Change language of timeline-stripplot

Hey dear all,

I really love what you guys provide with Altair and it is a lot of fun to play around with it. I was wondering, if there is a way to change ticks on a timeline-stripplot into another languages datetime-format (in my case German). I have tried just changing the locale but that had no effect on the graph. Is there a way to custom-map axis ticks from the data-values in the dataset to something converted without the order of the ticks being scrambled up?

Again thank you so much for all your work

alt.Chart(terrordata,
    description='Shows the frequency of terror attacks between two countries.',
).mark_tick(tickThickness=1.5, font="arial").encode(   
x=alt.X('date:T',axis=alt.Axis(format='%B %Y',title='', labelAngle=0, axisWidth=0,ticks=4, orient="top",)),
    y=alt.Y('country:N',axis=alt.Axis(title='', axisWidth=0), font="Helvetica Neue", fontsize=20),
    color=alt.Color("casualties:Q",
            legend=alt.Legend(
                title='Todeszahlen',
                titleFont="s-font-serif",
                titleFontWeight="12",
            ),
            scale=alt.Scale(
                domain=['0', '5'],
                range=['#ffb6b6', '#e23b3c'],
            ),
        ),).configure_cell( width=800).configure_scale(bandSize=100).configure_axis(
    titleFont="s-font-serif",
    titleFontSize=16,
    tickLabelFont="s-font-serif",
    tickLabelFontSize=12,
    tickSize=0
)

[jakevdp]

For time format locale, you can pass a dict object from https://github.com/d3/d3-time-format/tree/master/locale to the embed options. For example:

from urllib import request
import json

# fetch & enable a German time locale.
with request.urlopen('https://raw.githubusercontent.com/d3/d3-time-format/master/locale/de-DE.json') as f:
  de_time_format = json.load(f)
alt.renderers.set_embed_options(timeFormatLocale=de_time_format)

# plot the chart
df = pd.DataFrame({
    'date': pd.date_range('2020-01-01', freq='D', periods=180),
    'value': np.random.randn(180).cumsum()
})

alt.Chart(df).mark_line().encode(
    x='date',
    y='value',
)

It might be worth adding some convenience functions to Altair and put some examples in the documentation.

[domoritz]

Vega-Embed 6.1.0 supports formatLocale and timeFormatLocale. I think this issue can be closed.