feat(python): add tooltip by default to charts

py-polars/polars/dataframe/plotting.py

@@ -6,15 +6,12 @@
     import sys
 
     import altair as alt
-    from altair.typing import (
-        ChannelColor,
-        ChannelOrder,
-        ChannelSize,
-        ChannelTooltip,
-        ChannelX,
-        ChannelY,
-        EncodeKwds,
-    )
+    from altair.typing import ChannelColor as Color
+    from altair.typing import ChannelOrder as Order
+    from altair.typing import ChannelSize as Size
+    from altair.typing import ChannelX as X
+    from altair.typing import ChannelY as Y
+    from altair.typing import EncodeKwds
 
     from polars import DataFrame
 
@@ -29,12 +26,15 @@
 
     Encodings: TypeAlias = Dict[
         str,
-        Union[
-            ChannelX, ChannelY, ChannelColor, ChannelOrder, ChannelSize, ChannelTooltip
-        ],
+        Union[X, Y, Color, Order, Size],
     ]
 
 
+def _add_tooltip(chart: alt.Chart) -> alt.Chart:
+    chart.mark = {"type": chart.mark, "tooltip": True}
+    return chart
+
+
 class DataFramePlot:
     """DataFrame.plot namespace."""
 
@@ -45,10 +45,9 @@ def __init__(self, df: DataFrame) -> None:
 
     def bar(
         self,
-        x: ChannelX | None = None,
-        y: ChannelY | None = None,
-        color: ChannelColor | None = None,
-        tooltip: ChannelTooltip | None = None,
+        x: X | None = None,
+        y: Y | None = None,
+        color: Color | None = None,
         /,
         **kwargs: Unpack[EncodeKwds],
     ) -> alt.Chart:
@@ -77,8 +76,6 @@ def bar(
             Column with y-coordinates of bars.
         color
             Column to color bars by.
-        tooltip
-            Columns to show values of when hovering over bars with pointer.
         **kwargs
             Additional keyword arguments passed to Altair.
 
@@ -102,17 +99,16 @@ def bar(
             encodings["y"] = y
         if color is not None:
             encodings["color"] = color
-        if tooltip is not None:
-            encodings["tooltip"] = tooltip
-        return self._chart.mark_bar().encode(**encodings, **kwargs).interactive()
+        return _add_tooltip(
+            self._chart.mark_bar().encode(**encodings, **kwargs).interactive()
+        )
 
     def line(
         self,
-        x: ChannelX | None = None,
-        y: ChannelY | None = None,
-        color: ChannelColor | None = None,
-        order: ChannelOrder | None = None,
-        tooltip: ChannelTooltip | None = None,
+        x: X | None = None,
+        y: Y | None = None,
+        color: Color | None = None,
+        order: Order | None = None,
         /,
         **kwargs: Unpack[EncodeKwds],
     ) -> alt.Chart:
@@ -142,8 +138,6 @@ def line(
             Column to color lines by.
         order
             Column to use for order of data points in lines.
-        tooltip
-            Columns to show values of when hovering over lines with pointer.
         **kwargs
             Additional keyword arguments passed to Altair.
 
@@ -168,17 +162,16 @@ def line(
             encodings["color"] = color
         if order is not None:
             encodings["order"] = order
-        if tooltip is not None:
-            encodings["tooltip"] = tooltip
-        return self._chart.mark_line().encode(**encodings, **kwargs).interactive()
+        return _add_tooltip(
+            self._chart.mark_line().encode(**encodings, **kwargs).interactive()
+        )
 
     def point(
         self,
-        x: ChannelX | None = None,
-        y: ChannelY | None = None,
-        color: ChannelColor | None = None,
-        size: ChannelSize | None = None,
-        tooltip: ChannelTooltip | None = None,
+        x: X | None = None,
+        y: Y | None = None,
+        color: Color | None = None,
+        size: Size | None = None,
         /,
         **kwargs: Unpack[EncodeKwds],
     ) -> alt.Chart:
@@ -209,8 +202,6 @@ def point(
             Column to color points by.
         size
             Column which determines points' sizes.
-        tooltip
-            Columns to show values of when hovering over points with pointer.
         **kwargs
             Additional keyword arguments passed to Altair.
 
@@ -234,9 +225,7 @@ def point(
             encodings["color"] = color
         if size is not None:
             encodings["size"] = size
-        if tooltip is not None:
-            encodings["tooltip"] = tooltip
-        return (
+        return _add_tooltip(
             self._chart.mark_point()
             .encode(
                 **encodings,
@@ -253,4 +242,4 @@ def __getattr__(self, attr: str) -> Callable[..., alt.Chart]:
         if method is None:
             msg = "Altair has no method 'mark_{attr}'"
             raise AttributeError(msg)
-        return lambda **kwargs: method().encode(**kwargs).interactive()
+        return lambda **kwargs: _add_tooltip(method().encode(**kwargs).interactive())

py-polars/polars/series/plotting.py

@@ -2,6 +2,7 @@
 
 from typing import TYPE_CHECKING, Callable
 
+from polars.dataframe.plotting import _add_tooltip
 from polars.dependencies import altair as alt
 
 if TYPE_CHECKING:
@@ -62,7 +63,7 @@ def hist(
         if self._series_name == "count()":
             msg = "Cannot use `plot.hist` when Series name is `'count()'`"
             raise ValueError(msg)
-        return (
+        return _add_tooltip(
             alt.Chart(self._df)
             .mark_bar()
             .encode(x=alt.X(f"{self._series_name}:Q", bin=True), y="count()", **kwargs)  # type: ignore[misc]
@@ -104,7 +105,7 @@ def kde(
         if self._series_name == "density":
             msg = "Cannot use `plot.kde` when Series name is `'density'`"
             raise ValueError(msg)
-        return (
+        return _add_tooltip(
             alt.Chart(self._df)
             .transform_density(self._series_name, as_=[self._series_name, "density"])
             .mark_area()
@@ -147,7 +148,7 @@ def line(
         if self._series_name == "index":
             msg = "Cannot call `plot.line` when Series name is 'index'"
             raise ValueError(msg)
-        return (
+        return _add_tooltip(
             alt.Chart(self._df.with_row_index())
             .mark_line()
             .encode(x="index", y=self._series_name, **kwargs)  # type: ignore[misc]
@@ -165,8 +166,6 @@ def __getattr__(self, attr: str) -> Callable[..., alt.Chart]:
         if method is None:
             msg = "Altair has no method 'mark_{attr}'"
             raise AttributeError(msg)
-        return (
-            lambda **kwargs: method()
-            .encode(x="index", y=self._series_name, **kwargs)
-            .interactive()
+        return lambda **kwargs: _add_tooltip(
+            method().encode(x="index", y=self._series_name, **kwargs).interactive()
         )