vue+vant图片压缩后上传
![在这里插入图片描述](https://img-blog.csdnimg.cn/8707c74cf3804c08a4763f81099cda7f.png)
vue文件写入
<template>
<div class="home">
<van-field input-align="left">
<template #input>
<van-uploader
v-model="fileList.file"
:after-read="afterRead"
:max-count="5"
:preview-image="true"
/>
</template>
</van-field>
</div>
</template>
<script>
import { compressImg } from '@/utils'
export default {
components: {},
data() {
return {
fileList: { file: [], imgs: [] },
}
},
computed: {},
mounted() {},
methods: {
afterRead() {
this.fileList.imgs = []
this.fileList.file.forEach((item) => {
let img = new Image()
img.src = item.content
img.onload = () => {
this.fileList.imgs.push(compressImg(img))
}
})
console.log(this.fileList);
},
},
}
</script>
<style lang="scss" scoped>
.home {
}
.flex {
display: flex;
}
.flex-s {
display: flex;
justify-content: space-between;
}
</style>
在utils文件夹下的index中写入 图片压缩代码
/**
* @description: 图片压缩
* @param {*} img
* @return {*}
*/
export const compressImg = (img) => {
let canvas = document.createElement('canvas')
let ctx = canvas.getContext('2d')
let tCanvas = document.createElement('canvas')
let tctx = tCanvas.getContext('2d')
let width = img.width
let height = img.height
//如果图片大于四百万像素,计算压缩比并将大小压至400万以下
let ratio
if ((ratio = (width * height) / 4000000) > 1) {
console.log('大于400万像素')
ratio = Math.sqrt(ratio)
width /= ratio
height /= ratio
} else {
ratio = 1
}
canvas.width = width
canvas.height = height
// 铺底色
ctx.fillStyle = '#fff'
ctx.fillRect(0, 0, canvas.width, canvas.height)
//如果图片像素大于100万则使用瓦片绘制
let count
if ((count = (width * height) / 1000000) > 1) {
console.log('超过100W像素')
count = ~~(Math.sqrt(count) + 1) //计算要分成多少块瓦片
// 计算每块瓦片的宽和高
let nw = ~~(width / count)
let nh = ~~(height / count)
tCanvas.width = nw
tCanvas.height = nh
for (let i = 0; i < count; i++) {
for (let j = 0; j < count; j++) {
tctx.drawImage(
img,
i * nw * ratio,
j * nh * ratio,
nw * ratio,
nh * ratio,
0,
0,
nw,
nh
)
ctx.drawImage(tCanvas, i * nw, j * nh, nw, nh)
}
}
} else {
ctx.drawImage(img, 0, 0, width, height)
}
//进行最小压缩
let minData = canvas.toDataURL('image/jpeg', 0.1)
tCanvas.width = tCanvas.height = canvas.width = canvas.height = 0
return minData
}