77 lines
2.3 KiB
Python
77 lines
2.3 KiB
Python
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#!/usr/bin/env python
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from datetime import datetime
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import six
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from leather.scales.base import Scale
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from leather.ticks.score_time import ScoreTimeTicker
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class Temporal(Scale):
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"""
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A scale that linearly maps date/datetime values from a domain to a range.
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:param domain_min:
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The minimum date/datetime of the input domain.
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:param domain_max:
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The maximum date/datetime of the input domain.
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"""
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def __init__(self, domain_min, domain_max):
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if domain_min >= domain_max:
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raise ValueError('Domain minimum must be less than domain maximum. Inverted domains are not currently supported.')
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self._data_min = domain_min
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self._data_max = domain_max
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self._ticker = ScoreTimeTicker(self._data_min, self._data_max)
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def contains(self, v):
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"""
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Return :code:`True` if a given value is contained within this scale's
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domain.
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"""
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return self._data_min <= v <= self._data_max
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def project(self, value, range_min, range_max):
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"""
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Project a value in this scale's domain to a target range.
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"""
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numerator = value - self._ticker.min
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denominator = self._ticker.max - self._ticker.min
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# Python 2 does not support timedelta division
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if six.PY2:
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if isinstance(self._ticker.min, datetime):
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numerator = numerator.total_seconds()
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denominator = denominator.total_seconds()
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else:
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numerator = float(numerator.days)
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denominator = float(denominator.days)
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pos = numerator / denominator
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return ((range_max - range_min) * pos) + range_min
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def project_interval(self, value, range_min, range_max):
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"""
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Project a value in this scale's domain to an interval in the target
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range. This is used for places :class:`.Bars` and :class:`.Columns`.
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"""
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raise NotImplementedError
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def ticks(self):
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"""
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Generate a series of ticks for this scale.
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"""
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return self._ticker.ticks
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def format_tick(self, value, i, count):
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"""
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Format ticks for display.
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This method is used as a default which will be ignored if the user
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provides a custom tick formatter to the axis.
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"""
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return self._ticker.format_tick(value)
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