/vutils"
+}

packages/vutils/__tests__/angle.test.ts

@@ -1,4 +1,11 @@
-import { findBoundaryAngles, normalizeAngle, polarToCartesian, calculateMaxRadius, computeQuadrant } from '../src';
+import {
+  findBoundaryAngles,
+  normalizeAngle,
+  polarToCartesian,
+  calculateMaxRadius,
+  computeQuadrant,
+  cartesianToPolar
+} from '../src';
 
 describe('angle utils', () => {
   it('normalizeAngle', () => {
@@ -55,3 +62,28 @@ describe('angle utils', () => {
     expect(computeQuadrant(4)).toBe(4);
   });
 });
+
+describe('cartesianToPolar', () => {
+  test('should convert point at origin to polar coordinates', () => {
+    const result = cartesianToPolar({ x: 0, y: 0 });
+    expect(result).toEqual({ radius: 0, angle: 0 });
+  });
+
+  test('should convert point with center at origin', () => {
+    const result = cartesianToPolar({ x: 3, y: 4 });
+    expect(result.radius).toBe(5);
+    expect(result.angle).toBeCloseTo(Math.atan2(4, 3), 5);
+  });
+
+  test('should convert point with center not at origin', () => {
+    const result = cartesianToPolar({ x: 11, y: 11 }, { x: 10, y: 10 });
+    expect(result.radius).toBeCloseTo(Math.sqrt(2), 5);
+    expect(result.angle).toBeCloseTo(Math.PI / 4, 5);
+  });
+
+  test('should return correct polar coordinates within specified angle range', () => {
+    const result = cartesianToPolar({ x: 11, y: 11 }, { x: 10, y: 10 }, -Math.PI / 2, (3 * Math.PI) / 2);
+    expect(result.radius).toBeCloseTo(Math.sqrt(2), 5);
+    expect(result.angle).toBeCloseTo(Math.PI / 4, 5);
+  });
+});

packages/vutils/src/angle.ts

@@ -79,6 +79,54 @@ export function polarToCartesian(center: IPointLike, radius: number, angleInRadi
   };
 }
 
+/**
+ * 根据笛卡尔坐标系坐标计算极坐标坐标点
+ * @param point
+ * @param center 极坐标系中心点坐标
+ * @param startAngle 极坐标系起始角度
+ * @param endAngle 极坐标系结束角度
+ * @returns 极坐标系坐标点
+ */
+export function cartesianToPolar(
+  point: IPointLike,
+  center: IPointLike = { x: 0, y: 0 },
+  startAngle = 0,
+  endAngle = 2 * Math.PI
+) {
+  const { x, y } = point;
+  const { x: centerX, y: centerY } = center;
+
+  let dx = x - centerX;
+  let dy = y - centerY;
+  const radius = Math.sqrt(dx * dx + dy * dy);
+
+  if (radius === 0) {
+    return {
+      radius: 0,
+      angle: 0
+    };
+  }
+
+  dx /= radius;
+  dy /= radius;
+
+  let radian = Math.atan2(dy, dx);
+  if (radian < startAngle) {
+    while (radian <= startAngle) {
+      radian += Math.PI * 2;
+    }
+  }
+  if (radian > endAngle) {
+    while (radian >= endAngle) {
+      radian -= Math.PI * 2;
+    }
+  }
+  return {
+    radius,
+    angle: radian
+  };
+}
+
 /**
  * 根据点的笛卡尔坐标获取该点与圆心的连线同正 x 轴方向的夹角
  * @param center 圆心坐标