Kerning adjustments now use correct values

Due to an error in how kerning adjustments were applied, previous versions of

Matplotlib would under-correct kerning. This version will now correctly apply

kerning (for fonts supported by FreeType). To restore the old behavior (e.g.,

for test images), you may set :rc:`text.kerning_factor` to 6 (instead of 0).

Other values have undefined behavior.

.. plot::

import matplotlib.pyplot as plt

# Use old kerning values:

plt.rcParams['text.kerning_factor'] = 6

fig, ax = plt.subplots()

ax.text(0.0, 0.05, 'BRAVO\nAWKWARD\nVAT\nW.Test', fontsize=56)

ax.set_title('Before (text.kerning_factor = 6)')

Note how the spacing between characters is uniform between their bounding boxes

(above). With corrected kerning (below), slanted characters (e.g., AV or VA)

will be spaced closer together, as well as various other character pairs,

depending on font support (e.g., T and e, or the period after the W).

.. plot::

import matplotlib.pyplot as plt

# Use new kerning values:

plt.rcParams['text.kerning_factor'] = 0

fig, ax = plt.subplots()

ax.text(0.0, 0.05, 'BRAVO\nAWKWARD\nVAT\nW.Test', fontsize=56)

ax.set_title('After (text.kerning_factor = 0)')