fix: Plotting was not interacting well with Altair schema wrappers (#…

…19213)

docs/source/user-guide/misc/visualization.md

@@ -27,7 +27,7 @@ This is shorthand for:
 import altair as alt
 
 (
-    alt.Chart(df).mark_point().encode(
+    alt.Chart(df).mark_point(tooltip=True).encode(
         x="sepal_length",
         y="sepal_width",
         color="species",

py-polars/polars/dataframe/frame.py

@@ -627,17 +627,17 @@ def plot(self) -> DataFramePlot:
 
         - `df.plot.line(**kwargs)`
           is shorthand for
-          `alt.Chart(df).mark_line().encode(**kwargs).interactive()`
+          `alt.Chart(df).mark_line(tooltip=True).encode(**kwargs).interactive()`
         - `df.plot.point(**kwargs)`
           is shorthand for
-          `alt.Chart(df).mark_point().encode(**kwargs).interactive()` (and
+          `alt.Chart(df).mark_point(tooltip=True).encode(**kwargs).interactive()` (and
           `plot.scatter` is provided as an alias)
         - `df.plot.bar(**kwargs)`
           is shorthand for
-          `alt.Chart(df).mark_bar().encode(**kwargs).interactive()`
+          `alt.Chart(df).mark_bar(tooltip=True).encode(**kwargs).interactive()`
         - for any other attribute `attr`, `df.plot.attr(**kwargs)`
           is shorthand for
-          `alt.Chart(df).mark_attr().encode(**kwargs).interactive()`
+          `alt.Chart(df).mark_attr(tooltip=True).encode(**kwargs).interactive()`
 
         Examples
         --------

py-polars/polars/dataframe/plotting.py

@@ -30,21 +30,6 @@
     Encodings: TypeAlias = dict[str, Encoding]
 
 
-def _maybe_extract_shorthand(encoding: Encoding) -> Encoding:
-    if isinstance(encoding, alt.SchemaBase):
-        # e.g. for `alt.X('x:Q', axis=alt.Axis(labelAngle=30))`, return `'x:Q'`
-        return getattr(encoding, "shorthand", encoding)
-    return encoding
-
-
-def _add_tooltip(encodings: Encodings, /, **kwargs: Unpack[EncodeKwds]) -> None:
-    if "tooltip" not in kwargs:
-        encodings["tooltip"] = [
-            *[_maybe_extract_shorthand(x) for x in encodings.values()],
-            *[_maybe_extract_shorthand(x) for x in kwargs.values()],  # type: ignore[arg-type]
-        ]  # type: ignore[assignment]
-
-
 class DataFramePlot:
     """DataFrame.plot namespace."""
 
@@ -107,8 +92,11 @@ def bar(
             encodings["y"] = y
         if color is not None:
             encodings["color"] = color
-        _add_tooltip(encodings, **kwargs)
-        return self._chart.mark_bar().encode(**encodings, **kwargs).interactive()
+        return (
+            self._chart.mark_bar(tooltip=True)
+            .encode(**encodings, **kwargs)
+            .interactive()
+        )
 
     def line(
         self,
@@ -169,8 +157,11 @@ def line(
             encodings["color"] = color
         if order is not None:
             encodings["order"] = order
-        _add_tooltip(encodings, **kwargs)
-        return self._chart.mark_line().encode(**encodings, **kwargs).interactive()
+        return (
+            self._chart.mark_line(tooltip=True)
+            .encode(**encodings, **kwargs)
+            .interactive()
+        )
 
     def point(
         self,
@@ -231,9 +222,8 @@ def point(
             encodings["color"] = color
         if size is not None:
             encodings["size"] = size
-        _add_tooltip(encodings, **kwargs)
         return (
-            self._chart.mark_point()
+            self._chart.mark_point(tooltip=True)
             .encode(
                 **encodings,
                 **kwargs,
@@ -252,7 +242,6 @@ def __getattr__(self, attr: str) -> Callable[..., alt.Chart]:
         encodings: Encodings = {}
 
         def func(**kwargs: EncodeKwds) -> alt.Chart:
-            _add_tooltip(encodings, **kwargs)
-            return method().encode(**encodings, **kwargs).interactive()
+            return method(tooltip=True).encode(**encodings, **kwargs).interactive()
 
         return func

py-polars/polars/series/plotting.py

@@ -2,7 +2,6 @@
 
 from typing import TYPE_CHECKING, Callable
 
-from polars.dataframe.plotting import _add_tooltip
 from polars.dependencies import altair as alt
 
 if TYPE_CHECKING:
@@ -42,7 +41,7 @@ def hist(
         `Altair <https://altair-viz.github.io/>`_.
 
         `s.plot.hist(**kwargs)` is shorthand for
-        `alt.Chart(s.to_frame()).mark_bar().encode(x=alt.X(f'{s.name}:Q', bin=True), y='count()', **kwargs).interactive()`,
+        `alt.Chart(s.to_frame()).mark_bar(tooltip=True).encode(x=alt.X(f'{s.name}:Q', bin=True), y='count()', **kwargs).interactive()`,
         and is provided for convenience - for full customisatibility, use a plotting
         library directly.
 
@@ -69,9 +68,11 @@ def hist(
             "x": alt.X(f"{self._series_name}:Q", bin=True),
             "y": "count()",
         }
-        _add_tooltip(encodings, **kwargs)
         return (
-            alt.Chart(self._df).mark_bar().encode(**encodings, **kwargs).interactive()
+            alt.Chart(self._df)
+            .mark_bar(tooltip=True)
+            .encode(**encodings, **kwargs)
+            .interactive()
         )
 
     def kde(
@@ -86,7 +87,7 @@ def kde(
         `Altair <https://altair-viz.github.io/>`_.
 
         `s.plot.kde(**kwargs)` is shorthand for
-        `alt.Chart(s.to_frame()).transform_density(s.name, as_=[s.name, 'density']).mark_area().encode(x=s.name, y='density:Q', **kwargs).interactive()`,
+        `alt.Chart(s.to_frame()).transform_density(s.name, as_=[s.name, 'density']).mark_area(tooltip=True).encode(x=s.name, y='density:Q', **kwargs).interactive()`,
         and is provided for convenience - for full customisatibility, use a plotting
         library directly.
 
@@ -110,11 +111,10 @@ def kde(
             msg = "Cannot use `plot.kde` when Series name is `'density'`"
             raise ValueError(msg)
         encodings: Encodings = {"x": self._series_name, "y": "density:Q"}
-        _add_tooltip(encodings, **kwargs)
         return (
             alt.Chart(self._df)
             .transform_density(self._series_name, as_=[self._series_name, "density"])
-            .mark_area()
+            .mark_area(tooltip=True)
             .encode(**encodings, **kwargs)
             .interactive()
         )
@@ -131,7 +131,7 @@ def line(
         `Altair <https://altair-viz.github.io/>`_.
 
         `s.plot.line(**kwargs)` is shorthand for
-        `alt.Chart(s.to_frame().with_row_index()).mark_line().encode(x='index', y=s.name, **kwargs).interactive()`,
+        `alt.Chart(s.to_frame().with_row_index()).mark_line(tooltip=True).encode(x='index', y=s.name, **kwargs).interactive()`,
         and is provided for convenience - for full customisatibility, use a plotting
         library directly.
 
@@ -155,10 +155,9 @@ def line(
             msg = "Cannot call `plot.line` when Series name is 'index'"
             raise ValueError(msg)
         encodings: Encodings = {"x": "index", "y": self._series_name}
-        _add_tooltip(encodings, **kwargs)
         return (
             alt.Chart(self._df.with_row_index())
-            .mark_line()
+            .mark_line(tooltip=True)
             .encode(**encodings, **kwargs)
             .interactive()
         )
@@ -177,7 +176,6 @@ def __getattr__(self, attr: str) -> Callable[..., alt.Chart]:
         encodings: Encodings = {"x": "index", "y": self._series_name}
 
         def func(**kwargs: EncodeKwds) -> alt.Chart:
-            _add_tooltip(encodings, **kwargs)
-            return method().encode(**encodings, **kwargs).interactive()
+            return method(tooltip=True).encode(**encodings, **kwargs).interactive()
 
         return func

py-polars/polars/series/series.py

@@ -7477,13 +7477,13 @@ def plot(self) -> SeriesPlot:
 
         - `s.plot.hist(**kwargs)`
           is shorthand for
-          `alt.Chart(s.to_frame()).mark_bar().encode(x=alt.X(f'{s.name}:Q', bin=True), y='count()', **kwargs).interactive()`
+          `alt.Chart(s.to_frame()).mark_bar(tooltip=True).encode(x=alt.X(f'{s.name}:Q', bin=True), y='count()', **kwargs).interactive()`
         - `s.plot.kde(**kwargs)`
           is shorthand for
-          `alt.Chart(s.to_frame()).transform_density(s.name, as_=[s.name, 'density']).mark_area().encode(x=s.name, y='density:Q', **kwargs).interactive()`
+          `alt.Chart(s.to_frame()).transform_density(s.name, as_=[s.name, 'density']).mark_area(tooltip=True).encode(x=s.name, y='density:Q', **kwargs).interactive()`
         - for any other attribute `attr`, `s.plot.attr(**kwargs)`
           is shorthand for
-          `alt.Chart(s.to_frame().with_row_index()).mark_attr().encode(x='index', y=s.name, **kwargs).interactive()`
+          `alt.Chart(s.to_frame().with_row_index()).mark_attr(tooltip=True).encode(x='index', y=s.name, **kwargs).interactive()`
 
         Examples
         --------

py-polars/tests/unit/operations/namespaces/test_plot.py

@@ -28,11 +28,7 @@ def test_dataframe_plot_tooltip() -> None:
         }
     )
     result = df.plot.line(x="length", y="width", color="species").to_dict()
-    assert result["encoding"]["tooltip"] == [
-        {"field": "length", "type": "quantitative"},
-        {"field": "width", "type": "quantitative"},
-        {"field": "species", "type": "nominal"},
-    ]
+    assert result["mark"]["tooltip"] is True
     result = df.plot.line(
         x="length", y="width", color="species", tooltip=["length", "width"]
     ).to_dict()
@@ -54,10 +50,7 @@ def test_series_plot() -> None:
 def test_series_plot_tooltip() -> None:
     s = pl.Series("a", [1, 4, 4, 4, 7, 2, 5, 3, 6])
     result = s.plot.line().to_dict()
-    assert result["encoding"]["tooltip"] == [
-        {"field": "index", "type": "quantitative"},
-        {"field": "a", "type": "quantitative"},
-    ]
+    assert result["mark"]["tooltip"] is True
     result = s.plot.line(tooltip=["a"]).to_dict()
     assert result["encoding"]["tooltip"] == [{"field": "a", "type": "quantitative"}]
 
@@ -73,4 +66,4 @@ def test_nameless_series() -> None:
 def test_x_with_axis_18830() -> None:
     df = pl.DataFrame({"a": [1, 2, 3], "b": [4, 5, 6], "c": [7, 8, 9]})
     result = df.plot.line(x=alt.X("a", axis=alt.Axis(labelAngle=-90))).to_dict()
-    assert result["encoding"]["tooltip"] == [{"field": "a", "type": "quantitative"}]
+    assert result["mark"]["tooltip"] is True