Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/imageio-2.35.1-py3.8.egg/imageio/plugins/npz.py: 55%

1# -*- coding: utf-8 -*- 

2# imageio is distributed under the terms of the (new) BSD License. 

3 

4"""Read/Write NPZ files. 

5 

6Backend: `Numpy <https://numpy.org/doc/stable/reference/generated/numpy.savez.html>`_ 

7 

8NPZ is a file format by numpy that provides storage of array data using gzip 

9compression. This imageio plugin supports data of any shape, and also supports 

10multiple images per file. However, the npz format does not provide streaming; 

11all data is read/written at once. Further, there is no support for meta data. 

12 

13See the BSDF format for a similar (but more fully featured) format. 

14 

15Parameters 

16---------- 

17None 

18 

19Notes 

20----- 

21This format is not available on Pypy. 

22 

23""" 

24 

25import numpy as np 

26 

27from ..core import Format 

28 

29 

30class NpzFormat(Format): 

31 """See :mod:`imageio.plugins.npz`""" 

32 

33 def _can_read(self, request): 

34 # We support any kind of image data 

35 return request.extension in self.extensions 

36 

37 def _can_write(self, request): 

38 # We support any kind of image data 

39 return request.extension in self.extensions 

40 

41 # -- reader 

42 

43 class Reader(Format.Reader): 

44 def _open(self): 

45 # Load npz file, which provides another file like object 

46 self._npz = np.load(self.request.get_file()) 

47 assert isinstance(self._npz, np.lib.npyio.NpzFile) 

48 # Get list of names, ordered by name, but smarter 

49 self._names = sorted(self._npz.files, key=lambda x: x.split("_")[-1]) 

50 

51 def _close(self): 

52 self._npz.close() 

53 

54 def _get_length(self): 

55 return len(self._names) 

56 

57 def _get_data(self, index): 

58 # Get data 

59 if index < 0 or index >= len(self._names): 

60 raise IndexError("Index out of range while reading from nzp") 

61 im = self._npz[self._names[index]] 

62 # Return array and empty meta data 

63 return im, {} 

64 

65 def _get_meta_data(self, index): 

66 # Get the meta data for the given index 

67 raise RuntimeError("The npz format does not support meta data.") 

68 

69 # -- writer 

70 

71 class Writer(Format.Writer): 

72 def _open(self): 

73 # Npz is not such a great format. We cannot stream to the file. 

74 # So we remember all images and write them to file at the end. 

75 self._images = [] 

76 

77 def _close(self): 

78 # Write everything 

79 np.savez_compressed(self.request.get_file(), *self._images) 

80 

81 def _append_data(self, im, meta): 

82 self._images.append(im) # discart meta data 

83 

84 def set_meta_data(self, meta): 

85 raise RuntimeError("The npz format does not support meta data.")