# yt.visualization.color_maps module¶

yt.visualization.color_maps.add_cmap(name, cdict)[source]

Deprecated alias, kept for backwards compatibility.

yt.visualization.color_maps.add_colormap(name, cdict)[source]

Adds a colormap to the colormaps available in yt for this session

yt.visualization.color_maps.check_color(name)[source]
yt.visualization.color_maps.is_colormap(cmap)[source]
yt.visualization.color_maps.make_colormap(ctuple_list, name=None, interpolate=True)[source]

This generates a custom colormap based on the colors and spacings you provide. Enter a ctuple_list, which consists of tuples of (color, spacing) to return a colormap appropriate for use in yt. If you specify a name, it will automatically be added to the current session as a valid colormap.

Output colormap is in the format yt expects for adding a colormap to the current session: a dictionary with the appropriate RGB channels each consisting of a 256x3 array : First number is the number at which we are defining a color breakpoint Second number is the (0..1) number to interpolate to when coming from below Third number is the (0..1) number to interpolate to when coming from above

Parameters
• ctuple_list (list of (color, float) tuples) –

The ctuple_list consists of pairs of (color, interval) tuples identifying the colors to use in the colormap and the intervals they take to change to the next color in the list. A color can either be a string of the name of a color, or it can be an array of 3 floats, each representing the intensity of R, G, and B on a scale of 0 to 1. Valid color names and their equivalent arrays are listed below.

Any interval can be given for the different color tuples, and the total of all the intervals will be scaled to the 256 output elements.

If a ctuple_list ends with a color and a non-zero interval, a white 0-interval would be added to the end to finish the interpolation. To avoid finishing with white, specify your own zero-interval color at the end.

• name (string, optional) – If you wish this colormap to be added as a valid colormap to the current session, specify a name here. Default: None

• interpolate (boolean) – Designates whether or not the colormap will interpolate between the colors provided or just give solid colors across the intervals. Default: True

• Color Options (Preset) –

• --------------------

• 'white' (np.array([255, 255, 255 ])/255.) –

• 'gray' (np.array([130, 130, 130])/255.) –

• 'dgray' (np.array([80, 80, 80])/255.) –

• 'black' (np.array([0, 0, 0])/255.) –

• 'blue' (np.array([0, 0, 255])/255.) –

• 'dblue' (np.array([0, 0, 160])/255.) –

• 'purple' (np.array([100, 0, 200])/255.) –

• 'dpurple' (np.array([66, 0, 133])/255.) –

• 'dred' (np.array([160, 0, 0])/255.) –

• 'red' (np.array([255, 0, 0])/255.) –

• 'orange' (np.array([255, 128, 0])/255.) –

• 'dorange' (np.array([200,100, 0])/255.) –

• 'yellow' (np.array([255, 255, 0])/255.) –

• 'dyellow' (np.array([200, 200, 0])/255.) –

• 'green' (np.array([0, 255, 0])/255.) –

• 'dgreen' (np.array([0, 160, 0])/255.) –

Examples

To obtain a colormap that starts at black with equal intervals in green, blue, red, yellow in that order and interpolation between those colors. (In reality, it starts at black, takes an interval of 10 to interpolate to green, then an interval of 10 to interpolate to blue, then an interval of 10 to interpolate to red.)

>>> cm = make_colormap([("black", 10), ("green", 10), ("blue", 10), ("red", 0)])


To add a colormap that has five equal blocks of solid major colors to the current session as “steps”:

>>> make_colormap(
...     [("red", 10), ("orange", 10), ("yellow", 10), ("green", 10), ("blue", 10)],
...     name="steps",
...     interpolate=False,
... )


To add a colormap that looks like the French flag (i.e. equal bands of blue, white, and red) using your own RGB keys, then to display it:

>>> make_colormap(
...     [([0, 0, 1], 10), ([1, 1, 1], 10), ([1, 0, 0], 10)],
...     name="french_flag",
...     interpolate=False,
... )
>>> show_colormaps(["french_flag"])

yt.visualization.color_maps.show_colormaps(subset='all', filename=None)[source]

Displays the colormaps available to yt. Note, most functions can use both the matplotlib and the native yt colormaps; however, there are some special functions existing within image_writer.py (e.g. write_image() write_bitmap(), etc.), which cannot access the matplotlib colormaps.

In addition to the colormaps listed, one can access the reverse of each colormap by appending a “_r” to any map.

If you wish to only see certain colormaps, include them in the cmap_list attribute.

Parameters
• subset (string, or list of strings, optional) –

valid values : “all”, “yt_native”, or list of cmap names default : “all”

As mentioned above, a few functions can only access yt_native colormaps. To display only the yt_native colormaps, set this to “yt_native”.

If you wish to only see a few colormaps side by side, you can include them as a list of colormap names. Example: [‘algae’, ‘gist_stern’, ‘kamae’, ‘spectral’]

• filename (string, opt) –

default: None

If filename is set, then it will save the colormaps to an output file. If it is not set, it will “show” the result interactively.