let watermark = {}
let setWatermark = str => {
let id = '1.23452384164.123412416';
if (document.getElementById(id) !== null) {
document.body.removeChild(document.getElementById(id));
}
//创建一个画布
let can = document.createElement('canvas');
//设置画布的长宽
can.width = 120;
can.height = 120;
let cans = can.getContext('2d');
//旋转角度
cans.rotate(-15 * Math.PI / 180);
cans.font = '18px Vedana';
//设置填充绘画的颜色、渐变或者模式
cans.fillStyle = 'rgba(200,200,0.40)';
//设置文本内容的当前对齐方式
cans.textAlign = 'left';
//设置在绘制文本时使用的当前文本基线
cans.textBaseline = 'Middle';
//在画布上绘制填色的文本(输出的文本,开始绘制文本的X坐标位置,开始绘制文本的Y坐标位置)
cans.fillText(str,can.width / 8,can.height / 2);
let div = document.createElement('div');
div.id = id;
div.style.pointerEvents = 'none';
div.style.top = '30px';
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;
二,需要加水印的.vue页面中
<script>
import Watermark from '@/config/watermark';
export default {
mounted() {
Watermark.set(this.userName);
},destroyed() {
Watermark.set('');
}
data() {
return {
// 用户名存在vuex中
userName: this.$store.state.username|| "水印",}
}
}
</script>