# -*- coding: utf-8 -*-
# Copyright (c) 2015, imageio contributors
# imageio is distributed under the terms of the (new) BSD License.
"""
Various utilities for imageio
"""
from __future__ import absolute_import, print_function, division
import re
import os
import sys
import time
import struct
from warnings import warn
import numpy as np
IS_PYPY = '__pypy__' in sys.builtin_module_names
THIS_DIR = os.path.abspath(os.path.dirname(__file__))
# Taken from six.py
PY3 = sys.version_info[0] == 3
if PY3:
string_types = str,
text_type = str
binary_type = bytes
else: # pragma: no cover
string_types = basestring, # noqa
text_type = unicode # noqa
binary_type = str
def urlopen(*args, **kwargs):
""" Compatibility function for the urlopen function. Raises an
RuntimeError if urlopen could not be imported (which can occur in
frozen applications.
"""
try:
from urllib2 import urlopen
except ImportError:
try:
from urllib.request import urlopen # Py3k
except ImportError:
raise RuntimeError('Could not import urlopen.')
return urlopen(*args, **kwargs)
def image_as_uint(im, bitdepth=None):
""" Convert the given image to uint (default: uint8)
If the dtype already matches the desired format, it is returned
as-is. If the image is float, and all values are between 0 and 1,
the values are multiplied by np.power(2.0, bitdepth). In all other
situations, the values are scaled such that the minimum value
becomes 0 and the maximum value becomes np.power(2.0, bitdepth)-1
(255 for 8-bit and 65535 for 16-bit).
"""
if not bitdepth:
bitdepth = 8
if not isinstance(im, np.ndarray):
raise ValueError('Image must be a numpy array')
if bitdepth == 8:
out_type = np.uint8
elif bitdepth == 16:
out_type = np.uint16
else:
raise ValueError('Bitdepth must be either 8 or 16')
dtype_str = str(im.dtype)
if ((im.dtype == np.uint8 and bitdepth == 8) or
(im.dtype == np.uint16 and bitdepth == 16)):
# Already the correct format? Return as-is
return im
if (dtype_str.startswith('float') and
np.nanmin(im) >= 0 and np.nanmax(im) <= 1):
warn('Lossy conversion from {0} to {1}, range [0, 1]'.format(
dtype_str, out_type.__name__))
im = im.astype(np.float64) * (np.power(2.0, bitdepth)-1)
elif im.dtype == np.uint16 and bitdepth == 8:
warn('Lossy conversion from uint16 to uint8, '
'loosing 8 bits of resolution')
im = np.right_shift(im, 8)
elif im.dtype == np.uint32:
warn('Lossy conversion from uint32 to {0}, '
'loosing {1} bits of resolution'.format(out_type.__name__,
32-bitdepth))
im = np.right_shift(im, 32-bitdepth)
elif im.dtype == np.uint64:
warn('Lossy conversion from uint64 to {0}, '
'loosing {1} bits of resolution'.format(out_type.__name__,
64-bitdepth))
im = np.right_shift(im, 64-bitdepth)
else:
mi = np.nanmin(im)
ma = np.nanmax(im)
if not np.isfinite(mi):
raise ValueError('Minimum image value is not finite')
if not np.isfinite(ma):
raise ValueError('Maximum image value is not finite')
if ma == mi:
raise ValueError('Max value == min value, ambiguous given dtype')
warn('Conversion from {0} to {1}, '
'range [{2}, {3}]'.format(dtype_str, out_type.__name__, mi, ma))
# Now make float copy before we scale
im = im.astype('float64')
# Scale the values between 0 and 1 then multiply by the max value
im = (im - mi) / (ma - mi) * (np.power(2.0, bitdepth)-1)
assert np.nanmin(im) >= 0
assert np.nanmax(im) < np.power(2.0, bitdepth)
return im.astype(out_type)
# currently not used ... the only use it to easily provide the global meta info
class ImageList(list):
def __init__(self, meta=None):
list.__init__(self)
# Check
if not (meta is None or isinstance(meta, dict)):
raise ValueError('ImageList expects meta data to be a dict.')
# Convert and return
self._meta = meta if meta is not None else {}
@property
def meta(self):
""" The dict with the meta data of this image.
"""
return self._meta
class Image(np.ndarray):
""" Image(array, meta=None)
A subclass of np.ndarray that has a meta attribute.
Following scikit-image, we leave this as a normal numpy array as much
as we can.
"""
def __new__(cls, array, meta=None):
# Check
if not isinstance(array, np.ndarray):
raise ValueError('Image expects a numpy array.')
if not (meta is None or isinstance(meta, dict)):
raise ValueError('Image expects meta data to be a dict.')
# Convert and return
meta = meta if meta is not None else {}
try:
ob = array.view(cls)
except AttributeError: # pragma: no cover
# Just return the original; no metadata on the array in Pypy!
return array
ob._copy_meta(meta)
return ob
def _copy_meta(self, meta):
""" Make a 2-level deep copy of the meta dictionary.
"""
self._meta = Dict()
for key, val in meta.items():
if isinstance(val, dict):
val = Dict(val) # Copy this level
self._meta[key] = val
@property
def meta(self):
""" The dict with the meta data of this image.
"""
return self._meta
def __array_finalize__(self, ob):
""" So the meta info is maintained when doing calculations with
the array.
"""
if isinstance(ob, Image):
self._copy_meta(ob.meta)
else:
self._copy_meta({})
def __array_wrap__(self, out, context=None):
""" So that we return a native numpy array (or scalar) when a
reducting ufunc is applied (such as sum(), std(), etc.)
"""
if not out.shape:
return out.dtype.type(out) # Scalar
elif out.shape != self.shape:
return out.view(type=np.ndarray)
else:
return out # Type Image
def asarray(a):
""" Pypy-safe version of np.asarray. Pypy's np.asarray consumes a
*lot* of memory if the given array is an ndarray subclass. This
function does not.
"""
if isinstance(a, np.ndarray):
if IS_PYPY: # pragma: no cover
a = a.copy() # pypy has issues with base views
plain = a.view(type=np.ndarray)
return plain
return np.asarray(a)
try:
from collections import OrderedDict as _dict
except ImportError:
_dict = dict
class Dict(_dict):
""" A dict in which the keys can be get and set as if they were
attributes. Very convenient in combination with autocompletion.
This Dict still behaves as much as possible as a normal dict, and
keys can be anything that are otherwise valid keys. However,
keys that are not valid identifiers or that are names of the dict
class (such as 'items' and 'copy') cannot be get/set as attributes.
"""
__reserved_names__ = dir(_dict()) # Also from OrderedDict
__pure_names__ = dir(dict())
def __getattribute__(self, key):
try:
return object.__getattribute__(self, key)
except AttributeError:
if key in self:
return self[key]
else:
raise
def __setattr__(self, key, val):
if key in Dict.__reserved_names__:
# Either let OrderedDict do its work, or disallow
if key not in Dict.__pure_names__:
return _dict.__setattr__(self, key, val)
else:
raise AttributeError('Reserved name, this key can only ' +
'be set via ``d[%r] = X``' % key)
else:
# if isinstance(val, dict): val = Dict(val) -> no, makes a copy!
self[key] = val
def __dir__(self):
isidentifier = lambda x: bool(re.match(r'[a-z_]\w*$', x, re.I))
names = [k for k in self.keys() if
(isinstance(k, string_types) and isidentifier(k))]
return Dict.__reserved_names__ + names
class BaseProgressIndicator:
""" BaseProgressIndicator(name)
A progress indicator helps display the progres of a task to the
user. Progress can be pending, running, finished or failed.
Each task has:
* a name - a short description of what needs to be done.
* an action - the current action in performing the task (e.g. a subtask)
* progress - how far the task is completed
* max - max number of progress units. If 0, the progress is indefinite
* unit - the units in which the progress is counted
* status - 0: pending, 1: in progress, 2: finished, 3: failed
This class defines an abstract interface. Subclasses should implement
_start, _stop, _update_progress(progressText), _write(message).
"""
def __init__(self, name):
self._name = name
self._action = ''
self._unit = ''
self._max = 0
self._status = 0
self._last_progress_update = 0
def start(self, action='', unit='', max=0):
""" start(action='', unit='', max=0)
Start the progress. Optionally specify an action, a unit,
and a maxium progress value.
"""
if self._status == 1:
self.finish()
self._action = action
self._unit = unit
self._max = max
#
self._progress = 0
self._status = 1
self._start()
def status(self):
""" status()
Get the status of the progress - 0: pending, 1: in progress,
2: finished, 3: failed
"""
return self._status
def set_progress(self, progress=0, force=False):
""" set_progress(progress=0, force=False)
Set the current progress. To avoid unnecessary progress updates
this will only have a visual effect if the time since the last
update is > 0.1 seconds, or if force is True.
"""
self._progress = progress
# Update or not?
if not (force or (time.time() - self._last_progress_update > 0.1)):
return
self._last_progress_update = time.time()
# Compose new string
unit = self._unit or ''
progressText = ''
if unit == '%':
progressText = '%2.1f%%' % progress
elif self._max > 0:
percent = 100 * float(progress) / self._max
progressText = '%i/%i %s (%2.1f%%)' % (progress, self._max, unit,
percent)
elif progress > 0:
if isinstance(progress, float):
progressText = '%0.4g %s' % (progress, unit)
else:
progressText = '%i %s' % (progress, unit)
# Update
self._update_progress(progressText)
def increase_progress(self, extra_progress):
""" increase_progress(extra_progress)
Increase the progress by a certain amount.
"""
self.set_progress(self._progress + extra_progress)
def finish(self, message=None):
""" finish(message=None)
Finish the progress, optionally specifying a message. This will
not set the progress to the maximum.
"""
self.set_progress(self._progress, True) # fore update
self._status = 2
self._stop()
if message is not None:
self._write(message)
def fail(self, message=None):
""" fail(message=None)
Stop the progress with a failure, optionally specifying a message.
"""
self.set_progress(self._progress, True) # fore update
self._status = 3
self._stop()
message = 'FAIL ' + (message or '')
self._write(message)
def write(self, message):
""" write(message)
Write a message during progress (such as a warning).
"""
if self.__class__ == BaseProgressIndicator:
# When this class is used as a dummy, print explicit message
print(message)
else:
return self._write(message)
# Implementing classes should implement these
def _start(self):
pass
def _stop(self):
pass
def _update_progress(self, progressText):
pass
def _write(self, message):
pass
class StdoutProgressIndicator(BaseProgressIndicator):
""" StdoutProgressIndicator(name)
A progress indicator that shows the progress in stdout. It
assumes that the tty can appropriately deal with backspace
characters.
"""
def _start(self):
self._chars_prefix, self._chars = '', ''
# Write message
if self._action:
self._chars_prefix = '%s (%s): ' % (self._name, self._action)
else:
self._chars_prefix = '%s: ' % self._name
sys.stdout.write(self._chars_prefix)
sys.stdout.flush()
def _update_progress(self, progressText):
# If progress is unknown, at least make something move
if not progressText:
i1, i2, i3, i4 = '-\\|/'
M = {i1: i2, i2: i3, i3: i4, i4: i1}
progressText = M.get(self._chars, i1)
# Store new string and write
delChars = '\b'*len(self._chars)
self._chars = progressText
sys.stdout.write(delChars+self._chars)
sys.stdout.flush()
def _stop(self):
self._chars = self._chars_prefix = ''
sys.stdout.write('\n')
sys.stdout.flush()
def _write(self, message):
# Write message
delChars = '\b'*len(self._chars_prefix+self._chars)
sys.stdout.write(delChars+' '+message+'\n')
# Reprint progress text
sys.stdout.write(self._chars_prefix+self._chars)
sys.stdout.flush()
# From pyzolib/paths.py (https://bitbucket.org/pyzo/pyzolib/src/tip/paths.py)
def appdata_dir(appname=None, roaming=False):
""" appdata_dir(appname=None, roaming=False)
Get the path to the application directory, where applications are allowed
to write user specific files (e.g. configurations). For non-user specific
data, consider using common_appdata_dir().
If appname is given, a subdir is appended (and created if necessary).
If roaming is True, will prefer a roaming directory (Windows Vista/7).
"""
# Define default user directory
userDir = os.path.expanduser('~')
if not os.path.isdir(userDir): # pragma: no cover
userDir = '/var/tmp' # issue #54
# Get system app data dir
path = None
if sys.platform.startswith('win'):
path1, path2 = os.getenv('LOCALAPPDATA'), os.getenv('APPDATA')
path = (path2 or path1) if roaming else (path1 or path2)
elif sys.platform.startswith('darwin'):
path = os.path.join(userDir, 'Library', 'Application Support')
# On Linux and as fallback
if not (path and os.path.isdir(path)):
path = userDir
# Maybe we should store things local to the executable (in case of a
# portable distro or a frozen application that wants to be portable)
prefix = sys.prefix
if getattr(sys, 'frozen', None):
prefix = os.path.abspath(os.path.dirname(sys.path[0]))
for reldir in ('settings', '../settings'):
localpath = os.path.abspath(os.path.join(prefix, reldir))
if os.path.isdir(localpath): # pragma: no cover
try:
open(os.path.join(localpath, 'test.write'), 'wb').close()
os.remove(os.path.join(localpath, 'test.write'))
except IOError:
pass # We cannot write in this directory
else:
path = localpath
break
# Get path specific for this app
if appname:
if path == userDir:
appname = '.' + appname.lstrip('.') # Make it a hidden directory
path = os.path.join(path, appname)
if not os.path.isdir(path): # pragma: no cover
os.mkdir(path)
# Done
return path
def resource_dirs():
""" resource_dirs()
Get a list of directories where imageio resources may be located.
The first directory in this list is the "resources" directory in
the package itself. The second directory is the appdata directory
(~/.imageio on Linux). The list further contains the application
directory (for frozen apps), and may include additional directories
in the future.
"""
dirs = []
# Resource dir baked in the package
dirs.append(os.path.abspath(os.path.join(THIS_DIR, '..', 'resources')))
# Appdata directory
try:
dirs.append(appdata_dir('imageio'))
except Exception: # pragma: no cover
pass # The home dir may not be writable
# Directory where the app is located (mainly for frozen apps)
if sys.path and sys.path[0]:
# Get the path. If frozen, sys.path[0] is the name of the executable,
# otherwise it is the path to the directory that contains the script.
thepath = sys.path[0]
if getattr(sys, 'frozen', None):
thepath = os.path.dirname(thepath)
dirs.append(os.path.abspath(thepath))
return dirs
def get_platform():
""" get_platform()
Get a string that specifies the platform more specific than
sys.platform does. The result can be: linux32, linux64, win32,
win64, osx32, osx64. Other platforms may be added in the future.
"""
# Get platform
if sys.platform.startswith('linux'):
plat = 'linux%i'
elif sys.platform.startswith('win'):
plat = 'win%i'
elif sys.platform.startswith('darwin'):
plat = 'osx%i'
else: # pragma: no cover
return None
return plat % (struct.calcsize('P') * 8) # 32 or 64 bits
def has_module(module_name):
"""Check to see if a python module is available.
"""
if sys.version_info > (3, ):
import importlib
return importlib.find_loader(module_name) is not None
else: # pragma: no cover
import imp
try:
imp.find_module(module_name)
except ImportError:
return False
return True
