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