js_events.pyΒΆ
Demonstration of how to register event callbacks using an adaptation of the color_scatter example from the bokeh gallery
import numpy as np
from bokeh.io import show, output_file
from bokeh.plotting import figure
from bokeh import events
from bokeh.models import CustomJS, Div, Button
from bokeh.layouts import column, row
def display_event(div, attributes=[], style = 'float:left;clear:left;font_size=0.5pt'):
"Build a suitable CustomJS to display the current event in the div model."
return CustomJS(args=dict(div=div), code="""
var attrs = %s; var args = [];
for (var i=0; i<attrs.length; i++ ) {
args.push(attrs[i] + '=' + Number(cb_obj[attrs[i]]).toFixed(2));
}
var line = "<span style=%r><b>" + cb_obj.event_name + "</b>(" + args.join(", ") + ")</span>\\n";
var text = div.text.concat(line);
var lines = text.split("\\n")
if ( lines.length > 35 ) { lines.shift(); }
div.text = lines.join("\\n");
""" % (attributes, style))
x = np.random.random(size=4000) * 100
y = np.random.random(size=4000) * 100
radii = np.random.random(size=4000) * 1.5
colors = ["#%02x%02x%02x" % (int(r), int(g), 150) for r, g in zip(50+2*x, 30+2*y)]
p = figure(tools="pan,wheel_zoom,zoom_in,zoom_out,reset")
p.scatter(x, y, radius=np.random.random(size=4000) * 1.5,
fill_color=colors, fill_alpha=0.6, line_color=None)
div = Div(width=1000)
button = Button(label="Button", button_type="success")
layout = column(button, row(p, div))
## Events with no attributes
button.js_on_event(events.ButtonClick, display_event(div)) # Button click
p.js_on_event(events.LODStart, display_event(div)) # Start of LOD display
p.js_on_event(events.LODEnd, display_event(div)) # End of LOD display
## Events with attributes
point_attributes = ['x','y','sx','sy'] # Point events
wheel_attributes = point_attributes+['delta'] # Mouse wheel event
pan_attributes = point_attributes + ['delta_x', 'delta_y'] # Pan event
pinch_attributes = point_attributes + ['scale'] # Pinch event
point_events = [events.Tap, events.DoubleTap, events.Press,
events.MouseMove, events.MouseEnter, events.MouseLeave,
events.PanStart, events.PanEnd, events.PinchStart, events.PinchEnd]
for event in point_events:
p.js_on_event(event,display_event(div, attributes=point_attributes))
p.js_on_event(events.MouseWheel, display_event(div,attributes=wheel_attributes))
p.js_on_event(events.Pan, display_event(div, attributes=pan_attributes))
p.js_on_event(events.Pinch, display_event(div, attributes=pinch_attributes))
output_file("js_events.html", title="JS Events Example")
show(layout)