matplotlib.colorizer

The Colorizer class which handles the data to color pipeline via a normalization and a colormap.

Provisional status of colorizer

The colorizer module and classes in this file are considered provisional and may change at any time without a deprecation period.

See also

Colormap reference for a list of builtin colormaps.

Creating Colormaps in Matplotlib for examples of how to make colormaps.

Choosing Colormaps in Matplotlib for an in-depth discussion of choosing colormaps.

Colormap normalization for more details about data normalization.

class matplotlib.colorizer.Colorizer(cmap=None, norm=None)

Bases: object

Data to color pipeline.

This pipeline is accessible via Colorizer.to_rgba and executed via the Colorizer.norm and Colorizer.cmap attributes.

Parameters:

cmap: colorbar.Colorbar or str or None, default: None

The colormap used to color data.

norm: colors.Normalize or str or None, default: None

The normalization used to normalize the data

autoscale(A)

Autoscale the scalar limits on the norm instance using the current array

autoscale_None(A)

Autoscale the scalar limits on the norm instance using the current array, changing only limits that are None

changed()

Call this whenever the mappable is changed to notify all the callbackSM listeners to the 'changed' signal.

property clip

property cmap

get_clim()

Return the values (min, max) that are mapped to the colormap limits.

property norm

set_clim(vmin=None, vmax=None)

Set the norm limits for image scaling.

Parameters:

vmin, vmaxfloat

The limits.

The limits may also be passed as a tuple (vmin, vmax) as a single positional argument.

to_rgba(x, alpha=None, bytes=False, norm=True)

Return a normalized RGBA array corresponding to x.

In the normal case, x is a 1D or 2D sequence of scalars, and the corresponding ndarray of RGBA values will be returned, based on the norm and colormap set for this Colorizer.

There is one special case, for handling images that are already RGB or RGBA, such as might have been read from an image file. If x is an ndarray with 3 dimensions, and the last dimension is either 3 or 4, then it will be treated as an RGB or RGBA array, and no mapping will be done. The array can be uint8, or it can be floats with values in the 0-1 range; otherwise a ValueError will be raised. Any NaNs or masked elements will be set to 0 alpha. If the last dimension is 3, the alpha kwarg (defaulting to 1) will be used to fill in the transparency. If the last dimension is 4, the alpha kwarg is ignored; it does not replace the preexisting alpha. A ValueError will be raised if the third dimension is other than 3 or 4.

In either case, if bytes is False (default), the RGBA array will be floats in the 0-1 range; if it is True, the returned RGBA array will be uint8 in the 0 to 255 range.

If norm is False, no normalization of the input data is performed, and it is assumed to be in the range (0-1).

property vmax

property vmin

class matplotlib.colorizer.ColorizingArtist(colorizer, **kwargs)

Bases: _ScalarMappable, Artist

Base class for artists that make map data to color using a colorizer.Colorizer.

The colorizer.Colorizer applies data normalization before returning RGBA colors from a Colormap.

Parameters:

colorizercolorizer.Colorizer

property colorizer

draw(renderer)

Draw the Artist (and its children) using the given renderer.

This has no effect if the artist is not visible (Artist.get_visible returns False).

Parameters:

rendererRendererBase subclass.

Notes

This method is overridden in the Artist subclasses.

set(*, agg_filter=<UNSET>, alpha=<UNSET>, animated=<UNSET>, array=<UNSET>, clim=<UNSET>, clip_box=<UNSET>, clip_on=<UNSET>, clip_path=<UNSET>, cmap=<UNSET>, gid=<UNSET>, in_layout=<UNSET>, label=<UNSET>, mouseover=<UNSET>, norm=<UNSET>, path_effects=<UNSET>, picker=<UNSET>, rasterized=<UNSET>, sketch_params=<UNSET>, snap=<UNSET>, transform=<UNSET>, url=<UNSET>, visible=<UNSET>, zorder=<UNSET>)

Set multiple properties at once.

Supported properties are

Property	Description
agg_filter	a filter function, which takes a (m, n, 3) float array and a dpi value, and returns a (m, n, 3) array and two offsets from the bottom left corner of the image
alpha	float or None
animated	bool
array	array-like or None
clim	(vmin: float, vmax: float)
clip_box	BboxBase or None
clip_on	bool
clip_path	Patch or (Path, Transform) or None
cmap	Colormap or str or None
figure	Figure or SubFigure
gid	str
in_layout	bool
label	object
mouseover	bool
norm	Normalize or str or None
path_effects	list of AbstractPathEffect
picker	None or bool or float or callable
rasterized	bool
sketch_params	(scale: float, length: float, randomness: float)
snap	bool or None
transform	Transform
url	str
visible	bool
zorder	float

class matplotlib.colorizer._ColorizerInterface

Bases: object

Base class that contains the interface to Colorizer objects from a ColorizingArtist or cm.ScalarMappable.

Note: This class only contain functions that interface the .colorizer attribute. Other functions that as shared between ColorizingArtist and cm.ScalarMappable are not included.

autoscale()

Autoscale the scalar limits on the norm instance using the current array

autoscale_None()

Autoscale the scalar limits on the norm instance using the current array, changing only limits that are None

property cmap

property colorbar

The last colorbar associated with this object. May be None

get_alpha()

get_clim()

Return the values (min, max) that are mapped to the colormap limits.

get_cmap()

Return the Colormap instance.

property norm

set_clim(vmin=None, vmax=None)

Set the norm limits for image scaling.

Parameters:

vmin, vmaxfloat

The limits.

For scalar data, the limits may also be passed as a tuple (vmin, vmax) as a single positional argument.

set_cmap(cmap)

Set the colormap for luminance data.

Parameters:

cmapColormap or str or None

set_norm(norm)

Set the normalization instance.

Parameters:

normNormalize or str or None

Notes

If there are any colorbars using the mappable for this norm, setting the norm of the mappable will reset the norm, locator, and formatters on the colorbar to default.

to_rgba(x, alpha=None, bytes=False, norm=True)

Return a normalized RGBA array corresponding to x.

In the normal case, x is a 1D or 2D sequence of scalars, and the corresponding ndarray of RGBA values will be returned, based on the norm and colormap set for this Colorizer.

There is one special case, for handling images that are already RGB or RGBA, such as might have been read from an image file. If x is an ndarray with 3 dimensions, and the last dimension is either 3 or 4, then it will be treated as an RGB or RGBA array, and no mapping will be done. The array can be uint8, or it can be floats with values in the 0-1 range; otherwise a ValueError will be raised. Any NaNs or masked elements will be set to 0 alpha. If the last dimension is 3, the alpha kwarg (defaulting to 1) will be used to fill in the transparency. If the last dimension is 4, the alpha kwarg is ignored; it does not replace the preexisting alpha. A ValueError will be raised if the third dimension is other than 3 or 4.

In either case, if bytes is False (default), the RGBA array will be floats in the 0-1 range; if it is True, the returned RGBA array will be uint8 in the 0 to 255 range.

If norm is False, no normalization of the input data is performed, and it is assumed to be in the range (0-1).

class matplotlib.colorizer._ScalarMappable(norm=None, cmap=None, *, colorizer=None, **kwargs)

Bases: _ColorizerInterface

A mixin class to map one or multiple sets of scalar data to RGBA.

The ScalarMappable applies data normalization before returning RGBA colors from the given Colormap.

Parameters:

normNormalize (or subclass thereof) or str or None

The normalizing object which scales data, typically into the interval [0, 1]. If a str, a Normalize subclass is dynamically generated based on the scale with the corresponding name. If None, norm defaults to a colors.Normalize object which initializes its scaling based on the first data processed.

cmapstr or Colormap

The colormap used to map normalized data values to RGBA colors.

changed()

Call this whenever the mappable is changed to notify all the callbackSM listeners to the 'changed' signal.

get_array()

Return the array of values, that are mapped to colors.

The base class ScalarMappable does not make any assumptions on the dimensionality and shape of the array.

set_array(A)

Set the value array from array-like A.

Parameters:

Aarray-like or None

The values that are mapped to colors.

The base class ScalarMappable does not make any assumptions on the dimensionality and shape of the value array A.