Description
Hi matplotlib developers,
I recently needed to modify the mathtext font constants (the superscript height) of a non-standard font (Arial) and found that there is no public API to accomplish this. I did, however, find that I could do what I wanted by accessing the private mathtext._font_constant_mapping dictionary. A minimal working example is below:
import matplotlib.pyplot as plt
from matplotlib import mathtext
plt.rcParams.update({
'text.usetex':False,
'font.family':'sans-serif',
'font.sans-serif':['Arial'],
'mathtext.default':'regular',
})
class ArialFontConstants(mathtext.FontConstantsBase):
# Percentage of x-height that superscripts are raised from the baseline
sup1 = 0.4
# Register font constants for Arial
mathtext._font_constant_mapping['Arial'] = ArialFontConstants
text = r'$h = 6.62607004 \times 10^{-34}\; m^2\, kg\,/\,s$'
plt.figure(figsize=(3, 2))
plt.axis('off')
plt.text(0, 0.5, text)
plt.show()This works great, but I think there should be a public and documented method to customize mathtext font constants. Perhaps we should just remove the leading underscore of _font_constant_mapping to make it permanent and public? Also, I think that an example of the new public API should be added to the mathtext tutorial documentation.
Thanks,
Tested with matplotlib 2.0.2 and python 3.6.2 running on Arch Linux.