如何用Vue的class实现动态添加和移除水印效果？

本文共计540个文字，预计阅读时间需要3分钟。

页面添加水印的方法有很多，以下是一个使用class定义的示例，用于在内容中渲染水印：

javascript// 新建文件：WatermarkClass.jsexport default class WatermarkClass { constructor(id=watermarkID, str=, fontSize=18, width=100%) { this.id=id; this.str=str; this.fontSize=fontSize; this.width=width; }

render() { const container=document.createElement('div'); container.id=this.id; container.style.position='fixed'; container.style.top='0'; container.style.left='0'; container.style.width=this.width; container.style.height='100%'; container.style.display='flex'; container.style.justifyContent='center'; container.style.alignItems='center'; container.style.fontSize=this.fontSize + 'px'; container.style.color='rgba(0, 0, 0, 0.3)'; container.textContent=this.str;

document.body.appendChild(container); }}

页面添加水印的方法有很多，以下举例使用class定义的方法进行水印内容渲染：

1、新建文件：WatermarkClass.js

export default class WatermarkClass { constructor({id="watermarkID", str = "", fontSize = 18, width = 400, height = 400, fillStyle="#333333", opacity = 1 }) { this.id = id; this.str = str; this.fontSize = fontSize; this.width = width; this.height = height; this.fillStyle = fillStyle this.opacity = opacity; } // 绘制水印 draw() { if (document.getElementById(this.id) !== null) { document.body.removeChild(document.getElementById(this.id)); } const canvas = document.createElement("canvas"); // 设置canvas画布大小 canvas.width = this.width; canvas.height = this.height; const ctx = canvas.getContext("2d"); ctx.rotate(-(15 * Math.PI) / 180); // 水印旋转角度 ctx.font = `${this.fontSize}px Vedana`; ctx.fillStyle = this.fillStyle; ctx.textAlign = "center"; ctx.textBaseline = "middle"; this.str.split(",").forEach((item, index) => { ctx.fillText(item, canvas.width / 2, canvas.height / 2 + (index * this.fontSize + 10)); // 水印在画布的位置x，y轴 }); const div = document.createElement("div"); div.id = this.id; div.style.pointerEvents = "none"; div.style.top = "30px"; div.style.left = "10px"; div.style.opacity = this.opacity; div.style.position = "fixed"; div.style.zIndex = "999999"; div.style.width = `${document.documentElement.clientWidth}px`; div.style.height = `${document.documentElement.clientHeight}px`; div.style.background = `url(${canvas.toDataURL("image/png")}) left top repeat`; document.body.appendChild(div); } setOptions({fontSize = 18, width = 300, height = 300, opacity = 1, str = ""}) { this.fontSize = fontSize; this.width = width; this.height = height; this.fillStyle = fillStyle this.opacity = opacity; this.str = str; this.draw(); } // 绘制 render() { this.draw(); window.onresize = () => { this.draw(); }; } // 移除水印 removeWatermark() { if (document.getElementById(this.id) !== null) { document.body.removeChild(document.getElementById(this.id)); } } }

2、在页面种引入使用：

import watermarkClass from "@/libs/watermarkClass"; export default { name: "App", mounted: function () { this.initWatermark() }, methods: { initWatermark() { // 方法一 let watermark = new watermarkClass({ id: "watermarkID", str: "紫藤萝-watermarkClass", fontSize: 20, width: 300, height: 200, fillStyle: "#dddddd", opacity: 0.4, }); watermark.render(); // 5秒后，清除水印 setTimeout(() => { watermark.removeWatermark(); }, 5000); } }, };

以上就是vue 使用class创建和清除水印的示例代码的详细内容，更多关于vue 创建和清除水印的资料请关注易盾网络其它相关文章！