linestyle="None" argument for fill_between() doesn't work

[RafiKueng]

fill_between() doesn't accept all possible linestyles (esp. empty ones..)

import matplotlib.pyplot as plt
plt.fill_between([1,2,3], [4,5,6], 5, linestyle="None")

ValueError: Do not know how to convert None to dashes

The same for "" and " "

[ mpl: 1.5.1; python 2.7.9; OpenSUSE; user install by pip (pip install --user matplotlib) ]

[RafiKueng]

Unfortunately, I don't know the code at all, but I guess a fix would need to add here:
https://github.com/matplotlib/matplotlib/blob/master/lib/matplotlib/cbook.py#L2022

_linestyles = [('-', 'solid'),
               ('--', 'dashed'),
               ('-.', 'dashdot'),
               (':', 'dotted'),
               ('', 'none'),
               (' ', 'none'),
               ('None', 'none')
]

and then to add the a return value (offset, dashes) for style 'none' here:
https://github.com/matplotlib/matplotlib/blob/master/lib/matplotlib/lines.py#L37

Unfortunately, I don't know what are valid (offset, dashes) that lead to no line...

[tacaswell]

Can you try with the 2.0.0b1 or 1.5.2 releases? I think we fixed this in another way.

[afvincent]

@tacaswell Are you sure it has been fixed? Because with mpl '2.0.0b1.post1771+g5dfe000', plt.fill_between([1,2,3], [4,5,6], 5, linestyle=MyLS) with the tested “MyLS” being("None", " ", "") still raises ValueError: Do not know how to convert None to dashes

[tacaswell]

Then no 😞 We fixed some other normalization of the dashes then.

[afvincent]

It looks like @RafiKueng is right about the origin of the error: mlines.get_dash_pattern expects only an argument in {'solid', 'dashed', 'dotted', 'dashdot'}, but unfortunately, here this method is called by mcollections.Collection.set_linestyle which also accept arguments like "None" that are not transformed into any of those 4 names by cbook.ls_mapper.get before calling mlines.get_dash_pattern…

[afvincent]

I've been playing a bit with the linestyle options of fill_between and I've encountered several weird behaviors. Is the following script

import matplotlib as mpl
import matplotlib.pyplot as plt
from matplotlib.ticker import NullLocator


def plot_test(ax, ls=None, lw=None):
    _plot_opts = dict(facecolor='LightGrey', edgecolor='Black')
    ax.set_title("ls:'{ls}' & lw: {lw}".format(ls=ls, lw=lw))
    ax.fill_between([1, 2, 3], [4, 5, 6], 5, linestyle=ls, lw=lw, **_plot_opts)
    ax.xaxis.set_major_locator(NullLocator())
    ax.yaxis.set_major_locator(NullLocator())
    return ax


if __name__ == "__main__":

    fig, ((ax0, ax1), (ax2, ax3)) = plt.subplots(nrows=2, ncols=2,
                                                 num=mpl.__version__)

    ax0 = plot_test(ax0, ls='dashed', lw=2)
    ax1 = plot_test(ax1, ls='dashed', lw=10)
    ax2 = plot_test(ax2, ls='dashed', lw=None)
    ax3 = plot_test(ax3, ls='solid', lw=0)

    fig.savefig(fig.get_label() + '.png', dpi=100)

supposed to produce (with mpl 2.0.0b1.post1771+g5dfe000)

? First, the dashes don't seem to scale accordingly to the linewidth. Second if lw is None (default) then even with a named linestyle, no edge line is visible.

It seems however to me that the result was OK with mpl 1.5.1 (anaconda2):

[asker4ik]

fill_between() doesn't accept all possible linestyles (esp. empty ones..)

import matplotlib.pyplot as plt
plt.fill_between([1,2,3], [4,5,6], 5, linestyle="None")

ValueError: Do not know how to convert None to dashes

The same for "" and " "

[ mpl: 1.5.1; python 2.7.9; OpenSUSE; user install by pip (pip install --user matplotlib) ]

should be linestyle = 'none'. case sensitive

[bilderbuchi]

@asker4ik this works for you? When I do that, I still get ValueError: Do not know how to convert 'none' to dashes with mpl 3.1.3