notebook/IPython/html/widgets/interaction.py

191 lines
6.9 KiB
Python

"""Interact with functions using widgets.
"""
#-----------------------------------------------------------------------------
# Copyright (c) 2013, the IPython Development Team.
#
# Distributed under the terms of the Modified BSD License.
#
# The full license is in the file COPYING.txt, distributed with this software.
#-----------------------------------------------------------------------------
#-----------------------------------------------------------------------------
# Imports
#-----------------------------------------------------------------------------
try: # Python >= 3.3
from inspect import signature, Parameter
except ImportError:
from IPython.utils.signatures import signature, Parameter
from IPython.html.widgets import (Widget, TextWidget,
FloatSliderWidget, IntSliderWidget, CheckboxWidget, DropdownWidget,
ContainerWidget)
from IPython.display import display, clear_output
from IPython.utils.py3compat import string_types, unicode_type
#-----------------------------------------------------------------------------
# Classes and Functions
#-----------------------------------------------------------------------------
def _matches(o, pattern):
if not len(o) == len(pattern):
return False
comps = zip(o,pattern)
return all(isinstance(obj,kind) for obj,kind in comps)
def _get_min_max_value(min, max, value):
"""Return min, max, value given input values with possible None."""
if value is None:
if not max > min:
raise ValueError('max must be greater than min: (min={0}, max={1})'.format(min, max))
value = min + abs(min-max)/2
value = type(min)(value)
elif min is None and max is None:
if value == 0.0:
min, max, value = 0.0, 1.0, 0.5
elif value == 0:
min, max, value = 0, 1, 0
elif isinstance(value, float):
min, max = -value, 3.0*value
elif isinstance(value, int):
min, max = -value, 3*value
else:
raise TypeError('expected a number, got: %r' % value)
else:
raise ValueError('unable to infer range, value from: ({0}, {1}, {2})'.format(min, max, value))
return min, max, value
def _widget_abbrev_single_value(o):
"""Make widgets from single values, which can be used written as parameter defaults."""
if isinstance(o, string_types):
return TextWidget(value=unicode_type(o))
elif isinstance(o, dict):
labels = [unicode_type(k) for k in o]
values = o.values()
w = DropdownWidget(value=values[0], values=values, labels=labels)
return w
# Special case float and int == 0.0
# get_range(value):
elif isinstance(o, bool):
return CheckboxWidget(value=o)
elif isinstance(o, float):
min, max, value = _get_min_max_value(None, None, o)
return FloatSliderWidget(value=o, min=min, max=max)
elif isinstance(o, int):
min, max, value = _get_min_max_value(None, None, o)
return IntSliderWidget(value=o, min=min, max=max)
def _widget_abbrev(o):
"""Make widgets from abbreviations: single values, lists or tuples."""
if isinstance(o, (list, tuple)):
if _matches(o, (int, int)):
min, max, value = _get_min_max_value(o[0], o[1], None)
return IntSliderWidget(value=value, min=min, max=max)
elif _matches(o, (int, int, int)):
min, max, value = _get_min_max_value(o[0], o[1], None)
return IntSliderWidget(value=value, min=min, max=max, step=o[2])
elif _matches(o, (float, float)):
min, max, value = _get_min_max_value(o[0], o[1], None)
return FloatSliderWidget(value=value, min=min, max=max)
elif _matches(o, (float, float, float)):
min, max, value = _get_min_max_value(o[0], o[1], None)
return FloatSliderWidget(value=value, min=min, max=max, step=o[2])
elif _matches(o, (float, float, int)):
min, max, value = _get_min_max_value(o[0], o[1], None)
return FloatSliderWidget(value=value, min=min, max=max, step=float(o[2]))
elif all(isinstance(x, string_types) for x in o):
return DropdownWidget(value=unicode_type(o[0]),
values=[unicode_type(k) for k in o])
else:
return _widget_abbrev_single_value(o)
def _widget_or_abbrev(value):
if isinstance(value, Widget):
return value
widget = _widget_abbrev(value)
if widget is None:
raise ValueError("%r cannot be transformed to a Widget" % value)
return widget
def _widget_for_param(param, kwargs):
"""Get a widget for a parameter.
We look for, in this order:
- keyword arguments passed to interact[ive]() that match the parameter name.
- function annotations
- default values
Returns an instance of Widget, or None if nothing suitable is found.
Raises ValueError if the kwargs or annotation value cannot be made into
a widget.
"""
if param.name in kwargs:
return _widget_or_abbrev(kwargs.pop(param.name))
if param.annotation is not Parameter.empty:
return _widget_or_abbrev(param.annotation)
if param.default is not Parameter.empty:
# Returns None if it's not suitable
return _widget_abbrev_single_value(param.default)
return None
def interactive(f, **kwargs):
"""Build a group of widgets for setting the inputs to a function."""
co = kwargs.pop('clear_output', True)
# First convert all args to Widget instances
widgets = []
container = ContainerWidget()
container.result = None
container.kwargs = dict()
# Extract parameters from the function signature
for param in signature(f).parameters.values():
param_widget = _widget_for_param(param, kwargs)
if param_widget is not None:
param_widget.description = param.name
widgets.append(param_widget)
# Extra parameters from keyword args - we assume f takes **kwargs
for name, value in sorted(kwargs.items(), key = lambda x: x[0]):
widget = _widget_or_abbrev(value)
widget.description = name
widgets.append(widget)
# This has to be done as an assignment, not using container.children.append,
# so that traitlets notices the update.
container.children = widgets
# Build the callback
def call_f(name, old, new):
actual_kwargs = {}
for widget in widgets:
value = widget.value
container.kwargs[widget.description] = value
actual_kwargs[widget.description] = value
if co:
clear_output(wait=True)
container.result = f(**actual_kwargs)
# Wire up the widgets
for widget in widgets:
widget.on_trait_change(call_f, 'value')
container.on_displayed(lambda _: call_f(None, None, None))
return container
def interact(f, **kwargs):
"""Interact with a function using widgets."""
w = interactive(f, **kwargs)
f.widget = w
display(w)