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puyopuyotetr.is/app/javascript/mastodon/components/blurhash.tsx

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1.3 KiB
TypeScript

import React, { useRef, useEffect } from 'react';
import { decode } from 'blurhash';
interface Props extends React.HTMLAttributes<HTMLCanvasElement> {
hash: string;
width?: number;
height?: number;
dummy?: boolean; // Whether dummy mode is enabled. If enabled, nothing is rendered and canvas left untouched
children?: never;
}
const Blurhash: React.FC<Props> = ({
hash,
width = 32,
height = width,
dummy = false,
...canvasProps
}) => {
const canvasRef = useRef<HTMLCanvasElement>(null);
useEffect(() => {
// eslint-disable-next-line @typescript-eslint/no-non-null-assertion
const canvas = canvasRef.current!;
// eslint-disable-next-line no-self-assign
canvas.width = canvas.width; // resets canvas
if (dummy || !hash) return;
try {
const pixels = decode(hash, width, height);
const ctx = canvas.getContext('2d');
const imageData = new ImageData(pixels, width, height);
ctx?.putImageData(imageData, 0, 0);
} catch (err) {
console.error('Blurhash decoding failure', { err, hash });
}
}, [dummy, hash, width, height]);
return (
<canvas {...canvasProps} ref={canvasRef} width={width} height={height} />
);
};
const MemoizedBlurhash = React.memo(Blurhash);
export { MemoizedBlurhash as Blurhash };