Add subcoordinate_y keyword

[maximlt]

Closes #1160

• Add tests

import hvplot.pandas  # noqa
from bokeh.sampledata.sea_surface_temperature import sea_surface_temperature as sst

new_cols = {f'temperature{i}': sst.temperature.shift(i*1000) for i in range(1, 4)}
sst.assign(**new_cols).hvplot(subcoordinate_y=True, legend=False)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.89%. Comparing base (feffee5) to head (6316666).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1379      +/-   ##
==========================================
+ Coverage   88.87%   88.89%   +0.02%     
==========================================
  Files          51       51              
  Lines        7478     7494      +16     
==========================================
+ Hits         6646     6662      +16     
  Misses        832      832              

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[droumis]

Looks pretty good!

Code

import numpy as np
import pandas as pd
from pathlib import Path
import mne
import colorcet as cc
from hvplot import pandas
hv.extension('bokeh')

# data from https://datasets.holoviz.org/eeg/v1/S001R04.edf
data_path = 

raw = mne.io.read_raw_edf(data_path, preload=True)

raw.set_eeg_reference("average")
raw.rename_channels(lambda s: s.strip("."));

df = raw.to_data_frame()
df.set_index('time', inplace=True) 

df.hvplot(subcoordinate_y={'subcoordinate_scale':4}, responsive=True, min_height=700, legend=False, color='black', line_width=1)

Known issues:

• Group or hide hover tools in Bokeh toolbar holoviews#6252

Nice to haves eventually:

• apply a color key/cmap based on curve label. for instance, color grouping based first letter of columns:

entries = df.columns.tolist()
colors = cc.b_glasbey_bw
letter_to_color = {letter: colors[i % len(colors)] for i, letter in enumerate(sorted(set(e[0] for e in entries)))}
entry_to_color = {entry: letter_to_color[entry[0]] for entry in entries}
df.hvplot(subcoordinate_y={'subcoordinate_scale':4}, responsive=True, min_height=700, legend=False, line_width=1, cmap=entry_to_color)

• range linked minimap

[droumis]

made a couple of minor changes