vue网络图片url转Base64「建议收藏」

<script>
methods: { 

//异步执行
imageUrlToBase64() { 

//一定要设置为let，不然图片不显示
let image = new Image();
//解决跨域问题
image.setAttribute('crossOrigin', 'anonymous');
let imageUrl = "http://bigf.cqugeo.cn/landslip/res/defaultImages/default.png";
image.src = imageUrl
//image.onload为异步加载
image.onload = () => { 

var canvas = document.createElement("canvas");
canvas.width = image.width;
canvas.height = image.height;
var context = canvas.getContext('2d');
context.drawImage(image, 0, 0, image.width, image.height);
var quality = 0.8;
//这里的dataurl就是base64类型
var dataURL = canvas.toDataURL("image/jpeg", quality);//使用toDataUrl将图片转换成jpeg的格式,不要把图片压缩成png，因为压缩成png后base64的字符串可能比不转换前的长！
}
},
}
</script>

<script>
data() { 

return { 

base64Datas: [],
}
methods: { 

imageUrlToBase64(){ 

let data = [
"http://bigf.cqugeo.cn/landslip/res/defaultImages/default.png",
"http://bigf.cqugeo.cn/landslip/res/defaultImages/default.png",
"http://bigf.cqugeo.cn/landslip/res/defaultImages/default.png"
]
this.onloadImg(data, 1, data.length);
},
//采用递归同步执行
onloadImg(data, i, len) { 

//一定要设置为let，不然图片不显示
let image = new Image();
//解决跨域问题
image.setAttribute('crossOrigin', 'anonymous');
let imageUrl = "http://bigf.cqugeo.cn/landslip/res/defaultImages/default.png";
image.src = imageUrl
let that = this;
//image.onload为异步加载
image.onload = () => { 

var canvas = document.createElement("canvas");
canvas.width = image.width;
canvas.height = image.height;
var context = canvas.getContext('2d');
context.drawImage(image, 0, 0, image.width, image.height);
var quality = 0.8;
//这里的dataurl就是base64类型
var dataURL = canvas.toDataURL("image/jpeg", quality);//使用toDataUrl将图片转换成jpeg的格式,不要把图片压缩成png，因为压缩成png后base64的字符串可能比不转换前的长！
//数组存放图片base64
that.base64Datas.push(dataURL);
//递归执行图片url转base64
i = i + 1;
if (i <= len) { 

that.onloadImg(data1, i, len)
}
}
},
}
</script>