.. redirect-from:: /users/prev_whats_new/whats_new_3.3.0
For a list of all of the issues and pull requests since the last revision, see the :ref:`github-stats`.
Table of Contents
- What's new in Matplotlib 3.3.0 (Jul 16, 2020)
- Figure and Axes creation / management
- Colors and colormaps
- Titles, ticks, and labels
- Other changes
- Fonts
- rcParams improvements
- 3D Axes improvements
- Interactive tool improvements
- Functions to compute a Path's size
- Backend-specific improvements
savefig()gained a backend keyword argument- The SVG backend can now render hatches with transparency
- SVG supports URLs on more artists
- Images in SVG will no longer be blurred in some viewers
- Saving SVG now supports adding metadata
- Saving PDF metadata via PGF now consistent with PDF backend
- NbAgg and WebAgg no longer use jQuery & jQuery UI
.. toctree:: :maxdepth: 4
The .Figure class has a provisional method to generate complex grids of named .axes.Axes based on nested list input or ASCII art:
.. plot::
:include-source:
axd = plt.figure(constrained_layout=True).subplot_mosaic(
[['.', 'histx'],
['histy', 'scat']]
)
for k, ax in axd.items():
ax.text(0.5, 0.5, k,
ha='center', va='center', fontsize=36,
color='darkgrey')
or as a string (with single-character Axes labels):
.. plot::
:include-source:
axd = plt.figure(constrained_layout=True).subplot_mosaic(
"""
TTE
L.E
""")
for k, ax in axd.items():
ax.text(0.5, 0.5, k,
ha='center', va='center', fontsize=36,
color='darkgrey')
See :ref:`mosaic` for more details and examples.
The .GridSpec class gained a ~.GridSpecBase.subplots method, so that one can write
fig.add_gridspec(2, 2, height_ratios=[3, 1]).subplots()
as an alternative to
fig.subplots(2, 2, gridspec_kw={"height_ratios": [3, 1]})
These new methods allow sharing axes immediately after creating them. Note that behavior is indeterminate if axes are not shared immediately after creation.
For example, they can be used to selectively link some axes created all together using ~.Figure.subplot_mosaic:
fig = plt.figure(constrained_layout=True)
axd = fig.subplot_mosaic([['.', 'histx'], ['histy', 'scat']],
gridspec_kw={'width_ratios': [1, 7],
'height_ratios': [2, 7]})
axd['histx'].sharex(axd['scat'])
axd['histy'].sharey(axd['scat'])
.. plot::
np.random.seed(0)
x = np.random.random(100) * 100 + 20
y = np.random.random(100) * 50 + 25
c = np.random.random(100) - 0.5
fig = plt.figure(constrained_layout=True)
axd = fig.subplot_mosaic([['.', 'histx'], ['histy', 'scat']],
gridspec_kw={'width_ratios': [1, 7],
'height_ratios': [2, 7]})
axd['histy'].invert_xaxis()
axd['histx'].sharex(axd['scat'])
axd['histy'].sharey(axd['scat'])
im = axd['scat'].scatter(x, y, c=c, cmap='RdBu', picker=True)
fig.colorbar(im, orientation='horizontal', ax=axd['scat'], shrink=0.8)
axd['histx'].hist(x)
axd['histy'].hist(y, orientation='horizontal')
Previous versions did not consider .Figure.suptitle, so it may overlap with other artists after calling ~.Figure.tight_layout:
.. plot::
fig, axs = plt.subplots(1, 3)
for i, ax in enumerate(axs):
ax.plot([1, 2, 3])
ax.set_title(f'Axes {i}')
t = fig.suptitle('suptitle')
t.set_in_layout(False)
fig.tight_layout()
From now on, the suptitle will be considered:
.. plot::
fig, axs = plt.subplots(1, 3)
for i, ax in enumerate(axs):
ax.plot([1, 2, 3])
ax.set_title(f'Axes {i}')
fig.suptitle('suptitle')
fig.tight_layout()
It is now possible to set the aspect of an axes box directly via ~.Axes.set_box_aspect. The box aspect is the ratio between axes height and axes width in physical units, independent of the data limits. This is useful to, e.g., produce a square plot, independent of the data it contains, or to have a non-image plot with the same axes dimensions next to an image plot with fixed (data-)aspect.
For use cases check out the :doc:`Axes box aspect </gallery/subplots_axes_and_figures/axes_box_aspect>` example.
Turbo is an improved rainbow colormap for visualization, created by the Google AI team for computer vision and machine learning. Its purpose is to display depth and disparity data. Please see the Google AI Blog for further details.
.. plot::
gradient = np.linspace(0, 1, 256)
gradient = np.vstack((gradient, gradient))
cmaps = ['turbo', 'jet', 'gist_rainbow_r', 'hsv_r']
fig, axs = plt.subplots(len(cmaps), constrained_layout=True)
for name, ax in zip(cmaps, axs):
ax.imshow(gradient, aspect='auto', cmap=plt.get_cmap(name))
ax.set_title(name)
ax.set_axis_off()
~.colors.BoundaryNorm now has an extend keyword argument, analogous to
extend in ~.axes.Axes.contourf. When set to 'both', 'min', or 'max', it
maps the corresponding out-of-range values to ~.colors.Colormap lookup-table
indices near the appropriate ends of their range so that the colors for out-of
range values are adjacent to, but distinct from, their in-range neighbors. The
colorbar inherits the extend argument from the norm, so with
extend='both', for example, the colorbar will have triangular extensions
for out-of-range values with colors that differ from adjacent in-range colors.
.. plot::
import matplotlib.pyplot as plt
from matplotlib.colors import BoundaryNorm
import numpy as np
# Make the data
dx, dy = 0.05, 0.05
y, x = np.mgrid[slice(1, 5 + dy, dy),
slice(1, 5 + dx, dx)]
z = np.sin(x) ** 10 + np.cos(10 + y * x) * np.cos(x)
z = z[:-1, :-1]
# Z roughly varies between -1 and +1.
# Color boundary levels range from -0.8 to 0.8, so there are out-of-bounds
# areas.
levels = [-0.8, -0.5, -0.2, 0.2, 0.5, 0.8]
cmap = plt.get_cmap('PiYG')
fig, axs = plt.subplots(nrows=2, constrained_layout=True, sharex=True)
# Before this change:
norm = BoundaryNorm(levels, ncolors=cmap.N)
im = axs[0].pcolormesh(x, y, z, cmap=cmap, norm=norm)
fig.colorbar(im, ax=axs[0], extend='both')
axs[0].axis([x.min(), x.max(), y.min(), y.max()])
axs[0].set_title("Colorbar with extend='both'")
# With the new keyword:
norm = BoundaryNorm(levels, ncolors=cmap.N, extend='both')
im = axs[1].pcolormesh(x, y, z, cmap=cmap, norm=norm)
fig.colorbar(im, ax=axs[1]) # note that the colorbar is updated accordingly
axs[1].axis([x.min(), x.max(), y.min(), y.max()])
axs[1].set_title("BoundaryNorm with extend='both'")
plt.show()
The text color of legend labels can now be set by passing a parameter
labelcolor to ~.axes.Axes.legend. The labelcolor keyword can be:
- A single color (either a string or RGBA tuple), which adjusts the text color of all the labels.
- A list or tuple, allowing the text color of each label to be set individually.
linecolor, which sets the text color of each label to match the corresponding line color.markerfacecolor, which sets the text color of each label to match the corresponding marker face color.markeredgecolor, which sets the text color of each label to match the corresponding marker edge color.
.. plot::
options = ['C3', 'linecolor', 'markerfacecolor', 'markeredgecolor']
fig, axs = plt.subplots(2, 2, constrained_layout=True)
for ax, color in zip(axs.flat, options):
ax.plot([1, 2, 3], marker='o',
color='C0', markerfacecolor='C1', markeredgecolor='C2',
linewidth=3, markersize=10, markeredgewidth=3,
label='a line')
ax.legend(labelcolor=color)
ax.set_title(f'labelcolor={color!r}')
ax.margins(0.1)
Previously .axes.Axes.pcolor and .axes.Axes.pcolormesh handled the situation where x and y have the same (respective) size as C by dropping the last row and column of C, and x and y are regarded as the edges of the remaining rows and columns in C. However, many users want x and y centered on the rows and columns of C.
To accommodate this, shading='nearest' and shading='auto' are new
allowed strings for the shading keyword argument. 'nearest' will center
the color on x and y if x and y have the same dimensions as C
(otherwise an error will be thrown). shading='auto' will choose 'flat' or
'nearest' based on the size of X, Y, C.
If shading='flat' then X, and Y should have dimensions one larger than
C. If X and Y have the same dimensions as C, then the previous behavior
is used and the last row and column of C are dropped, and a
DeprecationWarning is emitted.
Users can also specify this by the new :rc:`pcolor.shading` in their
.matplotlibrc or via .rcParams.
See :doc:`pcolormesh </gallery/images_contours_and_fields/pcolormesh_grids>` for examples.
~.axes.Axes.set_xlabel, ~.axes.Axes.set_ylabel and
ColorbarBase.set_label support a parameter loc for simplified
positioning. For the xlabel, the supported values are 'left', 'center', or
'right'. For the ylabel, the supported values are 'bottom', 'center', or
'top'.
The default is controlled via :rc:`xaxis.labellocation` and :rc:`yaxis.labellocation`; the Colorbar label takes the rcParam based on its orientation.
.. plot::
options = ['left', 'center', 'right']
fig, axs = plt.subplots(len(options), 1, constrained_layout=True)
for ax, loc in zip(axs, options):
ax.plot([1, 2, 3])
ax.set_xlabel(f'xlabel loc={loc!r}', loc=loc)
options = ['bottom', 'center', 'top']
fig, axs = plt.subplots(1, len(options), constrained_layout=True)
for ax, loc in zip(axs, options):
ax.plot([1, 2, 3])
ax.set_ylabel(f'ylabel loc={loc!r}', loc=loc)
~.Axis.set_major_formatter and ~.Axis.set_minor_formatter now accept str or function inputs in addition to ~.ticker.Formatter instances. For a str a ~.ticker.StrMethodFormatter is automatically generated and used. For a function a ~.ticker.FuncFormatter is automatically generated and used. In other words,
ax.xaxis.set_major_formatter('{x} km')
ax.xaxis.set_minor_formatter(lambda x, pos: str(x-5))
are shortcuts for:
import matplotlib.ticker as mticker
ax.xaxis.set_major_formatter(mticker.StrMethodFormatter('{x} km'))
ax.xaxis.set_minor_formatter(
mticker.FuncFormatter(lambda x, pos: str(x-5))
.. plot::
from matplotlib import ticker
titles = ["'{x} km'", "lambda x, pos: str(x-5)"]
formatters = ['{x} km', lambda x, pos: str(x-5)]
fig, axs = plt.subplots(2, 1, figsize=(8, 2), constrained_layout=True)
for ax, title, formatter in zip(axs, titles, formatters):
# only show the bottom spine
ax.yaxis.set_major_locator(ticker.NullLocator())
for spine in ['top', 'left', 'right']:
ax.spines[spine].set_visible(False)
# define tick positions
ax.xaxis.set_major_locator(ticker.MultipleLocator(1.00))
ax.xaxis.set_minor_locator(ticker.MultipleLocator(0.25))
ax.tick_params(which='major', width=1.00, length=5)
ax.tick_params(which='minor', width=0.75, length=2.5, labelsize=10)
ax.set_xlim(0, 5)
ax.set_ylim(0, 1)
ax.text(0.0, 0.2, f'ax.xaxis.set_major_formatter({title})',
transform=ax.transAxes, fontsize=14, fontname='Monospace',
color='tab:blue')
ax.xaxis.set_major_formatter(formatter)
~.axes.Axes.set_title tries to auto-position the title to avoid any
decorators on the top x-axis. This is not always desirable so now y is an
explicit keyword argument of ~.axes.Axes.set_title. It defaults to None
which means to use auto-positioning. If a value is supplied (i.e. the pre-3.0
default was y=1.0) then auto-positioning is turned off. This can also be
set with the new rcParameter :rc:`axes.titley`.
.. plot::
fig, axs = plt.subplots(1, 2, constrained_layout=True, figsize=(5, 2))
axs[0].set_title('y=0.7\n$\\sum_{j_n} x_j$', y=0.7)
axs[1].set_title('y=None\n$\\sum_{j_n} x_j$')
plt.show()
Solves the issue that the power indicator (e.g., 1e4) stayed on the bottom, even if the ticks were on the top.
~.axes.Axes.clabel now accepts a zorder keyword argument making it easier
to set the zorder of contour labels. If not specified, the default zorder
of clabels used to always be 3 (i.e. the default zorder of ~.text.Text)
irrespective of the zorder passed to
~.axes.Axes.contour/~.axes.Axes.contourf. The new default zorder for
clabels has been changed to (2 + zorder passed to ~.axes.Axes.contour /
~.axes.Axes.contourf).
A new ~.axes.Axes.axline method has been added to draw infinitely long lines that pass through two points.
.. plot:: :include-source: True fig, ax = plt.subplots() ax.axline((.1, .1), slope=5, color='C0', label='by slope') ax.axline((.1, .2), (.8, .7), color='C3', label='by points') ax.legend()
Starting from this version arrays of size MxNx1 will be coerced into MxN
for displaying. This means commands like plt.imshow(np.random.rand(3, 3, 1))
will no longer return an error message that the image shape is invalid.
Previously, .Axes.pie would normalize its input x if sum(x) > 1, but
would do nothing if the sum were less than 1. This can be confusing, so an
explicit keyword argument normalize has been added. By default, the old
behavior is preserved.
By passing normalize, one can explicitly control whether any rescaling takes
place or whether partial pies should be created. If normalization is disabled,
and sum(x) > 1, then an error is raised.
.. plot::
def label(x):
return [str(v) for v in x]
x = np.array([0.25, 0.3, 0.3])
fig, ax = plt.subplots(2, 2, constrained_layout=True)
ax[0, 0].pie(x, autopct='%1.1f%%', labels=label(x), normalize=False)
ax[0, 0].set_title('normalize=False')
ax[0, 1].pie(x, autopct='%1.2f%%', labels=label(x), normalize=True)
ax[0, 1].set_title('normalize=True')
# This is supposed to show the 'old' behavior of not passing *normalize*
# explicitly, but for the purposes of keeping the documentation build
# warning-free, and future proof for when the deprecation is made
# permanent, we pass *normalize* here explicitly anyway.
ax[1, 0].pie(x, autopct='%1.2f%%', labels=label(x), normalize=False)
ax[1, 0].set_title('normalize unspecified\nsum(x) < 1')
ax[1, 1].pie(x * 10, autopct='%1.2f%%', labels=label(x * 10),
normalize=True)
ax[1, 1].set_title('normalize unspecified\nsum(x) > 1')
Matplotlib converts dates to days since an epoch using .dates.date2num (via
matplotlib.units). Previously, an epoch of 0000-12-31T00:00:00 was used
so that 0001-01-01 was converted to 1.0. An epoch so distant in the past
meant that a modern date was not able to preserve microseconds because 2000
years times the 2^(-52) resolution of a 64-bit float gives 14 microseconds.
Here we change the default epoch to the more reasonable UNIX default of
1970-01-01T00:00:00 which for a modern date has 0.35 microsecond
resolution. (Finer resolution is not possible because we rely on
datetime.datetime for the date locators). Access to the epoch is provided by
~.dates.get_epoch, and there is a new :rc:`date.epoch` rcParam. The user may
also call ~.dates.set_epoch, but it must be set before any date conversion
or plotting is used.
If you have data stored as ordinal floats in the old epoch, you can convert them to the new ordinal using the following formula:
new_ordinal = old_ordinal + mdates.date2num(np.datetime64('0000-12-31'))
Similar to ~.Axes.scatter, ~.Axes.plot and ~.lines.Line2D now accept ~.markers.MarkerStyle instances as input for the marker parameter:
plt.plot(..., marker=matplotlib.markers.MarkerStyle("D"))
Fonts can now be selected by passing an absolute pathlib.Path to the font keyword argument of .Text.
Matplotlib is now better able to determine the weight of fonts from their metadata, allowing to differentiate between fonts within the same family more accurately.
matplotlib.rc_context can now be used as a decorator (technically, it is now implemented as a contextlib.contextmanager), e.g.,
@rc_context({"lines.linewidth": 2})
def some_function(...):
...
The new config option :rc:`figure.raise_window` allows disabling of the raising
of the plot window when calling ~.pyplot.show or ~.pyplot.pause. The
MacOSX backend is currently not supported.
New :rc:`mathtext.fallback` rcParam. Takes "cm", "stix", "stixsans" or "none" to turn fallback off. The rcParam mathtext.fallback_to_cm is deprecated, but if used, will override new fallback.
The new config option :rc:`contour.linewidth` allows to control the default
line width of contours as a float. When set to None, the line widths fall
back to :rc:`lines.linewidth`. The config value is overridden as usual by the
linewidths argument passed to ~.axes.Axes.contour when it is not set to
None.
Plots made with :class:`~mpl_toolkits.mplot3d.axes3d.Axes3D` were previously stretched to fit a square bounding box. As this stretching was done after the projection from 3D to 2D, it resulted in distorted images if non-square bounding boxes were used. As of 3.3, this no longer occurs.
Currently, modes of setting the aspect (via ~mpl_toolkits.mplot3d.axes3d.Axes3D.set_aspect) in data space are not supported for Axes3D but may be in the future. If you want to simulate having equal aspect in data space, set the ratio of your data limits to match the value of ~.get_box_aspect. To control these ratios use the ~mpl_toolkits.mplot3d.axes3d.Axes3D.set_box_aspect method which accepts the ratios as a 3-tuple of X:Y:Z. The default aspect ratio is 4:4:3.
.. plot::
:include-source: True
ax = plt.figure().add_subplot(projection='3d')
ax.scatter([0, 1, 2], [1, 3, 5], [30, 50, 70])
ax.set_xticks([0.25, 0.75, 1.25, 1.75], minor=True)
ax.set_xticklabels(['a', 'b', 'c', 'd'], minor=True)
ax.set_yticks([1.5, 2.5, 3.5, 4.5], minor=True)
ax.set_yticklabels(['A', 'B', 'C', 'D'], minor=True)
ax.set_zticks([35, 45, 55, 65], minor=True)
ax.set_zticklabels([r'$\alpha$', r'$\beta$', r'$\delta$', r'$\gamma$'],
minor=True)
ax.tick_params(which='major', color='C0', labelcolor='C0', width=5)
ax.tick_params(which='minor', color='C1', labelcolor='C1', width=3)
Toolbar features are now more consistent across backends. The history buttons will auto-disable when there is no further action in a direction. The pan and zoom buttons will be marked active when they are in use.
In NbAgg and WebAgg, the toolbar buttons are now grouped similarly to other backends. The WebAgg toolbar now uses the same icons as other backends.
On dark themes, toolbar icons will now be inverted. When using the GTK3Agg backend, toolbar icons are now symbolic, and both foreground and background colors will follow the theme. Tooltips should also behave correctly.
Previously, the x/y position displayed by the cursor text would usually include far more significant digits than the mouse pointing precision (typically one pixel). This is now fixed for linear scales.
This makes it visible even over a dark background.
The .backend_bases.key_press_handler and
.backend_bases.button_press_handler event handlers can now be directly
connected to a canvas with canvas.mpl_connect("key_press_event",
key_press_handler) and canvas.mpl_connect("button_press_event",
button_press_handler), rather than having to write wrapper functions that
fill in the (now optional) canvas and toolbar parameters.
Various functions were added to ~.bezier.BezierSegment and ~.path.Path to allow computation of the shape/size of a ~.path.Path and its composite Bezier curves.
In addition to the fixes below, ~.bezier.BezierSegment has gained more documentation and usability improvements, including properties that contain its dimension, degree, control_points, and more.
~.path.Path.iter_bezier iterates through the ~.bezier.BezierSegment's that make up the Path. This is much more useful typically than the existing ~.path.Path.iter_segments function, which returns the absolute minimum amount of information possible to reconstruct the Path.
Historically, ~.path.Path.get_extents has always simply returned the Bbox of a curve's control points, instead of the Bbox of the curve itself. While this is a correct upper bound for the path's extents, it can differ dramatically from the Path's actual extents for non-linear Bezier curves.
The backend keyword argument to savefig can now be used to pick the
rendering backend without having to globally set the backend; e.g., one can
save PDFs using the pgf backend with savefig("file.pdf", backend="pgf").
The SVG backend now respects the hatch stroke alpha. Useful applications are, among others, semi-transparent hatches as a subtle way to differentiate columns in bar plots.
URLs on more artists (i.e., from .Artist.set_url) will now be saved in
SVG files, namely, Ticks and Line2Ds are now supported.
A style is now supplied to images without interpolation (imshow(...,
interpolation='none') so that SVG image viewers will no longer perform
interpolation when rendering themselves.
When saving SVG files, metadata can now be passed which will be saved in the file using Dublin Core and RDF. A list of valid metadata can be found in the documentation for .FigureCanvasSVG.print_svg.
When saving PDF files using the PGF backend, passed metadata will be interpreted in the same way as with the PDF backend. Previously, this metadata was only accepted by the PGF backend when saving a multi-page PDF with .backend_pgf.PdfPages, but is now allowed when saving a single figure, as well.
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