destogod/test/fontpreview.mjs
type-two 07977624ae DestoGod: replacement for the TP5 bus destination sign software
TP5 is a 2012 Windows application supplied with the Guangzhou-Tongda LED
destination signs fitted to Yutong buses. It has no preview, so building a
destination list is guess-and-check, and it only runs on Windows.

The bus never talks to TP5 — the sign controller reads a .td5 file off an SD
card, and that is the whole interface. So this replaces the software without
touching any hardware or protocol: it just has to write byte-correct .td5.

Formats reverse-engineered from the sample files and TP5(En).exe, then verified
byte-for-byte:

  .td5   the file the bus reads. Fixed-layout binary; each destination block
         carries a CRC-16/ARC over block[3..len] and a rand() block id, which
         together looked like one 4-byte field because RAND_MAX is 0x7fff.
  .tp5   the editable project. Line-based text, UTF-16BE hex strings.
  .font  the sign's own bitmap fonts, each glyph row XORed with its char code.

The app is one self-contained HTML file: live LED preview at the real sign size
with real scrolling, spreadsheet/CSV import, multi-page destinations, undoable
delete, and export to both .td5 and .tp5.

Verified:
  - rebuilds a real 46,080-byte TP5 export byte-for-byte with a recomputed CRC
  - all 36 stored CRCs verify against the implementation
  - driven through its own UI, re-exporting the real file differs in 7 bytes,
    all of them the export timestamp
  - running on a real bus: signs and driver's controller both correct

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-08-21 13:06:25 +10:00

54 lines
2.1 KiB
JavaScript

/** Render sample text in every 16-row font, next to the original TP5 bitmap. */
import { readFileSync, writeFileSync } from 'node:fs';
import { FONTS } from '../src/fonts.js';
import { fontFromJSON, renderText } from '../src/codec/bitfont.mjs';
import { parseTd5, frameToPixels } from '../src/codec/td5.mjs';
import { writePNG } from './png.mjs';
const SAMPLE = process.argv[2] ?? 'SCHOOL BUS';
const doc = parseTd5(new Uint8Array(readFileSync(new URL('../../test files/EXPRESS 1.td5', import.meta.url))));
const orig = doc.destinations.find((d) => d.name.startsWith(SAMPLE.slice(0, 10)));
const rows = [];
if (orig) {
const f = orig.frames[0];
rows.push({ label: 'TP5 original (Impact 20)', width: f.width, height: f.height, pixels: frameToPixels(f) });
}
for (const [name, j] of Object.entries(FONTS)) {
const font = fontFromJSON(j);
if (font.height > 16) continue;
const bmp = renderText(font, SAMPLE);
rows.push({ label: `${name} (${font.cellWidth}x${font.height})`, ...bmp });
}
const S = 3, PAD = 6, LABEL = 210, SCREEN = 112;
const maxW = Math.max(...rows.map((r) => r.width));
const W = LABEL + maxW * S + PAD * 2;
const H = rows.length * (16 * S + PAD) + PAD;
const px = new Map();
rows.forEach((r, i) => {
const oy = PAD + i * (16 * S + PAD);
for (let y = 0; y < r.height; y++)
for (let x = 0; x < r.width; x++)
if (r.pixels[y * r.width + x])
for (let dy = 0; dy < S; dy++)
for (let dx = 0; dx < S; dx++)
px.set((oy + y * S + dy) * W + LABEL + x * S + dx, 1);
});
writeFileSync(new URL('./fontpreview.png', import.meta.url), writePNG(W, H, (x, y) => {
if (px.has(y * W + x)) return [255, 176, 0];
// mark where the 112px screen ends
if (x === LABEL + SCREEN * S) return [80, 30, 30];
return [14, 14, 16];
}));
console.log(`sample: ${JSON.stringify(SAMPLE)} screen is ${SCREEN}px wide`);
for (const r of rows) {
const fits = r.width <= SCREEN ? 'fits' : `scrolls (+${r.width - SCREEN}px)`;
console.log(` ${r.label.padEnd(26)} ${String(r.width).padStart(3)}px ${fits}`);
}
console.log('wrote test/fontpreview.png');