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// @ts-check
import { decode } from 'blurhash';
import React, { useRef, useEffect } from 'react';
import PropTypes from 'prop-types';
/**
* @typedef BlurhashPropsBase
* @property {string?} hash Hash to render
* @property {number} width
* Width of the blurred region in pixels. Defaults to 32
* @property {number} [height]
* Height of the blurred region in pixels. Defaults to width
* @property {boolean} [dummy]
* Whether dummy mode is enabled. If enabled, nothing is rendered
* and canvas left untouched
*/
/** @typedef {JSX.IntrinsicElements['canvas'] & BlurhashPropsBase} BlurhashProps */
/**
* Component that is used to render blurred of blurhash string
*
* @param {BlurhashProps} param1 Props of the component
* @returns Canvas which will render blurred region element to embed
*/
function Blurhash({
hash,
width = 32,
height = width,
dummy = false,
...canvasProps
}) {
const canvasRef = /** @type {import('react').MutableRefObject<HTMLCanvasElement>} */ (useRef());
useEffect(() => {
const { current: canvas } = canvasRef;
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} />
);
}
Blurhash.propTypes = {
hash: PropTypes.string.isRequired,
width: PropTypes.number,
height: PropTypes.number,
dummy: PropTypes.bool,
};
export default React.memo(Blurhash);
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