chaco.transform_color_mapper module

class chaco.transform_color_mapper.TransformColorMapper(segmentdata, **kwtraits)

Bases: chaco.color_mapper.ColorMapper

This class adds arbitrary data transformations to a ColorMapper.

The default ColorMapper is basically a linear mapper from data space to color space. A TransformColorMapper allows a nonlinear mapper to be created.

A ColorMapper works by linearly transforming the data from data space to the unit interval [0,1], and then linearly mapping that interval to the color space.

A TransformColorMapper allows an arbitrary transform to be inserted at two places in this process. First, an initial transformation, data_func can be applied to the data before is it mapped to [0,1]. Then another function, unit_func, can be applied to the transformed data on [0,1] before it is mapped to color space. Normally, a unit_func is map of the unit interval [0,1] to itself (e.g. x^2 or sin(pi*x/2)).

classmethod factory_from_color_map(color_map, data_func=None, unit_func=None, **traits)

Create a TransformColorMapper factory function from a standard colormap factory function.

WARNING: This function is untested; I realized I didn’t need it shortly after writing it, so I haven’t tried it yet. –WW

classmethod from_color_map(color_map, data_func=None, unit_func=None, **traits)

Create a TransformColorMapper from a colormap generator function.

The return value is an instance of TransformColorMapper, not a factory function, so this does not provide a direct replacement for a standard colormap factory function. For that, use the class method TransoformColorMapper.factory_from_color_map().

classmethod from_color_mapper(color_mapper, data_func=None, unit_func=None, **traits)

Create a TransformColorMapper from an existing ColorMapper instance.

map_index(data_array)

Maps an array of values to their corresponding color band index.

map_screen(data_array)

Maps an array of data values to an array of colors.

map_uint8(data_array)

Maps an array of data values to an array of colors.