initial commit

fluxer_media_proxy/src/lib/ImageProcessing.ts

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+/*
+ * Copyright (C) 2026 Fluxer Contributors
+ *
+ * This file is part of Fluxer.
+ *
+ * Fluxer 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.
+ *
+ * Fluxer 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 Fluxer. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import sharp from 'sharp';
+import {rgbaToThumbHash} from 'thumbhash';
+
+export const generatePlaceholder = async (imageBuffer: Buffer): Promise<string> => {
+	const {data, info} = await sharp(imageBuffer)
+		.blur(10)
+		.resize(100, 100, {fit: 'inside', withoutEnlargement: true})
+		.ensureAlpha()
+		.raw()
+		.toBuffer({resolveWithObject: true});
+
+	if (data.length !== info.width * info.height * 4) {
+		throw new Error('Unexpected data length');
+	}
+
+	const placeholder = rgbaToThumbHash(info.width, info.height, data);
+	return Buffer.from(placeholder).toString('base64');
+};
+
+export const processImage = async (opts: {
+	buffer: Buffer;
+	width: number;
+	height: number;
+	format: string;
+	quality: string;
+	animated: boolean;
+}): Promise<Buffer> => {
+	const metadata = await sharp(opts.buffer).metadata();
+
+	const resizeWidth = Math.min(opts.width, metadata.width || 0);
+	const resizeHeight = Math.min(opts.height, metadata.height || 0);
+
+	return sharp(opts.buffer, {
+		animated: opts.format === 'gif' || (opts.format === 'webp' && opts.animated),
+	})
+		.resize(resizeWidth, resizeHeight, {
+			fit: 'cover',
+			withoutEnlargement: true,
+		})
+		.toFormat(opts.format as keyof sharp.FormatEnum, {
+			quality: opts.quality === 'high' ? 80 : opts.quality === 'low' ? 20 : 100,
+		})
+		.toBuffer();
+};