/usr/lib/python2.7/dist-packages/chaco/polar_mapper.py is in python-chaco 4.4.1-1.2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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Defines the PolarMapper class, which maps from a 1-D region in data space
into a 1-D output space.
"""
# Major library imports
from numpy import array
# Enthought library imports
from traits.api import Bool, Float
# Local relative imports
from abstract_mapper import AbstractMapper
###############################################################
# same as linear mapper at the moment... to be modified later #
###############################################################
class PolarMapper(AbstractMapper):
"""
Maps a 1-D data space to and from screen space by specifying a range in
data space and a corresponding fixed line in screen space.
This class concerns itself only with metric and not with orientation. So, to
"flip" the screen space orientation, swap the values for **low_pos**
and **high_pos**.
"""
#------------------------------------------------------------------------
# Private traits
#------------------------------------------------------------------------
_scale = Float(1.0) # number of screen space units per data space unit
_null_screen_range = Bool(False)
_null_data_range = Bool(False)
#------------------------------------------------------------------------
# Public methods
#------------------------------------------------------------------------
def map_screen(self, data_array):
""" map_screen(data_array) -> screen_array
Converts radius and theta values from *data_array*
to x and y values and then maps
values from data space into screen space.
"""
self._compute_scale()
if self._null_data_range:
return array([self.low_pos] * len(data_array))
else:
return (data_array - self.range.low) * self._scale + self.low_pos
def map_data(self, screen_val):
""" map_data(screen_val) -> data_val
Maps values from screen space into data space.
"""
self._compute_scale()
if self._null_screen_range:
return array([self.range.low])
else:
return (screen_val - self.low_pos) / self._scale + self.range.low
#------------------------------------------------------------------------
# Private methods
#------------------------------------------------------------------------
def _compute_scale(self):
if self._cache_valid:
return
if self.range is None:
self._cache_valid = False
return
d = self.range
screen_range = self.high_pos - self.low_pos
data_range = self._pol_to_rect(d.high) - self._pol_to_rect(d.low)
if screen_range == 0.0:
self._null_screen_range = True
else:
self._null_screen_range = False
if data_range == 0.0:
self._null_data_range = True
else:
self._scale = screen_range / data_range
self._null_data_range = False
self._cache_valid = True
return
# EOF
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