252 lines
7.5 KiB
JavaScript
252 lines
7.5 KiB
JavaScript
// 过滤掉无经纬度的数据
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export const filterNull = (
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arr = [],
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longitudeKey = "longitude",
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latitudeKey = "latitude",
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) => {
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return arr.filter(item => item[longitudeKey] && item[latitudeKey]);
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};
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// 格式化多边形
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export const formatPolygon = (item) => {
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const latitudeAndLongitude = [];
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item.position.forEach((item) => {
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latitudeAndLongitude.push(item.x);
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latitudeAndLongitude.push(item.y);
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});
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return latitudeAndLongitude;
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};
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// 分片加载方法
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export const chunkedLoad = async (dataArray, chunkSize = 10, processItem) => {
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const results = [];
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for (let i = 0; i < dataArray.length; i += chunkSize) {
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const chunk = dataArray.slice(i, i + chunkSize);
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const chunkResults = await Promise.all(chunk.map(processItem));
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results.push(...chunkResults.filter(Boolean));
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}
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return results;
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};
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// 创建文字图片
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const createTextCanvas = (text) => {
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return new Promise((resolve) => {
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// 如果没有文本，则返回 null
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if (!text) {
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resolve(null);
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return;
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}
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const canvas = document.createElement("canvas");
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const ctx = canvas.getContext("2d");
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// 1. 获取设备像素比
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const ratio = window.devicePixelRatio || 1;
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// 2. 字体配置参数
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const fontSize = 14 * ratio; // 按比例放大字体
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const fontFamily = "Arial, sans-serif"; // 优先使用系统字体
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const paddingX = Math.round(7 * ratio);
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const paddingY = Math.round(5 * ratio);
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// 3. 设置Canvas实际尺寸
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ctx.font = `${fontSize}px ${fontFamily}`;
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const textMetrics = ctx.measureText(text);
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const textWidth = textMetrics.width;
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const canvasWidth = Math.ceil(textWidth + paddingX * 2);
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const canvasHeight = Math.ceil(fontSize + paddingY * 2);
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// 4. 设置Canvas显示尺寸
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canvas.style.width = `${canvasWidth / ratio}px`;
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canvas.style.height = `${canvasHeight / ratio}px`;
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canvas.width = canvasWidth * ratio;
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canvas.height = canvasHeight * ratio;
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// 5. 缩放坐标系
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ctx.scale(ratio, ratio);
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ctx.font = `${fontSize}px ${fontFamily}`; // 缩放后需要重新设置字体
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// 6. 优化绘制参数
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ctx.fillStyle = "rgba(20, 58, 142, 1)";
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ctx.fillRect(0, 0, canvasWidth, canvasHeight);
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ctx.fillStyle = "#ffffff";
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ctx.textBaseline = "top";
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ctx.textRendering = "geometricPrecision"; // 优化文字渲染
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// 7. 整数坐标绘制
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const drawX = Math.round(paddingX);
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const drawY = Math.round(paddingY);
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ctx.fillText(text, drawX, drawY);
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resolve({
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base64: canvas.toDataURL(),
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width: canvasWidth,
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height: canvasHeight,
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});
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});
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};
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// 创建图片
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const createImgCanvas = (imageUrl) => {
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return new Promise((resolve, reject) => {
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// 创建Image对象
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const img = new Image();
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img.crossOrigin = "Anonymous"; // 处理跨域问题
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img.src = imageUrl;
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// 图片加载成功
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img.onload = () => {
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// 创建Canvas
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const canvas = document.createElement("canvas");
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const ctx = canvas.getContext("2d");
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// 设置Canvas宽高与图片一致
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canvas.width = img.width;
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canvas.height = img.height;
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// 将图片绘制到Canvas上
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ctx.drawImage(img, 0, 0);
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// 获取Canvas的base64数据
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const base64 = canvas.toDataURL();
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// 返回结果
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resolve({
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base64, // Canvas的base64数据
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width: img.width, // 图片宽度
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height: img.height, // 图片高度
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});
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};
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// 图片加载失败
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img.onerror = (error) => {
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reject(new Error(`Failed to load image: ${error}`));
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};
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});
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};
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const imgCanvasCache = new Map();
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// 创建图片和文字的Canvas
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export const getBillboardCanvases = async (imageUrl, text, spacing = 5) => {
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// 缓存检查逻辑
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let imgPromise;
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if (imgCanvasCache.has(imageUrl)) {
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imgPromise = imgCanvasCache.get(imageUrl);
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}
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else {
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imgPromise = createImgCanvas(imageUrl);
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imgCanvasCache.set(imageUrl, imgPromise);
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}
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// 并行获取内容（图片使用缓存，文字始终新建）
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const [imgResult, textResult] = await Promise.all([
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imgPromise,
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createTextCanvas(text),
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]);
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// 如果没有文字，直接返回图片结果
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if (!textResult) {
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return {
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base64: imgResult.base64,
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width: imgResult.width,
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height: imgResult.height,
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};
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}
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// 创建合并Canvas
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const canvas = document.createElement("canvas");
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const ctx = canvas.getContext("2d");
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// 计算合并尺寸
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const maxWidth = Math.max(imgResult.width, textResult.width);
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const totalHeight = textResult.height + imgResult.height + spacing;
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// 设置Canvas尺寸
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canvas.width = maxWidth;
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canvas.height = totalHeight;
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// 创建图片对象并等待加载
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const loadImage = base64 =>
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new Promise((resolve, reject) => {
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const img = new Image();
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img.onload = () => resolve(img);
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img.onerror = reject;
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img.src = base64;
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});
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// 并行加载图片和文字图像
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const [image, textImage] = await Promise.all([
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loadImage(imgResult.base64),
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loadImage(textResult.base64),
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]);
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// 计算水平居中偏移量
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const textX = (maxWidth - textResult.width) / 2;
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const imageX = (maxWidth - imgResult.width) / 2;
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// 绘制文字到Canvas（顶部对齐）
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ctx.drawImage(textImage, textX, 0); // y坐标为0表示顶部
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// 绘制图片到Canvas（底部对齐）
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ctx.drawImage(
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image,
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imageX, // x坐标
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textResult.height + spacing, // y坐标设置为文字高度
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imgResult.width,
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imgResult.height,
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);
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return {
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base64: canvas.toDataURL(),
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width: maxWidth,
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height: totalHeight,
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};
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};
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// 风向
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export const windDirection = (angle) => {
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const arr = [
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{ directions: "北", minAngle: "348.76", maxAngle: "11.25" },
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{ directions: "北东北", minAngle: "11.26", maxAngle: "33.75" },
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{ directions: "东北", minAngle: "33.76", maxAngle: "56.25" },
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{ directions: "东东北", minAngle: "56.26", maxAngle: "78.75" },
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{ directions: "东", minAngle: "78.76", maxAngle: "101.25" },
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{ directions: "东东南", minAngle: "101.26", maxAngle: "123.75" },
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{ directions: "东南", minAngle: "123.76", maxAngle: "146.25" },
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{ directions: "南东南", minAngle: "146.26", maxAngle: "168.75" },
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{ directions: "南", minAngle: "168.76", maxAngle: "191.25" },
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{ directions: "南西南", minAngle: "191.26", maxAngle: "213.75" },
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{ directions: "西南", minAngle: "213.76", maxAngle: "236.25" },
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{ directions: "西西南", minAngle: "236.26", maxAngle: "258.75" },
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{ directions: "西", minAngle: "258.76", maxAngle: "281.25" },
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{ directions: "西西北", minAngle: "281.26", maxAngle: "303.75" },
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{ directions: "西北", minAngle: "303.76", maxAngle: "326.25" },
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{ directions: "北西北", minAngle: "326.26", maxAngle: "348.75" },
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];
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for (let i = 0; i < arr.length; i++) {
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if (+angle >= +arr[i].minAngle && +angle <= +arr[i].maxAngle) {
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return `${arr[i].directions}风`;
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}
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}
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return "静风";
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};
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// 处理 Echarts 图标 X轴文字换行
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export function textFormatter(value, maxLength = 4) {
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let ret = ""; // 拼接加 \n 返回的类目项
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const valLength = value.length; // X轴类目项的文字个数
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const rowN = Math.ceil(valLength / maxLength); // 类目项需要换行的行数
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if (rowN > 1) {
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for (let i = 0; i < rowN; i++) {
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let temp = "";
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const start = i * maxLength;
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const end = start + maxLength;
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temp = `${value.substring(start, end)}\n`;
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ret += temp;
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}
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return ret;
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}
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else {
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return value;
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}
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}
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