48 lines
1.2 KiB
Markdown
48 lines
1.2 KiB
Markdown
<cn>
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#### 上传前转换文件
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使用 `transformFile` 转换上传的文件（例如添加水印）。
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</cn>
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<us>
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#### Transform file before request
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Use `transformFile` for transform file before request such as add a watermark.
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</us>
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```vue
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<template>
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<div>
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<a-upload
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action="https://www.mocky.io/v2/5cc8019d300000980a055e76"
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:transform-file="transformFile"
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>
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<a-button> <a-icon type="upload" /> Upload </a-button>
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</a-upload>
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</div>
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</template>
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<script>
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export default {
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methods: {
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transformFile(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 canvas = document.createElement('canvas');
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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 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.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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};
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</script>
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```
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