Vue3基于 rem 比例缩放方案示例详解

/**
 * 基于rem 的比例缩放方案
 * @author wangguanjie 2022.06.09
 */
import { onBeforeUnmount, onMounted, ref } from "vue";
/**
 * 设计稿参数
 * @example 1920 * 1080 下 {width: 1920, height: 1080, fontSize: 16, ...}
 * @example 1680 * 1050 下 {width: 1680, height: 1050, fontSize: 14, ...}
 * @example 1280 * 800 下 {width: 1280, height: 800, fontSize: 12, ...}
 */
export interface DesignParms {
  width: number;
  height: number;
  fontSize: number;
}
export interface UseRemOption {
  delay?: number;
}
export type Designs = DesignParms[];
/**
 * 默认设计稿方案
 */
const DEFAULT_DESIGNS: Designs = [
  { width: 800, height: 600, fontSize: 12 },
  { width: 1024, height: 500, fontSize: 12 },
  { width: 1024, height: 768, fontSize: 12 }, // HD
  { width: 1280, height: 800, fontSize: 12 }, // WXGA
  { width: 1280, height: 854, fontSize: 12 },
  { width: 1280, height: 1024, fontSize: 12 },
  { width: 1366, height: 768, fontSize: 14 },
  { width: 1440, height: 900, fontSize: 14 },
  { width: 1440, height: 1050, fontSize: 14 },
  { width: 1600, height: 1024, fontSize: 14 },
  { width: 1600, height: 1200, fontSize: 14 }, // UXGA
  { width: 1680, height: 1050, fontSize: 14 },
  { width: 1920, height: 937, fontSize: 16 }, // FHD
  { width: 1920, height: 1080, fontSize: 16 }, // FHD
  { width: 1920, height: 1200, fontSize: 16 }, // WUXGA
  { width: 2048, height: 1080, fontSize: 18 },
  { width: 2048, height: 1536, fontSize: 18 }, // QXGA
  { width: 2560, height: 1080, fontSize: 18 },
  { width: 2560, height: 1440, fontSize: 18 }, // QHD
  { width: 2560, height: 1600, fontSize: 18 }, // WQXGA
  { width: 3440, height: 1440, fontSize: 18 },
  { width: 3840, height: 1080, fontSize: 18 },
  { width: 3840, height: 2160, fontSize: 18 }, // UHD
  { width: 4096, height: 2160, fontSize: 18 }, // 4K Ultra HD
];
/**
 * 默认配置参数
 */
const DEFAULT_OPTION: Required<UseRemOption> = {
  // 触发延时，默认2022
  delay: 0,
};
/**
 * 等比缩放方案
 * @author wangguanjie 2022.06.09
 * @description 该方案支持多设计稿
 * @param designs 设计稿集合
 * @param option 缩放配置参数
 * @returns 缩放信息、方法
 */
export const useEqualScaling = function (
  designs: Designs = DEFAULT_DESIGNS,
  option: UseRemOption = DEFAULT_OPTION
) {
  let timer: number | undefined;
  // 确保有设计稿可参考
  designs = designs.length ? designs : DEFAULT_DESIGNS;
  // 将设计搞进行升序排序，供后续快速排查
  designs
    .filter((d) => d.width > 1 && d.height > 1)
    .sort((d1, d2) => {
      if (d1.width === d2.width) {
        return d1.height - d2.height;
      }
      return d1.width - d2.width;
    });
  // 降序排序的设计稿
  const descendingDesigns = designs.map((d) => d).reverse();
  // 浏览器适配所参考的设计稿
  const referDesign = ref(designs[0]);
  /**
   * 根据多份设计搞自适应根节点字号
   */
  const setHtmlFontSize = () => {
    if (timer) {
      clearTimeout(timer);
    }
    timer = setTimeout(() => {
      const { clientWidth: docW, clientHeight: docH } =
        document.documentElement;
      // 匹配最佳设计稿
      const hasNewReferDesignIndex = designs.findIndex(
        (d) => d.width >= docW && d.height >= docH
      );
      if (hasNewReferDesignIndex !== -1) {
        referDesign.value = designs[hasNewReferDesignIndex];
      } else {
        // 优先筛选宽度符合的设计搞
        const accordWidthDesigns = descendingDesigns.filter(
          (d) => d.width <= docW
        );
        // 再确认最接近设计稿高度的设计稿
        const designsHeightList = accordWidthDesigns.map((d) => d.height);
        const useDesignIndex = designsHeightList
          .map((designH) => Math.abs(docH - designH))
          .findIndex(
            (designH) =>
              designH ===
              Math.min(...designsHeightList.map((dh) => Math.abs(docH - dh)))
          );
        referDesign.value = accordWidthDesigns[useDesignIndex];
      }
      // 依据所参考的设计稿变更根节点字号
      const documentRatio = docW / docH;
      const {
        width: designW,
        height: designH,
        fontSize: designFontSize,
      } = referDesign.value;
      const designRatio = designW / designH;
      const htmlFontSize =
        documentRatio < designRatio
          ? (docW / designW) * designFontSize
          : (docH / designH) * designFontSize;
      const html = document.querySelector("html");
      if (html) {
        html.style.fontSize = `${htmlFontSize}px`;
      }
    }, option.delay ?? DEFAULT_OPTION.delay);
  };
  setHtmlFontSize();
  onMounted(() => {
    window.addEventListener("resize", setHtmlFontSize, false);
  });
  onBeforeUnmount(() => {
    window.removeEventListener("resize", setHtmlFontSize, false);
  });
  return {
    designs,
    referDesign,
    setHtmlFontSize,
  };
};

npm install postcss-px2rem px2rem-loader --save

// rem等比适配配置文件
// 基准大小
const baseSize = 16
// 设置 rem 函数
function setRem () {
  // 当前页面宽度相对于 1920宽的缩放比例，可根据自己需要修改。
  const scale = document.documentElement.clientWidth / 1920
  // 设置页面根节点字体大小（“Math.min(scale, 2)” 指最高放大比例为2，可根据实际业务需求调整）
  document.documentElement.style.fontSize = baseSize * Math.min(scale, 2) + 'px'
}
// 初始化
setRem()
// 改变窗口大小时重新设置 rem
window.onresize = function () {
  setRem()
}

import './utils/rem'

// 引入等比适配插件
const px2rem = require('postcss-px2rem')
// 配置基本大小
const postcss = px2rem({
  // 基准大小 baseSize，需要和rem.js中相同
  remUnit: 16
})
// 使用等比适配插件
module.exports = {
  lintOnSave: true,
  css: {
    loaderOptions: {
      postcss: {
        plugins: [
          postcss
        ]
      }
    }
  }
}