matplotlib.colors.makeMappingArray¶
-
matplotlib.colors.makeMappingArray(N, data, gamma=1.0)[source]¶ [Deprecated] Create an N -element 1-d lookup table.
This assumes a mapping \(f : [0, 1] \rightarrow [0, 1]\). The returned data is an array of N values \(y = f(x)\) where x is sampled from [0, 1].
By default (gamma = 1) x is equidistantly sampled from [0, 1]. The gamma correction factor \(\gamma\) distorts this equidistant sampling by \(x \rightarrow x^\gamma\).
Parameters: - Nint
The number of elements of the created lookup table; at least 1.
- dataMx3 array-like or callable
Defines the mapping \(f\).
If a Mx3 array-like, the rows define values (x, y0, y1). The x values must start with x=0, end with x=1, and all x values be in increasing order.
A value between \(x_i\) and \(x_{i+1}\) is mapped to the range \(y^1_{i-1} \ldots y^0_i\) by linear interpolation.
For the simple case of a y-continuous mapping, y0 and y1 are identical.
The two values of y are to allow for discontinuous mapping functions. E.g. a sawtooth with a period of 0.2 and an amplitude of 1 would be:
[(0, 1, 0), (0.2, 1, 0), (0.4, 1, 0), ..., [(1, 1, 0)]
In the special case of
N == 1, by convention the returned value is y0 for x == 1.If data is a callable, it must accept and return numpy arrays:
data(x : ndarray) -> ndarray
and map values between 0 - 1 to 0 - 1.
- gammafloat
Gamma correction factor for input distribution x of the mapping.
Returns: - array
The lookup table where
lut[x * (N-1)]gives the closest value for values of x between 0 and 1.
Notes
This function is internally used for
LinearSegmentedColormap.Deprecated since version 3.2.