Coverage for python/lsst/images/_generalized

1# This file is part of lsst-images.

3# Developed for the LSST Data Management System.

4# This product includes software developed by the LSST Project

5# (https://www.lsst.org).

6# See the COPYRIGHT file at the top-level directory of this distribution

7# for details of code ownership.

9# Use of this source code is governed by a 3-clause BSD-style

10# license that can be found in the LICENSE file.

12from __future__ import annotations

14__all__ = ("AbsoluteSliceProxy", "GeneralizedImage", "LocalSliceProxy")

16from abc import ABC, abstractmethod

17from functools import cached_property

18from types import EllipsisType

19from typing import TYPE_CHECKING, Any, Self, TypeVar

21import astropy.wcs

23from lsst.resources import ResourcePathExpression

25from ._geom import YX, Box

26from ._transforms import SkyProjection, SkyProjectionAstropyView

27from .serialization import (

28 ArchiveTree,

29 ButlerInfo,

30 MetadataValue,

31 OpaqueArchiveMetadata,

32)

33from .serialization import (

34 read as read_archive,

35)

36from .serialization import (

37 write as write_archive,

38)

40if TYPE_CHECKING:

41 from lsst.daf.butler import DatasetProvenance, SerializedDatasetRef

44T = TypeVar("T", bound="GeneralizedImage") # for sphinx

47class GeneralizedImage(ABC):

48 """A base class for types that represent one or more 2-d image-like arrays

49 with the same pixel grid and sky projection.

51 Parameters

52 ----------

53 metadata

54 Arbitrary flexible metadata to associate with the image.

55 """

57 def __init__(self, metadata: dict[str, MetadataValue] | None = None):

58 self._metadata = metadata if metadata is not None else {}

59 self._opaque_metadata: OpaqueArchiveMetadata | None = None

60 self._butler_info: ButlerInfo | None = None

62 @property

63 @abstractmethod

64 def bbox(self) -> Box:

65 """Bounding box for the image (`~lsst.images.Box`)."""

66 raise NotImplementedError()

68 @property

69 def yx0(self) -> YX[int]:

70 """The coordinates of the first pixel in the array

71 (`~lsst.geom.YX` [`int`]).

72 """

73 return self.bbox.start

75 @property

76 @abstractmethod

77 def sky_projection(self) -> SkyProjection[Any] | None:

78 """The projection that maps this image's pixel grid to the sky

79 (`~lsst.images.SkyProjection` | `None`).

81 Notes

82 -----

83 The pixel coordinates used by this projection account for the bounding

84 box ``start``; they are not just array indices.

85 """

86 raise NotImplementedError()

88 @property

89 def astropy_wcs(self) -> SkyProjectionAstropyView | None:

90 """An Astropy WCS for this image's pixel array.

92 Notes

93 -----

94 As expected for Astropy WCS objects, this defines pixel coordinates

95 such that the first row and column in any associated arrays are

96 ``(0, 0)``, not ``bbox.start``, as is the case for `sky_projection`.

98 This object satisfies the `astropy.wcs.wcsapi.BaseHighLevelWCS` and

99 `astropy.wcs.wcsapi.BaseLowLevelWCS` interfaces, but it is not an

100 `astropy.wcs.WCS` (use `fits_wcs` for that).

101 """

102 return self.sky_projection.as_astropy(self.bbox) if self.sky_projection is not None else None

103

104 @cached_property

105 def fits_wcs(self) -> astropy.wcs.WCS | None:

106 """An Astropy FITS WCS for this image's pixel array.

107

108 Notes

109 -----

110 As expected for Astropy WCS objects, this defines pixel coordinates

111 such that the first row and column in any associated arrays are

112 ``(0, 0)``, not ``bbox.start``, as is the case for `sky_projection`.

113

114 This may be an approximation or absent if `sky_projection` is not

115 naturally representable as a FITS WCS.

116 """

117 return (

118 self.sky_projection.as_fits_wcs(self.bbox, allow_approximation=True)

119 if self.sky_projection is not None

120 else None

121 )

122

123 @property

124 def local(self) -> LocalSliceProxy[Self]:

125 """A proxy object for slicing a generalized image using "local" or

126 "array" pixel coordinates.

127

128 Notes

129 -----

130 In this convention, the first row and column of the pixel grid is

131 always at ``(0, 0)``. This is also the convention used by

132 `astropy.wcs` objects. When a subimage is created from a parent image,

133 its "local" coordinate system is offset from the coordinate systems of

134 the parent image.

135

136 Note that most `lsst.images` types (e.g. `~lsst.images.Box`,

137 `~lsst.images.SkyProjection`, `~lsst.images.psfs.PointSpreadFunction`)

138 operate instead in "absolute" coordinates, which is shared by subimage

139 and their parents.

140

141 See Also

142 --------

143 lsst.images.BoxSliceFactory

144 lsst.images.IntervalSliceFactory

145 """

146 return LocalSliceProxy(self)

147

148 @property

149 def absolute(self) -> AbsoluteSliceProxy[Self]:

150 """A proxy object for slicing a generalized image using absolute pixel

151 coordinates.

152

153 Notes

154 -----

155 In this convention, the first row and column of the pixel grid is

156 ``bbox.start``. A subimage and its parent image share the same

157 absolute pixel coordinate system, and most `lsst.images` types (e.g.

158 `~lsst.images.Box`, `~lsst.images.SkyProjection`,

159 `~lsst.images.psfs.PointSpreadFunction`) operate exclusively in this

160 system.

161

162 Note that `astropy.wcs` and `numpy.ndarray` are not aware of the

163 ``bbox.start`` offset that defines tihs coordinates system; use

164 `local` slicing for indices obtained from those.

165

166 See Also

167 --------

168 lsst.images.BoxSliceFactory

169 lsst.images.IntervalSliceFactory

170 """

171 return AbsoluteSliceProxy(self)

172

173 @property

174 def metadata(self) -> dict[str, MetadataValue]:

175 """Arbitrary flexible metadata associated with the image (`dict`).

176

177 Notes

178 -----

179 Metadata is shared with subimages and other views. It can be

180 disconnected by reassigning to a copy explicitly:

181

182 image.metadata = image.metadata.copy()

183 """

184 return self._metadata

185

186 @metadata.setter

187 def metadata(self, value: dict[str, MetadataValue]) -> None:

188 self._metadata = value

189

190 # Subclasses should delegate to super().__getitem__ for some user-friendly

191 # argument type-checking before providing their own implementation.

192 @abstractmethod

193 def __getitem__(self, bbox: Box | EllipsisType) -> Self:

194 if not isinstance(bbox, Box): 194 ↛ 195line 194 didn't jump to line 195 because the condition on line 194 was never true

195 raise TypeError(

196 "Only Box objects can be used to subset image objects directly; "

197 "use .local[y, x] or .absolute[y, x] proxies for slice-based subsets."

198 )

199 return self

200

201 @abstractmethod

202 def copy(self) -> Self:

203 """Deep-copy the image and metadata.

204

205 Attached immutable objects (like `~lsst.images.SkyProjection`

206 instances) are not copied.

207 """

208 raise NotImplementedError()

209

210 @classmethod

211 def read(cls, path: ResourcePathExpression, **kwargs: Any) -> Self:

212 """Read an instance of this class from a file.

213

214 A thin convenience wrapper around `lsst.images.serialization.read`

215 that fixes the expected in-memory type to this class. The container

216 format is inferred from ``path``'s extension.

217

218 Parameters

219 ----------

220 path

221 File to read; convertible to `lsst.resources.ResourcePath`.

222 **kwargs

223 Forwarded to `~lsst.images.serialization.read` (e.g. ``bbox`` to

224 read a subimage).

225 """

226 return read_archive(path, cls, **kwargs)

227

228 def write(self, path: str, **kwargs: Any) -> None:

229 """Write this object to a file.

230

231 A thin convenience wrapper around `lsst.images.serialization.write`.

232 The container format is chosen from ``path``'s extension.

233

234 Parameters

235 ----------

236 path

237 Destination file path. Must not already exist.

238 **kwargs

239 Forwarded to `~lsst.images.serialization.write` (e.g.

240 ``compression_options`` and ``compression_seed`` for FITS).

241 """

242 write_archive(self, path, **kwargs)

243

244 @property

245 def butler_dataset(self) -> SerializedDatasetRef | None:

246 """The butler dataset reference for this image

247 (`lsst.daf.butler.SerializedDatasetRef` | `None`).

248 """

249 if self._butler_info is None: 249 ↛ 250line 249 didn't jump to line 250 because the condition on line 249 was never true

250 return None

251 from lsst.daf.butler import SerializedDatasetRef

252

253 # Guard against the unlikely case where the dataset was deserialized as

254 # Any because `lsst.daf.butler` couldn't be imported before, but can be

255 # imported now (*anything* can happen in Jupyter).

256 return SerializedDatasetRef.model_validate(self._butler_info.dataset)

257

258 @property

259 def butler_provenance(self) -> DatasetProvenance | None:

260 """The butler inputs and ID of the task quantum that produced this

261 dataset (`lsst.daf.butler.DatasetProvenance` | `None`)

262 """

263 if self._butler_info is None: 263 ↛ 264line 263 didn't jump to line 264 because the condition on line 263 was never true

264 return None

265

266 # Guard against the unlikely case where the provenance was deserialized

267 # as Any because `lsst.daf.butler` couldn't be imported before, but can

268 # be imported now (*anything* can happen in Jupyter).

269 from lsst.daf.butler import DatasetProvenance

270

271 return DatasetProvenance.model_validate(self._butler_info.provenance)

272

273 def _transfer_metadata[T: GeneralizedImage](

274 self, new: T, copy: bool = False, bbox: Box | None = None

275 ) -> T:

276 """Transfer metadata held by this base class to a new instance.

277

278 Parameters

279 ----------

280 new

281 New instance to modify and return.

282 copy

283 Whether the new instance is a deep-copy of ``self``.

284 bbox

285 Bounding box used to construct ``new`` as a subset of ``self``.

286

287 Returns

288 -------

289 GeneralizedImage

290 The new object passed in, modified in place.

291

292 Notes

293 -----

294 This is a utility method for subclasses to use when finishing

295 construction of a new one.

296 """

297 if bbox is not None:

298 opaque_metadata = (

299 self._opaque_metadata.subset(bbox) if self._opaque_metadata is not None else None

300 )

301 else:

302 opaque_metadata = self._opaque_metadata

303 metadata = self._metadata

304 if copy:

305 metadata = metadata.copy()

306 opaque_metadata = opaque_metadata.copy() if opaque_metadata is not None else None

307 new._metadata = metadata

308 new._opaque_metadata = opaque_metadata

309 new._butler_info = self._butler_info

310 return new

311

312 def _finish_deserialize(self, model: ArchiveTree) -> Self:

313 """Attach generic information from `ArchiveTree` to this instance

314 at the end of deserialization.

315 """

316 self._metadata = model.metadata

317 self._butler_info = model.butler_info

318 return self

319

320

321class LocalSliceProxy[T: GeneralizedImage]:

322 """A proxy object for obtaining a generalized image subset using local

323 slicing.

324

325 See `~lsst.images.GeneralizedImage.local` for more information.

326 """

327

328 def __init__(self, parent: T):

329 self._parent = parent

330

331 def __getitem__(self, slices: tuple[slice, slice]) -> T:

332 try:

333 return self._parent[self._parent.bbox.local[slices]]

334 except TypeError as err:

335 if hasattr(self._parent, "array"):

336 err.add_note("The .array attribute may provide more slicing flexibility.")

337 raise

338

339

340class AbsoluteSliceProxy[T: GeneralizedImage]:

341 """A proxy object for obtaining a generalized image subset using absolute

342 slicing.

343

344 See `~lsst.images.GeneralizedImage.absolute` for more information.

345 """

346

347 def __init__(self, parent: T):

348 self._parent = parent

349

350 def __getitem__(self, slices: tuple[slice, slice]) -> T:

351 try:

352 return self._parent[self._parent.bbox.absolute[slices]]

353 except TypeError as err:

354 if hasattr(self._parent, "array"):

355 err.add_note(

356 "The .array attribute may provide more slicing flexibility "

357 "(but only works in local coordinates)."

358 )

359 raise

Coverage for python/lsst/images/_generalized_image.py: 84%

106 statements