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Refactored out read_common, remove ambiguity on return type.

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It was the case that _read_common could return either a list, a view, or
an image cube depending upon the jp2 subsampling or the image
dimensions.  No more.  Closed #100
This commit is contained in:
jevans 2013-08-12 20:12:23 -04:00
commit 4db8763056
1 changed files with 81 additions and 75 deletions
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156
glymur/jp2k.py
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@ -686,12 +686,12 @@ class Jp2k(Jp2kBox):
if data.shape[2] == 1:
# The third dimension has just a single layer. Make the image
# data 2D instead of 3D.
data = data.view()
data.shape = data.shape[0:2]
return data
def _read_openjp2(self, **kwargs):
def _read_openjp2(self, rlevel=0, layer=0, area=None, tile=None,
verbose=False):
"""Read a JPEG 2000 image using libopenjp2.
Parameters
@ -721,10 +721,46 @@ class Jp2k(Jp2kBox):
"""
self._subsampling_sanity_check()
img_array = self._read_common(as_bands=False, **kwargs)
dparam = self._populate_dparam(layer, rlevel, area, tile)
with ExitStack() as stack:
if hasattr(opj2.OPENJP2,
'opj_stream_create_default_file_stream_v3'):
filename = self.filename
stream = opj2.stream_create_default_file_stream_v3(filename,
True)
stack.callback(opj2.stream_destroy_v3, stream)
else:
fptr = libc.fopen(self.filename, 'rb')
stack.callback(libc.fclose, fptr)
stream = opj2.stream_create_default_file_stream(fptr, True)
stack.callback(opj2.stream_destroy, stream)
codec = opj2.create_decompress(self._codec_format)
stack.callback(opj2.destroy_codec, codec)
opj2.set_error_handler(codec, _ERROR_CALLBACK)
opj2.set_warning_handler(codec, _WARNING_CALLBACK)
if verbose:
opj2.set_info_handler(codec, _INFO_CALLBACK)
else:
opj2.set_info_handler(codec, None)
opj2.setup_decoder(codec, dparam)
image = opj2.read_header(stream, codec)
stack.callback(opj2.image_destroy, image)
if dparam.nb_tile_to_decode:
opj2.get_decoded_tile(codec, stream, image, dparam.tile_index)
else:
opj2.set_decode_area(codec, image,
dparam.DA_x0, dparam.DA_y0,
dparam.DA_x1, dparam.DA_y1)
opj2.decode(codec, stream, image)
opj2.end_decompress(codec, stream)
img_array = extract_image_cube(image)
if img_array.shape[2] == 1:
img_array = img_array.view()
img_array.shape = img_array.shape[0:2]
return img_array
@ -782,76 +818,8 @@ class Jp2k(Jp2kBox):
return dparam
def _read_common(self, rlevel=0, layer=0, area=None, tile=None,
verbose=False, as_bands=False):
"""Read a JPEG 2000 image.
Parameters
----------
layer : int, optional
Number of quality layer to decode.
rlevel : int, optional
Factor by which to rlevel output resolution.
area : tuple, optional
Specifies decoding image area,
(first_row, first_col, last_row, last_col)
tile : int, optional
Number of tile to decode.
verbose : bool, optional
Print informational messages produced by the OpenJPEG library.
as_bands : bool, optional
If true, return the individual 2D components in a list.
Returns
-------
img_array : ndarray
The individual image components or a single array.
"""
dparam = self._populate_dparam(layer, rlevel, area, tile)
with ExitStack() as stack:
if hasattr(opj2.OPENJP2,
'opj_stream_create_default_file_stream_v3'):
filename = self.filename
stream = opj2.stream_create_default_file_stream_v3(filename,
True)
stack.callback(opj2.stream_destroy_v3, stream)
else:
fptr = libc.fopen(self.filename, 'rb')
stack.callback(libc.fclose, fptr)
stream = opj2.stream_create_default_file_stream(fptr, True)
stack.callback(opj2.stream_destroy, stream)
codec = opj2.create_decompress(self._codec_format)
stack.callback(opj2.destroy_codec, codec)
opj2.set_error_handler(codec, _ERROR_CALLBACK)
opj2.set_warning_handler(codec, _WARNING_CALLBACK)
if verbose:
opj2.set_info_handler(codec, _INFO_CALLBACK)
else:
opj2.set_info_handler(codec, None)
opj2.setup_decoder(codec, dparam)
image = opj2.read_header(stream, codec)
stack.callback(opj2.image_destroy, image)
if dparam.nb_tile_to_decode:
opj2.get_decoded_tile(codec, stream, image, dparam.tile_index)
else:
opj2.set_decode_area(codec, image,
dparam.DA_x0, dparam.DA_y0,
dparam.DA_x1, dparam.DA_y1)
opj2.decode(codec, stream, image)
opj2.end_decompress(codec, stream)
if as_bands:
data = extract_image_bands(image)
else:
data = extract_image_cube(image)
return data
def read_bands(self, **kwargs):
def read_bands(self, rlevel=0, layer=0, area=None, tile=None,
verbose=False):
"""Read a JPEG 2000 image.
The only time you should use this method is when the image has
@ -898,7 +866,45 @@ class Jp2k(Jp2kBox):
"of OpenJP2 installed before using "
"this functionality.")
lst = self._read_common(as_bands=True, **kwargs)
dparam = self._populate_dparam(layer, rlevel, area, tile)
with ExitStack() as stack:
if hasattr(opj2.OPENJP2,
'opj_stream_create_default_file_stream_v3'):
filename = self.filename
stream = opj2.stream_create_default_file_stream_v3(filename,
True)
stack.callback(opj2.stream_destroy_v3, stream)
else:
fptr = libc.fopen(self.filename, 'rb')
stack.callback(libc.fclose, fptr)
stream = opj2.stream_create_default_file_stream(fptr, True)
stack.callback(opj2.stream_destroy, stream)
codec = opj2.create_decompress(self._codec_format)
stack.callback(opj2.destroy_codec, codec)
opj2.set_error_handler(codec, _ERROR_CALLBACK)
opj2.set_warning_handler(codec, _WARNING_CALLBACK)
if verbose:
opj2.set_info_handler(codec, _INFO_CALLBACK)
else:
opj2.set_info_handler(codec, None)
opj2.setup_decoder(codec, dparam)
image = opj2.read_header(stream, codec)
stack.callback(opj2.image_destroy, image)
if dparam.nb_tile_to_decode:
opj2.get_decoded_tile(codec, stream, image, dparam.tile_index)
else:
opj2.set_decode_area(codec, image,
dparam.DA_x0, dparam.DA_y0,
dparam.DA_x1, dparam.DA_y1)
opj2.decode(codec, stream, image)
opj2.end_decompress(codec, stream)
lst = extract_image_bands(image)
return lst
def get_codestream(self, header_only=True):