使用react-cropper结合图片压缩方法对图片进行裁剪压缩处理

女爷i 2022-12-21 02:24 176阅读 0赞

最近项目要使用图片裁剪上传，因为项目采用的是react+antd，所以第一时间想到的是ImgCrop插件，但是这不满足项目需求，项目要求的是能够缩放裁剪框，最后确定了采用react-cropper来实现图片的自定义裁剪  
安装react-cropper  
`npm install --save react-cropper`  
新建一个CropperModal.jsx

import React, {  useState, useEffect, useCallback, useRef } from 'react'
    import PropTypes from 'prop-types'
    import Cropper from 'react-cropper' // 引入Cropper
    import 'cropperjs/dist/cropper.css' // 引入Cropper对应的css
    import {  Modal } from 'antd'
    
    function CropperModal({  uploadedImageFile, onClose, onSubmit, cropperModalVisible }) { 
        const [src, setSrc] = useState(uploadedImageFile)
        const cropperRef = useRef(null)
        const [cropperSrc, setCropperSrc] = useState(uploadedImageFile)
    
        // 裁剪
        function onCrop() { 
            setCropperSrc(this.cropper.getCroppedCanvas().toDataURL())
    
        }
        // 确定回传裁剪图片
        function handleSubmit() { 
            onSubmit(cropperSrc)
        }
        return (
            <Modal
                visible={ cropperModalVisible}
                onCancel={ onClose}
                onOk={ handleSubmit}
                maskClosable={ false}
            >
                <div className={ styles['cropper-container']}>
                    <Cropper
                        src={ src}
                        className="cropper"
                        ref={ cropperRef}
                        viewMode={ 1}
                        // initialAspectRatio={3}
                        zoomable={ true} // 是否缩放
                        guides={ false}
                        cropend={ onCrop} // 裁剪完成触发
                    // preview=".cropper-preview" // 预览框
                    />
                </div>
            </Modal>
        )
    }
    
    CropperModal.propTypes = { 
        uploadedImageFile: PropTypes.string.isRequired,
        onClose: PropTypes.func.isRequired,
        onSubmit: PropTypes.func.isRequired
    }
    
    export default CropperModal

上面代码会将裁剪图片的base64编码回传给父组件  
在父组件中

import React, {  useState, useEffect, useRef } from 'react';
    import {  Button, Modal, Input, Upload, message, Select, } from 'antd';
    import './index.less';
    import CropperModal from '@/components/CropperModal'
    import {  compressImage} from '@/utils/utils'
    
    const ToolsModal = props => { 
    	const {  dispatch, userInfo } = props;
        const [imgUrl, setImgUrl] = useState('')
        const toolModal = useRef(null);
        // 裁剪图片
        const [cropperSrc, setCropperSrc] = useState('')
        // 裁剪框
        const [cropperModalVisible, setCropperModalVisible] = useState(false)
    
        function getBase64(img, callback) { 
            const reader = new FileReader();
            reader.addEventListener('load', () => callback(reader.result));
            reader.readAsDataURL(img);
        }
        function beforeUpload(file) { 
            const isJpgOrPng = file.type === 'image/jpeg' || file.type === 'image/png' || file.type === 'image/x-icon';
            if (!isJpgOrPng) { 
                message.error('只支持上传JPG或PNG文件!');
            }
            const isLt2M = file.size / 1024 / 1024 < 2;
            if (!isLt2M) { 
                message.error('图片必须小于2M');
            }
            return isJpgOrPng && isLt2M;
        }
    
        // 上传logo
        const handleChange = info => { 
            setShow(false)
            if (info.file.status === 'done') { 
                getBase64(info.file.originFileObj, imageUrl => { 
                    setCropperSrc(imageUrl)
                    setCropperModalVisible(true)
                    // setImgUrl(imageUrl)
                });
            }
        };
    
        // 关闭裁剪modal
        function closeCropperModal() { 
            setCropperModalVisible(false)
        }
    
        // 裁剪回调
        function submitCropperModal(imgUrl) { 
            // console.log(imgUrl.length)
            setCropperModalVisible(false)
            // 压缩函数
            compressImage(imgUrl, 200, useImg)
        }
    
        // 压缩回调+
        function useImg(base64) { 
            setImgUrl(base64)
        }
        return (
            <Modal>
                <div className='tool-content' ref={ toolModal}>
                    <div className='tool-logo'>
                        <div className='name'>工具logo</div>
                        <div className='content' style={ {  position: 'relative', height: 150 }}>
                            <div className='logo'>
                                <div className='logo-preview'>
                                    <img src={ objVal.icon ? objVal.icon : clue} alt="" />
                                    <Button
                                        className='logo-edit'
                                        onClick={ showIconList}
                                        icon={ <EditOutlined />}></Button>
                                </div>  
                            </div>
                            <Upload
                                method='get'
                                className='btn'
                                name='file'
                                listType='picture'
                                accept={ 'image/*'}
                                beforeUpload={ beforeUpload}
                                onChange={ handleChange}
                                showUploadList={ false}
                            >
                                <Button>自定义logo上传</Button>
                            </Upload>
                        </div>
                    </div>
                  </div>
    
                { 
                    cropperModalVisible ?
                        <CropperModal
                            uploadedImageFile={ cropperSrc}
                            onClose={ closeCropperModal}
                            onSubmit={ submitCropperModal}
                            cropperModalVisible={ cropperModalVisible}
                        />
                        : null
                }
            </Modal>
        )
    }
    export default connect(({  }) => ({ 
    }))(ToolsModal)

utils.js

//图片压缩函数
    /* base64: 图片base64编码 w：默认宽度 callback： 回调函数，及时监听压缩后的base64编码 */
    export function compressImage(base64, w, callback) { 
      var newImage = new Image();
      var quality = 0.5; //压缩系数0-1之间
      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 = 0.5;
        }
        ctx.clearRect(0, 0, canvas.width, canvas.height);
        // 在canvas绘制前填充白色背景
        ctx.fillStyle = '#fff';
        ctx.fillRect(0, 0, canvas.width, canvas.height);
    
        ctx.drawImage(this, 0, 0, canvas.width, canvas.height);
        var base64 = 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(base64); //必须通过回调函数返回，否则无法及时拿到该值
      };
    }

到这里就完成了对上传图片的裁剪以及压缩