react 椭圆形转盘 点击左右箭头 图片位置变换

效果图：

 目前已实现功能 ：图片围绕椭圆排列，图片大小视觉效果，正中间图片为选中状态，点击左右箭头图片位置依次变化；

实现思路：

图片排列 ：通过计算角度和弧度，计算出每个元素的定位left top值；

图片大小： 通过对比top值，设置图片的transfrom scal值

左右箭头：图片之间间距相等，每次点击会更新元素位置数据 left top值

高亮图片：判断位置，切换图片；

上代码：

import React, { useState, useEffect} from 'react';
import img1 from '../../assets/images/1im.png'; //车辆
import img2 from '../../assets/images/2im.png'; //供电
import img3 from '../../assets/images/3im.png'; //土建
import img4 from '../../assets/images/4im.png'; //信号
import img5 from '../../assets/images/5im.png'; //通信
import img6 from '../../assets/images/6im.png'; //机电
import img7 from '../../assets/images/7im.png'; //线路
import img8 from '../../assets/images/8im.png'; //AFC
// 点击切换高亮图
import img1_2 from '../../assets/images/1-2.png';
import img2_2 from '../../assets/images/2-2.png';
import img3_2 from '../../assets/images/3-2.png';
import img4_2 from '../../assets/images/4-2.png';
import img5_2 from '../../assets/images/5-2.png';
import img6_2 from '../../assets/images/6-2.png';
import img7_2 from '../../assets/images/7-2.png';
import img8_2 from '../../assets/images/8-2.png';
import './turntable.scss';const imgs = [img5, img3, img8, img7, img6, img4, img2, img1];
const imgs1 = [img5_2, img3_2, img8_2, img7_2, img6_2, img4_2, img2_2, img1_2];
// 图片比例缩放
const setScale = (num) => {if (num === 84) {return 0.9;} else if (num === 20) {return 0.8;} else if (num === 44) {return 0.7;} else if (num === 70) {return 0.65;} else if (num === 110) {return 1;}
};
const Turntable = () => {const [nodes, setNodes] = useState([]);const [speeds, setSpeed] = useState(1);const width = 1126;const height = 180;const leng = 8;const domWidth = 170;const domHeight = 180;function carousel() {const arr = [];//中心点横坐标var dotLeft = width / 2 - domWidth / 2;//中心点纵坐标var dotTop = height / 2 - domHeight / 2 + 20;//椭圆长边let a = width / 2;//椭圆短边let b = height / 2;//每一个BOX对应的角度;var avd = 360 / leng;//每一个BOX对应的弧度;var ahd = (avd * Math.PI) / 180;//运动距离，即运动的弧度数;var ainhd1 = (speeds * Math.PI) / 180;var ainhd = speeds * ahd;for (let i = 0; i < leng; i++) {let left = Math.round(Math.sin(ahd * i + ainhd) * a + dotLeft);let top = Math.round(Math.cos(ahd * i + ainhd) * b + dotTop);let obj = {left: left,top: top,img: imgs[i],img1: imgs1[i],scale: setScale(Math.floor(Math.abs(top)))};arr.push(obj);}setNodes(arr);}useEffect(() => {carousel(); //旋转}, [speeds]);// 点击左右箭头const checkImg = (a) => {if (a === 'right') {let speed = speeds < 8 ? speeds : 1;setSpeed(speed + 1);}if (a === 'left') {let speed = speeds > -8 ? speeds : 1;setSpeed(speed - 1);}};return (<div className="turntable"><div className="leftRow" onClick={() => checkImg('left')}></div><div className="centerTurn">{nodes.map((res, index) => {const img = res.top === 110 ? res?.img : res?.img1;let styleobj = {top: res.top,left: res.left,transform: `scale(${res.scale})`};return (<divclassName="zhunpng"style={styleobj}key={index}onClick={() => move(res)}><img src={img} className="zhunimg" alt="" /></div>);})}</div><div className="rightRow" onClick={() => checkImg('right')}></div></div>);
};
export default Turntable;