Let us look at how to access the configuration parameters and update them for customizing matplotlib plots.
21 Mar 2021 - fubar - Sreekar Guddeti
Let us look at how to access the configuration parameters and update them for customizing matplotlib plots.
rcParamsMatplotlib has various plot parameters and offers freedom to tweak them. For default settings, matplotlib uses a configuration file called rcParams in colloquial language for setting default values to these parameters. The file is located at 1
INSTALL/matplotlib/mpl-data/matplotlibrc, where INSTALL is something like /usr/lib/python3.7/site-packages on Linux, and maybe C:\Python37\Lib\site-packages on Windows.
We also can get the file location of the file by
import matplotlib as mpl
mpl.matplotlib_fname()
The params are listed in a dictionary-like object mpl.rcParams as key-value pairs for each parameter and its default value.
type(mpl.rcParams)
matplotlib.RcParams
type(mpl.rcParams) is dict
False
Though mpl.rcParams is not exactly a dictionary, it is dictionary-like. As a result, the dictionary methods are applicable. For example, to list the available keys, use
print(mpl.rcParams.keys)
RcParams({...,
'font.size': 8.0,
'font.stretch': 'normal',
'font.style': 'normal',
'font.variant': 'normal',
'font.weight': 'bold',
...,
})
len(mpl.rcParams.keys())
305
There are more than 300 keys!
The keys are categorized logically into
## Matplotlib configuration are currently divided into following parts:
## - BACKENDS
## - LINES
## - PATCHES
## - HATCHES
## - BOXPLOT
## - FONT
## - TEXT
## - LaTeX
## - AXES
## - DATES
## - TICKS
## - GRIDS
## - LEGEND
## - FIGURE
## - IMAGES
## - CONTOUR PLOTS
## - ERRORBAR PLOTS
## - HISTOGRAM PLOTS
## - SCATTER PLOTS
## - AGG RENDERING
## - PATHS
## - SAVING FIGURES
## - INTERACTIVE KEYMAPS
## - ANIMATION
If we want to get the value of a particular key, use
mpl.rcParams.get('font.size')
8.0
Now if we need to change the value of a particular key, use
mpl.rcParams['font.size'] = 10.0
Sometimes, we need change more than a single key-value pair. In such a sitution, create a dictionary of these pairs, and pass to update() method.
dictLaTeX = {'text.usetex' : True, "text.latex.preamble": r"\usepackage{amsmath}" }
mpl.rcParams.update(dictLaTeX)
rcParams fileAfter optimizing the keys, we want to have a repeatable behaviour across all the scripts. Instead of updating the keys per script, we can use our own matplotlibrc file in a different rcParams file. The original file is at
mpl.matplotlib_fname()
'd:\\databases\\pythonprojects\\numscimat\\env\\lib\\site-packages\\matplotlib\\mpl-data\\matplotlibrc'
A portion of the file corresponding to LaTeX keys reads
## ***************************************************************************
## * LaTeX *
## ***************************************************************************
## For more information on LaTex properties, see
## https://matplotlib.org/tutorials/text/usetex.html
#text.usetex: False # use latex for all text handling. The following fonts
# are supported through the usual rc parameter settings:
# new century schoolbook, bookman, times, palatino,
# zapf chancery, charter, serif, sans-serif, helvetica,
# avant garde, courier, monospace, computer modern roman,
# computer modern sans serif, computer modern typewriter
# If another font is desired which can loaded using the
# LaTeX \usepackage command, please inquire at the
# matplotlib mailing list
#text.latex.preamble: # IMPROPER USE OF THIS FEATURE WILL LEAD TO LATEX FAILURES
# AND IS THEREFORE UNSUPPORTED. PLEASE DO NOT ASK FOR HELP
# IF THIS FEATURE DOES NOT DO WHAT YOU EXPECT IT TO.
# text.latex.preamble is a single line of LaTeX code that
# will be passed on to the LaTeX system. It may contain
# any code that is valid for the LaTeX "preamble", i.e.
# between the "\documentclass" and "\begin{document}"
# statements.
# Note that it has to be put on a single line, which may
# become quite long.
# The following packages are always loaded with usetex, so
# beware of package collisions: color, geometry, graphicx,
# type1cm, textcomp.
# Adobe Postscript (PSSNFS) font packages may also be
# loaded, depending on your font settings.
Let us copy this file to the project working directory pwd and modify lines corresponding to LaTeX keys to
text.usetex: True
text.latex.preamble: r"\usepackage{amsmath}", # for the align enivironment
To use this file, we need to reload the matplotlib package as it has already been configured to use the default rcParams file. We use reload() method from importlib built-in module
pwd
'E:\\Databases\\CheggProjects\\NuclearShellTemperature'
mpl.matplotlib_fname()
'd:\\databases\\pythonprojects\\numscimat\\env\\lib\\site-packages\\matplotlib\\mpl-data\\matplotlibrc'
from importlib import reload
reload(mpl)
<module 'matplotlib' from 'd:\\databases\\pythonprojects\\numscimat\\env\\lib\\site-packages\\matplotlib\\__init__.py'>
mpl.matplotlib_fname()
'E:\\Databases\\CheggProjects\\NuclearShellTemperature\\matplotlibrc'
Instead of using a custom matplotlibrc file, we can use a custom stylesheet that contains only the optimized keys.
Instead of writing down all the keys, the file contains key-value pairs of only the ones we want to change. On importing the style file, the values of the default rcParams get updated.
It is necessary that file has extension
.mplstyle.
A portion of the file myMatplotlibStylesheet.mplstyle reads
#text-font parameters
font.family : Arial
font.size : 8.0
font.weight : bold
#math-font parameters
mathtext.fontset : cm
mathtext.default : regular
#LaTeX parameters
text.usetex : True
text.latex.preamble: r"\usepackage{amsmath}", # for the align enivironment
Before importing the
.mplstylefile, we assume there is no file namedmatplotlibrc.
To use this custom style sheet,
mpl.style.use('myMatplotlibStylesheet.mplstyle')
Customize matplotlib style sheet