Bokeh how to get GlyphRenderer for Annotation

Question

With Bokeh, how do I get a handle to the Renderer (or GlyphRenderer) for an Annotation? Is this possible?

I would like to be able to toggle a Band (which is an Annotation) on and off with an interactive legend, so I need to be able to pass a list of Renderers to the LegendItem constructor.

This code:

maxline = fig.line(x='Date', y=stn_max, line_width=0.5, legend=stn_max, name="{}_line".format(stn_max), color=stn_color, alpha=0.75, source=source)
minline = fig.line(x='Date', y=stn_min, line_width=0.5, legend=stn_min, name="{}_line".format(stn_min), color=stn_color, alpha=0.75, source=source)
band = bkm.Band(base='Date', lower=stn_min, upper=stn_max, fill_alpha=0.50, line_width=0.5, fill_color=stn_color, source=source)
bkm.LegendItem(label=stn, renderers=[maxline, minline, band])

Produces this error

...
ValueError: expected an element of List(Instance(GlyphRenderer)), got seq with invalid items [Band(id='1091', ...)]

Answer 1

For LegendItem only instances of GlyphRenderer can be passed to its renderers attribute and Band is not based on GlyphRenderer so it gives error. In the code below the Band visibility is being toggled by means of a callback:

from bokeh.plotting import figure, show
from bokeh.models import Band, ColumnDataSource, Legend, LegendItem, CustomJS
import pandas as pd
import numpy as np

x = np.random.random(2500) * 140 - 20
y = np.random.normal(size = 2500) * 2 + 5
df = pd.DataFrame(data = dict(x = x, y = y)).sort_values(by = "x")

sem = lambda x: x.std() / np.sqrt(x.size)
df2 = df.y.rolling(window = 100).agg({"y_mean": np.mean, "y_std": np.std, "y_sem": sem})
df2 = df2.fillna(method = 'bfill')
df = pd.concat([df, df2], axis = 1)
df['lower'] = df.y_mean - df.y_std
df['upper'] = df.y_mean + df.y_std

source = ColumnDataSource(df.reset_index())
p = figure(tools = "pan,wheel_zoom,box_zoom,reset,save")
scatter = p.scatter(x = 'x', y = 'y', line_color = None, fill_alpha = 0.3, size = 5, source = source)
band = Band(base = 'x', lower = 'lower', upper = 'upper', source = source)
p.add_layout(band)
p.title.text = "Rolling Standard Deviation"
p.xaxis.axis_label = 'X'
p.yaxis.axis_label = 'Y'

callback = CustomJS(args = dict(band = band), code = """
if (band.visible == false)
    band.visible = true;
else
    band.visible = false; """)

legend = Legend(items = [ LegendItem(label = "x", renderers = [scatter, band.source.selection_policy]) ])
legend.click_policy = 'hide'
scatter.js_on_change('visible', callback)
p.add_layout(legend)
show(p)

Result: