From 0da36ae3a105b0ffa3792c882fad124cfb009fb4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=A9mie=20du=20Boisberranger?=
 <jeremie@probabl.ai>
Date: Tue, 29 Jul 2025 15:38:04 +0200
Subject: [PATCH 01/11] wip

---
 sklearn/metrics/_plot/roc_curve.py | 44 ++++++++++++++++++++++++++++--
 1 file changed, 41 insertions(+), 3 deletions(-)

diff --git a/sklearn/metrics/_plot/roc_curve.py b/sklearn/metrics/_plot/roc_curve.py
index 59c01f2db91a0..97aee3811da1c 100644
--- a/sklearn/metrics/_plot/roc_curve.py
+++ b/sklearn/metrics/_plot/roc_curve.py
@@ -132,6 +132,7 @@ def __init__(
         *,
         fpr,
         tpr,
+        thresholds=None,
         roc_auc=None,
         name=None,
         pos_label=None,
@@ -139,6 +140,7 @@ def __init__(
     ):
         self.fpr = fpr
         self.tpr = tpr
+        self.thresholds = thresholds
         self.roc_auc = roc_auc
         self.name = _deprecate_estimator_name(estimator_name, name, "1.7")
         self.pos_label = pos_label
@@ -148,6 +150,7 @@ def _validate_plot_params(self, *, ax, name):
 
         fpr = _convert_to_list_leaving_none(self.fpr)
         tpr = _convert_to_list_leaving_none(self.tpr)
+        thresholds = _convert_to_list_leaving_none(self.thresholds)
         roc_auc = _convert_to_list_leaving_none(self.roc_auc)
         name = _convert_to_list_leaving_none(name)
 
@@ -159,7 +162,7 @@ def _validate_plot_params(self, *, ax, name):
             optional=optional,
             class_name="RocCurveDisplay",
         )
-        return fpr, tpr, roc_auc, name
+        return fpr, tpr, thresholds,roc_auc, name
 
     def plot(
         self,
@@ -233,7 +236,7 @@ def plot(
         display : :class:`~sklearn.metrics.RocCurveDisplay`
             Object that stores computed values.
         """
-        fpr, tpr, roc_auc, name = self._validate_plot_params(ax=ax, name=name)
+        fpr, tpr, thresholds, roc_auc, name = self._validate_plot_params(ax=ax, name=name)
         n_curves = len(fpr)
         if not isinstance(curve_kwargs, list) and n_curves > 1:
             if roc_auc:
@@ -273,6 +276,40 @@ def plot(
         if len(self.line_) == 1:
             self.line_ = self.line_[0]
 
+        annot = self.ax_.annotate(
+            "", xy=(0,0), xytext=(20,20),textcoords="offset points", bbox=dict(boxstyle="round", fc="w"), arrowprops=dict(arrowstyle="->")
+        )
+        annot.set_visible(False)
+
+        def update_annot(ind):
+            x,y = self.line_.get_data()
+            annot.xy = (x[ind["ind"][0]], y[ind["ind"][0]])
+
+            # Find the index of the closest point in fpr to x[ind['ind'][0]]
+            # use it to get the corresponding threshold
+            idx = np.argmin(np.abs(self.fpr - x[ind["ind"][0]]))
+
+            text = f"FPR: {x[ind['ind'][0]]:.2f}, TPR: {y[ind['ind'][0]]:.2f}, Threshold: {self.thresholds[idx]:.2f}"
+            # text = f"Threshold: {self.thresholds[idx]:.2f}"
+
+            annot.set_text(text)
+            annot.get_bbox_patch().set_alpha(0.4)        
+
+        def hover(event):
+            vis = annot.get_visible()
+            if event.inaxes == self.ax_:
+                cont, ind = self.line_.contains(event)
+                if cont:
+                    update_annot(ind)
+                    annot.set_visible(True)
+                    self.figure_.canvas.draw_idle()
+                else:
+                    if vis:
+                        annot.set_visible(False)
+                        self.figure_.canvas.draw_idle()
+
+        self.figure_.canvas.mpl_connect("motion_notify_event", hover)
+
         info_pos_label = (
             f" (Positive label: {self.pos_label})" if self.pos_label is not None else ""
         )
@@ -580,7 +617,7 @@ def from_predictions(
             y_true, y_score, sample_weight=sample_weight, pos_label=pos_label, name=name
         )
 
-        fpr, tpr, _ = roc_curve(
+        fpr, tpr, thresholds = roc_curve(
             y_true,
             y_score,
             pos_label=pos_label,
@@ -592,6 +629,7 @@ def from_predictions(
         viz = cls(
             fpr=fpr,
             tpr=tpr,
+            thresholds=thresholds,
             roc_auc=roc_auc,
             name=name,
             pos_label=pos_label_validated,

From 30ad5c4ec25a8a694867b65cc5be8e5f6354ada9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=A9mie=20du=20Boisberranger?=
 <jeremie@probabl.ai>
Date: Thu, 31 Jul 2025 11:45:39 +0200
Subject: [PATCH 02/11] wip

---
 sklearn/metrics/_plot/roc_curve.py |  56 +++++---------
 sklearn/utils/_plotting.py         | 118 ++++++++++++++++++++++++++++-
 2 files changed, 136 insertions(+), 38 deletions(-)

diff --git a/sklearn/metrics/_plot/roc_curve.py b/sklearn/metrics/_plot/roc_curve.py
index 97aee3811da1c..21c4457250a15 100644
--- a/sklearn/metrics/_plot/roc_curve.py
+++ b/sklearn/metrics/_plot/roc_curve.py
@@ -7,6 +7,7 @@
 from ...utils import _safe_indexing
 from ...utils._plotting import (
     _BinaryClassifierCurveDisplayMixin,
+    _LineTooltipMixin,
     _check_param_lengths,
     _convert_to_list_leaving_none,
     _deprecate_estimator_name,
@@ -18,7 +19,7 @@
 from .._ranking import auc, roc_curve
 
 
-class RocCurveDisplay(_BinaryClassifierCurveDisplayMixin):
+class RocCurveDisplay(_BinaryClassifierCurveDisplayMixin, _LineTooltipMixin):
     """ROC Curve visualization.
 
     It is recommended to use
@@ -49,6 +50,13 @@ class RocCurveDisplay(_BinaryClassifierCurveDisplayMixin):
         .. versionchanged:: 1.7
             Now accepts a list for plotting multiple curves.
 
+    threshold : ndarray or list of ndarrays, default=None
+        The thresholds at which the fpr and tpr have been computed. Each ndarray should
+        contain values for a single curve. If plotting multiple curves, list should be
+        of same length as `fpr` and `tpr`.
+        Only used to display the threshold values along the curve as a tooltip. If None,
+        only the fpr and tpr values are displayed.
+
     roc_auc : float or list of floats, default=None
         Area under ROC curve, used for labeling each curve in the legend.
         If plotting multiple curves, should be a list of the same length as `fpr`
@@ -162,7 +170,7 @@ def _validate_plot_params(self, *, ax, name):
             optional=optional,
             class_name="RocCurveDisplay",
         )
-        return fpr, tpr, thresholds,roc_auc, name
+        return fpr, tpr, thresholds, roc_auc, name
 
     def plot(
         self,
@@ -236,7 +244,9 @@ def plot(
         display : :class:`~sklearn.metrics.RocCurveDisplay`
             Object that stores computed values.
         """
-        fpr, tpr, thresholds, roc_auc, name = self._validate_plot_params(ax=ax, name=name)
+        fpr, tpr, thresholds, roc_auc, name = self._validate_plot_params(
+            ax=ax, name=name
+        )
         n_curves = len(fpr)
         if not isinstance(curve_kwargs, list) and n_curves > 1:
             if roc_auc:
@@ -276,39 +286,9 @@ def plot(
         if len(self.line_) == 1:
             self.line_ = self.line_[0]
 
-        annot = self.ax_.annotate(
-            "", xy=(0,0), xytext=(20,20),textcoords="offset points", bbox=dict(boxstyle="round", fc="w"), arrowprops=dict(arrowstyle="->")
+        self._add_line_tooltip(
+            x_label="FPR", y_label="TPR", t_label="threshold", t_vals=thresholds
         )
-        annot.set_visible(False)
-
-        def update_annot(ind):
-            x,y = self.line_.get_data()
-            annot.xy = (x[ind["ind"][0]], y[ind["ind"][0]])
-
-            # Find the index of the closest point in fpr to x[ind['ind'][0]]
-            # use it to get the corresponding threshold
-            idx = np.argmin(np.abs(self.fpr - x[ind["ind"][0]]))
-
-            text = f"FPR: {x[ind['ind'][0]]:.2f}, TPR: {y[ind['ind'][0]]:.2f}, Threshold: {self.thresholds[idx]:.2f}"
-            # text = f"Threshold: {self.thresholds[idx]:.2f}"
-
-            annot.set_text(text)
-            annot.get_bbox_patch().set_alpha(0.4)        
-
-        def hover(event):
-            vis = annot.get_visible()
-            if event.inaxes == self.ax_:
-                cont, ind = self.line_.contains(event)
-                if cont:
-                    update_annot(ind)
-                    annot.set_visible(True)
-                    self.figure_.canvas.draw_idle()
-                else:
-                    if vis:
-                        annot.set_visible(False)
-                        self.figure_.canvas.draw_idle()
-
-        self.figure_.canvas.mpl_connect("motion_notify_event", hover)
 
         info_pos_label = (
             f" (Positive label: {self.pos_label})" if self.pos_label is not None else ""
@@ -769,7 +749,7 @@ def from_cv_results(
             pos_label=pos_label,
         )
 
-        fpr_folds, tpr_folds, auc_folds = [], [], []
+        fpr_folds, tpr_folds, thresholds_folds, auc_folds = [], [], [], []
         for estimator, test_indices in zip(
             cv_results["estimator"], cv_results["indices"]["test"]
         ):
@@ -785,7 +765,7 @@ def from_cv_results(
                 if sample_weight is None
                 else _safe_indexing(sample_weight, test_indices)
             )
-            fpr, tpr, _ = roc_curve(
+            fpr, tpr, thresholds = roc_curve(
                 y_true,
                 y_pred,
                 pos_label=pos_label_,
@@ -796,11 +776,13 @@ def from_cv_results(
 
             fpr_folds.append(fpr)
             tpr_folds.append(tpr)
+            thresholds_folds.append(thresholds)
             auc_folds.append(roc_auc)
 
         viz = cls(
             fpr=fpr_folds,
             tpr=tpr_folds,
+            thresholds=thresholds_folds,
             roc_auc=auc_folds,
             name=name,
             pos_label=pos_label_,
diff --git a/sklearn/utils/_plotting.py b/sklearn/utils/_plotting.py
index e4447978df78f..c864189ad1c7e 100644
--- a/sklearn/utils/_plotting.py
+++ b/sklearn/utils/_plotting.py
@@ -2,7 +2,7 @@
 # SPDX-License-Identifier: BSD-3-Clause
 import warnings
 from collections.abc import Mapping
-
+from functools import partial
 import numpy as np
 
 from . import check_consistent_length
@@ -250,6 +250,122 @@ def _validate_curve_kwargs(
         return curve_kwargs_
 
 
+class _LineTooltipMixin:
+    """Mixin class to add a tooltip to a line in a plot.
+
+    The tooltip displays 2 to 3 informations: the x value, the y value and an optional
+    t value for parametric curves (x(t), y(t)).
+    """
+
+    def _add_line_tooltip(self, *, x_label, y_label, t_label=None, t_vals=None):
+        """Create the line tooltip and connect it to a mouse hover event.
+
+        Parameters
+        ----------
+        x_label : str
+            The label for the x value.
+
+        y_label : str
+            The label for the y value.
+
+        t_label : str, default=None
+            The label for the parameter value.
+
+        t_vals : list of ndarrays, default=None
+            The parameter values along the line.
+        """
+        self._x_label_short = x_label
+        self._y_label_short = y_label
+        self._t_label = t_label
+
+        self.line_tooltip_ = self.ax_.annotate(
+            text="",
+            xy=(0, 0),
+            xytext=(20, 20),
+            textcoords="offset points",
+            fontsize="small",
+            bbox=dict(boxstyle="round", fc=(0.8, 0.8, 0.8, 0.8)),
+            arrowprops=dict(arrowstyle="-"),
+            zorder=10,  # bring to front
+        )
+        self.line_tooltip_.set_visible(False)
+
+        # Set an attribute on the axes annotation to be able to keep only one visible
+        # at a time when there are multiple display instances that share an axes.
+        setattr(self.line_tooltip_, "_skl_line_tooltip", True)
+
+        self.ax_.figure.canvas.mpl_connect(
+            "motion_notify_event", partial(self._hover, t_vals=t_vals)
+        )
+
+    def _hover(self, event, t_vals):
+        """Callback for the mouse over event.
+
+        Parameters
+        ----------
+        event : matplotlib event
+            the event triggering the callback.
+
+        t_vals : list of ndarrays or None
+            The parameter values along the line.
+        """
+        if event.inaxes != self.ax_:
+            return
+
+        lines = _convert_to_list_leaving_none(self.line_)
+        for i, line in enumerate(lines):
+            contains, indexes = line.contains(event)
+            # stop at the first line on which the event occured
+            if contains:
+                idx = indexes["ind"][0]
+                x_vals, y_vals = line.get_data()
+                t = t_vals[i][idx] if t_vals is not None else t_vals
+                self._update_line_tooltip(x_vals[idx], y_vals[idx], t)
+                self.line_tooltip_.set_visible(True)
+                break
+        else:  # hide the tooltip if the event didn't occur on any line
+            if self.line_tooltip_.get_visible():
+                self.line_tooltip_.set_visible(False)
+
+        found_visible = False
+        for child in self.ax_.get_children():
+            if hasattr(child, "_skl_line_tooltip") and child.get_visible():
+                if not found_visible:
+                    found_visible = True
+                else:
+                    child.set_visible(False)
+
+        self.figure_.canvas.draw_idle()
+
+    def _update_line_tooltip(self, x, y, t):
+        """Update the text in the line tooltip.
+
+        Parameters
+        ----------
+        x : float
+            the x value to display.
+
+        y : float
+            the y value to display.
+
+        t : float or None
+            the parameter value to display.
+        """
+        text = f"{self._x_label_short}: {x:.2f}, {self._y_label_short}: {y:.2f}"
+        if t is not None:
+            text += f", {self._t_label}: {t:.2f}"
+
+        # Compute an offset for the text depending on the quadrant where the cursor is
+        # to keep the tooltip somewhat inside the axes.
+        xlim, ylim = self.ax_.get_xlim(), self.ax_.get_ylim()
+        x_offset = 20 if x < (xlim[0] + xlim[1]) / 2 else -160
+        y_offset = 20 if y < (ylim[0] + ylim[1]) / 2 else -30
+
+        self.line_tooltip_.xyann = (x_offset, y_offset)
+        self.line_tooltip_.xy = (x, y)
+        self.line_tooltip_.set_text(text)
+
+
 def _validate_score_name(score_name, scoring, negate_score):
     """Validate the `score_name` parameter.
 

From 4454932d0718cf971e3de81332e4bee68a264c31 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=A9mie=20du=20Boisberranger?=
 <jeremie@probabl.ai>
Date: Thu, 31 Jul 2025 17:07:18 +0200
Subject: [PATCH 03/11] add tests and doc

---
 sklearn/metrics/_plot/roc_curve.py            |   2 +-
 .../_plot/tests/test_roc_curve_display.py     |  27 +++-
 sklearn/utils/_plotting.py                    |   1 +
 sklearn/utils/tests/test_plotting.py          | 130 ++++++++++++++++++
 4 files changed, 157 insertions(+), 3 deletions(-)

diff --git a/sklearn/metrics/_plot/roc_curve.py b/sklearn/metrics/_plot/roc_curve.py
index 21c4457250a15..1c8c0dd1f938b 100644
--- a/sklearn/metrics/_plot/roc_curve.py
+++ b/sklearn/metrics/_plot/roc_curve.py
@@ -7,12 +7,12 @@
 from ...utils import _safe_indexing
 from ...utils._plotting import (
     _BinaryClassifierCurveDisplayMixin,
-    _LineTooltipMixin,
     _check_param_lengths,
     _convert_to_list_leaving_none,
     _deprecate_estimator_name,
     _deprecate_y_pred_parameter,
     _despine,
+    _LineTooltipMixin,
     _validate_style_kwargs,
 )
 from ...utils._response import _get_response_values_binary
diff --git a/sklearn/metrics/_plot/tests/test_roc_curve_display.py b/sklearn/metrics/_plot/tests/test_roc_curve_display.py
index 33461456d8e84..31b3de3aa2a8c 100644
--- a/sklearn/metrics/_plot/tests/test_roc_curve_display.py
+++ b/sklearn/metrics/_plot/tests/test_roc_curve_display.py
@@ -16,6 +16,7 @@
 from sklearn.preprocessing import StandardScaler
 from sklearn.utils import _safe_indexing, shuffle
 from sklearn.utils._response import _get_response_values_binary
+from sklearn.utils.tests.test_plotting import _simulate_mouse_event
 
 
 @pytest.fixture(scope="module")
@@ -201,6 +202,7 @@ def test_validate_plot_params(pyplot):
     """Check `_validate_plot_params` returns the correct variables."""
     fpr = np.array([0, 0.5, 1])
     tpr = [np.array([0, 0.5, 1])]
+    thresholds = np.array([1, 0.5, 0])
     roc_auc = None
     name = "test_curve"
 
@@ -208,18 +210,21 @@ def test_validate_plot_params(pyplot):
     display = RocCurveDisplay(
         fpr=fpr,
         tpr=tpr,
+        thresholds=thresholds,
         roc_auc=roc_auc,
         name=name,
         pos_label=None,
     )
-    fpr_out, tpr_out, roc_auc_out, name_out = display._validate_plot_params(
-        ax=None, name=None
+    fpr_out, tpr_out, thresholds_out, roc_auc_out, name_out = (
+        display._validate_plot_params(ax=None, name=None)
     )
 
     assert isinstance(fpr_out, list)
     assert isinstance(tpr_out, list)
+    assert isinstance(thresholds_out, list)
     assert len(fpr_out) == 1
     assert len(tpr_out) == 1
+    assert len(thresholds_out) == 1
     assert roc_auc_out is None
     assert name_out == ["test_curve"]
 
@@ -980,3 +985,21 @@ def test_plot_roc_curve_despine(pyplot, data_binary, despine, constructor_name):
     if despine:
         for s in ["bottom", "left"]:
             assert display.ax_.spines[s].get_bounds() == (0, 1)
+
+
+def test_roc_curve_display_line_tooltip(pyplot, data_binary):
+    """Test the line tooltip on a Roc curve."""
+    X, y = data_binary
+
+    lr = LogisticRegression().fit(X, y)
+    display = RocCurveDisplay.from_estimator(lr, X, y)
+
+    assert hasattr(display, "line_tooltip_")
+
+    # simulate a mouse event on the line
+    x, y = display.fpr[10], display.tpr[10]
+    _simulate_mouse_event(display, x, y)
+
+    assert display.line_tooltip_.get_visible()
+    text = display.line_tooltip_.get_text()
+    assert all(name in text for name in ("FPR", "TPR", "threshold"))
diff --git a/sklearn/utils/_plotting.py b/sklearn/utils/_plotting.py
index c864189ad1c7e..2c73899004c48 100644
--- a/sklearn/utils/_plotting.py
+++ b/sklearn/utils/_plotting.py
@@ -3,6 +3,7 @@
 import warnings
 from collections.abc import Mapping
 from functools import partial
+
 import numpy as np
 
 from . import check_consistent_length
diff --git a/sklearn/utils/tests/test_plotting.py b/sklearn/utils/tests/test_plotting.py
index db2f797ac2547..e315b171c4160 100644
--- a/sklearn/utils/tests/test_plotting.py
+++ b/sklearn/utils/tests/test_plotting.py
@@ -7,6 +7,7 @@
     _deprecate_estimator_name,
     _despine,
     _interval_max_min_ratio,
+    _LineTooltipMixin,
     _validate_score_name,
     _validate_style_kwargs,
 )
@@ -542,3 +543,132 @@ def test_deprecate_estimator_name(estimator_name, name):
         )
         with pytest.raises(ValueError, match=error_message):
             _deprecate_estimator_name(estimator_name, name, version)
+
+
+class _TestCurveDisplay(_LineTooltipMixin):
+    def __init__(self, n_curves=1, x_max=1.0, y_max=1.0, parametric=False):
+        self.n_curves = n_curves
+        self.x_max = x_max
+        self.y_max = y_max
+        self.parametric = parametric
+
+    def plot(self, ax=None):
+        import matplotlib.pyplot as plt
+
+        if ax is None:
+            _, ax = plt.subplots()
+        self.ax_, self.figure_ = ax, ax.figure
+
+        self.line_ = []
+        self.t_vals, self.x_vals, self.y_vals = [], [], []
+        x_ends = np.linspace(
+            self.x_max if self.n_curves == 1 else self.x_max / 2,
+            self.x_max,
+            self.n_curves,
+        )
+        for i, x_end in enumerate(x_ends):
+            self.t_vals.append(t := np.linspace(0, 1, 100))
+            self.x_vals.append(x := x_end * t)
+            self.y_vals.append(y := self.y_max * t)
+            self.line_.extend(self.ax_.plot(x, y, label=f"curve {i + 1}"))
+
+        params = {"t_label": "t", "t_vals": self.t_vals} if self.parametric else {}
+        self._add_line_tooltip(x_label="x", y_label="y", **params)
+
+        return self
+
+
+def _simulate_mouse_event(display, x, y):
+    """Emit a mouse location event at data coordinates (x, y)."""
+    import matplotlib as mpl
+
+    # needed to update xlim and ylim before using transData since we're not calling
+    # plt.show(). See https://github.com/matplotlib/matplotlib/issues/28075.
+    display.ax_.autoscale_view()
+
+    x_display, y_display = display.ax_.transData.transform((x, y))
+    event = mpl.backend_bases.MouseEvent(
+        name="motion_notify_event",
+        canvas=display.figure_.canvas,
+        x=x_display,
+        y=y_display,
+    )
+    display.ax_.figure.canvas.callbacks.process("motion_notify_event", event)
+
+
+@pytest.mark.parametrize("n_curves", [1, 5])
+@pytest.mark.parametrize("x_max", [1, 10])
+@pytest.mark.parametrize("y_max", [1, 10])
+@pytest.mark.parametrize("parametric", [True, False])
+def test_line_tooltip(n_curves, x_max, y_max, parametric, pyplot):
+    """Test the behavior for the line tooltip."""
+    import matplotlib as mpl
+
+    display = _TestCurveDisplay(
+        n_curves=n_curves,
+        x_max=x_max,
+        y_max=y_max,
+        parametric=parametric,
+    ).plot()
+
+    assert hasattr(display, "line_tooltip_")
+    assert isinstance(display.line_tooltip_, mpl.text.Annotation)
+    assert display.line_tooltip_.get_text() == ""
+    assert not display.line_tooltip_.get_visible()
+
+    # simulate a mouse event occuring on a line. Take the point in the middle of the
+    # last curve for instance
+    x = display.x_vals[-1][50]
+    y = display.y_vals[-1][50]
+    _simulate_mouse_event(display, x, y)
+
+    assert display.line_tooltip_.get_visible()
+    text = display.line_tooltip_.get_text()
+    assert all(name in text for name in ("x", "y"))
+    if parametric:
+        assert "t" in text
+
+    # simulate a second event, not occuring on any line this time. None of these curves
+    # ever touch the lower right corner
+    _simulate_mouse_event(display, x_max, 0)
+
+    assert not display.line_tooltip_.get_visible()
+
+    # simulate a third event occuring on several lines at once. (0, 0) belongs to all
+    # curves.
+    _simulate_mouse_event(display, 0, 0)
+
+    assert display.line_tooltip_.get_visible()
+    text = display.line_tooltip_.get_text()
+    assert all(name in text for name in ("x", "y"))
+    if parametric:
+        assert "t" in text
+
+
+@pytest.mark.parametrize("y_max", [1, 10])
+def test_line_tooltip_multiple_displays(pyplot, y_max):
+    """Test the line tooltip when different displays share the same axes."""
+    display = _TestCurveDisplay(x_max=0.5, y_max=y_max).plot()
+    display2 = _TestCurveDisplay(x_max=1, y_max=y_max).plot(ax=display.ax_)
+
+    assert hasattr(display, "line_tooltip_")
+    assert hasattr(display2, "line_tooltip_")
+    assert not display.line_tooltip_.get_visible()
+    assert not display2.line_tooltip_.get_visible()
+
+    # simulate a mouse event occuring on the first line
+    _simulate_mouse_event(display, 0.5, y_max)
+
+    assert display.line_tooltip_.get_visible()
+    assert not display2.line_tooltip_.get_visible()
+
+    # simulate a mouse event occuring on the second line
+    _simulate_mouse_event(display2, 1, y_max)
+
+    assert not display.line_tooltip_.get_visible()
+    assert display2.line_tooltip_.get_visible()
+
+    # simulate a mouse event occuring on both lines. Only 1 line tooltip is visible
+    _simulate_mouse_event(display, 0, 0)
+
+    assert display.line_tooltip_.get_visible() != display2.line_tooltip_.get_visible()

From 1ecf20b5de86f4314fd31ebe2ee74529458cade8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=A9mie=20du=20Boisberranger?=
 <jeremie@probabl.ai>
Date: Thu, 31 Jul 2025 17:22:37 +0200
Subject: [PATCH 04/11] fix docstring

---
 sklearn/metrics/_plot/roc_curve.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sklearn/metrics/_plot/roc_curve.py b/sklearn/metrics/_plot/roc_curve.py
index 1c8c0dd1f938b..edfb5018091fa 100644
--- a/sklearn/metrics/_plot/roc_curve.py
+++ b/sklearn/metrics/_plot/roc_curve.py
@@ -50,7 +50,7 @@ class RocCurveDisplay(_BinaryClassifierCurveDisplayMixin, _LineTooltipMixin):
         .. versionchanged:: 1.7
             Now accepts a list for plotting multiple curves.
 
-    threshold : ndarray or list of ndarrays, default=None
+    thresholds : ndarray or list of ndarrays, default=None
         The thresholds at which the fpr and tpr have been computed. Each ndarray should
         contain values for a single curve. If plotting multiple curves, list should be
         of same length as `fpr` and `tpr`.

From 4006c57858e157bf9b454181ae60898ed0af4d8c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=A9mie=20du=20Boisberranger?=
 <jeremie@probabl.ai>
Date: Thu, 31 Jul 2025 17:54:35 +0200
Subject: [PATCH 05/11] comment

---
 sklearn/utils/_plotting.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sklearn/utils/_plotting.py b/sklearn/utils/_plotting.py
index 2c73899004c48..259d4a3f1a3aa 100644
--- a/sklearn/utils/_plotting.py
+++ b/sklearn/utils/_plotting.py
@@ -328,6 +328,9 @@ def _hover(self, event, t_vals):
             if self.line_tooltip_.get_visible():
                 self.line_tooltip_.set_visible(False)
 
+        # Loop through all line tooltips contained the axes and hide all but one.
+        # This is necessary in addition to the loop over the display lines above to
+        # account for the case when multiple display instances share the same axes.
         found_visible = False
         for child in self.ax_.get_children():
             if hasattr(child, "_skl_line_tooltip") and child.get_visible():

From 26b2b1210141d80b255abf1a635c309a883db38c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=A9mie=20du=20Boisberranger?=
 <jeremie@probabl.ai>
Date: Thu, 31 Jul 2025 18:15:47 +0200
Subject: [PATCH 06/11] typos

---
 sklearn/utils/_plotting.py           |  6 +++---
 sklearn/utils/tests/test_plotting.py | 12 ++++++------
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/sklearn/utils/_plotting.py b/sklearn/utils/_plotting.py
index 259d4a3f1a3aa..b6e2592e2dd1d 100644
--- a/sklearn/utils/_plotting.py
+++ b/sklearn/utils/_plotting.py
@@ -254,8 +254,8 @@ def _validate_curve_kwargs(
 class _LineTooltipMixin:
     """Mixin class to add a tooltip to a line in a plot.
 
-    The tooltip displays 2 to 3 informations: the x value, the y value and an optional
-    t value for parametric curves (x(t), y(t)).
+    The tooltip displays 2 to 3 info: the x value, the y value and an optional t value
+    for parametric curves (x(t), y(t)).
     """
 
     def _add_line_tooltip(self, *, x_label, y_label, t_label=None, t_vals=None):
@@ -316,7 +316,7 @@ def _hover(self, event, t_vals):
         lines = _convert_to_list_leaving_none(self.line_)
         for i, line in enumerate(lines):
             contains, indexes = line.contains(event)
-            # stop at the first line on which the event occured
+            # stop at the first line on which the event occurred
             if contains:
                 idx = indexes["ind"][0]
                 x_vals, y_vals = line.get_data()
diff --git a/sklearn/utils/tests/test_plotting.py b/sklearn/utils/tests/test_plotting.py
index e315b171c4160..c4bbf8d52b2b6 100644
--- a/sklearn/utils/tests/test_plotting.py
+++ b/sklearn/utils/tests/test_plotting.py
@@ -616,7 +616,7 @@ def test_line_tooltip(n_curves, x_max, y_max, parametric, pyplot):
     assert display.line_tooltip_.get_text() == ""
     assert not display.line_tooltip_.get_visible()
 
-    # simulate a mouse event occuring on a line. Take the point in the middle of the
+    # simulate a mouse event occurring on a line. Take the point in the middle of the
     # last curve for instance
     x = display.x_vals[-1][50]
     y = display.y_vals[-1][50]
@@ -628,13 +628,13 @@ def test_line_tooltip(n_curves, x_max, y_max, parametric, pyplot):
     if parametric:
         assert "t" in text
 
-    # simulate a second event, not occuring on any line this time. None of these curves
+    # simulate a second event, not occurring on any line this time. None of these curves
     # ever touch the lower right corner
     _simulate_mouse_event(display, x_max, 0)
 
     assert not display.line_tooltip_.get_visible()
 
-    # simulate a third event occuring on several lines at once. (0, 0) belongs to all
+    # simulate a third event occurring on several lines at once. (0, 0) belongs to all
     # curves.
     _simulate_mouse_event(display, 0, 0)
 
@@ -656,19 +656,19 @@ def test_line_tooltip_multiple_displays(pyplot, y_max):
     assert not display.line_tooltip_.get_visible()
     assert not display2.line_tooltip_.get_visible()
 
-    # simulate a mouse event occuring on the first line
+    # simulate a mouse event occurring on the first line
     _simulate_mouse_event(display, 0.5, y_max)
 
     assert display.line_tooltip_.get_visible()
     assert not display2.line_tooltip_.get_visible()
 
-    # simulate a mouse event occuring on the second line
+    # simulate a mouse event occurring on the second line
     _simulate_mouse_event(display2, 1, y_max)
 
     assert not display.line_tooltip_.get_visible()
     assert display2.line_tooltip_.get_visible()
 
-    # simulate a mouse event occuring on both lines. Only 1 line tooltip is visible
+    # simulate a mouse event occurring on both lines. Only 1 line tooltip is visible
     _simulate_mouse_event(display, 0, 0)
 
     assert display.line_tooltip_.get_visible() != display2.line_tooltip_.get_visible()

From d6d699871a3774b184d1765ef0b22b5cc42693c9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=A9mie=20du=20Boisberranger?=
 <jeremie@probabl.ai>
Date: Mon, 4 Aug 2025 18:20:09 +0200
Subject: [PATCH 07/11] try %matplotlib widget in an example

---
 build_tools/circle/doc_environment.yml        |  1 +
 build_tools/circle/doc_linux-64_conda.lock    | 28 +++++++++++++++----
 .../update_environments_and_lock_files.py     |  1 +
 .../plot_cost_sensitive_learning.py           |  3 ++
 4 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/build_tools/circle/doc_environment.yml b/build_tools/circle/doc_environment.yml
index dcf3f0b0db699..c1c9095c6b475 100644
--- a/build_tools/circle/doc_environment.yml
+++ b/build_tools/circle/doc_environment.yml
@@ -39,6 +39,7 @@ dependencies:
   - towncrier
   - jupyterlite-sphinx
   - jupyterlite-pyodide-kernel
+  - ipympl
   - pip
   - pip:
     - sphinxcontrib-sass
diff --git a/build_tools/circle/doc_linux-64_conda.lock b/build_tools/circle/doc_linux-64_conda.lock
index d179ba70af52c..d258abd0bb584 100644
--- a/build_tools/circle/doc_linux-64_conda.lock
+++ b/build_tools/circle/doc_linux-64_conda.lock
@@ -1,6 +1,6 @@
 # Generated by conda-lock.
 # platform: linux-64
-# input_hash: 9bc9ca426bc05685148b1ae7e671907e9d514e40b6bb1c8d7c916d4fdc8b70f2
+# input_hash: afdbcc323f4c61ff76aa07208fd051f771b8199561066eb3d776125c9fee92ec
 @EXPLICIT
 https://conda.anaconda.org/conda-forge/linux-64/_libgcc_mutex-0.1-conda_forge.tar.bz2#d7c89558ba9fa0495403155b64376d81
 https://conda.anaconda.org/conda-forge/noarch/font-ttf-dejavu-sans-mono-2.37-hab24e00_0.tar.bz2#0c96522c6bdaed4b1566d11387caaf45
@@ -107,6 +107,7 @@ https://conda.anaconda.org/conda-forge/linux-64/xcb-util-wm-0.4.2-hb711507_0.con
 https://conda.anaconda.org/conda-forge/linux-64/xorg-libsm-1.2.6-he73a12e_0.conda#1c74ff8c35dcadf952a16f752ca5aa49
 https://conda.anaconda.org/conda-forge/linux-64/xorg-libx11-1.8.12-h4f16b4b_0.conda#db038ce880f100acc74dba10302b5630
 https://conda.anaconda.org/conda-forge/noarch/alabaster-1.0.0-pyhd8ed1ab_1.conda#1fd9696649f65fd6611fcdb4ffec738a
+https://conda.anaconda.org/conda-forge/noarch/asttokens-3.0.0-pyhd8ed1ab_1.conda#8f587de4bcf981e26228f268df374a9b
 https://conda.anaconda.org/conda-forge/noarch/attrs-25.3.0-pyh71513ae_0.conda#a10d11958cadc13fdb43df75f8b1903f
 https://conda.anaconda.org/conda-forge/linux-64/brotli-1.1.0-hb9d3cd8_3.conda#5d08a0ac29e6a5a984817584775d4131
 https://conda.anaconda.org/conda-forge/linux-64/brotli-python-1.1.0-py310hf71b8c6_3.conda#63d24a5dd21c738d706f91569dbd1892
@@ -116,14 +117,17 @@ https://conda.anaconda.org/conda-forge/noarch/charset-normalizer-3.4.2-pyhd8ed1a
 https://conda.anaconda.org/conda-forge/noarch/click-8.2.2-pyh707e725_0.conda#2cc16494e4ce28efc52fb29ec3c348a1
 https://conda.anaconda.org/conda-forge/noarch/cloudpickle-3.1.1-pyhd8ed1ab_0.conda#364ba6c9fb03886ac979b482f39ebb92
 https://conda.anaconda.org/conda-forge/noarch/colorama-0.4.6-pyhd8ed1ab_1.conda#962b9857ee8e7018c22f2776ffa0b2d7
+https://conda.anaconda.org/conda-forge/noarch/comm-0.2.3-pyhe01879c_0.conda#2da13f2b299d8e1995bafbbe9689a2f7
 https://conda.anaconda.org/conda-forge/linux-64/conda-gcc-specs-14.3.0-hb991d5c_4.conda#b6025bc20bf223d68402821f181707fb
 https://conda.anaconda.org/conda-forge/noarch/cpython-3.10.18-py310hd8ed1ab_0.conda#7004cb3fa62ad44d1cb70f3b080dfc8f
 https://conda.anaconda.org/conda-forge/noarch/cycler-0.12.1-pyhd8ed1ab_1.conda#44600c4667a319d67dbe0681fc0bc833
 https://conda.anaconda.org/conda-forge/linux-64/cyrus-sasl-2.1.28-hd9c7081_0.conda#cae723309a49399d2949362f4ab5c9e4
 https://conda.anaconda.org/conda-forge/linux-64/cython-3.1.2-py310had8cdd9_2.conda#be416b1d5ffef48c394cbbb04bc864ae
+https://conda.anaconda.org/conda-forge/noarch/decorator-5.2.1-pyhd8ed1ab_0.conda#9ce473d1d1be1cc3810856a48b3fab32
 https://conda.anaconda.org/conda-forge/noarch/defusedxml-0.7.1-pyhd8ed1ab_0.tar.bz2#961b3a227b437d82ad7054484cfa71b2
 https://conda.anaconda.org/conda-forge/noarch/docutils-0.21.2-pyhd8ed1ab_1.conda#24c1ca34138ee57de72a943237cde4cc
 https://conda.anaconda.org/conda-forge/noarch/execnet-2.1.1-pyhd8ed1ab_1.conda#a71efeae2c160f6789900ba2631a2c90
+https://conda.anaconda.org/conda-forge/noarch/executing-2.2.0-pyhd8ed1ab_0.conda#81d30c08f9a3e556e8ca9e124b044d14
 https://conda.anaconda.org/conda-forge/linux-64/gcc_linux-64-14.3.0-h1382650_11.conda#2e650506e6371ac4289c9bf7fc207f3b
 https://conda.anaconda.org/conda-forge/linux-64/gfortran_impl_linux-64-14.3.0-h7db7018_4.conda#4cb71ecc31f139f8bf96963c53b5b8a1
 https://conda.anaconda.org/conda-forge/linux-64/gxx_impl_linux-64-14.3.0-he663afc_4.conda#1f7b059bae1fc5e72ae23883e04abc48
@@ -134,6 +138,7 @@ https://conda.anaconda.org/conda-forge/noarch/imagesize-1.4.1-pyhd8ed1ab_0.tar.b
 https://conda.anaconda.org/conda-forge/noarch/iniconfig-2.0.0-pyhd8ed1ab_1.conda#6837f3eff7dcea42ecd714ce1ac2b108
 https://conda.anaconda.org/conda-forge/noarch/json5-0.12.0-pyhd8ed1ab_0.conda#56275442557b3b45752c10980abfe2db
 https://conda.anaconda.org/conda-forge/linux-64/jsonpointer-3.0.0-py310hff52083_1.conda#ce614a01b0aee1b29cee13d606bcb5d5
+https://conda.anaconda.org/conda-forge/noarch/jupyterlab_widgets-3.0.15-pyhd8ed1ab_0.conda#ad100d215fad890ab0ee10418f36876f
 https://conda.anaconda.org/conda-forge/linux-64/kiwisolver-1.4.8-py310h3788b33_1.conda#b70dd76da5231e6073fd44c42a1d78c5
 https://conda.anaconda.org/conda-forge/noarch/lark-1.2.2-pyhd8ed1ab_1.conda#3a8063b25e603999188ed4bbf3485404
 https://conda.anaconda.org/conda-forge/linux-64/lcms2-2.17-h717163a_0.conda#000e85703f0fd9594c81710dd5066471
@@ -141,9 +146,9 @@ https://conda.anaconda.org/conda-forge/linux-64/libavif16-1.3.0-h766b0b6_0.conda
 https://conda.anaconda.org/conda-forge/linux-64/libblas-3.9.0-32_h59b9bed_openblas.conda#2af9f3d5c2e39f417ce040f5a35c40c6
 https://conda.anaconda.org/conda-forge/linux-64/libcups-2.3.3-hb8b1518_5.conda#d4a250da4737ee127fb1fa6452a9002e
 https://conda.anaconda.org/conda-forge/linux-64/libfreetype-2.13.3-ha770c72_1.conda#51f5be229d83ecd401fb369ab96ae669
-https://conda.anaconda.org/conda-forge/linux-64/libglib-2.84.2-h3618099_0.conda#072ab14a02164b7c0c089055368ff776
+https://conda.anaconda.org/conda-forge/linux-64/libglib-2.84.3-hf39c6af_0.conda#467f23819b1ea2b89c3fc94d65082301
 https://conda.anaconda.org/conda-forge/linux-64/libglx-1.7.0-ha4b6fd6_2.conda#c8013e438185f33b13814c5c488acd5c
-https://conda.anaconda.org/conda-forge/linux-64/libxml2-2.13.8-h4bc477f_0.conda#14dbe05b929e329dbaa6f2d0aa19466d
+https://conda.anaconda.org/conda-forge/linux-64/libxml2-2.13.8-h04c0eec_1.conda#10bcbd05e1c1c9d652fccb42b776a9fa
 https://conda.anaconda.org/conda-forge/linux-64/markupsafe-3.0.2-py310h89163eb_1.conda#8ce3f0332fd6de0d737e2911d329523f
 https://conda.anaconda.org/conda-forge/noarch/mdurl-0.1.2-pyhd8ed1ab_1.conda#592132998493b3ff25fd7479396e8351
 https://conda.anaconda.org/conda-forge/noarch/meson-1.8.3-pyhe01879c_0.conda#ed40b34242ec6d216605db54d19c6df5
@@ -151,15 +156,18 @@ https://conda.anaconda.org/conda-forge/noarch/munkres-1.1.4-pyhd8ed1ab_1.conda#3
 https://conda.anaconda.org/conda-forge/noarch/narwhals-2.0.1-pyhe01879c_0.conda#5f0dea40791cecf0f82882b9eea7f7c1
 https://conda.anaconda.org/conda-forge/noarch/networkx-3.4.2-pyh267e887_2.conda#fd40bf7f7f4bc4b647dc8512053d9873
 https://conda.anaconda.org/conda-forge/linux-64/openblas-0.3.30-pthreads_h6ec200e_1.conda#611fcf119d77a78439794c43f7667664
-https://conda.anaconda.org/conda-forge/linux-64/openjpeg-2.5.3-h5fbd93e_0.conda#9e5816bc95d285c115a3ebc2f8563564
+https://conda.anaconda.org/conda-forge/linux-64/openjpeg-2.5.3-h55fea9a_1.conda#01243c4aaf71bde0297966125aea4706
 https://conda.anaconda.org/conda-forge/noarch/packaging-25.0-pyh29332c3_1.conda#58335b26c38bf4a20f399384c33cbcf9
 https://conda.anaconda.org/conda-forge/noarch/pandocfilters-1.5.0-pyhd8ed1ab_0.tar.bz2#457c2c8c08e54905d6954e79cb5b5db9
+https://conda.anaconda.org/conda-forge/noarch/parso-0.8.4-pyhd8ed1ab_1.conda#5c092057b6badd30f75b06244ecd01c9
+https://conda.anaconda.org/conda-forge/noarch/pickleshare-0.7.5-pyhd8ed1ab_1004.conda#11a9d1d09a3615fc07c3faf79bc0b943
 https://conda.anaconda.org/conda-forge/noarch/pkginfo-1.12.1.2-pyhd8ed1ab_0.conda#dc702b2fae7ebe770aff3c83adb16b63
 https://conda.anaconda.org/conda-forge/noarch/platformdirs-4.3.8-pyhe01879c_0.conda#424844562f5d337077b445ec6b1398a7
 https://conda.anaconda.org/conda-forge/noarch/pluggy-1.6.0-pyhd8ed1ab_0.conda#7da7ccd349dbf6487a7778579d2bb971
 https://conda.anaconda.org/conda-forge/noarch/prometheus_client-0.22.1-pyhd8ed1ab_0.conda#c64b77ccab10b822722904d889fa83b5
 https://conda.anaconda.org/conda-forge/linux-64/psutil-7.0.0-py310ha75aee5_0.conda#da7d592394ff9084a23f62a1186451a2
 https://conda.anaconda.org/conda-forge/noarch/ptyprocess-0.7.0-pyhd8ed1ab_1.conda#7d9daffbb8d8e0af0f769dbbcd173a54
+https://conda.anaconda.org/conda-forge/noarch/pure_eval-0.2.3-pyhd8ed1ab_1.conda#3bfdfb8dbcdc4af1ae3f9a8eb3948f04
 https://conda.anaconda.org/conda-forge/noarch/pycparser-2.22-pyh29332c3_1.conda#12c566707c80111f9799308d9e265aef
 https://conda.anaconda.org/conda-forge/noarch/pygments-2.19.2-pyhd8ed1ab_0.conda#6b6ece66ebcae2d5f326c77ef2c5a066
 https://conda.anaconda.org/conda-forge/noarch/pyparsing-3.2.3-pyhe01879c_2.conda#aa0028616c0750c773698fdc254b2b8d
@@ -188,10 +196,12 @@ https://conda.anaconda.org/conda-forge/noarch/typing_extensions-4.14.1-pyhe01879
 https://conda.anaconda.org/conda-forge/noarch/typing_utils-0.1.0-pyhd8ed1ab_1.conda#f6d7aa696c67756a650e91e15e88223c
 https://conda.anaconda.org/conda-forge/linux-64/unicodedata2-16.0.0-py310ha75aee5_0.conda#1d7a4b9202cdd10d56ecdd7f6c347190
 https://conda.anaconda.org/conda-forge/noarch/uri-template-1.3.0-pyhd8ed1ab_1.conda#e7cb0f5745e4c5035a460248334af7eb
+https://conda.anaconda.org/conda-forge/noarch/wcwidth-0.2.13-pyhd8ed1ab_1.conda#b68980f2495d096e71c7fd9d7ccf63e6
 https://conda.anaconda.org/conda-forge/noarch/webcolors-24.11.1-pyhd8ed1ab_0.conda#b49f7b291e15494aafb0a7d74806f337
 https://conda.anaconda.org/conda-forge/noarch/webencodings-0.5.1-pyhd8ed1ab_3.conda#2841eb5bfc75ce15e9a0054b98dcd64d
 https://conda.anaconda.org/conda-forge/noarch/websocket-client-1.8.0-pyhd8ed1ab_1.conda#84f8f77f0a9c6ef401ee96611745da8f
 https://conda.anaconda.org/conda-forge/noarch/wheel-0.45.1-pyhd8ed1ab_1.conda#75cb7132eb58d97896e173ef12ac9986
+https://conda.anaconda.org/conda-forge/noarch/widgetsnbextension-4.0.14-pyhd8ed1ab_0.conda#2f1f99b13b9d2a03570705030a0b3e7c
 https://conda.anaconda.org/conda-forge/linux-64/xcb-util-image-0.4.0-hb711507_2.conda#a0901183f08b6c7107aab109733a3c91
 https://conda.anaconda.org/conda-forge/linux-64/xkeyboard-config-2.45-hb9d3cd8_0.conda#397a013c2dc5145a70737871aaa87e98
 https://conda.anaconda.org/conda-forge/linux-64/xorg-libxext-1.3.6-hb9d3cd8_0.conda#febbab7d15033c913d53c7a2c102309d
@@ -215,6 +225,7 @@ https://conda.anaconda.org/conda-forge/linux-64/gxx_linux-64-14.3.0-ha7acb78_11.
 https://conda.anaconda.org/conda-forge/noarch/h2-4.2.0-pyhd8ed1ab_0.conda#b4754fb1bdcb70c8fd54f918301582c6
 https://conda.anaconda.org/conda-forge/noarch/importlib-metadata-8.7.0-pyhe01879c_1.conda#63ccfdc3a3ce25b027b8767eb722fca8
 https://conda.anaconda.org/conda-forge/noarch/importlib_resources-6.5.2-pyhd8ed1ab_0.conda#c85c76dc67d75619a92f51dfbce06992
+https://conda.anaconda.org/conda-forge/noarch/jedi-0.19.2-pyhd8ed1ab_1.conda#a4f4c5dc9b80bc50e0d3dc4e6e8f1bd9
 https://conda.anaconda.org/conda-forge/noarch/jinja2-3.1.6-pyhd8ed1ab_0.conda#446bd6c8cb26050d528881df495ce646
 https://conda.anaconda.org/conda-forge/noarch/joblib-1.5.1-pyhd8ed1ab_0.conda#fb1c14694de51a476ce8636d92b6f42c
 https://conda.anaconda.org/conda-forge/noarch/jupyter_core-5.8.1-pyh31011fe_0.conda#b7d89d860ebcda28a5303526cdee68ab
@@ -226,13 +237,16 @@ https://conda.anaconda.org/conda-forge/linux-64/libllvm20-20.1.8-hecd9e04_0.cond
 https://conda.anaconda.org/conda-forge/linux-64/libxkbcommon-1.10.0-h65c71a3_0.conda#fedf6bfe5d21d21d2b1785ec00a8889a
 https://conda.anaconda.org/conda-forge/linux-64/libxslt-1.1.43-h7a3aeb2_0.conda#31059dc620fa57d787e3899ed0421e6d
 https://conda.anaconda.org/conda-forge/noarch/markdown-it-py-3.0.0-pyhd8ed1ab_1.conda#fee3164ac23dfca50cfcc8b85ddefb81
+https://conda.anaconda.org/conda-forge/noarch/matplotlib-inline-0.1.7-pyhd8ed1ab_1.conda#af6ab708897df59bd6e7283ceab1b56b
 https://conda.anaconda.org/conda-forge/noarch/memory_profiler-0.61.0-pyhd8ed1ab_1.conda#71abbefb6f3b95e1668cd5e0af3affb9
 https://conda.anaconda.org/conda-forge/noarch/mistune-3.1.3-pyh29332c3_0.conda#7ec6576e328bc128f4982cd646eeba85
 https://conda.anaconda.org/conda-forge/linux-64/openldap-2.6.10-he970967_0.conda#2e5bf4f1da39c0b32778561c3c4e5878
 https://conda.anaconda.org/conda-forge/noarch/overrides-7.7.0-pyhd8ed1ab_1.conda#e51f1e4089cad105b6cac64bd8166587
+https://conda.anaconda.org/conda-forge/noarch/pexpect-4.9.0-pyhd8ed1ab_1.conda#d0d408b1f18883a944376da5cf8101ea
 https://conda.anaconda.org/conda-forge/linux-64/pillow-11.3.0-py310h7e6dc6c_0.conda#e609995f031bc848be8ea159865e8afc
 https://conda.anaconda.org/conda-forge/noarch/pip-25.2-pyh8b19718_0.conda#dfce4b2af4bfe90cdcaf56ca0b28ddf5
 https://conda.anaconda.org/conda-forge/noarch/plotly-6.2.0-pyhd8ed1ab_0.conda#8a9590843af49b36f37ac3dbcf5fc3d9
+https://conda.anaconda.org/conda-forge/noarch/prompt-toolkit-3.0.51-pyha770c72_0.conda#d17ae9db4dc594267181bd199bf9a551
 https://conda.anaconda.org/conda-forge/noarch/pyproject-metadata-0.9.1-pyhd8ed1ab_0.conda#22ae7c6ea81e0c8661ef32168dda929b
 https://conda.anaconda.org/conda-forge/noarch/python-dateutil-2.9.0.post0-pyhe01879c_2.conda#5b8d21249ff20967101ffa321cab24e8
 https://conda.anaconda.org/conda-forge/noarch/python-gil-3.10.18-hd8ed1ab_0.conda#a40e3a920f2c46f94e027bd599b88b17
@@ -240,6 +254,7 @@ https://conda.anaconda.org/conda-forge/linux-64/pyzmq-27.0.1-py310h9a5fd63_0.con
 https://conda.anaconda.org/conda-forge/noarch/referencing-0.36.2-pyh29332c3_0.conda#9140f1c09dd5489549c6a33931b943c7
 https://conda.anaconda.org/conda-forge/noarch/rfc3339-validator-0.1.4-pyhd8ed1ab_1.conda#36de09a8d3e5d5e6f4ee63af49e59706
 https://conda.anaconda.org/conda-forge/noarch/rfc3987-syntax-1.1.0-pyhe01879c_1.conda#7234f99325263a5af6d4cd195035e8f2
+https://conda.anaconda.org/conda-forge/noarch/stack_data-0.6.3-pyhd8ed1ab_1.conda#b1b505328da7a6b246787df4b5a49fbc
 https://conda.anaconda.org/conda-forge/noarch/terminado-0.18.1-pyh0d859eb_0.conda#efba281bbdae5f6b0a1d53c6d4a97c93
 https://conda.anaconda.org/conda-forge/noarch/tinycss2-1.4.0-pyhd8ed1ab_0.conda#f1acf5fdefa8300de697982bcb1761c9
 https://conda.anaconda.org/conda-forge/noarch/typing-extensions-4.14.1-h4440ef1_0.conda#75be1a943e0a7f99fcf118309092c635
@@ -251,7 +266,7 @@ https://conda.anaconda.org/conda-forge/linux-64/xorg-libxi-1.8.2-hb9d3cd8_0.cond
 https://conda.anaconda.org/conda-forge/linux-64/xorg-libxrandr-1.5.4-hb9d3cd8_0.conda#2de7f99d6581a4a7adbff607b5c278ca
 https://conda.anaconda.org/conda-forge/linux-64/xorg-libxxf86vm-1.1.6-hb9d3cd8_0.conda#5efa5fa6243a622445fdfd72aee15efa
 https://conda.anaconda.org/conda-forge/noarch/_python_abi3_support-1.0-hd8ed1ab_2.conda#aaa2a381ccc56eac91d63b6c1240312f
-https://conda.anaconda.org/conda-forge/noarch/anyio-4.9.0-pyh29332c3_0.conda#9749a2c77a7c40d432ea0927662d7e52
+https://conda.anaconda.org/conda-forge/noarch/anyio-4.10.0-pyhe01879c_0.conda#cc2613bfa71dec0eb2113ee21ac9ccbf
 https://conda.anaconda.org/conda-forge/linux-64/argon2-cffi-bindings-25.1.0-py310h7c4b9e2_0.conda#3fd41ccdb9263ad51cf89b05cade6fb7
 https://conda.anaconda.org/conda-forge/noarch/arrow-1.3.0-pyhd8ed1ab_1.conda#46b53236fdd990271b03c3978d4218a9
 https://conda.anaconda.org/conda-forge/noarch/beautifulsoup4-4.13.4-pyha770c72_0.conda#9f07c4fc992adb2d6c30da7fab3959a7
@@ -263,6 +278,7 @@ https://conda.anaconda.org/conda-forge/noarch/fqdn-1.5.1-pyhd8ed1ab_1.conda#d354
 https://conda.anaconda.org/conda-forge/linux-64/gfortran-14.3.0-he448592_4.conda#6f88c38cdf941173e9aec76f967d4d28
 https://conda.anaconda.org/conda-forge/linux-64/gxx-14.3.0-he448592_4.conda#26ccfde67e88b646e57a7e56ce4ef56d
 https://conda.anaconda.org/conda-forge/noarch/importlib-resources-6.5.2-pyhd8ed1ab_0.conda#e376ea42e9ae40f3278b0f79c9bf9826
+https://conda.anaconda.org/conda-forge/noarch/ipython-8.37.0-pyh8f84b5b_0.conda#177cfa19fe3d74c87a8889286dc64090
 https://conda.anaconda.org/conda-forge/noarch/jsonschema-specifications-2025.4.1-pyh29332c3_0.conda#41ff526b1083fde51fbdc93f29282e0e
 https://conda.anaconda.org/conda-forge/noarch/jupyter_client-8.6.3-pyhd8ed1ab_1.conda#4ebae00eae9705b0c3d6d1018a81d047
 https://conda.anaconda.org/conda-forge/noarch/jupyter_server_terminals-0.5.3-pyhd8ed1ab_1.conda#2d983ff1b82a1ccb6f2e9d8784bdd6bd
@@ -285,6 +301,7 @@ https://conda.anaconda.org/conda-forge/linux-64/cxx-compiler-1.11.0-hfcd1e18_0.c
 https://conda.anaconda.org/conda-forge/linux-64/fortran-compiler-1.11.0-h9bea470_0.conda#d5596f445a1273ddc5ea68864c01b69f
 https://conda.anaconda.org/conda-forge/linux-64/imagecodecs-2025.3.30-py310h4eb8eaf_2.conda#a9c921699d37e862f9bf8dcf9d343838
 https://conda.anaconda.org/conda-forge/noarch/imageio-2.37.0-pyhfb79c49_0.conda#b5577bc2212219566578fd5af9993af6
+https://conda.anaconda.org/conda-forge/noarch/ipywidgets-8.1.7-pyhd8ed1ab_0.conda#7c9449eac5975ef2d7753da262a72707
 https://conda.anaconda.org/conda-forge/noarch/isoduration-20.11.0-pyhd8ed1ab_1.conda#0b0154421989637d424ccf0f104be51a
 https://conda.anaconda.org/conda-forge/noarch/jsonschema-4.25.0-pyhe01879c_0.conda#c6e3fd94e058dba67d917f38a11b50ab
 https://conda.anaconda.org/conda-forge/noarch/jupyterlite-core-0.6.3-pyhe01879c_0.conda#36ebdbf67840763b491045b5a36a2b78
@@ -308,6 +325,7 @@ https://conda.anaconda.org/conda-forge/linux-64/pyamg-5.2.1-py310ha2bacc8_1.cond
 https://conda.anaconda.org/conda-forge/noarch/requests-2.32.4-pyhd8ed1ab_0.conda#f6082eae112814f1447b56a5e1f6ed05
 https://conda.anaconda.org/conda-forge/linux-64/statsmodels-0.14.5-py310haaf2d95_0.conda#92b4b51b83f2cfded298f1b8c7a99e32
 https://conda.anaconda.org/conda-forge/noarch/tifffile-2025.5.10-pyhd8ed1ab_0.conda#1fdb801f28bf4987294c49aaa314bf5e
+https://conda.anaconda.org/conda-forge/noarch/ipympl-0.9.7-pyhd8ed1ab_1.conda#f5b7e17a56dd953c80c77cbdab378467
 https://conda.anaconda.org/conda-forge/noarch/jupyter_events-0.12.0-pyh29332c3_0.conda#f56000b36f09ab7533877e695e4e8cb0
 https://conda.anaconda.org/conda-forge/noarch/jupytext-1.17.2-pyh80e38bb_0.conda#6d0652a97ef103de0c77b9c610d0c20d
 https://conda.anaconda.org/conda-forge/noarch/nbclient-0.10.2-pyhd8ed1ab_0.conda#6bb0d77277061742744176ab555b723c
diff --git a/build_tools/update_environments_and_lock_files.py b/build_tools/update_environments_and_lock_files.py
index b99e0e8f8d416..758be24970a96 100644
--- a/build_tools/update_environments_and_lock_files.py
+++ b/build_tools/update_environments_and_lock_files.py
@@ -378,6 +378,7 @@ def remove_from(alist, to_remove):
             "towncrier",
             "jupyterlite-sphinx",
             "jupyterlite-pyodide-kernel",
+            "ipympl",
         ],
         "pip_dependencies": [
             "sphinxcontrib-sass",
diff --git a/examples/model_selection/plot_cost_sensitive_learning.py b/examples/model_selection/plot_cost_sensitive_learning.py
index 6b5b651463b05..893e7cb4449fd 100644
--- a/examples/model_selection/plot_cost_sensitive_learning.py
+++ b/examples/model_selection/plot_cost_sensitive_learning.py
@@ -38,6 +38,9 @@
 # Authors: The scikit-learn developers
 # SPDX-License-Identifier: BSD-3-Clause
 
+# %%
+%matplotlib widget
+
 # %%
 # Cost-sensitive learning with constant gains and costs
 # -----------------------------------------------------

From d0735d5f3ed1b48133814f72c3638071917d4d48 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=A9mie=20du=20Boisberranger?=
 <jeremie@probabl.ai>
Date: Fri, 8 Aug 2025 12:54:08 +0200
Subject: [PATCH 08/11] try sg config to add magic command

---
 doc/conf.py                                              | 1 +
 examples/model_selection/plot_cost_sensitive_learning.py | 3 ---
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/doc/conf.py b/doc/conf.py
index 71c9ec5bb60c3..999c2e197c3fa 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -745,6 +745,7 @@ def reset_sklearn_config(gallery_conf, fname):
     "plot_gallery": "True",
     "recommender": {"enable": True, "n_examples": 4, "min_df": 12},
     "reset_modules": ("matplotlib", "seaborn", reset_sklearn_config),
+    "first_notebook_cell": "%matplotlib widget",
 }
 if with_jupyterlite:
     sphinx_gallery_conf["jupyterlite"] = {
diff --git a/examples/model_selection/plot_cost_sensitive_learning.py b/examples/model_selection/plot_cost_sensitive_learning.py
index 893e7cb4449fd..6b5b651463b05 100644
--- a/examples/model_selection/plot_cost_sensitive_learning.py
+++ b/examples/model_selection/plot_cost_sensitive_learning.py
@@ -38,9 +38,6 @@
 # Authors: The scikit-learn developers
 # SPDX-License-Identifier: BSD-3-Clause
 
-# %%
-%matplotlib widget
-
 # %%
 # Cost-sensitive learning with constant gains and costs
 # -----------------------------------------------------

From e916a77b2dc49a29f6603f43f035526717d4675a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=A9mie=20du=20Boisberranger?=
 <jeremie@probabl.ai>
Date: Fri, 8 Aug 2025 16:10:13 +0200
Subject: [PATCH 09/11] add to pr curve

---
 .../metrics/_plot/precision_recall_curve.py   | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/sklearn/metrics/_plot/precision_recall_curve.py b/sklearn/metrics/_plot/precision_recall_curve.py
index 3e64fd776ae16..4dc3e72de9dca 100644
--- a/sklearn/metrics/_plot/precision_recall_curve.py
+++ b/sklearn/metrics/_plot/precision_recall_curve.py
@@ -6,13 +6,14 @@
 from sklearn.metrics._ranking import average_precision_score, precision_recall_curve
 from sklearn.utils._plotting import (
     _BinaryClassifierCurveDisplayMixin,
+    _LineTooltipMixin,
     _deprecate_y_pred_parameter,
     _despine,
     _validate_style_kwargs,
 )
 
 
-class PrecisionRecallDisplay(_BinaryClassifierCurveDisplayMixin):
+class PrecisionRecallDisplay(_BinaryClassifierCurveDisplayMixin, _LineTooltipMixin):
     """Precision Recall visualization.
 
     It is recommended to use
@@ -34,6 +35,13 @@ class PrecisionRecallDisplay(_BinaryClassifierCurveDisplayMixin):
     recall : ndarray
         Recall values.
 
+    thresholds : ndarray or list of ndarrays, default=None
+        The thresholds at which the fpr and tpr have been computed. Each ndarray should
+        contain values for a single curve. If plotting multiple curves, list should be
+        of same length as `fpr` and `tpr`.
+        Only used to display the threshold values along the curve as a tooltip. If None,
+        only the fpr and tpr values are displayed.
+
     average_precision : float, default=None
         Average precision. If None, the average precision is not shown.
 
@@ -117,6 +125,7 @@ def __init__(
         precision,
         recall,
         *,
+        thresholds=None,
         average_precision=None,
         estimator_name=None,
         pos_label=None,
@@ -125,6 +134,7 @@ def __init__(
         self.estimator_name = estimator_name
         self.precision = precision
         self.recall = recall
+        self.thresholds = thresholds
         self.average_precision = average_precision
         self.pos_label = pos_label
         self.prevalence_pos_label = prevalence_pos_label
@@ -206,6 +216,10 @@ def plot(
 
         (self.line_,) = self.ax_.plot(self.recall, self.precision, **line_kwargs)
 
+        self._add_line_tooltip(
+            x_label="R", y_label="P", t_label="threshold", t_vals=[self.thresholds]
+        )
+
         info_pos_label = (
             f" (Positive label: {self.pos_label})" if self.pos_label is not None else ""
         )
@@ -537,7 +551,7 @@ def from_predictions(
             y_true, y_score, sample_weight=sample_weight, pos_label=pos_label, name=name
         )
 
-        precision, recall, _ = precision_recall_curve(
+        precision, recall, thresholds = precision_recall_curve(
             y_true,
             y_score,
             pos_label=pos_label,
@@ -554,6 +568,7 @@ def from_predictions(
         viz = cls(
             precision=precision,
             recall=recall,
+            thresholds=thresholds,
             average_precision=average_precision,
             estimator_name=name,
             pos_label=pos_label,

From aea3c925a860a147bd4cc6fa0be0c33579d3158b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=A9mie=20du=20Boisberranger?=
 <jeremie@probabl.ai>
Date: Fri, 8 Aug 2025 16:10:27 +0200
Subject: [PATCH 10/11] subclass Annotation instead

---
 sklearn/utils/_plotting.py | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/sklearn/utils/_plotting.py b/sklearn/utils/_plotting.py
index 4101f98c64f52..fa16570b5c6a7 100644
--- a/sklearn/utils/_plotting.py
+++ b/sklearn/utils/_plotting.py
@@ -251,6 +251,16 @@ def _validate_curve_kwargs(
         return curve_kwargs_
 
 
+try:
+    from matplotlib.text import Annotation
+
+    class LineTooltip(Annotation):
+        """Custom annotation class to be able identify it among the axes children."""
+
+except:
+    pass
+
+
 class _LineTooltipMixin:
     """Mixin class to add a tooltip to a line in a plot.
 
@@ -289,12 +299,9 @@ def _add_line_tooltip(self, *, x_label, y_label, t_label=None, t_vals=None):
             arrowprops=dict(arrowstyle="-"),
             zorder=10,  # bring to front
         )
+        self.line_tooltip_.__class__ = LineTooltip
         self.line_tooltip_.set_visible(False)
 
-        # Set an attribute on the axes annotation to be able to keep only one visible
-        # at a time when there are multiple display instances that share an axes.
-        setattr(self.line_tooltip_, "_skl_line_tooltip", True)
-
         self.ax_.figure.canvas.mpl_connect(
             "motion_notify_event", partial(self._hover, t_vals=t_vals)
         )
@@ -333,7 +340,7 @@ def _hover(self, event, t_vals):
         # account for the case when multiple display instances share the same axes.
         found_visible = False
         for child in self.ax_.get_children():
-            if hasattr(child, "_skl_line_tooltip") and child.get_visible():
+            if isinstance(child, LineTooltip) and child.get_visible():
                 if not found_visible:
                     found_visible = True
                 else:

From 7f7e30ebb8b7254179c360897611382f7b6c76b4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=A9mie=20du=20Boisberranger?=
 <jeremie@probabl.ai>
Date: Fri, 8 Aug 2025 16:12:56 +0200
Subject: [PATCH 11/11] lint

---
 sklearn/metrics/_plot/precision_recall_curve.py | 2 +-
 sklearn/utils/_plotting.py                      | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/sklearn/metrics/_plot/precision_recall_curve.py b/sklearn/metrics/_plot/precision_recall_curve.py
index 4dc3e72de9dca..8d0785115aa80 100644
--- a/sklearn/metrics/_plot/precision_recall_curve.py
+++ b/sklearn/metrics/_plot/precision_recall_curve.py
@@ -6,9 +6,9 @@
 from sklearn.metrics._ranking import average_precision_score, precision_recall_curve
 from sklearn.utils._plotting import (
     _BinaryClassifierCurveDisplayMixin,
-    _LineTooltipMixin,
     _deprecate_y_pred_parameter,
     _despine,
+    _LineTooltipMixin,
     _validate_style_kwargs,
 )
 
diff --git a/sklearn/utils/_plotting.py b/sklearn/utils/_plotting.py
index fa16570b5c6a7..784a47009d417 100644
--- a/sklearn/utils/_plotting.py
+++ b/sklearn/utils/_plotting.py
@@ -257,7 +257,7 @@ def _validate_curve_kwargs(
     class LineTooltip(Annotation):
         """Custom annotation class to be able identify it among the axes children."""
 
-except:
+except ImportError:
     pass