<p dir="auto">Currently, one can set default line properties like color, marker style, line width, etc. with <code class="notranslate">mpl.rcParams</code>. However, the ability to set a default line alpha seems to be missing. It would be great to have <code class="notranslate">'lines.alpha'</code> as a key in the <code class="notranslate">rcParams</code> dict, similar to <code class="notranslate">'lines.color'</code>, <code class="notranslate">'lines.marker'</code>, etc.</p>
<h3 dir="auto">Bug summary</h3>
<p dir="auto">When you invoke pyplot.show() to show your plot, the plot is not shown but instead crashes Python. This came about when I updated the package 'freetype' in a conda installation, from version 2.10.4 to 2.11.0.</p>
<h3 dir="auto">Code for reproduction</h3>
<div class="highlight highlight-source-python notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="import matplotlib.pyplot as plt
plt.plot(1,1)
plt.show()"><pre class="notranslate"><span class="pl-k">import</span> <span class="pl-s1">matplotlib</span>.<span class="pl-s1">pyplot</span> <span class="pl-k">as</span> <span class="pl-s1">plt</span>
<span class="pl-s1">plt</span>.<span class="pl-en">plot</span>(<span class="pl-c1">1</span>,<span class="pl-c1">1</span>)
<span class="pl-s1">plt</span>.<span class="pl-en">show</span>()</pre></div>
<h3 dir="auto">Actual outcome</h3>
<p dir="auto">Python simply crashes with no error messages.</p>
<h3 dir="auto">Expected outcome</h3>
<p dir="auto">It should plot a single point at (1,1) and show that plot.</p>
<h3 dir="auto">Operating system</h3>
<p dir="auto">Windows 10</p>
<h3 dir="auto">Matplotlib Version</h3>
<p dir="auto">3.4.3</p>
<h3 dir="auto">Matplotlib Backend</h3>
<p dir="auto">Qt5Agg</p>
<h3 dir="auto">Python version</h3>
<p dir="auto">3.8.12</p>
<h3 dir="auto">Jupyter version</h3>
<p dir="auto">N/A</p>
<h3 dir="auto">Other libraries</h3>
<p dir="auto">The bug came about when I updated package freetype, from version 2.10.4 to 2.11.0. The output of conda list (before the update):</p>
<p dir="auto">packages in environment at C:\juhasz-local\Anaconda3\envs\plttest:</p>
<p dir="auto">Name                    Version                   Build  Channel<br>
blas                      1.0                         mkl<br>
blosc                     1.21.0               h19a0ad4_0<br>
brotli                    1.0.9                ha925a31_2<br>
bzip2                     1.0.8                he774522_0<br>
ca-certificates           2021.10.26           haa95532_2<br>
certifi                   2021.10.8        py38haa95532_0<br>
cfitsio                   3.470                he774522_6<br>
charls                    2.2.0                h6c2663c_0<br>
cycler                    0.10.0                   py38_0<br>
fonttools                 4.25.0             pyhd3eb1b0_0<br>
freetype                  2.10.4               hd328e21_0<br>
giflib                    5.2.1                h62dcd97_0<br>
icu                       58.2                 ha925a31_3<br>
imagecodecs               2021.8.26        py38ha1f97ea_0<br>
intel-openmp              2021.3.0          haa95532_3372<br>
jpeg                      9d                   h2bbff1b_0<br>
kiwisolver                1.3.1            py38hd77b12b_0<br>
lcms2                     2.12                 h83e58a3_0<br>
lerc                      3.0                  hd77b12b_0<br>
libaec                    1.0.4                h33f27b4_1<br>
libdeflate                1.8                  h2bbff1b_5<br>
libpng                    1.6.37               h2a8f88b_0<br>
libtiff                   4.2.0                hd0e1b90_0<br>
libwebp                   1.2.0                h2bbff1b_0<br>
libzopfli                 1.0.3                ha925a31_0<br>
lz4-c                     1.9.3                h2bbff1b_1<br>
matplotlib                3.4.3            py38haa95532_0<br>
matplotlib-base           3.4.3            py38h49ac443_0<br>
mkl                       2021.3.0           haa95532_524<br>
mkl-service               2.4.0            py38h2bbff1b_0<br>
mkl_fft                   1.3.1            py38h277e83a_0<br>
mkl_random                1.2.2            py38hf11a4ad_0<br>
munkres                   1.1.4                      py_0<br>
numpy                     1.21.2           py38hfca59bb_0<br>
numpy-base                1.21.2           py38h0829f74_0<br>
olefile                   0.46               pyhd3eb1b0_0<br>
openjpeg                  2.4.0                h4fc8c34_0<br>
openssl                   1.1.1l               h2bbff1b_0<br>
pillow                    8.4.0            py38hd45dc43_0<br>
pip                       21.2.2           py38haa95532_0<br>
pyparsing                 2.4.7              pyhd3eb1b0_0<br>
pyqt                      5.9.2            py38ha925a31_4<br>
python                    3.8.12               h6244533_0<br>
python-dateutil           2.8.2              pyhd3eb1b0_0<br>
qt                        5.9.7            vc14h73c81de_0<br>
setuptools                58.0.4           py38haa95532_0<br>
sip                       4.19.13          py38ha925a31_0<br>
six                       1.16.0             pyhd3eb1b0_0<br>
snappy                    1.1.8                h33f27b4_0<br>
sqlite                    3.36.0               h2bbff1b_0<br>
tk                        8.6.11               h2bbff1b_0<br>
tornado                   6.1              py38h2bbff1b_0<br>
vc                        14.2                 h21ff451_1<br>
vs2015_runtime            14.27.29016          h5e58377_2<br>
wheel                     0.37.0             pyhd3eb1b0_1<br>
wincertstore              0.2              py38haa95532_2<br>
xz                        5.2.5                h62dcd97_0<br>
zfp                       0.5.5                hd77b12b_6<br>
zlib                      1.2.11               h62dcd97_4<br>
zstd                      1.4.9                h19a0ad4_0</p>
<h3 dir="auto">Installation</h3>
<p dir="auto">conda</p>
<h3 dir="auto">Conda channel</h3>
<p dir="auto">default</p>