vue实现文字水印效果

.vue文件代码

<template>
    <div>
        <div class="watermark" ref="content"></div>
    </div>
</template>
<script>
import watermark from './config/watermark'
export default {
    mounted(){
        watermark.set("文字水印",this.$refs.content)
    },
    beforeDestroy(){
        watermark.set("",this.$refs.content)
    },
}
</script>
<style lang="less" scoped>
    .watermark{
        width:1000px;
        height:600px;
        margin: 0 auto;
    }
</style>

js文件代码

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 = 200; //设置水印之间的左右间距
    can.height = 150; //设置水印之间的上下间距

    let cans = can.getContext("2d");
    cans.rotate((-20 * Math.PI) / 180);
    cans.font = "20px 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;

实现效果