1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
|
#------------------------------------------------------------------------------
# Copyright (c) 2013-2025, Nucleic Development Team.
#
# Distributed under the terms of the Modified BSD License.
#
# The full license is in the file LICENSE, distributed with this software.
#------------------------------------------------------------------------------
""" Enaml Standard Library - Slider Transforms
This module contains declarative classes which can be used as children
of a `Slider` to transform the integer range of the slider into an
alternative data space.
"""
from atom.api import Value, Bool, Float, Range
from enaml.core.declarative import Declarative, d_
class SliderTransform(Declarative):
""" A base class for creating declarative slider transforms.
A SliderTransform must be subclassed to be useful. The abstract api
defined below must be implemented by the subclass.
When using a transform with a slider, the transform takes complete
ownership of the slider range. No effort is made to observe outside
changes to the slider range, so all changes should be made on the
transform.
"""
#: The data-space minimum for the transform. This may be redefined
#: by a subclass to enforce stronger typing.
minimum = d_(Value())
#: The data-space maximum for the transform. This may be redefined
#: by a subclass to enforce stronger typing.
maximum = d_(Value())
#: The data-space value for the transform. This may be redefined
#: by a subclass to enforce stronger typing.
value = d_(Value())
#: A boolean flag used to prevent loopback cycles.
_guard = Bool(False)
#--------------------------------------------------------------------------
# Private API
#--------------------------------------------------------------------------
def initialize(self):
""" A reimplemented initialization handler.
The parent slider values are initialized during the transform
initialization pass.
"""
super(SliderTransform, self).initialize()
self._apply_transform()
def parent_changed(self, old, new):
""" Handle the parent changed event for the transform.
"""
super(SliderTransform, self).parent_changed(old, new)
if old is not None:
old.unobserve('value', self._on_slider_value_changed)
if new is not None:
new.observe('value', self._on_slider_value_changed)
def _apply_transform(self, minimum=True, maximum=True, value=True):
""" Apply the current transform to the parent slider.
Parameters
----------
minimum : bool, optional
Whether or not to update the slider minimum. The default
is False.
maximum : bool, optional
Whether or not to update the slider maximum. The default
is False.
value : bool, optional
Whether or not to update the slider value. The default
is False.
"""
parent = self.parent
if parent is not None:
if minimum:
parent.minimum = self.get_minimum()
if maximum:
parent.maximum = self.get_maximum()
if value:
parent.value = self.get_value()
def _on_slider_value_changed(self, change):
""" Update the transformed value when slider changes.
"""
if change['type'] == 'update':
self._guard = True
try:
self.set_value(change['value'])
finally:
self._guard = False
def _observe_minimum(self, change):
""" Update the slider minimum on transform minimum change.
"""
if change['type'] == 'update':
self._apply_transform(maximum=False, value=False)
def _observe_maximum(self, change):
""" Update the slider maximum on transform maximum change.
"""
if change['type'] == 'update':
self._apply_transform(minimum=False, value=False)
def _observe_value(self, change):
""" Update the slider value on transform value change.
"""
if change['type'] == 'update' and not self._guard:
self._apply_transform(minimum=False, maximum=False)
#--------------------------------------------------------------------------
# Abstract API
#--------------------------------------------------------------------------
def get_minimum(self):
""" Get the minimum value of the transform as an int.
Returns
-------
result : int
The minimum value of the transform converted to an int.
"""
raise NotImplementedError
def get_maximum(self):
""" Get the maximum value of the transform as an int.
Returns
-------
result : int
The maximum value of the transform converted to an int.
"""
raise NotImplementedError
def get_value(self):
""" Get the value of the transform as an int.
Returns
-------
result : int
The value of the transform converted to an int.
"""
raise NotImplementedError
def set_value(self, value):
""" Set the value of the transform from an int.
Parameters
----------
value : int
The integer value of the slider.
"""
raise NotImplementedError
class FloatTransform(SliderTransform):
""" A concreted SliderTransform for floating point values.
"""
#: A redeclared parent class member which enforces float values.
minimum = d_(Float(0.0))
#: A redeclared parent class member which enforces float values.
maximum = d_(Float(1.0))
#: A redeclared parent class member which enforces float values.
value = d_(Float(0.0))
#: The number of stops to use between the minimum and maximum.
precision = d_(Range(low=1, value=100))
#--------------------------------------------------------------------------
# Abstract API Implementation
#--------------------------------------------------------------------------
def get_minimum(self):
""" Get the minimum value of the transform as an int.
Returns
-------
result : int
The minimum value of the transform converted to an int.
"""
return 0
def get_maximum(self):
""" Get the maximum value of the transform as an int.
Returns
-------
result : int
The maximum value of the transform converted to an int.
"""
return self.precision
def get_value(self):
""" Get the value of the transform as an int.
Returns
-------
result : int
The value of the transform converted to an int.
"""
offset = self.value - self.minimum
delta = self.maximum - self.minimum
return int(offset * self.precision / delta)
def set_value(self, val):
""" Set the value of the transform from an int.
Parameters
----------
value : int
The integer value of the slider.
"""
delta = self.maximum - self.minimum
self.value = (val * delta / self.precision) + self.minimum
|
