matplotlib

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New in matplotlib 1.3

Note

matplotlib 1.3 supports Python 2.6, 2.7, 3.2, and 3.3

New in 1.3.1

1.3.1 is a bugfix release, primarily dealing with improved setup and handling of dependencies, and correcting and enhancing the documentation.

The following changes were made in 1.3.1 since 1.3.0.

Enhancements

Bug fixes

  • Histogram plots now contain the endline.
  • Fixes to the Molleweide projection.
  • Handling recent fonts from Microsoft and Macintosh-style fonts with non-ascii metadata is improved.
  • Hatching of fill between plots now works correctly in the PDF backend.
  • Tight bounding box support now works in the PGF backend.
  • Transparent figures now display correctly in the Qt4Agg backend.
  • Drawing lines from one subplot to another now works.
  • Unit handling on masked arrays has been improved.

Setup and dependencies

  • Now works with any version of pyparsing 1.5.6 or later, without displaying hundreds of warnings.
  • Now works with 64-bit versions of Ghostscript on MS-Windows.
  • When installing from source into an environment without Numpy, Numpy will first be downloaded and built and then used to build matplotlib.
  • Externally installed backends are now always imported using a fully-qualified path to the module.
  • Works with newer version of wxPython.
  • Can now build with a PyCXX installed globally on the system from source.
  • Better detection of Gtk3 dependencies.

Testing

  • Tests should now work in non-English locales.
  • PEP8 conformance tests now report on locations of issues.

New plotting features

xkcd-style sketch plotting

To give your plots a sense of authority that they may be missing, Michael Droettboom (inspired by the work of many others in PR #1329) has added an xkcd-style sketch plotting mode. To use it, simply call matplotlib.pyplot.xkcd() before creating your plot. For really fine control, it is also possible to modify each artist’s sketch parameters individually with matplotlib.artist.Artist.set_sketch_params().

(Source code)

../../_images/xkcd_00.png

(png, pdf)

../../_images/xkcd_01.png

(png, pdf)

Updated Axes3D.contour methods

Damon McDougall updated the tricontour() and tricontourf() methods to allow 3D contour plots on abitrary unstructured user-specified triangulations.

(Source code, png, pdf)

../../_images/tricontour3d_demo.png

New eventplot plot type

Todd Jennings added a eventplot() function to create multiple rows or columns of identical line segments

(Source code, png, pdf)

../../_images/eventplot_demo2.png

As part of this feature, there is a new EventCollection class that allows for plotting and manipulating rows or columns of identical line segments.

Triangular grid interpolation

Geoffroy Billotey and Ian Thomas added classes to perform interpolation within triangular grids: (LinearTriInterpolator and CubicTriInterpolator) and a utility class to find the triangles in which points lie (TrapezoidMapTriFinder). A helper class to perform mesh refinement and smooth contouring was also added (UniformTriRefiner). Finally, a class implementing some basic tools for triangular mesh improvement was added (TriAnalyzer).

(Source code, png, pdf)

../../_images/tricontour_smooth_user2.png

Baselines for stackplot

Till Stensitzki added non-zero baselines to stackplot(). They may be symmetric or weighted.

(Source code, png, pdf)

../../_images/stackplot_demo2.png

Rectangular colorbar extensions

Andrew Dawson added a new keyword argument extendrect to colorbar() to optionally make colorbar extensions rectangular instead of triangular.

More robust boxplots

Paul Hobson provided a fix to the boxplot() method that prevent whiskers from being drawn inside the box for oddly distributed data sets.

Calling subplot() without arguments

A call to subplot() without any arguments now acts the same as subplot(111) or subplot(1,1,1) – it creates one axes for the whole figure. This was already the behavior for both axes() and subplots(), and now this consistency is shared with subplot().

Drawing

Independent alpha values for face and edge colors

Wes Campaigne modified how Patch objects are drawn such that (for backends supporting transparency) you can set different alpha values for faces and edges, by specifying their colors in RGBA format. Note that if you set the alpha attribute for the patch object (e.g. using set_alpha() or the alpha keyword argument), that value will override the alpha components set in both the face and edge colors.

Path effects on lines

Thanks to Jae-Joon Lee, path effects now also work on plot lines.

(Source code, png, pdf)

../../_images/patheffect_demo.png

Easier creation of colormap and normalizer for levels with colors

Phil Elson added the matplotlib.colors.from_levels_and_colors() function to easily create a colormap and normalizer for representation of discrete colors for plot types such as matplotlib.pyplot.pcolormesh(), with a similar interface to that of contourf().

Full control of the background color

Wes Campaigne and Phil Elson fixed the Agg backend such that PNGs are now saved with the correct background color when fig.patch.get_alpha() is not 1.

Improved bbox_inches="tight" functionality

Passing bbox_inches="tight" through to plt.save() now takes into account all artists on a figure - this was previously not the case and led to several corner cases which did not function as expected.

Initialize a rotated rectangle

Damon McDougall extended the Rectangle constructor to accept an angle kwarg, specifying the rotation of a rectangle in degrees.

Text

Anchored text support

The svg and pgf backends are now able to save text alignment information to their output formats. This allows to edit text elements in saved figures, using Inkscape for example, while preserving their intended position. For svg please note that you’ll have to disable the default text-to-path conversion (mpl.rc('svg', fonttype='none')).

Better vertical text alignment and multi-line text

The vertical alignment of text is now consistent across backends. You may see small differences in text placement, particularly with rotated text.

If you are using a custom backend, note that the draw_text renderer method is now passed the location of the baseline, not the location of the bottom of the text bounding box.

Multi-line text will now leave enough room for the height of very tall or very low text, such as superscripts and subscripts.

Left and right side axes titles

Andrew Dawson added the ability to add axes titles flush with the left and right sides of the top of the axes using a new keyword argument loc to title().

Improved manual contour plot label positioning

Brian Mattern modified the manual contour plot label positioning code to interpolate along line segments and find the actual closest point on a contour to the requested position. Previously, the closest path vertex was used, which, in the case of straight contours was sometimes quite distant from the requested location. Much more precise label positioning is now possible.

Configuration (rcParams)

Quickly find rcParams

Phil Elson made it easier to search for rcParameters by passing a valid regular expression to matplotlib.RcParams.find_all(). matplotlib.RcParams now also has a pretty repr and str representation so that search results are printed prettily:

>>> import matplotlib
>>> print(matplotlib.rcParams.find_all('\.size'))
RcParams({'font.size': 12,
          'xtick.major.size': 4,
          'xtick.minor.size': 2,
          'ytick.major.size': 4,
          'ytick.minor.size': 2})

axes.xmargin and axes.ymargin added to rcParams

rcParam values (axes.xmargin and axes.ymargin) were added to configure the default margins used. Previously they were hard-coded to default to 0, default value of both rcParam values is 0.

Changes to font rcParams

The font.* rcParams now affect only text objects created after the rcParam has been set, and will not retroactively affect already existing text objects. This brings their behavior in line with most other rcParams.

savefig.jpeg_quality added to rcParams

rcParam value savefig.jpeg_quality was added so that the user can configure the default quality used when a figure is written as a JPEG. The default quality is 95; previously, the default quality was 75. This change minimizes the artifacting inherent in JPEG images, particularly with images that have sharp changes in color as plots often do.

Backends

WebAgg backend

Michael Droettboom, Phil Elson and others have developed a new backend, WebAgg, to display figures in a web browser. It works with animations as well as being fully interactive.

../../_images/webagg_screenshot.png

Future versions of matplotlib will integrate this backend with the IPython notebook for a fully web browser based plotting frontend.

Remember save directory

Martin Spacek made the save figure dialog remember the last directory saved to. The default is configurable with the new savefig.directory rcParam in matplotlibrc.

Documentation and examples

Numpydoc docstrings

Nelle Varoquaux has started an ongoing project to convert matplotlib’s docstrings to numpydoc format. See MEP10 for more information.

Example reorganization

Tony Yu has begun work reorganizing the examples into more meaningful categories. The new gallery page is the fruit of this ongoing work. See MEP12 for more information.

Examples now use subplots()

For the sake of brevity and clarity, most of the examples now use the newer subplots(), which creates a figure and one (or multiple) axes object(s) in one call. The old way involved a call to figure(), followed by one (or multiple) subplot() calls.

Infrastructure

Housecleaning

A number of features that were deprecated in 1.2 or earlier, or have not been in a working state for a long time have been removed. Highlights include removing the Qt version 3 backends, and the FltkAgg and Emf backends. See Changes in 1.3.x for a complete list.

New setup script

matplotlib 1.3 includes an entirely rewritten setup script. We now ship fewer dependencies with the tarballs and installers themselves. Notably, pytz, dateutil, pyparsing and six are no longer included with matplotlib. You can either install them manually first, or let pip install them as dependencies along with matplotlib. It is now possible to not include certain subcomponents, such as the unit test data, in the install. See setup.cfg.template for more information.

XDG base directory support

On Linux, matplotlib now uses the XDG base directory specification to find the matplotlibrc configuration file. matplotlibrc should now be kept in config/matplotlib, rather than matplotlib. If your configuration is found in the old location, it will still be used, but a warning will be displayed.

Catch opening too many figures using pyplot

Figures created through pyplot.figure are retained until they are explicitly closed. It is therefore common for new users of matplotlib to run out of memory when creating a large series of figures in a loop without closing them.

matplotlib will now display a RuntimeWarning when too many figures have been opened at once. By default, this is displayed for 20 or more figures, but the exact number may be controlled using the figure.max_open_warning rcParam.