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Download src/data/gen_pilot.py from sinhal/HindiText-Pilot: direct link, hf CLI and curl.
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8.54 kB
| """Generate the pilot training set. | |
| Clean backgrounds only -- the pilot answers "can SD1.5 + a TE LoRA learn | |
| Devanagari glyph shapes at all", so scene compositing is deliberately out of | |
| scope (see PLAN.md §4b: that decision is deferred until the pilot reports). | |
| Hard invariants, asserted rather than assumed: | |
| * font em size >= MIN_EM (the measured VAE floor -- FINDINGS.md §2) | |
| * text fits the canvas with margin | |
| * caption fits CLIP's 77-token window, template included | |
| * fg/bg luminance contrast is real | |
| """ | |
| from __future__ import annotations | |
| import argparse | |
| import json | |
| import pathlib | |
| import random | |
| import sys | |
| sys.path.insert(0, str(pathlib.Path(__file__).resolve().parents[1])) | |
| import numpy as np | |
| from PIL import Image, ImageFilter | |
| from data.captions import make_caption | |
| from render.shaper import load_face, render_line | |
| RES = 512 | |
| MIN_EM = 32 # measured VAE floor; below this diacritics are destroyed | |
| MAX_EM = 120 | |
| MARGIN = 24 | |
| MAX_TOKENS = 77 | |
| def load_words(path: pathlib.Path) -> list[str]: | |
| out = [] | |
| for line in path.read_text(encoding="utf-8").splitlines(): | |
| line = line.strip() | |
| if line and not line.startswith("#"): | |
| out.append(line) | |
| return out | |
| def luminance(rgb) -> float: | |
| r, g, b = [c / 255 for c in rgb] | |
| return 0.2126 * r + 0.7152 * g + 0.0722 * b | |
| def pick_colors(rng: random.Random) -> tuple[tuple, tuple]: | |
| """Foreground/background with guaranteed contrast. | |
| Low-contrast text would be destroyed by the VAE just as surely as small | |
| text, so this is enforced, not sampled and hoped for. | |
| """ | |
| for _ in range(64): | |
| if rng.random() < 0.45: # dark on light: the common signage case | |
| bg = tuple(rng.randint(190, 255) for _ in range(3)) | |
| fg = tuple(rng.randint(0, 70) for _ in range(3)) | |
| elif rng.random() < 0.5: # light on dark | |
| bg = tuple(rng.randint(0, 80) for _ in range(3)) | |
| fg = tuple(rng.randint(185, 255) for _ in range(3)) | |
| else: # saturated colour pair | |
| bg = tuple(rng.randint(0, 255) for _ in range(3)) | |
| fg = tuple(rng.randint(0, 255) for _ in range(3)) | |
| if abs(luminance(fg) - luminance(bg)) >= 0.35: | |
| return fg, bg | |
| return (0, 0, 0), (255, 255, 255) | |
| def make_background(rng: random.Random, bg: tuple) -> Image.Image: | |
| kind = rng.random() | |
| if kind < 0.55: | |
| return Image.new("RGB", (RES, RES), bg) | |
| if kind < 0.85: | |
| # linear gradient -- mild, so it never competes with the glyphs | |
| other = tuple(max(0, min(255, c + rng.randint(-45, 45))) for c in bg) | |
| ramp = np.linspace(0.0, 1.0, RES, dtype=np.float32) | |
| # broadcast the ramp across the full canvas, vertically or horizontally | |
| a = (np.tile(ramp[:, None], (1, RES)) if rng.random() < 0.5 | |
| else np.tile(ramp[None, :], (RES, 1)))[..., None] | |
| arr = np.array(bg, dtype=np.float32) * (1 - a) + np.array(other, dtype=np.float32) * a | |
| assert arr.shape == (RES, RES, 3), f"bad gradient shape {arr.shape}" | |
| return Image.fromarray(arr.astype(np.uint8)) | |
| # faint noise/texture | |
| base = np.array(Image.new("RGB", (RES, RES), bg), dtype=np.float32) | |
| base += np.random.normal(0, 6, base.shape) | |
| img = Image.fromarray(np.clip(base, 0, 255).astype(np.uint8)) | |
| return img.filter(ImageFilter.GaussianBlur(0.6)) | |
| def render_sample(word: str, fonts: list[str], rng: random.Random): | |
| """Returns (image, mask, meta) or None if no valid layout was found.""" | |
| avail = RES - 2 * MARGIN | |
| for _ in range(12): | |
| font = rng.choice(fonts) | |
| # Measure once at a reference size, then solve for the largest em that | |
| # fits. Sampling em blindly would systematically shrink long words -- | |
| # word length would end up correlated with text size in the dataset. | |
| try: | |
| ref = load_face(f"fonts/{font}", 64) | |
| rm, _ = render_line(ref, word, pad=6) | |
| except Exception: | |
| continue | |
| fit = int(64 * min(avail / rm.width, avail / rm.height)) | |
| hi = min(MAX_EM, fit) | |
| if hi < MIN_EM: | |
| continue # cannot satisfy the VAE floor here | |
| em = rng.randint(MIN_EM, hi) | |
| try: | |
| face = load_face(f"fonts/{font}", em) | |
| mask, m = render_line(face, word, pad=6) | |
| except Exception: | |
| continue | |
| if mask.width > avail or mask.height > avail: | |
| continue # rounding slop at the boundary | |
| assert em >= MIN_EM, "VAE floor violated" | |
| fg, bg = pick_colors(rng) | |
| img = make_background(rng, bg) | |
| x = rng.randint(MARGIN, RES - MARGIN - mask.width) | |
| y = rng.randint(MARGIN, RES - MARGIN - mask.height) | |
| img.paste(fg, (x, y), mask) | |
| full_mask = Image.new("L", (RES, RES), 0) | |
| full_mask.paste(mask, (x, y)) | |
| assert img.size == (RES, RES), f"bad canvas {img.size}" | |
| return img, full_mask, { | |
| "font": font, "em": em, "x": x, "y": y, | |
| "w": mask.width, "h": mask.height, "glyphs": m["n_glyphs"], | |
| } | |
| return None | |
| def main() -> int: | |
| ap = argparse.ArgumentParser() | |
| ap.add_argument("--n", type=int, default=4000) | |
| ap.add_argument("--out", default="data/pilot") | |
| ap.add_argument("--holdout", type=int, default=20, help="words reserved for eval") | |
| ap.add_argument("--seed", type=int, default=0) | |
| ap.add_argument("--masks", action="store_true", help="also write glyph masks") | |
| args = ap.parse_args() | |
| rng = random.Random(args.seed) | |
| np.random.seed(args.seed) | |
| from transformers import CLIPTokenizer | |
| # local copy when present (offline), else pull SD1.5's own tokenizer | |
| try: | |
| tok = CLIPTokenizer.from_pretrained("models/clip") | |
| except Exception: | |
| tok = CLIPTokenizer.from_pretrained( | |
| "stable-diffusion-v1-5/stable-diffusion-v1-5", subfolder="tokenizer") | |
| words = load_words(pathlib.Path("corpus/pilot_words.txt")) | |
| fonts = [l.strip() for l in pathlib.Path("configs/fonts_ok.txt") | |
| .read_text(encoding="utf-8").splitlines() if l.strip()] | |
| if not fonts: | |
| print("no usable fonts -- run src/diag/font_audit.py"); return 1 | |
| # Split by WORD before anything else, so no held-out word appears in training | |
| # in any form. Leakage here would make the eval meaningless. | |
| shuffled = words[:] | |
| rng.shuffle(shuffled) | |
| holdout = sorted(shuffled[: args.holdout]) | |
| train = sorted(shuffled[args.holdout:]) | |
| out = pathlib.Path(args.out) | |
| (out / "images").mkdir(parents=True, exist_ok=True) | |
| if args.masks: | |
| (out / "masks").mkdir(parents=True, exist_ok=True) | |
| recs, skipped, over = [], 0, 0 | |
| for i in range(args.n): | |
| word = rng.choice(train) | |
| got = render_sample(word, fonts, rng) | |
| if got is None: | |
| skipped += 1 | |
| continue | |
| img, mask, meta = got | |
| cap = make_caption(word, rng) | |
| n_tok = len(tok(cap)["input_ids"]) | |
| if n_tok > MAX_TOKENS: # exact check, template included | |
| over += 1 | |
| continue | |
| name = f"{i:06d}" | |
| img.save(out / "images" / f"{name}.jpg", quality=95) | |
| if args.masks: | |
| mask.save(out / "masks" / f"{name}.png") | |
| recs.append({"file": f"images/{name}.jpg", "text": word, | |
| "caption": cap, "tokens": n_tok, **meta}) | |
| with (out / "metadata.jsonl").open("w", encoding="utf-8") as fh: | |
| for r in recs: | |
| fh.write(json.dumps(r, ensure_ascii=False) + "\n") | |
| (out / "train_words.txt").write_text("\n".join(train) + "\n", encoding="utf-8") | |
| (out / "holdout_words.txt").write_text("\n".join(holdout) + "\n", encoding="utf-8") | |
| ems = [r["em"] for r in recs] | |
| print(f"wrote {len(recs)} samples to {out}") | |
| print(f" skipped(layout)={skipped} skipped(tokens)={over}") | |
| print(f" train words={len(train)} holdout={len(holdout)}") | |
| print(f" em size: min={min(ems)} max={max(ems)} mean={sum(ems)/len(ems):.1f}") | |
| print(f" tokens : max={max(r['tokens'] for r in recs)}") | |
| print(f" fonts used: {len({r['font'] for r in recs})}/{len(fonts)}") | |
| print(f"\nholdout: {' '.join(holdout)}") | |
| return 0 | |
| if __name__ == "__main__": | |
| raise SystemExit(main()) | |