How can I dynamically change the renderer via a widget. I remember seeing that in a tutorial, but I can’t find it anymore. Anyone has a reference for that? I have tried the following but it did not work:
view = param.rx(hvplot.render)(view, backend=backend_widget)
Are you running it in a notebook?
import holoviews as hv
import panel as pn
def render(plot, backend):
hv.extension(backend)
output = pn.panel(hv.render(plot, backend=backend))
return output
curve = hv.Curve([0, 1, 2])
select = pn.widgets.Select(options=["matplotlib", "bokeh", "plotly"])
pn.Column(
select,
pn.bind(render, curve, select.param.value)
).show()
This seems to work if its served on the browser
Your example indeed works, but if I add a few more indirections it starts to fail. Here is an example of the backend that I want and where it fails:
import holoviews
import panel
import param
import dataclasses
from panel.layout import Panel
holoviews.extension("bokeh", "matplotlib")
backend = panel.widgets.Select(options=["matplotlib", "bokeh"])
@dataclasses.dataclass
class Plotter:
backend: panel.widgets.Select
def view(self, view: param.rx | holoviews.Element) -> Panel:
widgets = panel.WidgetBox()
widgets.insert(0, self.backend)
# view = param.rx(hvplot.render)(view, backend=self.backend)
view = param.rx(holoviews.render)(view, backend=self.backend)
widgets += panel.ReactiveExpr(view).widgets
view_item = panel.ReactiveExpr(view, show_widgets=False)
return panel.Row(widgets, view_item)
plot = Plotter(backend)
curve = holoviews.Curve([0, 1, 2])
plot.view(curve)
Using param.rx in your example still works, so it’s somewhere in the middle of that where it starts to fail. I’ll try to hunt it down a bit more
I have narrowed down the issue being the widgets += panel.ReactiveExpr(view).widgets. Interestingly this works around it:
for widget in view_item.widgets:
if widget == self.backend:
continue
widgets.append(widget)
Well there is another issue with using holoviews.render, when I backend specific options, e.g. line_dash vs linestyle, I get issues of “linestyle option not found for line plot with bokeh”