如何使散景散点图具有交互性（使用滑块）

Question

I'm trying to make a scatter plot in Bokeh based on the simple example code posted here .

The following code produces a working demo for a line plot:

from bokeh.layouts import column
from bokeh.models import CustomJS, ColumnDataSource, Slider
from bokeh.plotting import Figure, show

# fetch and clear the document
from bokeh.io import curdoc
curdoc().clear()

x = [x*0.005 for x in range(0, 100)]
y = x

source = ColumnDataSource(data=dict(x=x, y=y))

plot = Figure(plot_width=400, plot_height=400)

plot.line(x='x', y='y', source=source)

def callback(source=source, window=None):
    data = source.data
    f = cb_obj.value
    x, y = data['x'], data['y']
    for i in range(len(x)):
        y[i] = window.Math.pow(x[i], f)
    source.trigger('change')

slider = Slider(start=0.1, end=4, value=1, step=.1, title="Start week",
                callback=CustomJS.from_py_func(callback))

layout = column(slider, plot)

show(layout)

It looks like this:

In this demo, when you adjust the slider and press the 'reset' icon, the plot re-draws itself based on the updated formula for y=f(x).

However, I want to make a scatter plot that changes, not a line plot.

Problem:

When I simply change plot.line in above code to plot.circle , the plot renders okay but it is static - it does not change when you shift the slider and press 'reset'. No error messages that I can see.

Answer 1

I found the answer in the documentation .

The final line in callback should be source.change.emit() not source.trigger('change') . I do not know the difference between these two but the latter works with circle plots.

Ie

def callback(source=source, window=None):
    data = source.data
    f = cb_obj.value
    x, y = data['x'], data['y']
    for i in range(len(x)):
        y[i] = window.Math.pow(x[i], f)
    source.change.emit()