1 files changed, 75 insertions, 0 deletions
diff --git a/web/source/settings/components/blurhash.tsx b/web/source/settings/components/blurhash.tsx
new file mode 100644
index 000000000..25d973d03
--- /dev/null
+++ b/web/source/settings/components/blurhash.tsx
@@ -0,0 +1,75 @@
+/*
+	GoToSocial
+	Copyright (C) GoToSocial Authors admin@gotosocial.org
+	SPDX-License-Identifier: AGPL-3.0-or-later
+
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Affero General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Affero General Public License for more details.
+
+	You should have received a copy of the GNU Affero General Public License
+	along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+import React, { useEffect, useRef } from "react";
+import { MediaAttachment } from "../lib/types/status";
+import { decode } from "blurhash";
+
+export default function BlurhashCanvas({ media }: { media: MediaAttachment }) {
+	const hash = media.blurhash;
+	const thumbHeight = media.meta.small.height;
+	const thumbWidth = media.meta.small.width;
+	const thumbAspect = media.meta.small.aspect;	
+
+	/*
+		It's very expensive to draw big canvases
+		with blurhashes, so use tiny ones, keeping
+		aspect ratio of the original thumbnail.
+	*/
+	var useWidth = 32;
+	var useHeight = 32;
+	switch (true) {
+		case thumbWidth > thumbHeight:
+			useHeight = Math.round(useWidth / thumbAspect);
+			break;
+		case thumbHeight > thumbWidth:
+			useWidth = Math.round(useHeight * thumbAspect);
+			break;
+	}
+
+	const pixels = decode(
+		hash,
+		useWidth,
+		useHeight,
+	);
+
+	const canvasRef = useRef<HTMLCanvasElement>(null);
+
+	useEffect(() => {
+		const ctx = canvasRef.current?.getContext("2d");
+		if (!ctx) {
+			return;
+		}
+    
+		const imageData = ctx.createImageData(
+			useWidth,
+			useHeight,
+		);
+		imageData.data.set(pixels);
+		ctx.putImageData(imageData, 0, 0);
+	}, [pixels, useHeight, useWidth]);
+
+	return (
+		<canvas
+			width={useWidth}
+			height={useHeight}
+			ref={canvasRef}
+		></canvas>
+	);
+}