Vue - 页面添加水印效果

水印效果

1. 全屏水印
   

2. 指定容器水印
   

使用方法

1. 项目中新建一个 watermark.js 文件

   let watermark = {};
   
   let setWatermark = (text, sourceBody) => {
     let id =
       Math.random() * 10000 +
       "-" +
       Math.random() * 10000 +
       "/" +
       Math.random() * 10000;
   
     if (document.getElementById(id) !== null) {
       document.body.removeChild(document.getElementById(id));
     }
   
     let can = document.createElement("canvas");
     can.width = 120; //设置水印之间的左右间距
     can.height = 80; //设置水印之间的上下间距
   
     let cans = can.getContext("2d");
     cans.rotate((-20 * Math.PI) / 180);
     cans.font = "15px Vedana";
     cans.fillStyle = "rgba(0, 0, 0, .5)";
     cans.textAlign = "left";
     cans.textBaseline = "Middle";
     cans.fillText(text, can.width / 20, can.height);
   
     let water_div = document.createElement("div");
     water_div.id = id;
     water_div.className = "watermarkClass";
     water_div.style.pointerEvents = "none";
     water_div.style.background =
       "url(" + can.toDataURL("image/png") + ") left top repeat";
     if (sourceBody) {
       water_div.style.width = "100%";
       water_div.style.height = "100%";
       sourceBody.appendChild(water_div);
     } else {
       water_div.style.top = "3px";
       water_div.style.left = "0px";
       water_div.style.position = "fixed";
       water_div.style.zIndex = "100000";
       water_div.style.width = document.documentElement.clientWidth + "px";
       water_div.style.height = document.documentElement.clientHeight + "px";
       document.body.appendChild(water_div);
     }
   
     return id;
   };
   
   /**
    *  该方法只允许调用一次
    *  @param:
    *  @text == 水印内容
    *  @sourceBody == 水印添加的位置，不传就是body
    * */
   watermark.set = (text, sourceBody) => {
     const domArr = Array.from(document.getElementsByClassName("watermarkClass"));
     for (let i = 0; i < domArr.length; i++) {
       const element = domArr[i];
       // element.parentNode.removeChild(element);
       element.remove();
     }
     if (text == "") {
       return;
     }
     setWatermark(text, sourceBody);
     // let id = setWatermark(text, sourceBody);
     // setInterval(() => {
     //   if (document.getElementById(id) === null) {
     //     id = setWatermark(text, sourceBody);
     //   }
     // }, 2000);
     // window.onresize = () => {
     //   setWatermark(text, sourceBody);
     // };
   };
   
   export default watermark;
   

2. main.js 中引入 watermark.js

   // 引入水印文件地址
   import watermark from './util/watermark.js'
   Vue.prototype.$watermark = watermark
   

3. 页面中使用
   this.$watermark.set(text，dom)

   参数	说明	是否必填
   text	水印内容	是
   dom	水印容器。若不传，则全屏水印，若传，则指定容器。	否

   （1）全屏水印

   <template>
     <div class="page">
     </div>
   </template>
   
   <script>
   export default {
     data() {
       return {};
     },
     mounted(){
       this.$watermark.set("水印")
     },
     beforeDestroy() {
       this.$watermark.set("");
     }
   };
   </script>
   
   <style scoped>
   .page{
     width: 100%;
     height: 100%;
     background-color: skyblue;
   }
   </style>
   

   （2）指定容器水印

   <template>
     <div class="page">
       <div ref="content" style="width: 500px;height: 500px;border: 2px solid red;"></div>
     </div>
   </template>
   
   <script>
   export default {
     data() {
       return {};
     },
     mounted(){
       this.$watermark.set("水印",this.$refs.content)
     },
     beforeDestroy() {
       this.$watermark.set("",this.$refs.content);
     }
   };
   </script>
   
   <style scoped>
   .page{
     width: 100%;
     height: 100%;
     background-color: skyblue;
   }
   </style>