js_events.py — Anaconda Enterprise 4.4 documentation

Anaconda Enterprise: Documentation

# js_events.py

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)