Cannot link tap to float slider #6384
Description
For widgets, there’s pn.Param and from_param.
What’s the equivalent for HoloViews streams?
I thought the following would work, but I get TypeError: Constant parameter 'x' cannot be modified
Can we remove the constant=True, or create a dedicated method like from_param or from_params?
import param
import holoviews as hv
import panel as pn
pn.extension()
class TapTest(pn.custom.PyComponent):
x = param.Number(default=0)
y = param.Number(default=0)
def __init__(self, **params):
super().__init__(**params)
self._tap = hv.streams.Tap()
hv_pane = pn.pane.HoloViews()
hv_pane.object = hv.DynamicMap(self.plot, streams=[self._tap])
x_spinner = pn.widgets.FloatSlider.from_param(self.param.x)
y_spinner = pn.widgets.FloatSlider.from_param(self.param.y)
x_spinner.link(self._tap, value='x', bidirectional=True)
y_spinner.link(self._tap, value='y', bidirectional=True)
self._layout = pn.Column(hv_pane, x_spinner, y_spinner)
def plot(self, x, y):
return hv.Points([(x, y)]).opts(tools=['tap'])
def __panel__(self):
return self._layout
pn.serve(TapTest())The workaround is a bit more code
import param
import holoviews as hv
import panel as pn
pn.extension()
class TapTest(pn.custom.PyComponent):
x = param.Number(default=0)
y = param.Number(default=0)
def __init__(self, **params):
super().__init__(**params)
self._tap = hv.streams.Tap()
hv_pane = pn.pane.HoloViews()
hv_pane.object = hv.DynamicMap(self.plot, streams=[self._tap])
pn.bind(self.update_tap, self.param.x, self.param.y, watch=True)
self._layout = pn.Column(hv_pane, self.param.x, self.param.y)
def update_tap(self, x, y):
self._tap.event(x=x, y=y)
def plot(self, x, y):
if x and y:
self.param.update(x=x, y=y)
return hv.Points([(self.x, self.y)]).opts(tools=['tap'])
def __panel__(self):
return self._layout
pn.serve(TapTest())