reactjs - 通过 react-image-crop 模块获取裁剪图像

Question

你能帮我如何通过 react-image-crop 模块获得输出(裁剪图像的来源)吗？
上传组件如下所示:

class MyUpload extends Component {
constructor() {
    super();
    this.state = {
        src: 'source-to-image',
        crop: {
            x: 10,
            y: 10,
            aspect: 9 / 16,
            width: 100
        }
    }
}

onCropComplete = (crop, pixelCrop) => {
    this.setState({
        crop
    })
};

render() {
    return (
           <ReactCrop
                    src={this.state.src}
                    onComplete={this.onCropComplete}
                />
    );
} }

onCropComplete 方法只返回裁剪图像的坐标、宽度和高度，而不是源。我想获取 blob 文件。

编辑(工作解决方案——感谢 Mosè Raguzzini 的回复):

如果有人遇到类似问题，请从组件中的教程中调用 getCropptedImg 函数，并从返回的 Blob 对象创建 url，如下所示:

getCroppedImg(this.state.image, pixelCrop, 'preview.jpg')
            .then((res) => {
                const blobUrl = URL.createObjectURL(res);
                console.log(blobUrl); // it returns cropped image in this shape of url: "blob:http://something..."
            })

Answer 1

react-image-crop 不是用来产生 blob，只是用来裁剪图像内联。可能你需要像 https://foliotek.github.io/Croppie/ 这样的东西

更新:
检查“如何在客户端显示裁剪？”部分在底部
https://www.npmjs.com/package/react-image-crop , 该 blob 可作为隐藏功能使用

/**
 * @param {File} image - Image File Object
 * @param {Object} pixelCrop - pixelCrop Object provided by react-image-crop
 * @param {String} fileName - Name of the returned file in Promise
 */
function getCroppedImg(image, pixelCrop, fileName) {
 
  const canvas = document.createElement('canvas');
  canvas.width = pixelCrop.width;
  canvas.height = pixelCrop.height;
  const ctx = canvas.getContext('2d');
 
  ctx.drawImage(
    image,
    pixelCrop.x,
    pixelCrop.y,
    pixelCrop.width,
    pixelCrop.height,
    0,
    0,
    pixelCrop.width,
    pixelCrop.height
  );
 
  // As Base64 string
  // const base64Image = canvas.toDataURL('image/jpeg');
 
  // As a blob
  return new Promise((resolve, reject) => {
    canvas.toBlob(file => {
      file.name = fileName;
      resolve(file);
    }, 'image/jpeg');
  });
}
 
async test() {
  const croppedImg = await getCroppedImg(image, pixelCrop, returnedFileName);
}