Add popup position and anchor

[ahuang11]

Closes #6266

import numpy as np
import holoviews as hv

hv.extension("bokeh")


def popup_stats(index):
    if not index:
        return
    return points.iloc[index].dframe().describe()


points = hv.Points(np.random.randn(1000, 2))

hv.streams.Selection1D(
    source=points,
    popup=popup_stats,
    popup_position="right"
)

points.opts(
    tools=["xbox_select"],
    active_tools=["xbox_select"],
    size=6,
    color="black",
    fill_color=None,
    width=500,
    height=500
)

import numpy as np
import holoviews as hv

hv.extension("bokeh")


def popup_stats(index):
    if not index:
        return
    return points.iloc[index].dframe().describe()


points = hv.Points(np.random.randn(1000, 2))

hv.streams.BoundsXY(source=points, popup="Used Box Select", popup_position="top_right")
hv.streams.Lasso(source=points, popup="Used Lasso Select", popup_position="bottom_right")
hv.streams.Tap(source=points, popup="Used Tap")

points.opts(
    tools=["box_select", "lasso_select", "tap"],
    active_tools=["lasso_select"],
    size=6,
    color="black",
    fill_color=None,
    width=500,
    height=500
)

[codecov]

Codecov Report

Attention: Patch coverage is 74.45652% with 47 lines in your changes missing coverage. Please review.

Project coverage is 88.51%. Comparing base (2e4979b) to head (ab04349).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
holoviews/tests/ui/bokeh/test_callback.py	74.28%	45 Missing ⚠️
holoviews/plotting/bokeh/callbacks.py	66.66%	1 Missing ⚠️
holoviews/streams.py	83.33%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6414      +/-   ##
==========================================
+ Coverage   88.50%   88.51%   +0.01%     
==========================================
  Files         323      323              
  Lines       68620    68599      -21     
==========================================
- Hits        60730    60722       -8     
+ Misses       7890     7877      -13     

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[hoxbro]

It's unfortunate that there is so much "almost" repeatable code, but I can't think of a better way to do it.

Because most of the logic is inside CustomJS, I'm leaning toward testing every position/geometry type case. Hopefully, this can be done with parameterized unit tests.

Also the test_stream_popup_polygons_selection1d fails which is somewhat

[ahuang11]

Okay I think I addressed your review comments; let me know if there's anything else.

[hoxbro]

We could benefit from having a class with some helper functions for the popup tests. There seems to be a lot of repeating code, which makes it somewhat hard to read.

The helper functions should have long descriptive names so we don't need to look into the functions to understand what happens and don't need to write comments.

[ahuang11]

Okay it's now all tidy~

[hoxbro]

Looks much better!

However, one test is failing. Can you take a look at it before I review it?

[ahuang11]

It was passing locally :| but anyways fixed