Anaconda Enterprise: Documentation

# extensions_example_widget.py

Example implementation of two double ended sliders as extension widgets

    from bokeh.core.properties import Float, Instance, Tuple, Bool, Enum
    from bokeh.models import InputWidget
    from bokeh.models.callbacks import Callback
    from bokeh.core.enums import SliderCallbackPolicy

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

    class IonRangeSlider(InputWidget):
        # The special class attribute ``__implementation__`` should contain a string
        # of JavaScript (or CoffeeScript) code that implements the JavaScript side
        # of the custom extension model or a string name of a JavaScript (or
        # CoffeeScript) file with the implementation.

        __implementation__ = 'extensions_ion_range_slider.coffee'
        __javascript__ = ["https://ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js",
                          "https://cdnjs.cloudflare.com/ajax/libs/ion-rangeslider/2.1.4/js/ion.rangeSlider.js"]
        __css__ = ["https://cdnjs.cloudflare.com/ajax/libs/normalize/4.2.0/normalize.css",
                   "https://cdnjs.cloudflare.com/ajax/libs/ion-rangeslider/2.1.4/css/ion.rangeSlider.css",
                   "https://cdnjs.cloudflare.com/ajax/libs/ion-rangeslider/2.1.4/css/ion.rangeSlider.skinFlat.min.css",
                   "https://cdnjs.cloudflare.com/ajax/libs/ion-rangeslider/2.1.4/img/sprite-skin-flat.png"]

        # Below are all the "properties" for this model. Bokeh properties are
        # class attributes that define the fields (and their types) that can be
        # communicated automatically between Python and the browser. Properties
        # also support type validation. More information about properties in
        # can be found here:
        #
        #    https://bokeh.pydata.org/en/latest/docs/reference/core.html#bokeh-core-properties

        disable = Bool(default=True, help="""
        Enable or disable the slider.
        """)

        grid = Bool(default=True, help="""
        Show or hide the grid beneath the slider.
        """)

        start = Float(default=0, help="""
        The minimum allowable value.
        """)

        end = Float(default=1, help="""
        The maximum allowable value.
        """)

        range = Tuple(Float, Float, help="""
        The start and end values for the range.
        """)

        step = Float(default=0.1, help="""
        The step between consecutive values.
        """)

        callback = Instance(Callback, help="""
        A callback to run in the browser whenever the current Slider value changes.
        """)

        callback_throttle = Float(default=200, help="""
        Number of microseconds to pause between callback calls as the slider is moved.
        """)

        callback_policy = Enum(SliderCallbackPolicy, default="throttle", help="""
        When the callback is initiated. This parameter can take on only one of three options:
           "continuous": the callback will be executed immediately for each movement of the slider
           "throttle": the callback will be executed at most every ``callback_throttle`` milliseconds.
           "mouseup": the callback will be executed only once when the slider is released.
           The `mouseup` policy is intended for scenarios in which the callback is expensive in time.
        """)

    x = [x*0.005 for x in range(2, 198)]
    y = x

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

    plot = Figure(plot_width=400, plot_height=400)
    plot.line('x', 'y', source=source, line_width=3, line_alpha=0.6, color='#ed5565')

    callback_single = CustomJS(args=dict(source=source), code="""
            var data = source.data;
            var f = cb_obj.value
            x = data['x']
            y = data['y']
            for (i = 0; i < x.length; i++) {
                y[i] = Math.pow(x[i], f)
            }
            source.change.emit();
        """)

    callback_ion = CustomJS(args=dict(source=source), code="""
            var data = source.data;
            var f = cb_obj.range
            x = data['x']
            y = data['y']
            pow = (Math.log(y[100])/Math.log(x[100]))
            console.log(pow)
            delta = (f[1]-f[0])/x.length
            for (i = 0; i < x.length; i++) {
                x[i] = delta*i + f[0]
                y[i] = Math.pow(x[i], pow)
            }
            source.change.emit();
        """)

    slider = Slider(start=0, end=5, step=0.1, value=1, title="Bokeh Slider - Power", callback=callback_single)
    ion_range_slider = IonRangeSlider(start=0.01, end=0.99, step=0.01, range=(min(x), max(x)),
        title='Ion Range Slider - Range', callback=callback_ion, callback_policy='continuous')

    layout = column(plot, slider, ion_range_slider)
    show(layout)