196 lines
6.3 KiB
Python
196 lines
6.3 KiB
Python
"""
|
|
The classes here provide support for using custom classes with
|
|
Matplotlib, e.g., those that do not expose the array interface but know
|
|
how to convert themselves to arrays. It also supports classes with
|
|
units and units conversion. Use cases include converters for custom
|
|
objects, e.g., a list of datetime objects, as well as for objects that
|
|
are unit aware. We don't assume any particular units implementation;
|
|
rather a units implementation must register with the Registry converter
|
|
dictionary and provide a `ConversionInterface`. For example,
|
|
here is a complete implementation which supports plotting with native
|
|
datetime objects::
|
|
|
|
import matplotlib.units as units
|
|
import matplotlib.dates as dates
|
|
import matplotlib.ticker as ticker
|
|
import datetime
|
|
|
|
class DateConverter(units.ConversionInterface):
|
|
|
|
@staticmethod
|
|
def convert(value, unit, axis):
|
|
"Convert a datetime value to a scalar or array."
|
|
return dates.date2num(value)
|
|
|
|
@staticmethod
|
|
def axisinfo(unit, axis):
|
|
"Return major and minor tick locators and formatters."
|
|
if unit != 'date':
|
|
return None
|
|
majloc = dates.AutoDateLocator()
|
|
majfmt = dates.AutoDateFormatter(majloc)
|
|
return units.AxisInfo(majloc=majloc, majfmt=majfmt, label='date')
|
|
|
|
@staticmethod
|
|
def default_units(x, axis):
|
|
"Return the default unit for x or None."
|
|
return 'date'
|
|
|
|
# Finally we register our object type with the Matplotlib units registry.
|
|
units.registry[datetime.date] = DateConverter()
|
|
"""
|
|
|
|
from decimal import Decimal
|
|
from numbers import Number
|
|
|
|
import numpy as np
|
|
from numpy import ma
|
|
|
|
from matplotlib import cbook
|
|
|
|
|
|
class ConversionError(TypeError):
|
|
pass
|
|
|
|
|
|
def _is_natively_supported(x):
|
|
"""
|
|
Return whether *x* is of a type that Matplotlib natively supports or an
|
|
array of objects of such types.
|
|
"""
|
|
# Matplotlib natively supports all number types except Decimal.
|
|
if np.iterable(x):
|
|
# Assume lists are homogeneous as other functions in unit system.
|
|
for thisx in x:
|
|
if thisx is ma.masked:
|
|
continue
|
|
return isinstance(thisx, Number) and not isinstance(thisx, Decimal)
|
|
else:
|
|
return isinstance(x, Number) and not isinstance(x, Decimal)
|
|
|
|
|
|
class AxisInfo:
|
|
"""
|
|
Information to support default axis labeling, tick labeling, and limits.
|
|
|
|
An instance of this class must be returned by
|
|
`ConversionInterface.axisinfo`.
|
|
"""
|
|
def __init__(self, majloc=None, minloc=None,
|
|
majfmt=None, minfmt=None, label=None,
|
|
default_limits=None):
|
|
"""
|
|
Parameters
|
|
----------
|
|
majloc, minloc : Locator, optional
|
|
Tick locators for the major and minor ticks.
|
|
majfmt, minfmt : Formatter, optional
|
|
Tick formatters for the major and minor ticks.
|
|
label : str, optional
|
|
The default axis label.
|
|
default_limits : optional
|
|
The default min and max limits of the axis if no data has
|
|
been plotted.
|
|
|
|
Notes
|
|
-----
|
|
If any of the above are ``None``, the axis will simply use the
|
|
default value.
|
|
"""
|
|
self.majloc = majloc
|
|
self.minloc = minloc
|
|
self.majfmt = majfmt
|
|
self.minfmt = minfmt
|
|
self.label = label
|
|
self.default_limits = default_limits
|
|
|
|
|
|
class ConversionInterface:
|
|
"""
|
|
The minimal interface for a converter to take custom data types (or
|
|
sequences) and convert them to values Matplotlib can use.
|
|
"""
|
|
|
|
@staticmethod
|
|
def axisinfo(unit, axis):
|
|
"""Return an `.AxisInfo` for the axis with the specified units."""
|
|
return None
|
|
|
|
@staticmethod
|
|
def default_units(x, axis):
|
|
"""Return the default unit for *x* or ``None`` for the given axis."""
|
|
return None
|
|
|
|
@staticmethod
|
|
def convert(obj, unit, axis):
|
|
"""
|
|
Convert *obj* using *unit* for the specified *axis*.
|
|
|
|
If *obj* is a sequence, return the converted sequence. The output must
|
|
be a sequence of scalars that can be used by the numpy array layer.
|
|
"""
|
|
return obj
|
|
|
|
|
|
class DecimalConverter(ConversionInterface):
|
|
"""Converter for decimal.Decimal data to float."""
|
|
|
|
@staticmethod
|
|
def convert(value, unit, axis):
|
|
"""
|
|
Convert Decimals to floats.
|
|
|
|
The *unit* and *axis* arguments are not used.
|
|
|
|
Parameters
|
|
----------
|
|
value : decimal.Decimal or iterable
|
|
Decimal or list of Decimal need to be converted
|
|
"""
|
|
if isinstance(value, Decimal):
|
|
return float(value)
|
|
# value is Iterable[Decimal]
|
|
elif isinstance(value, ma.MaskedArray):
|
|
return ma.asarray(value, dtype=float)
|
|
else:
|
|
return np.asarray(value, dtype=float)
|
|
|
|
# axisinfo and default_units can be inherited as Decimals are Numbers.
|
|
|
|
|
|
class Registry(dict):
|
|
"""Register types with conversion interface."""
|
|
|
|
def get_converter(self, x):
|
|
"""Get the converter interface instance for *x*, or None."""
|
|
# Unpack in case of e.g. Pandas or xarray object
|
|
x = cbook._unpack_to_numpy(x)
|
|
|
|
if isinstance(x, np.ndarray):
|
|
# In case x in a masked array, access the underlying data (only its
|
|
# type matters). If x is a regular ndarray, getdata() just returns
|
|
# the array itself.
|
|
x = np.ma.getdata(x).ravel()
|
|
# If there are no elements in x, infer the units from its dtype
|
|
if not x.size:
|
|
return self.get_converter(np.array([0], dtype=x.dtype))
|
|
for cls in type(x).__mro__: # Look up in the cache.
|
|
try:
|
|
return self[cls]
|
|
except KeyError:
|
|
pass
|
|
try: # If cache lookup fails, look up based on first element...
|
|
first = cbook._safe_first_finite(x)
|
|
except (TypeError, StopIteration):
|
|
pass
|
|
else:
|
|
# ... and avoid infinite recursion for pathological iterables for
|
|
# which indexing returns instances of the same iterable class.
|
|
if type(first) is not type(x):
|
|
return self.get_converter(first)
|
|
return None
|
|
|
|
|
|
registry = Registry()
|
|
registry[Decimal] = DecimalConverter()
|