@micrio/tiler-base/dist/lib/archive.js

The base Micrio client-side tiler package used by the Micrio CLI and GUI tools

import { promises as fs } from 'node:fs';
import path from 'path';
import { walkSync } from './utils.js';
/** Generate a single preloader .bin file containing omni/album image thumbnails */
export async function getArchiveBin(outDir, format, containerId, entries, omniId) {
    const archiveDir = path.join(outDir, containerId + '_basebin');
    const start = Date.now();
    const isOmni = !!omniId;
    await fs.mkdir(archiveDir);
    const delta = isOmni ? 0 : entries.length > 200 ? 2 : entries.length > 50 ? 1 : 0;
    const albumImages = [];
    for (let [fileName, info] of entries) {
        const level = getThumbLevel(info, delta).toString();
        const archiveImgDir = path.join(archiveDir, (info.omniFrame ?? info.id).toString());
        await fs.mkdir(archiveImgDir);
        await fs.rename(path.join(info.baseDir, level), path.join(archiveImgDir, level));
        if (!isOmni)
            albumImages.push({
                id: info.id,
                width: info.width,
                height: info.height,
                created: start,
                title: fileName,
                isWebP: format == 'webp',
                isPng: format == 'png',
                isDeepZoom: true
            });
    }
    // Files to be included in the binary
    const bundleFiles = [];
    // For (PDF) album, include static album JSON
    if (!isOmni)
        bundleFiles.push({
            path: `${containerId}.json`,
            buffer: new Uint8Array(new TextEncoder().encode(JSON.stringify({
                delta,
                images: albumImages
            })))
        });
    // Add the tiles
    await walkSync(archiveDir).then(async (files) => {
        for (const f of files)
            bundleFiles.push({
                path: f.replace(/\\/g, '/').replace(/^.*_basebin\//, ''),
                buffer: await fs.readFile(f)
            });
    });
    return generateMDP(bundleFiles).arrayBuffer().then(r => new Uint8Array(r));
}
function getThumbLevel(info, delta) {
    let d = Math.max(info.width, info.height), l = delta;
    while (d > 1024) {
        d /= 2;
        l++;
    }
    let dzLevels = 0, max = Math.max(info.width, info.height);
    do
        dzLevels++;
    while ((max /= 2) > 1);
    return dzLevels - l;
}
function generateMDP(files) {
    const enc = new TextEncoder();
    const arr = [];
    files.forEach(i => {
        if (!i.buffer || !i.path)
            return;
        const name = enc.encode(i.path); // byte[20]
        const size = i.buffer.byteLength.toString(8); // byte[12]
        arr.push(name, new Uint8Array(20 - name.byteLength));
        arr.push(enc.encode('0'.repeat(12 - size.length) + size));
        arr.push(i.buffer);
    });
    return new Blob(arr, { type: 'application/octet-stream' });
}