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default value of lines.dash_capstyle #7174
Description
In #7087 @rougier asked about changing the default dash_capstyle to 'round'. This is what it would look like on top of the rest of the changes.
import numpy as np
import matplotlib.pyplot as plt
import matplotlib as mpl
from cycler import cycler
fig, (ax1, ax2) = plt.subplots(1, 2, figsize=(6, 3))
N = 15
x = np.arange(N)
y = np.ones_like(x)
sty_cycle = (cycler('ls', ['--' ,':', '-.']) *
cycler('lw', [None, 1, 2, 5]))
classic = {'lines.dash_capstyle': 'butt'}
v2 = {'lines.dash_capstyle': 'round'}
def demo(ax, rcparams, title):
ax.axis('off')
ax.set_title(title)
with mpl.rc_context(rc=rcparams):
for j, sty in enumerate(sty_cycle):
ax.plot(x, y + j, **sty)
demo(ax1, classic, 'v2.0')
demo(ax2, {}, 'v2.0 + rounded')I am not a huge fan of the rounded caps, it is barely noticeable at small line widths and looks worse at large linewidths (IMO).
It would also require re-doing the dash patterns.
Activity
rougier commentedon Sep 25, 2016
Note also that dots with cap are not round. Does that mean the default is "butt" cap (= no cap) and not "square" ?
tacaswell commentedon Sep 25, 2016
Yes, the current default is 'butt'
rougier commentedon Sep 25, 2016
Maybe square would a better option such that when you replace square caps with round caps, you get actual dot. But this would mean changing all the dash styles I imagine.
efiring commentedon Sep 25, 2016
An advantage of butt is that it means the line from A to B actually goes exactly from A to B--it doesn't overshoot by half the line thickness. I don't see any advantage to square caps, only disadvantages. I think that under some circumstances the round caps might look better, but this is not worth the fuss of changing combined with the disadvantages under other circumstances. I recommend that we close this now.
dopplershift commentedon Oct 10, 2016
I agree with @efiring -- it's about having the clearest and most useful visualization with good aesthetics by default. The caps obscure the end points of a line, so we should leave those to users who can justify to themselves the need for "pretty" over exactness.
NelleV commentedon Oct 10, 2016
There seems to be a consensus that butt is better.