创建 watermark.js 文件

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let watermark = {};
let setWatermark = (str) => {
  let id = "1.23452384164.123412415";
  if (document.getElementById(id) !== null) {
    document.body.removeChild(document.getElementById(id));
  }
  let can = document.createElement("canvas");
  can.width = 150;
  can.height = 120;
  let cans = can.getContext("2d");
  cans.rotate((-20 * Math.PI) / 180);
  cans.font = "20px Vedana";
  cans.fillStyle = "rgba(200, 200, 200, 0.20)";
  cans.textAlign = "left";
  cans.textBaseline = "Middle";
  cans.fillText(str, can.width / 3, can.height / 2);
  let div = document.createElement("div");
  div.id = id;
  div.style.pointerEvents = "none";
  div.style.top = "0px";
  div.style.left = "0px";
  div.style.position = "fixed";
  div.style.zIndex = "100000";
  div.style.width = document.documentElement.clientWidth + "px";
  div.style.height = document.documentElement.clientHeight + "px";
  div.style.background =
    "url(" + can.toDataURL("image/png") + ") left top repeat";
  document.body.appendChild(div);
  return id;
};
// 该方法只允许调用一次
watermark.set = (str) => {
  let id = setWatermark(str);
  setInterval(() => {
    if (document.getElementById(id) === null) {
      id = setWatermark(str);
    }
  }, 500);
  window.onresize = () => {
    setWatermark(str);
  };
};

export default watermark;

在 app.vue 中 mounted 方法内调用该方法即可全局添加如个别页面需要单独添加可在单个文件的 mounted 生命周期里调用方法

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mounted: function () {
    Watermark.set("水印内容")
}