日常业务开发中,无论是后台管理系统还是前台界面,都会遇到图片裁剪的业务需求,选择合适的尺寸或者图片的关键部分,满足我们的功能需求!!
效果预览
效果一:
效果二:
实现过程
1.原生js实现方式
引入cropperjs的库文件和样式
<script src="https://cdn.jsdelivr.net/npm/cropperjs/dist/cropper.js"></script>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/cropperjs/dist/cropper.css" rel="external nofollow" >
*{
padding: 0;
margin: 0;
box-sizing: border-box;
font-family: "Poppins",sans-serif;
}
body{
background-color: #025bee;
}
.wrapper{
width: min(90%,800px);
position: absolute;
transform: translateX(-50%);
left:50%;
top:1em;
background-color: #fff;
padding: 2em 3em;
border-radius: .5em;
}
.container{
display: grid;
grid-template-columns: 1fr 1fr;
gap:1em;
}
.container .image-container,.container .preview-container{
width: 100%;
/* background-color: aquamarine; */
}
input[type="file"]{
display: none;
}
label{
display: block;
position: relative;
background-color: #025bee;
font-size: 16px;
text-align: center;
width: 250px;
color:#fff;
padding: 16px 0;
margin: 16px auto;
cursor: pointer;
border-radius: 5px;
}
img{
display: block;
/**is key to cropper.js**/
max-width: 100%;
}
.image-container{
width: 60%;
margin: 0 auto;
}
.options{
display: flex;
justify-content: center;
gap:1em;
}
input[type="number"]{
width: 100px;
padding: 16px 5px;
border-radius: .3em;
border: 2px solid #000;
}
button{
padding: 1em;
border-radius: .3em;
border: 2px solid #025bee;
background-color: #fff;
color: #025bee;
}
.btns{
display: flex;
justify-content: center;
gap: 1em;
margin-top: 1em;
}
.btns button{
font-size: 1em;
}
.btns a {
border: 2px solid #025bee;
background-color: #025bee;
color: #fff;
text-decoration: none;
padding: 1em;
font-size: 1em;
border-radius: .3em;
}
.hide{
display: none;
}
<div class="wrapper">
<div class="container">
<div class="image-container">
<img src="" alt="" id="image">
</div>
<div class="preview-container">
<img src="" alt="" id="preview-image">
</div>
</div>
<input type="file" name="" id="file" accept="image/*">
<label for="file">选择一张图片</label>
<div class="options hide">
<input type="number" name="" id="height-input" placeholder="输入高度" max="780" min="0">
<input type="number" name="" id="width-input" placeholder="输入宽度" max="780" min="0">
<button class="aspect-ration-button">16:9</button>
<button class="aspect-ration-button">4:3</button>
<button class="aspect-ration-button">1:1</button>
<button class="aspect-ration-button">2:3</button>
<button class="aspect-ration-button">自由高度</button>
</div>
<div class="btns">
<button id="preview" class="hide">
预览
</button>
<a href="" id="download" class="hide">下载</a>
</div>
</div>
核心步骤:
<script>
const oFile = document.querySelector('#file')
const oImage = document.querySelector('#image')
const oDownload = document.querySelector('#download')
const oAspectRation = document.querySelectorAll('.aspect-ration-button')
const oOptions = document.querySelector('.options')
const oPreview = document.querySelector('#preview-image')
const oPreviewBtn = document.querySelector('#preview')
const heightInput = document.querySelector('#height-input')
const widthInput = document.querySelector('#width-input')
let cropper = '',filename = ''
/**
* 上传事件
*
* /
*/
oFile.onchange = function(e){
oPreview.src=""
heightInput.value = 0
widthInput.value = 0
oDownload.classList.add('hide')
const reader = new FileReader()
reader.readAsDataURL(e.target.files[0])
reader.onload = function(e){
oImage.setAttribute('src',e.target.result)
if(cropper){
cropper.destory()
}
cropper = new Cropper(oImage)
oOptions.classList.remove('hide')
oPreviewBtn.classList.remove('hide')
}
filename = oFile.files[0].name.split(".")[0]
oAspectRation.forEach(ele => {
ele.addEventListener('click', () => {
if(ele.innerText === '自由高度'){
cropper.setAspectRatio(NaN)
}else{
cropper.setAspectRatio(eval(ele.innerText.replace(":",'/')))
}
}, false)
})
heightInput.addEventListener('input', () => {
const {height} = cropper.getImageData()
if(parseInt(heightInput.value) > Math.round(height)){
heightInput.value = Math.round(height)
}
let newHeight = parseInt(heightInput.value)
cropper.setCropBoxData({
height:newHeight
})
}, false)
widthInput.addEventListener('input', () => {
const {width} = cropper.getImageData()
if(parseInt(widthInput.value) > Math.round(width)){
widthInput.value = Math.round(width)
}
let newWidth = parseInt(widthInput.value)
cropper.setCropBoxData({
width:newWidth
})
}, false)
oPreviewBtn.addEventListener('click', (e) => {
e.preventDefault();
oDownload.classList.remove('hide');
let imgSrc = cropper.getCroppedCanvas({}).toDataURL();
oPreview.src = imgSrc;
oDownload.download = `cropped_${filename}.png`;
oDownload.setAttribute('href',imgSrc)
}, false)
}
</script>
- vue2+elementui实现
安装vue-cropper库
npm i vue-cropper
静态页面
<template>
<g-container>
<div>
<span>点击头像,更换头像:</span>
<el-avatar @click.native="handleShowCropper" :src="avatarUrl"></el-avatar>
</div>
<el-dialog
title="更换头像"
:visible.sync="dialogVisible"
width="800px"
:before-close="dialogBeforeClose"
v-if="dialogVisible"
append-to-body
>
<el-row :gutter="10">
<el-col :span="12" :style="{ height: '350px' }">
<vueCropper
ref="cropper"
:img="option.img"
:info="true"
:auto-crop="option.autoCrop"
:outputSize="option.size"
:outputType="option.outputType"
@realTime="realTime"
centerBox
></vueCropper>
</el-col>
<el-col :span="12" class="preview-container">
<div class="avatar-upload-preview">
<div :style="previews.div">
<img :src="previews.url" :style="previews.img" />
</div>
</div>
</el-col>
</el-row>
<el-row :gutter="10" style="margin-top:20px;text-align:center" justify="center">
<el-col :span="4">
<el-upload
action
name="file"
accept="image/*"
:before-upload="beforeUpload"
:show-upload-list="false"
>
<el-button icon="upload">选择图片</el-button>
</el-upload>
</el-col>
<el-col :span="3">
<el-button type="primary" @click="changeScale(1)">放大</el-button>
</el-col>
<el-col :span="3">
<el-button type="primary" @click="changeScale(-1)">缩小</el-button>
</el-col>
<el-col :span="3">
<el-button type="primary" @click="rotateLeft">左旋转</el-button>
</el-col>
<el-col :span="3">
<el-button type="primary" @click="rotateRight">右旋转</el-button>
</el-col>
<el-col :span="3">
<el-button type="primary" @click="saveHandle('blob')">保存</el-button>
</el-col>
</el-row>
<div slot="footer">
<el-button @click="dialogVisible = false">取 消</el-button>
<el-button type="primary" @click="dialogVisible = false">确 定</el-button>
</div>
</el-dialog>
</g-container>
</template>
关键的js代码实现
export default {
components: {
VueCropper,
},
data() {
return {
option: { img: "", size: 1, outputType: "", autoCrop: true },
dialogVisible: false,
previews: {},
avatarUrl:
"https://cube.elemecdn.com/0/88/03b0d39583f48206768a7534e55bcpng.png",
};
},
methods: {
handleShowCropper() {
this.dialogVisible = true;
},
dialogBeforeClose() {
this.dialogVisible = false;
},
changeScale(num) {
this.$refs.cropper.changeScale(num);
},
// 左旋转
rotateLeft() {
this.$refs.cropper.rotateLeft();
},
// 右旋转
rotateRight() {
this.$refs.cropper.rotateRight();
},
beforeUpload(file) {
console.log("🚀 ~ beforeUpload ~ file:", file);
const reader = new FileReader();
//转化为base64
reader.readAsDataURL(file);
reader.onload = () => {
console.log(reader, "reader");
// this.previews.url = reader.result;
this.option.img = reader.result;
};
},
// 裁剪之后的数据
realTime(data) {
console.log("🚀 ~ realTime ~ data:", data);
this.previews = data;
},
// 上传图片(点击保存按钮)
saveHandle(type) {
this.$refs.cropper.getCropData((data) => {
this.dialogVisible = false;
console.log(data);
// data为base64图片,供接口使用
this.avatarUrl = data;
this.$emit("save", data);
});
},
beforeDestory() {
this.previews = null;
this.option = null;
},
},
};
</script>
组件的option配置项,大家可以去逐个测试下,体验下效果!!
这样,我们就实现了两种不同的图像裁剪上传!!
附上参考资料:Cropperjs官网