用vue的项目里需要对图片进行裁剪，于是使用了cropperjs，在使用的过程中也踩过一些坑，以下是在.vue文件里cropperjs的使用方法和经验教训总结：
在使用之前，先引入：
在项目里，运行：
npm install cropperjs -save
在template里：
<div> <!-- 遮罩层 --> <div v-show="panel"> <div> <img :src="url" alt="Picture"> </div> <button type="button" @click="crop">确定</button> </div> <div> <div> <div :style="'backgroundImage:url('+headerImage+')'"> </div> </div> <div> <input type="file" accept="image" @change="change"> <label for="change"></label> </div> </div> </div>
js代码：
import Cropper from 'cropperjs' export default { components: { }, data () { return { headerImage:'', picValue:'', cropper:'', croppable:false, panel:false, url:'' } }, mounted () { //初始化这个裁剪框 var self = this; var image = document.getElementById('image'); this.cropper = new Cropper(image, { aspectRatio: 1, viewMode: 1, background:false, zoomable:false, ready: function () { self.croppable = true; } }); }, methods: { getObjectURL (file) { var 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 ; }, change (e) { let files = e.target.files || e.dataTransfer.files; if (!files.length) return; this.panel = true; this.picValue = files[0]; this.url = 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.url); } this.panel = true; }, crop () { this.panel = false; var croppedCanvas; var roundedCanvas; if (!this.croppable) { return; } // Crop croppedCanvas = this.cropper.getCroppedCanvas(); console.log(this.cropper) // Round roundedCanvas = this.getRoundedCanvas(croppedCanvas); this.headerImage = roundedCanvas.toDataURL(); this.postImg() }, getRoundedCanvas (sourceCanvas) { var canvas = document.createElement('canvas'); var context = canvas.getContext('2d'); var width = sourceCanvas.width; var 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.arc(width / 2, height / 2, Math.min(width, height) / 2, 0, 2 * Math.PI, true); context.fill(); return canvas; }, postImg () { //这边写图片的上传 } } }
整体效果：
css代码（比较长，本来想不贴上了，但是为了一下童鞋可以直接运行demo，还是贴上了，篇幅过长，望见谅）：
*{ margin: 0; padding: 0; } #demo #button { position: absolute; right: 10px; top: 10px; width: 80px; height: 40px; border:none; border-radius: 5px; background:white; } #demo .show { width: 100px; height: 100px; overflow: hidden; position: relative; border-radius: 50%; border: 1px solid #d5d5d5; } #demo .picture { width: 100%; height: 100%; overflow: hidden; background-position: center center; background-repeat: no-repeat; background-size: cover; } #demo .container { z-index: 99; position: fixed; padding-top: 60px; left: 0; top: 0; right: 0; bottom: 0; background:rgba(0,0,0,1); } #demo #image { max-width: 100%; } .cropper-view-box,.cropper-face { border-radius: 50%; } /*! * Cropper.js v1.0.0-rc * https://github.com/fengyuanchen/cropperjs * * Copyright (c) 2017 Fengyuan Chen * Released under the MIT license * * Date: 2017-03-25T12:02:21.062Z */ .cropper-container { font-size: 0; line-height: 0; position: relative; -webkit-user-select: none; -moz-user-select: none; -ms-user-select: none; user-select: none; direction: ltr; -ms-touch-action: none; touch-action: none } .cropper-container img { /* Avoid margin top issue (Occur only when margin-top <= -height) */ display: block; min-width: 0 !important; max-width: none !important; min-height: 0 !important; max-height: none !important; width: 100%; height: 100%; image-orientation: 0deg } .cropper-wrap-box, .cropper-canvas, .cropper-drag-box, .cropper-crop-box, .cropper-modal { position: absolute; top: 0; right: 0; bottom: 0; left: 0; } .cropper-wrap-box { overflow: hidden; } .cropper-drag-box { opacity: 0; background-color: #fff; } .cropper-modal { opacity: .5; background-color: #000; } .cropper-view-box { display: block; overflow: hidden; width: 100%; height: 100%; outline: 1px solid #39f; outline-color: rgba(51, 153, 255, 0.75); } .cropper-dashed { position: absolute; display: block; opacity: .5; border: 0 dashed #eee } .cropper-dashed.dashed-h { top: 33.33333%; left: 0; width: 100%; height: 33.33333%; border-top-width: 1px; border-bottom-width: 1px } .cropper-dashed.dashed-v { top: 0; left: 33.33333%; width: 33.33333%; height: 100%; border-right-width: 1px; border-left-width: 1px } .cropper-center { position: absolute; top: 50%; left: 50%; display: block; width: 0; height: 0; opacity: .75 } .cropper-center:before, .cropper-center:after { position: absolute; display: block; content: ' '; background-color: #eee } .cropper-center:before { top: 0; left: -3px; width: 7px; height: 1px } .cropper-center:after { top: -3px; left: 0; width: 1px; height: 7px } .cropper-face, .cropper-line, .cropper-point { position: absolute; display: block; width: 100%; height: 100%; opacity: .1; } .cropper-face { top: 0; left: 0; background-color: #fff; } .cropper-line { background-color: #39f } .cropper-line.line-e { top: 0; right: -3px; width: 5px; cursor: e-resize } .cropper-line.line-n { top: -3px; left: 0; height: 5px; cursor: n-resize } .cropper-line.line-w { top: 0; left: -3px; width: 5px; cursor: w-resize } .cropper-line.line-s { bottom: -3px; left: 0; height: 5px; cursor: s-resize } .cropper-point { width: 5px; height: 5px; opacity: .75; background-color: #39f } .cropper-point.point-e { top: 50%; right: -3px; margin-top: -3px; cursor: e-resize } .cropper-point.point-n { top: -3px; left: 50%; margin-left: -3px; cursor: n-resize } .cropper-point.point-w { top: 50%; left: -3px; margin-top: -3px; cursor: w-resize } .cropper-point.point-s { bottom: -3px; left: 50%; margin-left: -3px; cursor: s-resize } .cropper-point.point-ne { top: -3px; right: -3px; cursor: ne-resize } .cropper-point.point-nw { top: -3px; left: -3px; cursor: nw-resize } .cropper-point.point-sw { bottom: -3px; left: -3px; cursor: sw-resize } .cropper-point.point-se { right: -3px; bottom: -3px; width: 20px; height: 20px; cursor: se-resize; opacity: 1 } @media (min-width: 768px) { .cropper-point.point-se { width: 15px; height: 15px } } @media (min-width: 992px) { .cropper-point.point-se { width: 10px; height: 10px } } @media (min-width: 1200px) { .cropper-point.point-se { width: 5px; height: 5px; opacity: .75 } } .cropper-point.point-se:before { position: absolute; right: -50%; bottom: -50%; display: block; width: 200%; height: 200%; content: ' '; opacity: 0; background-color: #39f } .cropper-invisible { opacity: 0; } .cropper-bg { background-image: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQAQMAAAAlPW0iAAAAA3NCSVQICAjb4U/gAAAABlBMVEXMzMz////TjRV2AAAACXBIWXMAAArrAAAK6wGCiw1aAAAAHHRFWHRTb2Z0d2FyZQBBZG9iZSBGaXJld29ya3MgQ1M26LyyjAAAABFJREFUCJlj+M/AgBVhF/0PAH6/D/HkDxOGAAAAAElFTkSuQmCC'); } .cropper-hide { position: absolute; display: block; width: 0; height: 0; } .cropper-hidden { display: none !important; } .cropper-move { cursor: move; } .cropper-crop { cursor: crosshair; } .cropper-disabled .cropper-drag-box, .cropper-disabled .cropper-face, .cropper-disabled .cropper-line, .cropper-disabled .cropper-point { cursor: not-allowed; }
整体图：
把以上这些代码放入你的项目，或者单独建个.vue放进项目，就可以实现这样的效果：
总结