Files
tono/backend/exporters/image.py

130 lines
3.9 KiB
Python

"""
Exporter for IMAGE values (numpy arrays, ImageData annotation sources).
Images are raw pixel arrays — no physical calibration by design — so none of
the formats here round-trip dimensions. PNG/TIFF convert to uint8 via the
same image_to_uint8 helper the preview pipeline uses; NPZ preserves the raw
array.
Multi-layer stacks are supported for TIFF (multi-page uint8) and NPZ (one
named array per layer). PNG is single-layer only and raises if extra layers
are connected.
"""
from __future__ import annotations
import re
from pathlib import Path
from typing import Any, Sequence
import numpy as np
from backend.data_types import image_to_uint8
from backend.exporters._base import FormatSpec
accepted_types: tuple[str, ...] = ("IMAGE", "ANNOTATION_SOURCE")
FORMATS: dict[str, FormatSpec] = {
"PNG": FormatSpec(ext=".png", round_trip=False, label="PNG"),
"TIFF": FormatSpec(ext=".tiff", round_trip=False, label="TIFF"),
"NPZ": FormatSpec(ext=".npz", round_trip=False, label="NumPy (.npz)"),
}
_SINGLE_LAYER_ONLY: frozenset[str] = frozenset({"PNG"})
def save(
path: Path,
value: np.ndarray,
format_name: str,
*,
extra_layers: Sequence[Any] | None = None,
layer_names: Sequence[str] | None = None,
**_opts,
) -> None:
extras = list(extra_layers or [])
layers: list[Any] = [value, *extras]
names = _resolve_layer_names(len(layers), layer_names, default_primary=path.stem or "image")
if extras and format_name in _SINGLE_LAYER_ONLY:
raise ValueError(
f"{format_name} only supports a single layer. Use 'TIFF' or 'NPZ' "
f"for multi-layer image saves."
)
if format_name == "PNG":
from PIL import Image
Image.fromarray(image_to_uint8(np.asarray(value))).save(str(path))
return
if format_name == "TIFF":
_save_tiff(path, layers, names)
return
if format_name == "NPZ":
_save_npz(path, layers, names)
return
raise ValueError(f"Format {format_name!r} is not supported for IMAGE.")
def _save_tiff(path: Path, layers: Sequence[Any], names: Sequence[str]) -> None:
import tifffile
if len(layers) == 1:
tifffile.imwrite(str(path), image_to_uint8(np.asarray(layers[0])))
return
with tifffile.TiffWriter(str(path)) as tif:
for layer, layer_name in zip(layers, names):
tif.write(image_to_uint8(np.asarray(layer)), description=layer_name)
def _save_npz(path: Path, layers: Sequence[Any], names: Sequence[str]) -> None:
if len(layers) == 1:
# Preserve the single-layer key used by the legacy test suite.
np.savez(str(path), image=np.asarray(layers[0]))
return
raw_keys = [_safe_identifier(name, i) for i, name in enumerate(names)]
keys = _dedupe_keys(raw_keys)
arrays = {key: np.asarray(layer) for key, layer in zip(keys, layers)}
np.savez(str(path), **arrays)
def _resolve_layer_names(
count: int,
raw_names: Sequence[str] | None,
*,
default_primary: str,
) -> list[str]:
raw_names = list(raw_names or [])
out: list[str] = []
for i in range(count):
raw = str(raw_names[i]).strip() if i < len(raw_names) and raw_names[i] is not None else ""
if raw:
out.append(raw)
elif i == 0:
out.append(default_primary)
else:
out.append(f"layer_{i + 1}")
return out
def _safe_identifier(name: str, index: int) -> str:
key = re.sub(r"[^0-9A-Za-z_]+", "_", str(name).strip()).strip("_")
if not key:
key = f"layer_{index + 1}"
if key[0].isdigit():
key = f"layer_{key}"
return key
def _dedupe_keys(raw_keys: Sequence[str]) -> list[str]:
used: set[str] = set()
result: list[str] = []
for k in raw_keys:
candidate = k
suffix = 2
while candidate in used:
candidate = f"{k}_{suffix}"
suffix += 1
used.add(candidate)
result.append(candidate)
return result