vue中添加文字或图片水印

'use strict'
 
var watermark = (className,str,type) =>{
    let dom =document.getElementsByClassName(className)
    let canvas = document.createElement('canvas')
    let cxt = canvas.getContext('2d')
    let div = document.createElement('div')
    
    let imgScale = 0.6canvas.width = 200
    if(type == 'text'){
      cxt.font = '16px Microsoft JhengHei'cxt.fillStyle = 'rgba(200, 200, 200, 0.3)'cxt.textAlign = 'left'cxt.textBaseline = 'Middle'cxt.fillText(str, 10, 50)
      cxt.clearRect(0, 0, canvas.width, canvas.height);
       div.style.background = 'url(' + canvas.toDataURL('image/png') + ') left top repeat'drawImage(div,dom)  
    }else{
        //创建新的图片对象
        let img = newImage();
        //指定图片的URL
        img.src =str;
        //浏览器加载图片完毕后再绘制图片
        img.onload = function() {
            //cxt.drawImage(img,0,0);
            cxt.rotate(-20 * Math.PI / 180)
            let whScale = img.width /img.height
            cxt.clearRect(0, 0, canvas.width, canvas.height);
             cxt.drawImage(img, //规定要使用的图像、画布或视频。
                            0, 0, //开始剪切的 x 坐标位置。
                            img.width, img.height,  //被剪切图像的高度。
                            0, 50,//在画布上放置图像的 x 、y坐标位置。
                            img.width * imgScale, img.height * imgScale  //要使用的图像的宽度、高度
)
            div.style.opacity = 0.3div.style.background = 'url(' + canvas.toDataURL('image/png') + ') left top repeat'drawImage(div,dom) 
        }
    }
}
var drawImage = function(div,dom) {
    div.style.pointerEvents = 'none'div.className = 'weterbox'div.style.top = 0div.style.left = 0div.style.position = 'absolute'div.style.zIndex = '100000'div.style.width = '100%'div.style.height = '100%'
    //console.log(dom) 
    if( dom.length > 0){
        for(let i = 0; i< dom.length;i++){
            let child = dom[i].getElementsByClassName('weterbox')
            if(child.length > 0){
                dom[i].removeChild(child[0])
            }
            dom[i].appendChild(div.cloneNode(true))
        //console.log(i,dom[i])
}
    }
}
 
export default watermark

watermark('需要添加水印的div元素的className','水印图片路径')
 

watermark('需要添加水印的div元素的className','水印文字'，'text')

.viewWeb{
		position: relative;
	}