Source code for bokeh.models.mappers

''' Models for mapping values from one range or space to another.

'''
from __future__ import absolute_import

import warnings

from .. import palettes
from ..core.has_props import abstract
from ..core.properties import Color, Either, Enum, Float, Int, Seq, String, Tuple
from ..core.enums import Palette
from .transforms import Transform

@abstract
[docs]class ColorMapper(Transform): ''' Base class for color mapper types. ''' palette = Seq(Color, help=""" A sequence of colors to use as the target palette for mapping. This property can also be set as a ``String``, to the name of any of the palettes shown in :ref:`bokeh.palettes`. """).accepts(Enum(Palette), lambda pal: getattr(palettes, pal)) nan_color = Color(default="gray", help=""" Color to be used if data is NaN. Default: 'gray' """) def __init__(self, palette=None, **kwargs): if palette is not None: kwargs['palette'] = palette super(ColorMapper, self).__init__(**kwargs)
[docs]class CategoricalColorMapper(ColorMapper): ''' Map categories to colors. Values that are passed to this mapper that aren't in factors will be assigned the nan_color. ''' factors = Either(Seq(String), Seq(Tuple(String, String)), Seq(Tuple(String, String, String)), default=None, help=""" A sequence of factors / categories that map to the color palette. For example the following color mapper: .. code-block:: python mapper = CategoricalColorMapper(palette=["red", "blue"], factors=["foo", "bar"]) will map the factor ``"foo"`` to red and the factor ``"bar"`` to blue. """) start = Int(default=0, help=""" A start index to "slice" data factors with before color mapping. For example, if the data to color map consists of 2-level factors such as ``["2016", "sales"]`` and ``["2016", "marketing"]``, then setting ``start=1`` will perform color mapping only based on the second sub-factor (i.e. in this case based on the department ``"sales"`` or ``"marketing"``) """) end = Int(help=""" A start index to "slice" data factors with before color mapping. For example, if the data to color map consists of 2-level factors such as ``["2016", "sales"]`` and ``["2017", "marketing"]``, then setting ``end=1`` will perform color mapping only based on the first sub-factor (i.e. in this case based on the year ``"2016"`` or ``"2017"``) If ``None`` then all sub-factors from ``start`` to the end of the factor will be used for color mapping. """) def __init__(self, **kwargs): super(ColorMapper, self).__init__(**kwargs) palette = self.palette factors = self.factors if palette and factors: if len(palette) < len(factors): extra_factors = factors[len(palette):] warnings.warn("Palette length does not match number of factors. %s will be assigned to `nan_color` %s" % (extra_factors, self.nan_color))
@abstract
[docs]class ContinuousColorMapper(ColorMapper): ''' Base class for continuous color mapper types. ''' low = Float(help=""" The minimum value of the range to map into the palette. Values below this are clamped to ``low``. """) high = Float(help=""" The maximum value of the range to map into the palette. Values above this are clamped to ``high``. """) low_color = Color(default=None, help=""" Color to be used if data is lower than ``low`` value. If None, values lower than ``low`` are mapped to the first color in the palette. """) high_color = Color(default=None, help=""" Color to be used if data is lower than ``high`` value. If None, values lower than ``high`` are mapped to the last color in the palette. """)
[docs]class LinearColorMapper(ContinuousColorMapper): ''' Map numbers in a range [*low*, *high*] linearly into a sequence of colors (a palette). For example, if the range is [0, 99] and the palette is ``['red', 'green', 'blue']``, the values would be mapped as follows:: x < 0 : 'red' # values < low are clamped 0 >= x < 33 : 'red' 33 >= x < 66 : 'green' 66 >= x < 99 : 'blue' 99 >= x : 'blue' # values > high are clamped '''
[docs]class LogColorMapper(ContinuousColorMapper): ''' Map numbers in a range [*low*, *high*] into a sequence of colors (a palette) on a natural logarithm scale. For example, if the range is [0, 25] and the palette is ``['red', 'green', 'blue']``, the values would be mapped as follows:: x < 0 : 'red' # values < low are clamped 0 >= x < 2.72 : 'red' # math.e ** 1 2.72 >= x < 7.39 : 'green' # math.e ** 2 7.39 >= x < 20.09 : 'blue' # math.e ** 3 20.09 >= x : 'blue' # values > high are clamped .. warning:: The LogColorMapper only works for images with scalar values that are non-negative. '''