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colors

For a visual representation of the matplotlib colormaps, see the “Color” section in the gallery.

matplotlib.colors

A module for converting numbers or color arguments to RGB or RGBA

RGB and RGBA are sequences of, respectively, 3 or 4 floats in the range 0-1.

This module includes functions and classes for color specification conversions, and for mapping numbers to colors in a 1-D array of colors called a colormap. Colormapping typically involves two steps: a data array is first mapped onto the range 0-1 using an instance of Normalize or of a subclass; then this number in the 0-1 range is mapped to a color using an instance of a subclass of Colormap. Two are provided here: LinearSegmentedColormap, which is used to generate all the built-in colormap instances, but is also useful for making custom colormaps, and ListedColormap, which is used for generating a custom colormap from a list of color specifications.

The module also provides functions for checking whether an object can be interpreted as a color (is_color_like()), for converting such an object to an RGBA tuple (to_rgba()) or to an HTML-like hex string in the #rrggbb format (to_hex()), and a sequence of colors to an (n, 4) RGBA array (to_rgba_array()). Caching is used for efficiency.

Matplotlib recognizes the following formats to specify a color:

  • an RGB or RGBA tuple of float values in [0, 1] (e.g., (0.1, 0.2, 0.5) or (0.1, 0.2, 0.5, 0.3));
  • a hex RGB or RGBA string (e.g., '#0F0F0F' or '#0F0F0F0F');
  • a string representation of a float value in [0, 1] inclusive for gray level (e.g., '0.5');
  • one of {'b', 'g', 'r', 'c', 'm', 'y', 'k', 'w'};
  • a X11/CSS4 color name;
  • a name from the xkcd color survey; prefixed with 'xkcd:' (e.g., 'xkcd:sky blue');
  • one of {'tab:blue', 'tab:orange', 'tab:green', 'tab:red', 'tab:purple', 'tab:brown', 'tab:pink', 'tab:gray', 'tab:olive', 'tab:cyan'} which are the Tableau Colors from the ‘T10’ categorical palette (which is the default color cycle);
  • a “CN” color spec, i.e. 'C' followed by a single digit, which is an index into the default property cycle (matplotlib.rcParams['axes.prop_cycle']); the indexing occurs at artist creation time and defaults to black if the cycle does not include color.

All string specifications of color, other than “CN”, are case-insensitive.

Classes

BoundaryNorm(boundaries, ncolors[, clip]) Generate a colormap index based on discrete intervals.
Colormap(name[, N]) Baseclass for all scalar to RGBA mappings.
LightSource([azdeg, altdeg, hsv_min_val, …]) Create a light source coming from the specified azimuth and elevation.
LinearSegmentedColormap(name, segmentdata[, …]) Colormap objects based on lookup tables using linear segments.
ListedColormap(colors[, name, N]) Colormap object generated from a list of colors.
LogNorm([vmin, vmax, clip]) Normalize a given value to the 0-1 range on a log scale
NoNorm([vmin, vmax, clip]) Dummy replacement for Normalize, for the case where we want to use indices directly in a ScalarMappable .
Normalize([vmin, vmax, clip]) A class which, when called, can normalize data into the [0.0, 1.0] interval.
PowerNorm(gamma[, vmin, vmax, clip]) Normalize a given value to the [0, 1] interval with a power-law scaling.
SymLogNorm(linthresh[, linscale, vmin, …]) The symmetrical logarithmic scale is logarithmic in both the positive and negative directions from the origin.

Functions

from_levels_and_colors(levels, colors[, extend]) A helper routine to generate a cmap and a norm instance which behave similar to contourf’s levels and colors arguments.
hsv_to_rgb(hsv) convert hsv values in a numpy array to rgb values
rgb_to_hsv(arr) convert float rgb values (in the range [0, 1]), in a numpy array to hsv
to_hex(c[, keep_alpha]) Convert c to a hex color.
to_rgb(c) Convert c to an RGB color, silently dropping the alpha channel.
to_rgba(c[, alpha]) Convert c to an RGBA color.
to_rgba_array(c[, alpha]) Convert c to a (n, 4) array of RGBA colors.
is_color_like(c) Return whether c can be interpreted as an RGB(A) color.
makeMappingArray(N, data[, gamma]) Create an N -element 1-d lookup table
get_named_colors_mapping() Return the global mapping of names to named colors.