我使用的是vue，移动端的项目。
官网地址：cropperjs
GitHub地址：https://github.com/fengyuanchen/cropperjs/blob/master/README.md
先看效果图，不然没有吸引力啊！！哈哈
这里只记录使用方法，至于怎么实现和要修改一些参数，大家前往官网api了解。
首先我们先安装 npm install cropperjs exif-js
新建一个文件 存放cropperjs 处理图片的方法
import Cropper from 'cropperjs'
import Exif from 'exif-js'
export default {
install( Vue ){
//初始化方法
Vue.prototype.initilize = function( opt ){
let self = this;
this.options = opt;
//创建dom
this.createElement();
this.resultObj = opt.resultObj;
//初始化裁剪对象
this.cropper = new Cropper( this.preview , {
aspectRatio : opt.aspectRatio || 1 ,
autoCropArea : opt.autoCropArea || 0.8 ,
viewMode : 1,
guides : opt.aspectRatio == 'Free' ? false : true ,
cropBoxResizable : opt.aspectRatio == 'Free' ? false : true ,
cropBoxMovable : opt.aspectRatio == 'Free' ? false : true ,
dragCrop : opt.aspectRatio == 'Free' ? false : true ,
background : false,
checkOrientation : true ,
checkCrossOrigin : true ,
zoomable : false,
zoomOnWheel : false ,
center : false ,
toggleDragModeOnDblclick : false ,
ready : function () {
// console.log(self.cropper.rotate(90))
if( opt.aspectRatio == 'Free' ){
let cropBox = self.cropper.cropBox;
cropBox.querySelector('span.cropper-view-box').style.outline = 'none';
self.cropper.disable();
}
}
});
}
//创建一些必要的DOM，用于图片裁剪
Vue.prototype.createElement = function () {
//初始化图片为空对象
this.preview = null;
let str = '<div><img id="clip_image" src="originUrl"></div><button type="button" id="cancel_clip">取消</button><button type="button" id="clip_button">确定</button>';
str+= '<div class="crop_loading"><div class="crop_content"><img src="../static/loading.gif"><div class="crop_text">图片上传中</div></div></div>';
str+= '<div class="crop_success"><div class="crop_success_text">上传成功</div></div></div>';
let body = document.getElementsByTagName('body')[0];
this.reagion = document.createElement('div');
this.reagion.id = 'clip_container';
this.reagion.className = 'container';
this.reagion.innerHTML = str;
//添加创建好的DOM元素
body.appendChild(this.reagion);
this.preview = document.getElementById('clip_image');
//绑定一些方法
this.initFunction();
}
//初始化一些函数绑定
Vue.prototype.initFunction = function () {
let self =this;
this.clickBtn = document.getElementById('clip_button');
this.cancelBtn = document.getElementById('cancel_clip');
//确定事件
this.addEvent( this.clickBtn , 'click' , function () {
self.crop();
})
//取消事件
this.addEvent( this.cancelBtn , 'click' , function () {
self.destoried();
})
//清空input的值
this.addEvent( this.fileObj , 'click' , function () {
this.value = '';
})
}
//外部接口，用于input['file']对象change时的调用
Vue.prototype.clip = function ( e , opt ) {
let self = this;
this.fileObj = e.srcElement;
let files = e.target.files || e.dataTransfer.files;
if (!files.length) return false; //不是图片直接返回
//调用初始化方法
this.initilize( opt );
//获取图片文件资源
this.picValue = files[0];
//去获取拍照时的信息，解决拍出来的照片旋转问题
// Exif.getData( files[0] , function(){
// self.Orientation = Exif.getTag( files[0], 'Orientation');
// console.log(self.Orientation)
// });
//调用方法转成url格式
this.originUrl = this.getObjectURL( this.picValue );
//每次替换图片要重新得到新的url
if(this.cropper){
this.cropper.replace(this.originUrl);
}
}
//图片转码方法
Vue.prototype.getObjectURL = function(file) {
let url = null ;
if (window.createObjectURL!=undefined) { // basic
url = window.createObjectURL(file) ;
} else if (window.URL!=undefined) { // mozilla(firefox)
url = window.URL.createObjectURL(file) ;
} else if (window.webkitURL!=undefined) { // webkit or chrome
url = window.webkitURL.createObjectURL(file) ;
}
return url ;
}
//点击确定进行裁剪
Vue.prototype.crop = function () {
let self = this;
let image = new Image();
let croppedCanvas;
let roundedCanvas;
// Crop
document.querySelector('.crop_loading').style.display = 'block';
setTimeout(function () {
croppedCanvas = self.cropper.getCroppedCanvas();
// Round
roundedCanvas = self.getRoundedCanvas(croppedCanvas);
let imgData = roundedCanvas.toDataURL();
image.src = imgData;
//判断图片是否大于100k,不大于直接上传，反之压缩
if( imgData.length < (100 * 1024) ){
self.resultObj.src = imgData;
//图片上传
self.postImg( imgData );
}else{
image.onload = function () {
//压缩处理
let data = self.compress( image , self.Orientation );
self.resultObj.src = data;
//图片上传
self.postImg( data );
}
}
},20)
}
//获取裁剪图片资源
Vue.prototype.getRoundedCanvas = function(sourceCanvas) {
let canvas = document.createElement('canvas');
let context = canvas.getContext('2d');
let width = sourceCanvas.width;
let height = sourceCanvas.height;
canvas.width = width;
canvas.height = height;
context.imageSmoothingEnabled = true;
context.drawImage(sourceCanvas, 0, 0, width, height);
context.globalCompositeOperation = 'destination-in';
context.beginPath();
context.rect(0 , 0 , width , height );
context.fill();
return canvas;
}
//销毁原来的对象
Vue.prototype.destoried = function () {
let self = this;
//移除事件
this.removeEvent( this.clickBtn , 'click' , null );
this.removeEvent( this.cancelBtn , 'click' , null );
this.removeEvent( this.fileObj , 'click' , null );
//移除裁剪框
this.reagion.parentNode.removeChild(this.reagion);
//销毁裁剪对象
this.cropper.destroy();
this.cropper = null;
}
//图片上传
Vue.prototype.postImg = function( imageData ) {
//这边写图片的上传
let self = this;
self.destoried();
window.setTimeout( function () {
document.querySelector('.crop_loading').style.display = 'none';
document.querySelector('.crop_success').style.display = 'block';
//裁剪完后摧毁对象
self.destoried();
},3000)
}
//图片旋转
Vue.prototype.rotateImg = function( img , direction , canvas ) {
//最小与最大旋转方向，图片旋转4次后回到原方向
const min_step = 0;
const max_step = 3;
if (img == null )return;
//img的高度和宽度不能在img元素隐藏后获取，否则会出错
let height = img.height;
let width = img.width;
let step = 2;
if (step == null) {
step = min_step;
}
if ( direction == 'right') {
step++;
//旋转到原位置，即超过最大值
step > max_step && (step = min_step);
} else {
step--;
step < min_step && (step = max_step);
}
//旋转角度以弧度值为参数
let degree = step * 90 * Math.PI / 180;
let ctx = canvas.getContext('2d');
switch (step) {
case 0:
canvas.width = width;
canvas.height = height;
ctx.drawImage(img, 0, 0);
break;
case 1:
canvas.width = height;
canvas.height = width;
ctx.rotate(degree);
ctx.drawImage(img, 0, -height);
break;
case 2:
canvas.width = width;
canvas.height = height;
ctx.rotate(degree);
ctx.drawImage(img, -width, -height);
break;
case 3:
canvas.width = height;
canvas.height = width;
ctx.rotate(degree);
ctx.drawImage(img, -width, 0);
break;
}
}
//图片压缩
Vue.prototype.compress = function ( img , Orientation ) {
let canvas = document.createElement("canvas");
let ctx = canvas.getContext('2d');
//瓦片canvas
let tCanvas = document.createElement("canvas");
let tctx = tCanvas.getContext("2d");
let initSize = img.src.length;
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) {
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);
}
//修复ios上传图片的时候 被旋转的问题
if( Orientation != "" && Orientation != 1){
switch(Orientation){
case 6://需要顺时针（向左）90度旋转
this.rotateImg(img,'left',canvas);
break;
case 8://需要逆时针（向右）90度旋转
this.rotateImg(img,'right',canvas);
break;
case 3://需要180度旋转
this.rotateImg(img,'right',canvas);//转两次
this.rotateImg(img,'right',canvas);
break;
}
}
//进行最小压缩
let ndata = canvas.toDataURL( 'image/jpeg' , 0.1);
console.log('压缩前：' + initSize);
console.log('压缩后：' + ndata.length);
console.log('压缩率：' + ~~(100 * (initSize - ndata.length) / initSize) + "%");
tCanvas.width = tCanvas.height = canvas.width = canvas.height = 0;
return ndata;
}
//添加事件
Vue.prototype.addEvent = function ( obj , type , fn ) {
if( obj.addEventListener ){
obj.addEventListener( type , fn , false );
}else{
obj.attachEvent( 'on' + type , fn );
}
}
//移除事件
Vue.prototype.removeEvent = function ( obj , type , fn ) {
if( obj.removeEventListener ){
obj.removeEventListener( type , fn , false );
}else{
obj.detachEvent( 'on' + type , fn );
}
}
}
}
组件中调用cropperjs的方法
<template>
<div class="hello">
<img src="./assets/upload.png" alt="" id="img">
<input type="file" accept="image/jpeg,image/png,image/jpeg" @change="change($event)">
</div>
</template>
<script>
export default{
data(){
return{
}
},
methods:{
change(event){
let image=document.getElementById('img');
this.clip(event,{
resultObj:image,
aspectRatio:1,
})
}
}
}
</script>
恭喜你又成功，搬运了一次代码！！！