How to set active tools in Holoviews

Question

Sometimes my plots get drawn with the pan tool active and sometimes they draw with pan and wheel_zoom active. I'd like to force wheel_zoom to be active upon rendering. Is there a way to do this?

Answer 1

Since holoviews 1.11.0 was released the original answer has been outdated. HoloViews now has an explicit option to set the active tool(s), called active_tools which accepts a list of tool names or instances, e.g. to activate the wheel_zoom tool by default you would do this:

 hv.Curve([1, 2, 3]).options(active_tools=['wheel_zoom'])

The rest of the answer below is outdated:

For any options that are not directly exposed in HoloViews you can define hooks which can directly modify the bokeh models. Here is a simple example that defines a hook to set the active scroll tool (as described in the bokeh docs):

def set_active_tool(plot, element):
    plot.state.toolbar.active_scroll = plot.state.tools[2]

hv.Curve([1, 2, 3]).options(finalize_hooks=[set_active_tool])

Setting the active tool seems like a fairly common action though, so filing an issue to request that the active tools can be declared directly as a plot option would be appreciated.