Coverage for python/lsst/images/_cell_grid.py: 41%
142 statements
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« prev ^ index » next coverage.py v7.15.2, created at 2026-07-30 08:38 +0000
1# This file is part of lsst-images.
2#
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.
8#
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# This module is conceptually part of the 'cells' subpackage, but we don't
15# want the stuff in '_concrete_bounds' to depend on all of that. So the
16# basic CellGrid and CellGridBounds objects are defined here, used in both
17# places, and exported from 'cells'.
19__all__ = (
20 "CellGrid",
21 "CellGridBounds",
22 "CellIJ",
23 "PatchDefinition",
24)
26import dataclasses
27import math
28from collections.abc import Iterator
29from functools import cached_property
30from typing import TYPE_CHECKING, Any, assert_type, overload
32import numpy as np
33import numpy.typing as npt
34import pydantic
36from ._geom import XY, YX, Bounds, Box, SerializableYX
38if TYPE_CHECKING:
39 try:
40 from lsst.cell_coadds import UniformGrid as LegacyUniformGrid
41 from lsst.skymap import Index2D as LegacyIndex2D
42 except ImportError:
43 type LegacyUniformGrid = Any # type: ignore[no-redef]
44 type LegacyIndex2D = Any # type: ignore[no-redef]
47@dataclasses.dataclass(frozen=True, order=True)
48class CellIJ:
49 """An index in a grid of cells.
51 Notes
52 -----
53 This is deliberately not a `tuple` or other `~collections.abc.Sequence` in
54 order to make it typing-incompatible with sequence-based pixel coordinate
55 pairs (e.g. `.YX`). This also allows it to have addition and subtraction
56 operators.
57 """
59 i: int
60 """The y / row object."""
62 j: int
63 """The x / column object."""
65 def __add__(self, other: CellIJ) -> CellIJ:
66 return CellIJ(i=self.i + other.i, j=self.j + other.j)
68 def __sub__(self, other: CellIJ) -> CellIJ:
69 return CellIJ(i=self.i - other.i, j=self.j - other.j)
71 @staticmethod
72 def from_legacy(legacy_index: LegacyIndex2D) -> CellIJ:
73 """Convert from a legacy `lsst.skymap.Index2D` instance.
75 Parameters
76 ----------
77 legacy_index
78 Legacy `lsst.skymap.Index2D` to convert.
80 Notes
81 -----
82 `lsst.skymap.Index2D` is ordered ``(x, y)``, i.e. ``(j, i)``.
83 """
84 return CellIJ(i=legacy_index.y, j=legacy_index.x)
86 def to_legacy(self) -> LegacyIndex2D:
87 """Convert to a legacy `lsst.skymap.Index2D` instance.
89 Notes
90 -----
91 `lsst.skymap.Index2D` is ordered ``(x, y)``, i.e. ``(j, i)``.
92 """
93 from lsst.skymap import Index2D as LegacyIndex2D
95 return LegacyIndex2D(x=self.j, y=self.i)
97 def as_tuple(self) -> tuple[int, int]:
98 """Convert to an (i, j) `tuple`."""
99 return (self.i, self.j)
102class CellGrid(pydantic.BaseModel, frozen=True):
103 """A grid of rectangular cells with no overlaps or space between cells.
105 Notes
106 -----
107 A cell grid usually corresponds to a full patch, but we do not explicitly
108 encode this in the type to permit full-tract grids, which would have to
109 drop the cells in patch overlap regions and re-label all cells.
111 Subsets of grids are usually represented via `CellGridBounds`.
112 """
114 bbox: Box = pydantic.Field(
115 description=(
116 "Bounding box of the grid of cells (snapped to cell boundaries. "
117 "The cell with index (i=0, j=0) always has a corner at ``(y=bbox.y.min, x=bbox.x.min)`` "
118 "but there is no expectation that ``(y=bbox.y.min, x=bbox.x.min)`` be ``(y=0, x=0)``."
119 )
120 )
121 cell_shape: SerializableYX[int] = pydantic.Field(description="Shape of each cell in pixels.")
123 def __str__(self) -> str:
124 return f"{self.bbox}, cell_shape=(y={self.cell_shape.y}, x={self.cell_shape.x})"
126 @property
127 def grid_size(self) -> CellIJ:
128 """The number of cells in each dimension (`CellIJ`)."""
129 return CellIJ(i=self.bbox.y.size // self.cell_shape.y, j=self.bbox.x.size // self.cell_shape.x)
131 def index_of(self, *, y: int, x: int) -> CellIJ:
132 """Return the 2-d index of the cell that contains the given pixel.
134 Parameters
135 ----------
136 y
137 Y cell index.
138 x
139 X cell index.
140 """
141 return CellIJ(
142 i=(y - self.bbox.y.start) // self.cell_shape.y,
143 j=(x - self.bbox.x.start) // self.cell_shape.x,
144 )
146 def bbox_of(self, cell: CellIJ) -> Box:
147 """Return the bounding box of the given cell.
149 Parameters
150 ----------
151 cell
152 Index of the cell whose bounding box is returned.
153 """
154 return Box.from_shape(
155 self.cell_shape,
156 start=YX(
157 y=cell.i * self.cell_shape.y + self.bbox.y.start,
158 x=cell.j * self.cell_shape.x + self.bbox.x.start,
159 ),
160 )
162 @staticmethod
163 def from_legacy(legacy: LegacyUniformGrid) -> CellGrid:
164 """Construct from a legacy `lsst.cell_coadds.UniformGrid` object.
166 Parameters
167 ----------
168 legacy
169 Legacy grid to convert.
170 """
171 if legacy.padding:
172 raise ValueError("Only cell grids with no padding are supported.")
173 bbox = Box.from_legacy(legacy.bbox)
174 cell_shape = YX(y=legacy.cell_size.y, x=legacy.cell_size.x)
175 return CellGrid(bbox=bbox, cell_shape=cell_shape)
177 def to_legacy(self) -> LegacyUniformGrid:
178 """Convert to a legacy `lsst.cell_coadds.UniformGrid` object."""
179 from lsst.cell_coadds import UniformGrid as LegacyUniformGrid
181 return LegacyUniformGrid(
182 self.cell_shape.to_legacy_int_extent(),
183 self.grid_size.to_legacy(),
184 min=self.bbox.min.to_legacy_int_point(),
185 )
188class CellGridBounds(pydantic.BaseModel, frozen=True):
189 """A region of pixels defined by a set of cells within a grid.
191 Notes
192 -----
193 This data structure is optimized for the case where a continguous
194 rectangular region of the grid (the `bbox` attribute) is populated with
195 only a few exceptions (the `missing` set).
197 Slicing a `CellGridBounds` with a `.Box` returns a new `CellGridBounds`
198 with just the cells that overlap that box. As always,
199 `CellGridBounds.bbox` will be snapped to the outer boundaries of those
200 cells, so it will contain (and not generally equal) the given box.
201 """
203 grid: CellGrid = pydantic.Field(description="Definition of the grid that defines the cells.")
204 bbox: Box = pydantic.Field(description="Pixel bounding box of the region (snapped to cell boundaries).")
205 missing: frozenset[CellIJ] = pydantic.Field(
206 default=frozenset(),
207 description=(
208 "Indices of cells that are missing, where (i=0, j=0) is the cell that starts at grid.bbox.start."
209 ),
210 )
212 def __str__(self) -> str:
213 text = f"{self.bbox} in grid ({self.grid})"
214 if self.missing:
215 missing = ", ".join(f"(i={c.i}, j={c.j})" for c in sorted(self.missing))
216 text = f"{text}, missing={{{missing}}}"
217 return text
219 @cached_property
220 def subgrid_start(self) -> CellIJ:
221 """The index of the first cell in this bounds' bounding box within
222 its grid.
223 """
224 return self.grid.index_of(y=self.bbox.y.start, x=self.bbox.x.start)
226 @cached_property
227 def subgrid_stop(self) -> CellIJ:
228 """One-past-the-last indices for the cells in these bounds, within
229 its grid.
230 """
231 return self.grid.index_of(y=self.bbox.y.stop, x=self.bbox.x.stop)
233 @cached_property
234 def subgrid_size(self) -> CellIJ:
235 """Number of cells within these bounds in both dimensions, not
236 accounting for `missing`.
237 """
238 return self.subgrid_stop - self.subgrid_start
240 @overload
241 def contains(self, point: XY[int | float] | YX[int | float], /) -> bool: ...
243 @overload
244 def contains(self, point: XY[npt.ArrayLike] | YX[npt.ArrayLike], /) -> np.ndarray: ...
246 @overload
247 def contains(self, *, x: int | float, y: int | float) -> bool: ...
249 @overload
250 def contains(self, *, x: npt.ArrayLike, y: npt.ArrayLike) -> np.ndarray: ...
252 def contains(self, point: XY[Any] | YX[Any] | None = None, /, *, x: Any = None, y: Any = None) -> Any: # type: ignore[misc]
253 """Test whether these bounds contain one or more points.
255 Parameters
256 ----------
257 point
258 An `.XY` or `.YX` coordinate pair to test for containment.
259 Mutually exclusive with ``x`` and ``y``.
260 x
261 One or more X coordinates to test for containment, as a scalar or
262 any array-like. Results are broadcast against ``y``.
263 Mutually exclusive with ``point``.
264 y
265 One or more Y coordinates to test for containment, as a scalar or
266 any array-like. Results are broadcast against ``x``.
267 Mutually exclusive with ``point``.
269 Returns
270 -------
271 `bool` | `numpy.ndarray`
272 If ``x`` and ``y`` are both scalars, a single `bool` value. If
273 ``x`` and ``y`` are array-like, a boolean array with their
274 broadcasted shape.
275 """
276 match point:
277 case None:
278 if x is None or y is None: 278 ↛ 279line 278 didn't jump to line 279 because the condition on line 278 was never true
279 raise TypeError("Pass either a point or both x= and y= to 'CellGridBounds.contains'.")
280 case XY() | YX(): 280 ↛ 286line 280 didn't jump to line 286 because the pattern on line 280 always matched
281 if x is not None or y is not None: 281 ↛ 282line 281 didn't jump to line 282 because the condition on line 281 was never true
282 raise TypeError(
283 "'CellGridBounds.contains' point argument is mutually exclusive with x= and y=."
284 )
285 x, y = point.x, point.y
286 case _:
287 raise TypeError(f"Unexpected positional argument type: {type(point)!r}.")
288 result = self.bbox.contains(x=x, y=y)
289 if not self.missing: 289 ↛ 290line 289 didn't jump to line 290 because the condition on line 289 was never true
290 return result
291 match result:
292 case False:
293 return False
294 case True:
295 return self.grid.index_of(x=x, y=y) not in self.missing
296 case np.ndarray(): 296 ↛ 299line 296 didn't jump to line 299 because the pattern on line 296 always matched
297 for box in self.missing_boxes():
298 result = np.logical_and(result, np.logical_not(box.contains(x=x, y=y)))
299 return result
301 def intersection(self, other: Bounds) -> Bounds:
302 """Compute the intersection of this bounds object with another.
304 Parameters
305 ----------
306 other
307 Bounds to intersect with this one.
308 """
309 from ._concrete_bounds import _intersect_cgb
311 return _intersect_cgb(self, other)
313 def contains_cell(self, index: CellIJ) -> bool:
314 """Test whether the given cell is in the bounds.
316 Parameters
317 ----------
318 index
319 Index of the cell to test.
320 """
321 return (
322 (index.i >= self.subgrid_start.i and index.i < self.subgrid_stop.i)
323 and (index.j >= self.subgrid_start.j and index.j < self.subgrid_stop.j)
324 and index not in self.missing
325 )
327 def missing_boxes(self) -> Iterator[Box]:
328 """Iterate over the bounding boxes of the missing cells."""
329 for index in sorted(self.missing):
330 yield self.grid.bbox_of(index)
332 def cell_indices(self) -> Iterator[CellIJ]:
333 """Iterate over the indices of the cells in these bounds."""
334 for i in range(self.subgrid_start.i, self.subgrid_stop.i):
335 for j in range(self.subgrid_start.j, self.subgrid_stop.j):
336 index = CellIJ(i=i, j=j)
337 if index not in self.missing:
338 yield index
340 def __getitem__(self, bbox: Box) -> CellGridBounds:
341 if not self.bbox.contains(bbox): 341 ↛ 342line 341 didn't jump to line 342 because the condition on line 341 was never true
342 raise ValueError(
343 f"Original grid bounding box {self.bbox} does not contain the subset bounding box {bbox}."
344 )
345 c = self.grid.cell_shape
346 s = self.grid.bbox.start
347 i1 = (bbox.y.start - s.y) // c.y
348 j1 = (bbox.x.start - s.x) // c.x
349 i2 = math.ceil((bbox.y.stop - s.y) / c.y)
350 j2 = math.ceil((bbox.x.stop - s.x) / c.x)
351 subset_bbox = Box.factory[i1 * c.y + s.y : i2 * c.y + s.y, j1 * c.x + s.x : j2 * c.x + s.x]
352 grid_as_box = Box.factory[i1:i2, j1:j2]
353 subset_missing = {index for index in self.missing if grid_as_box.contains(y=index.i, x=index.j)}
354 return CellGridBounds(grid=self.grid, bbox=subset_bbox, missing=frozenset(subset_missing))
356 def serialize(self) -> CellGridBounds:
357 """Convert a bounds instance into a serializable object."""
358 return self
360 def deserialize(self) -> CellGridBounds:
361 """Deserialize a bounds object on the assumption it is a
362 `CellGridBounds`.
364 This method just returns the `CellGridBounds` itself, since that
365 already provides Pydantic serialization hooks. It exists for
366 compatibility with the `.Bounds` protocol.
367 """
368 return self
371class PatchDefinition(pydantic.BaseModel, frozen=True):
372 """Identifiers and geometry for a full patch."""
374 id: int = pydantic.Field(description="ID for the patch.")
375 index: SerializableYX[int] = pydantic.Field(description="2-d index of this patch within the tract.")
376 inner_bbox: Box = pydantic.Field(description="Inner bounding box of this patch.")
377 cells: CellGrid = pydantic.Field(description="Cell grid for the full patch.")
379 def __str__(self) -> str:
380 return (
381 f"id={self.id}, index=(y={self.index.y}, x={self.index.x}), "
382 f"inner_bbox={self.inner_bbox}, cells=({self.cells})"
383 )
385 @property
386 def outer_bbox(self) -> Box:
387 """The outer bounding box of this patch (`.Box`)."""
388 return self.cells.bbox
391if TYPE_CHECKING:
393 def _test_types() -> None:
394 arr = np.zeros(3)
395 bbox = Box.from_shape((100, 200))
396 grid = CellGrid(bbox=bbox, cell_shape=YX(10, 20))
397 cgb = CellGridBounds(grid=grid, bbox=bbox)
399 # CellGridBounds satisfies the Bounds Protocol.
400 bounds: Bounds = cgb
402 # CellGridBounds.contains: XY/YX, scalar, array-like
403 assert_type(cgb.contains(x=1, y=2), bool)
404 assert_type(cgb.contains(x=1.0, y=2.0), bool)
405 assert_type(cgb.contains(x=arr, y=arr), np.ndarray)
406 assert_type(cgb.contains(XY(1, 2)), bool)
407 assert_type(cgb.contains(YX(2, 1)), bool)
408 assert_type(cgb.contains(XY(arr, arr)), np.ndarray)
409 assert_type(cgb.contains(YX(arr, arr)), np.ndarray)
411 # Via the Bounds Protocol view, same signatures hold.
412 assert_type(bounds.contains(x=1, y=1), bool)
413 assert_type(bounds.contains(x=1.0, y=1.0), bool)
414 assert_type(bounds.contains(x=arr, y=arr), np.ndarray)
415 assert_type(bounds.contains(XY(1, 1)), bool)
416 assert_type(bounds.contains(YX(1, 1)), bool)
417 assert_type(bounds.contains(XY(arr, arr)), np.ndarray)
418 assert_type(bounds.contains(YX(arr, arr)), np.ndarray)