Function extractTgsFirstFrame

xmsl/xmsl.ts:101–140

* 从 TGS (Lottie) 动画渲染第一帧 PNG * 需要 rlottie-python 和 ffmpeg

(tgsBuffer: Buffer)

/**
 * 从 TGS (Lottie) 动画渲染第一帧 PNG
 * 需要 rlottie-python 和 ffmpeg
 */
async function extractTgsFirstFrame(tgsBuffer: Buffer): Promise<Buffer | null> {
	const uniqueId = Date.now().toString() + '_' + Math.random().toString(36).slice(2);
	const tgsPath = path.join(XMSL_TEMP_DIR, `sticker_${uniqueId}.tgs`);
	const gifPath = path.join(XMSL_TEMP_DIR, `sticker_${uniqueId}.gif`);
	const pngPath = path.join(XMSL_TEMP_DIR, `sticker_${uniqueId}.png`);

	try {
		fs.writeFileSync(tgsPath, tgsBuffer);

		// 使用 rlottie-python 渲染 TGS 到 GIF
		const pythonScript = `
import sys
from rlottie_python import LottieAnimation
anim = LottieAnimation.from_tgs(sys.argv[1])
anim.save_animation(sys.argv[2])
`;
		await execFileAsync('python3', ['-c', pythonScript, tgsPath, gifPath]);

		// 从 GIF 提取第一帧
		await execFileAsync('ffmpeg', [
			'-i', gifPath,
			'-vf', 'select=eq(n\\,0)',
			'-vframes', '1',
			'-y',
			pngPath
		]);

		if (fs.existsSync(pngPath)) {
			return fs.readFileSync(pngPath);
		}
		return null;
	} catch (error) {
		console.error('[xmsl] TGS 第一帧提取失败:', error);
		return null;
	} finally {
		try { fs.unlinkSync(tgsPath); } catch {}
		try { fs.unlinkSync(gifPath); } catch {}
		try { fs.unlinkSync(pngPath); } catch {}
	}
}