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6776bb8916
* docs: update demo * chore: add script * test: fix demo test * docs: convert demos * chore: move script * test: remove react-dom import * chore: update deps * docs: update riddle js * test: fix image test * docs: fix riddle demo
53 lines
1.3 KiB
Markdown
53 lines
1.3 KiB
Markdown
---
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order: 10
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title:
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zh-CN: 上传前转换文件
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en-US: Transform file before request
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---
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## zh-CN
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使用 `beforeUpload` 转换上传的文件（例如添加水印）。
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## en-US
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Use `beforeUpload` for transform file before request such as add a watermark.
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```jsx
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import { Upload, Button } from 'antd';
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import { UploadOutlined } from '@ant-design/icons';
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const props = {
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action: 'https://www.mocky.io/v2/5cc8019d300000980a055e76',
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listType: 'picture',
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beforeUpload(file) {
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return new Promise(resolve => {
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const reader = new FileReader();
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reader.readAsDataURL(file);
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reader.onload = () => {
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const img = document.createElement('img');
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img.src = reader.result;
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img.onload = () => {
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const canvas = document.createElement('canvas');
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canvas.width = img.naturalWidth;
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canvas.height = img.naturalHeight;
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const ctx = canvas.getContext('2d');
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ctx.drawImage(img, 0, 0);
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ctx.fillStyle = 'red';
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ctx.textBaseline = 'middle';
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ctx.font = '33px Arial';
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ctx.fillText('Ant Design', 20, 20);
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canvas.toBlob(resolve);
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};
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};
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});
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},
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};
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export default () => (
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<Upload {...props}>
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<Button icon={<UploadOutlined />}>Upload</Button>
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</Upload>
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);
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```
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