Merge pull request #189 from VisActor/feat/angle-utils

Feat/angle utils

common/changes/@visactor/vutils/feat-angle-utils_2024-05-24-07-02.json

@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "comment": "feat: add `calculateMaxRadius()` and `findBoundaryAngles()`\n\n",
+      "type": "none",
+      "packageName": "@visactor/vutils"
+    }
+  ],
+  "packageName": "@visactor/vutils",
+  "email": "dingling112@gmail.com"
+}

packages/vutils/__tests__/angle.test.ts

@@ -1,4 +1,4 @@
-import { normalizeAngle } from '../src';
+import { findBoundaryAngles, normalizeAngle, polarToCartesian, calculateMaxRadius } from '../src';
 
 describe('angle utils', () => {
   it('normalizeAngle', () => {
@@ -11,4 +11,34 @@ describe('angle utils', () => {
     expect(normalizeAngle(-2 * Math.PI)).toBe(0);
     expect(normalizeAngle(-Math.PI)).toBe(Math.PI);
   });
+
+  it('polarToCartesian', () => {
+    expect(polarToCartesian({ x: 0, y: 0 }, undefined, undefined)).toEqual({ x: 0, y: 0 });
+  });
+
+  it('findBoundaryAngles', () => {
+    expect(findBoundaryAngles(Math.PI / 4, Math.PI)).toEqual([Math.PI / 4, Math.PI, Math.PI / 2]);
+    expect(findBoundaryAngles(Math.PI / 4, 1.5 * Math.PI)).toEqual([Math.PI / 4, 1.5 * Math.PI, Math.PI / 2, Math.PI]);
+    expect(findBoundaryAngles(Math.PI / 4, 3 * Math.PI)).toEqual([0, Math.PI / 2, Math.PI, 1.5 * Math.PI]);
+
+    expect(findBoundaryAngles(-Math.PI, -Math.PI / 4)).toEqual([Math.PI, 1.75 * Math.PI, 1.5 * Math.PI]);
+
+    expect(findBoundaryAngles(-0.2 * Math.PI, -0.8 * Math.PI)).toEqual([1.2 * Math.PI, 1.8 * Math.PI, 1.5 * Math.PI]);
+  });
+
+  it('calculateMaxRadius', () => {
+    expect(
+      calculateMaxRadius({ width: 400, height: 300 }, { x: 200, y: 120 }, -1.25 * Math.PI, 0.25 * Math.PI)
+    ).toBeCloseTo(120);
+    expect(
+      calculateMaxRadius({ width: 400, height: 300 }, { x: 200, y: 200 }, -1.25 * Math.PI, 0.25 * Math.PI)
+    ).toBeCloseTo(141.42135623730948);
+
+    expect(
+      calculateMaxRadius({ width: 400, height: 500 }, { x: 200, y: 150 }, -0.8 * Math.PI, 0.1 * Math.PI)
+    ).toBeCloseTo(150);
+    expect(
+      calculateMaxRadius({ width: 400, height: 500 }, { x: 200, y: 350 }, -0.8 * Math.PI, 0.1 * Math.PI)
+    ).toBeCloseTo(157.71933363574007);
+  });
 });

packages/vutils/src/angle.ts

@@ -69,6 +69,10 @@ export const clampAngleByDegree = clampDegree;
  * @returns 返回笛卡尔坐标点
  */
 export function polarToCartesian(center: IPointLike, radius: number, angleInRadian: number): { x: number; y: number } {
+  if (!radius) {
+    return { x: center.x, y: center.y };
+  }
+
   return {
     x: center.x + radius * Math.cos(angleInRadian),
     y: center.y + radius * Math.sin(angleInRadian)
@@ -98,3 +102,82 @@ export function normalizeAngle(angle: number): number {
   }
   return angle;
 }
+
+/**
+ * 指定开始角度和结束角度，计算这个范围内的边界角度，
+ * 即起始角度以及经过的东、南、西、北四个方向的角度
+ * 计算这个角度，可以用于计算一个弧度的bounding box 等
+ * @param startAngle 起始角度的弧度值
+ * @param endAngle    结束角度的弧度值
+ * @returns 边界角度数组
+ */
+export function findBoundaryAngles(startAngle: number, endAngle: number) {
+  const deltaAngle = Math.abs(endAngle - startAngle);
+
+  if (deltaAngle >= 2 * Math.PI || 2 * Math.PI - deltaAngle < 1e-6) {
+    return [0, Math.PI / 2, Math.PI, 1.5 * Math.PI];
+  }
+  const min = Math.min(startAngle, endAngle);
+  const normalMin = normalizeAngle(min);
+  const normalMax = normalMin + deltaAngle;
+  const steps = [normalMin, normalMax];
+  let directionAngle = (Math.floor(normalMin / Math.PI) * Math.PI) / 2;
+
+  while (directionAngle < normalMax) {
+    if (directionAngle > normalMin) {
+      steps.push(directionAngle);
+    }
+    directionAngle += Math.PI / 2;
+  }
+
+  return steps;
+}
+/**
+ * 计算指定范围内，指定中心的情况下，不超出边界的最大可用半径
+ * @param rect 矩形的大小
+ * @param center 中心点
+ * @param startAngle 起始角度的弧度值
+ * @param endAngle 结束角度的弧度值
+ * @returns 最大半径
+ */
+export function calculateMaxRadius(
+  rect: { width: number; height: number },
+  center: { x: number; y: number },
+  startAngle: number,
+  endAngle: number
+) {
+  const { x, y } = center;
+  const steps = findBoundaryAngles(startAngle, endAngle);
+  const { width, height } = rect;
+
+  const radiusList: number[] = [];
+
+  steps.forEach(step => {
+    const sin = Math.sin(step);
+    const cos = Math.cos(step);
+
+    if (sin === 1) {
+      radiusList.push(height - y);
+    } else if (sin === -1) {
+      radiusList.push(y);
+    } else if (cos === 1) {
+      radiusList.push(width - x);
+    } else if (cos === -1) {
+      radiusList.push(x);
+    } else {
+      if (sin > 0) {
+        radiusList.push(Math.abs((height - y) / cos));
+      } else {
+        radiusList.push(Math.abs(y / cos));
+      }
+
+      if (cos > 0) {
+        radiusList.push(Math.abs((width - x) / sin));
+      } else {
+        radiusList.push(Math.abs(x / sin));
+      }
+    }
+  });
+
+  return Math.min.apply(null, radiusList);
+}