.. _users_artists:

Using Artists

Almost all objects you interact with on a Matplotlib plot are called "Artist"

(and are subclasses of the `.Artist` class). :doc:`Figure <../figure/index>`

and :doc:`Axes <../axes/index>` are Artists, and generally contain :doc:`Axis

<../axis/index>` Artists and Artists that contain data or annotation

information.

Creating Artists

Usually we do not instantiate Artists directly, but rather use a plotting

method on `~.axes.Axes`. Some examples of plotting methods and the Artist

object they create is given below:

Axes helper method Artist

`~.axes.Axes.annotate` - text annotations `.Annotation`

`~.axes.Axes.bar` - bar charts `.Rectangle`

`~.axes.Axes.errorbar` - error bar plots `.Line2D` and

`.Rectangle`

`~.axes.Axes.fill` - shared area `.Polygon`

`~.axes.Axes.hist` - histograms `.Rectangle`

`~.axes.Axes.imshow` - image data `.AxesImage`

`~.axes.Axes.legend` - Axes legend `.Legend`

`~.axes.Axes.plot` - xy plots `.Line2D`

`~.axes.Axes.scatter` - scatter charts `.PolyCollection`

`~.axes.Axes.text` - text `.Text`

As an example, we can save the Line2D Artist returned from `.axes.Axes.plot`:

.. sourcecode:: ipython

In [209]: import matplotlib.pyplot as plt

In [210]: import matplotlib.artist as martist

In [211]: import numpy as np

In [212]: fig, ax = plt.subplots()

In [213]: x, y = np.random.rand(2, 100)

In [214]: lines = ax.plot(x, y, '-', label='example')

In [215]: print(lines)

[<matplotlib.lines.Line2D at 0xd378b0c>]

Note that ``plot`` returns a _list_ of lines because you can pass in multiple x,

y pairs to plot. The line has been added to the Axes, and we can retrieve the

Artist via `~.Axes.get_lines()`:

.. sourcecode:: ipython

In [216]: print(ax.get_lines())

<a list of 1 Line2D objects>

In [217]: print(ax.get_lines()[0])

Line2D(example)

Changing Artist properties

Getting the ``lines`` object gives us access to all the properties of the

Line2D object. So if we want to change the *linewidth* after the fact, we can do so using `.Artist.set`.

.. plot::

:include-source:

fig, ax = plt.subplots(figsize=(4, 2.5))

x = np.arange(0, 13, 0.2)

y = np.sin(x)

lines = ax.plot(x, y, '-', label='example', linewidth=0.2, color='blue')

lines[0].set(color='green', linewidth=2)

We can interrogate the full list of settable properties with

`matplotlib.artist.getp`:

.. sourcecode:: ipython

In [218]: martist.getp(lines[0])

agg_filter = None

alpha = None

animated = False

antialiased or aa = True

bbox = Bbox(x0=0.004013842290585101, y0=0.013914221641967...

children = []

clip_box = TransformedBbox( Bbox(x0=0.0, y0=0.0, x1=1.0, ...

clip_on = True

clip_path = None

color or c = blue

dash_capstyle = butt

dash_joinstyle = round

data = (array([0.91377845, 0.58456834, 0.36492019, 0.0379...

drawstyle or ds = default

figure = Figure(550x450)

fillstyle = full

gapcolor = None

gid = None

in_layout = True

label = example

linestyle or ls = -

linewidth or lw = 2.0

marker = None

markeredgecolor or mec = blue

markeredgewidth or mew = 1.0

markerfacecolor or mfc = blue

markerfacecoloralt or mfcalt = none

markersize or ms = 6.0

markevery = None

mouseover = False

path = Path(array([[0.91377845, 0.51224793], [0.58...

path_effects = []

picker = None

pickradius = 5

rasterized = False

sketch_params = None

snap = None

solid_capstyle = projecting

solid_joinstyle = round

tightbbox = Bbox(x0=70.4609002763619, y0=54.321277798941786, x...

transform = CompositeGenericTransform( TransformWrapper( ...

transformed_clip_path_and_affine = (None, None)

url = None

visible = True

window_extent = Bbox(x0=70.4609002763619, y0=54.321277798941786, x...

xdata = [0.91377845 0.58456834 0.36492019 0.03796664 0.884...

xydata = [[0.91377845 0.51224793] [0.58456834 0.9820474 ] ...

ydata = [0.51224793 0.9820474 0.24469912 0.61647032 0.483...

zorder = 2

Note most Artists also have a distinct list of setters; e.g.

`.Line2D.set_color` or `.Line2D.set_linewidth`.

Changing Artist data

In addition to styling properties like *color* and *linewidth*, the Line2D

object has a *data* property. You can set the data after the line has been

created using `.Line2D.set_data`. This is often used for Animations, where the

same line is shown evolving over time (see :doc:`../animations`)

.. plot::

:include-source:

fig, ax = plt.subplots(figsize=(4, 2.5))

x = np.arange(0, 13, 0.2)

y = np.sin(x)

lines = ax.plot(x, y, '-', label='example')

lines[0].set_data([x, np.cos(x)])

Manually adding Artists

Not all Artists have helper methods, or you may want to use a low-level method

for some reason. For example the `.patches.Circle` Artist does not have a

helper, but we can still create and add to an Axes using the

`.axes.Axes.add_artist` method:

.. plot::

:include-source:

import matplotlib.patches as mpatches

fig, ax = plt.subplots(figsize=(4, 2.5))

circle = mpatches.Circle((0.5, 0.5), 0.25, ec="none")

ax.add_artist(circle)

clipped_circle = mpatches.Circle((1, 0.5), 0.125, ec="none", facecolor='C1')

ax.add_artist(clipped_circle)

ax.set_aspect(1)

The Circle takes the center and radius of the Circle as arguments to its

constructor; optional arguments are passed as keyword arguments.

Note that when we add an Artist manually like this, it doesn't necessarily

adjust the axis limits like most of the helper methods do, so the Artists can

be clipped, as is the case above for the `clipped_circle` patch.

See :doc:`artist_reference` for other patches.

Removing Artists

Sometimes we want to remove an Artist from a figure without re-specifying the

whole figure from scratch. Most Artists have a usable *remove* method that

will remove the Artist from its Axes list. For instance ``lines[0].remove()``

would remove the *Line2D* artist created in the example above.

More details

.. toctree::

:maxdepth: 1

imshow_extent

transforms_tutorial

artists/index