1 files changed, 65 insertions, 0 deletions
diff --git a/app/javascript/flavours/glitch/components/blurhash.jsx b/app/javascript/flavours/glitch/components/blurhash.jsx
new file mode 100644
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+++ b/app/javascript/flavours/glitch/components/blurhash.jsx
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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);