Support plots with initial selection

[yairchu]

Description

When a Plotly or Altair plot is constructed with an initial selection value, the wrapping mo.ui.plotly/mo.ui.altair objects's ranges and values properties are not populated until the selection is modified by the user.

See example:

import altair as alt
import marimo as mo
import numpy as np
import pandas as pd
import plotly.graph_objects

df = pd.DataFrame(
    {
        "x": np.random.random(100),
        "y": np.random.random(100),
    }
)

plotly_fig = plotly.graph_objects.Figure()
plotly_fig.add_scatter(
    x=df["x"],
    y=df["y"],
    mode="markers",
)
plotly_fig.add_selection(x0=0.2, x1=0.5, y0=0.3, y1=0.9)
plotly_fig.update_layout(width=400, height=400)
plotly_mo = mo.ui.plotly(plotly_fig)

alt_chart = (
    alt.Chart(df, width=400, height=400)
    .mark_point()
    .encode(
        x="x",
        y="y",
    )
    .add_params(
        alt.selection_interval(
            encodings=["x", "y"],
            value={"x": [0.2, 0.5], "y": [0.3, 0.9]},  # initial selection
        )
    )
)
alt_mo = mo.ui.altair_chart(alt_chart)

mo.hstack([plotly_mo, alt_mo])

### Next cell ###

plotly_mo.ranges, plotly_mo.value, alt_mo.selections, alt_mo.value

Suggested solution

Add support for initial selections in plots.
This would save users from needing to take redundant steps for the values to propagate.

Are you willing to submit a PR?

• Yes

Alternatives

• Require users to take extra steps
• Treat missing selection as initial selection (but no selection is also a valid state)

Additional context

Regarding submitting PRs: I can try to investigate the issue but am not sure if I'll be able to solve it.