Coverage for python / lsst / images / _transforms / _frame_set.py: 75%

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. 

11 

12from __future__ import annotations 

13 

14__all__ = ("FrameLookupError", "FrameSet") 

15 

16from abc import ABC, abstractmethod 

17 

18from . import _frames # use this import style to facilitate pattern matching 

19from ._transform import Transform 

20 

21 

22class FrameLookupError(LookupError): 

23 """Exception raised when a frame cannot be found in a `FrameSet`.""" 

24 

25 

26class FrameSet(ABC): 

27 """A container or factory for `Transform` objects that relates frames. 

28 

29 Notes 

30 ----- 

31 `FrameSet` supposes ``in`` (``__contains__``) tests on individual `Frame` 

32 objects to test whether they are known to the frame set, and indexing 

33 (``__getitem__``) of **pairs** of frames to return a `Transform` that maps 

34 the first to the second. 

35 """ 

36 

37 @abstractmethod 

38 def __contains__(self, frame: _frames.Frame) -> bool: 

39 raise NotImplementedError() 

40 

41 @abstractmethod 

42 def __getitem__[I: _frames.Frame, O: _frames.Frame](self, key: tuple[I, O]) -> Transform[I, O]: 

43 raise NotImplementedError() 

44 

45 def get[I: _frames.Frame, O: _frames.Frame](self, in_frame: I, out_frame: O) -> Transform[I, O] | None: 

46 """Return the `Transform` that maps the two frames, or `None` if at 

47 least one is not known to the `FrameSet`. 

48 """ 

49 try: 

50 return self[in_frame, out_frame] 

51 except FrameLookupError: 

52 return None