elementUI+react
布局
<Dialog title="充值" visible={ dialogVisible } onCancel={ () => this.setState({ dialogVisible: false }) } > <Dialog.Body> <Form labelWidth="120" ref={ e => {this.form=e} } model={ form } rules={ rules }> <Form.Item label="支付凭证" prop="voucher"> <div className="my-upload"> <input className="upload-input" type="file" id="input" name="file1" onChange={ this.inputfile } /> { voucher ? <img src={ voucher } className="avatar" /> : <i className="el-icon-plus avatar-uploader-icon" /> } </div> </Form.Item> </Form> </Dialog.Body> <Dialog.Footer className="dialog-footer"> <Button onClick={ () => this.setState({ dialogVisible: false }) }>{‘取 消‘}</Button> <Button type="primary" onClick={ this.saveContent } loading={ btnLoading }>{‘确 定‘}</Button> </Dialog.Footer> </Dialog>
完整方法:
beforeAvatarUpload(file) { const isJPG = file.type === ‘image/jpeg‘ const isLt2M = file.size / 1024 / 1024 < 2 if (!isJPG) { Message(‘上传头像图片只能是 JPG 格式!‘) } if (!isLt2M) { Message(‘上传头像图片大小不能超过 2MB!‘) } return isJPG && isLt2M } // input onchange上传方法 inputfile =()=> { const file1 = document.querySelector(‘#input‘).files[0] // const flag = this.beforeAvatarUpload(file1) // if(!flag){ // return false // } console.log(file1) const that=this if(file1){ var reader = new FileReader() // 图片文件转换为base64 reader.readAsDataURL(file1) reader.onload = function(){ // 显示图片 // document.getElementById(‘file1_img‘).src = this.result // that.setState({ // voucher:this.result // }) that.dealImage(this.result, 800, that.printing) } } } //回调方法 printing = base64 => { // console.log(‘压缩后‘, base64.length / 1024) this.setState({ voucher: base64 }) } //压缩方法 dealImage = (base64, w, callback) => { var newImage = new Image() //压缩系数0-1之间 var quality = 0.6 newImage.src = base64 newImage.setAttribute(‘crossOrigin‘, ‘Anonymous‘) //url为外域时需要 var imgWidth, imgHeight newImage.onload = function () { imgWidth = this.width imgHeight = this.height var canvas = document.createElement(‘canvas‘) var ctx = canvas.getContext(‘2d‘) if (Math.max(imgWidth, imgHeight) > w) { if (imgWidth > imgHeight) { canvas.width = w canvas.height = w * imgHeight / imgWidth } else { canvas.height = w canvas.width = w * imgWidth / imgHeight } } else { canvas.width = imgWidth canvas.height = imgHeight quality = 0.6 } ctx.clearRect(0, 0, canvas.width, canvas.height) ctx.drawImage(this, 0, 0, canvas.width, canvas.height) var ba = canvas.toDataURL(‘image/jpeg‘, quality) //压缩语句 // 如想确保图片压缩到自己想要的尺寸,如要求在50-150kb之间,请加以下语句,quality初始值根据情况自定 // while (base64.length / 1024 > 150) { // quality -= 0.01; // base64 = canvas.toDataURL("image/jpeg", quality); // } // 防止最后一次压缩低于最低尺寸,只要quality递减合理,无需考虑 // while (base64.length / 1024 < 50) { // quality += 0.001; // base64 = canvas.toDataURL("image/jpeg", quality); // } callback(ba) //必须通过回调函数返回,否则无法及时拿到该值 } }
原文地址:https://www.cnblogs.com/wang715100018066/p/11434214.html
时间: 2024-10-08 01:13:19