From f6dce5ebfb128fbaee5e3dd18de8fb65c167432c Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@ess.eu>
Date: Thu, 7 Aug 2025 21:33:23 +0200
Subject: [PATCH 01/10] initial version of value selecting tool

---
 src/plopp/widgets/clip3d.py | 155 +++++++++++++++++++++++++++++++++---
 1 file changed, 142 insertions(+), 13 deletions(-)

diff --git a/src/plopp/widgets/clip3d.py b/src/plopp/widgets/clip3d.py
index cb414ab3a..e18105329 100644
--- a/src/plopp/widgets/clip3d.py
+++ b/src/plopp/widgets/clip3d.py
@@ -187,6 +187,103 @@ def _throttled_update(self):
         self._update()
 
 
+class ClipValueTool(ipw.HBox):
+    """
+    A tool that provides a slider to extract a points in a three-dimensional
+    scatter plot based on a value selection criterion, and add it to the scene as an
+    opaque cut. The slider controls the range of the selection.
+
+    .. versionadded:: 25.08.0
+
+    Parameters
+    ----------
+    limits:
+        The spatial extent of the points in the 3d figure in the XYZ directions.
+    update:
+        A function to update the scene.
+    """
+
+    def __init__(
+        self,
+        limits: sc.Variable,
+        update: Callable,
+    ):
+        self._limits = limits
+        self._unit = self._limits.unit
+        self.visible = True
+        self._update = update
+        self._direction = 'v'
+
+        center = self._limits.mean().value
+        vmin = self._limits[0].value
+        vmax = self._limits[1].value
+        dx = vmax - vmin
+        delta = 0.05 * dx
+        self.slider = ipw.FloatRangeSlider(
+            min=vmin,
+            max=vmax,
+            value=[center - delta, center + delta],
+            step=dx * 0.01,
+            description="Values",
+            style={'description_width': 'initial'},
+            layout={'width': '470px', 'padding': '0px'},
+        )
+
+        self.cut_visible = ipw.Button(
+            icon='eye-slash',
+            tooltip='Hide cut',
+            layout={'width': '16px', 'padding': '0px'},
+        )
+
+        self.unit_label = ipw.Label(f'[{self._unit}]')
+        self.cut_visible.on_click(self.toggle)
+        self.slider.observe(self._throttled_update, names='value')
+
+        super().__init__([self.slider, ipw.Label(f'[{self._unit}]'), self.cut_visible])
+
+    def toggle(self, owner: ipw.Button):
+        """
+        Toggle the visibility of the cut on and off.
+        """
+        self.visible = not self.visible
+        self.slider.disabled = not self.visible
+        owner.icon = 'eye-slash' if self.visible else 'eye'
+        owner.tooltip = 'Hide cut' if self.visible else 'Show cut'
+        self._update()
+
+    def toggle_border(self, value: bool):
+        """ """
+        return
+
+    # def move(self, value: dict[str, Any]):
+    #     """
+    #     """
+    #     return
+    #     # Early return if relative difference between new and old value is small.
+    #     # This also prevents flickering of an existing cut when a new cut is added.
+    #     if (
+    #         np.abs(np.array(value['new']) - np.array(value['old'])).max()
+    #         < 0.01 * self.slider.step
+    #     ):
+    #         return
+    #     for outline, val in zip(self.outlines, value['new'], strict=True):
+    #         pos = list(outline.position)
+    #         axis = 'xyz'.index(self._direction)
+    #         pos[axis] = val
+    #         outline.position = pos
+    #     self._throttled_update()
+
+    @property
+    def range(self):
+        return sc.scalar(self.slider.value[0], unit=self._unit), sc.scalar(
+            self.slider.value[1], unit=self._unit
+        )
+
+    @debounce(0.3)
+    def _throttled_update(self):
+        self._update()
+
+
 class ClippingPlanes(ipw.HBox):
     """
     A widget to make clipping planes for spatial cutting (see :class:`Clip3dTool`) to
@@ -230,6 +327,14 @@ def __init__(self, fig: BaseFig):
         self._original_nodes = list(self._view.graph_nodes.values())
         self._nodes = {}
 
+        self._value_limits = sc.concat(
+            [
+                min(n().min() for n in self._original_nodes),
+                max(n().max() for n in self._original_nodes),
+            ],
+            dim="dummy",
+        )
+
         self.add_cut_label = ipw.Label('Add cut:')
         layout = {'width': '45px', 'padding': '0px 0px 0px 0px'}
         self.add_x_cut = ipw.Button(
@@ -250,9 +355,16 @@ def __init__(self, fig: BaseFig):
             tooltip='Add Z cut',
             layout=layout,
         )
+        self.add_v_cut = ipw.Button(
+            description='V',
+            icon='plus',
+            tooltip='Add Value cut',
+            layout=layout,
+        )
         self.add_x_cut.on_click(lambda _: self._add_cut('x'))
         self.add_y_cut.on_click(lambda _: self._add_cut('y'))
         self.add_z_cut.on_click(lambda _: self._add_cut('z'))
+        self.add_v_cut.on_click(lambda _: self._add_cut('v'))
 
         self.opacity = ipw.BoundedFloatText(
             min=0,
@@ -300,7 +412,14 @@ def __init__(self, fig: BaseFig):
                 self.tabs,
                 ipw.VBox(
                     [
-                        ipw.HBox([self.add_x_cut, self.add_y_cut, self.add_z_cut]),
+                        ipw.HBox(
+                            [
+                                self.add_x_cut,
+                                self.add_y_cut,
+                                self.add_z_cut,
+                                self.add_v_cut,
+                            ]
+                        ),
                         self.opacity,
                         ipw.HBox(
                             [
@@ -316,17 +435,23 @@ def __init__(self, fig: BaseFig):
 
         self.layout.display = 'none'
 
-    def _add_cut(self, direction: Literal['x', 'y', 'z']):
+    def _add_cut(self, direction: Literal['x', 'y', 'z', 'v']):
         """
         Add a cut in the specified direction.
         """
-        cut = Clip3dTool(
-            direction=direction,
-            limits=self._limits,
-            update=self.update_state,
-            border_visible=self.cut_borders_visibility.value,
-        )
-        self._view.canvas.add(cut.outlines)
+        if direction == 'v':
+            cut = ClipValueTool(
+                limits=self._value_limits,
+                update=self.update_state,
+            )
+        else:
+            cut = Clip3dTool(
+                direction=direction,
+                limits=self._limits,
+                update=self.update_state,
+                border_visible=self.cut_borders_visibility.value,
+            )
+            self._view.canvas.add(cut.outlines)
         self.cuts.append(cut)
         self.tabs.children = [*self.tabs.children, cut]
         self.tabs.selected_index = len(self.cuts) - 1
@@ -335,7 +460,8 @@ def _add_cut(self, direction: Literal['x', 'y', 'z']):
 
     def _remove_cut(self, _):
         cut = self.cuts.pop(self.tabs.selected_index)
-        self._view.canvas.remove(cut.outlines)
+        if cut._direction != 'v':
+            self._view.canvas.remove(cut.outlines)
         self.tabs.children = self.cuts
         self.update_state()
         self.update_controls()
@@ -406,9 +532,12 @@ def update_state(self):
             selections = []
             for cut in visible_cuts:
                 xmin, xmax = cut.range
-                selections.append(
-                    (da.coords[cut.dim] >= xmin) & (da.coords[cut.dim] < xmax)
-                )
+                if cut._direction == 'v':
+                    selections.append((da.data >= xmin) & (da.data < xmax))
+                else:
+                    selections.append(
+                        (da.coords[cut.dim] >= xmin) & (da.coords[cut.dim] < xmax)
+                    )
             selection = OPERATIONS[self._operation](selections)
             if selection.sum().value > 0:
                 if n.id not in self._nodes:

From 9964e5738a98766e89599eea752bf22ad6a2dc2b Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@ess.eu>
Date: Thu, 7 Aug 2025 22:10:00 +0200
Subject: [PATCH 02/10] fix update and better layout

---
 src/plopp/widgets/clip3d.py | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/plopp/widgets/clip3d.py b/src/plopp/widgets/clip3d.py
index e18105329..81630cf55 100644
--- a/src/plopp/widgets/clip3d.py
+++ b/src/plopp/widgets/clip3d.py
@@ -280,7 +280,7 @@ def range(self):
         )
 
     @debounce(0.3)
-    def _throttled_update(self):
+    def _throttled_update(self, _):
         self._update()
 
 
@@ -336,30 +336,30 @@ def __init__(self, fig: BaseFig):
         )
 
         self.add_cut_label = ipw.Label('Add cut:')
-        layout = {'width': '45px', 'padding': '0px 0px 0px 0px'}
+        # layout = {'width': '40px', 'padding': '0px 0px 0px 0px'}
         self.add_x_cut = ipw.Button(
             description='X',
             icon='plus',
             tooltip='Add X cut',
-            layout=layout,
+            **BUTTON_LAYOUT,
         )
         self.add_y_cut = ipw.Button(
             description='Y',
             icon='plus',
             tooltip='Add Y cut',
-            layout=layout,
+            **BUTTON_LAYOUT,
         )
         self.add_z_cut = ipw.Button(
             description='Z',
             icon='plus',
             tooltip='Add Z cut',
-            layout=layout,
+            **BUTTON_LAYOUT,
         )
         self.add_v_cut = ipw.Button(
             description='V',
             icon='plus',
             tooltip='Add Value cut',
-            layout=layout,
+            **BUTTON_LAYOUT,
         )
         self.add_x_cut.on_click(lambda _: self._add_cut('x'))
         self.add_y_cut.on_click(lambda _: self._add_cut('y'))
@@ -375,7 +375,7 @@ def __init__(self, fig: BaseFig):
             description='Opacity:',
             tooltip='Set the opacity of the background',
             style={'description_width': 'initial'},
-            layout={'width': '142px', 'padding': '0px 0px 0px 0px'},
+            layout={'width': '160px', 'padding': '0px 0px 0px 0px'},
         )
         self.opacity.observe(self._set_opacity, names='value')
 
@@ -395,7 +395,7 @@ def __init__(self, fig: BaseFig):
             value='OR',
             disabled=True,
             tooltip='Operation to combine multiple cuts',
-            layout={'width': '60px', 'padding': '0px 0px 0px 0px'},
+            layout={'width': '78px', 'padding': '0px 0px 0px 0px'},
         )
         self.cut_operation.observe(self.change_operation, names='value')
 

From fc6f3ce490d728a4d0be79cde15c0bca219c3021 Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@ess.eu>
Date: Thu, 7 Aug 2025 22:42:04 +0200
Subject: [PATCH 03/10] add unit tests

---
 src/plopp/widgets/clip3d.py  | 32 +++--------------
 tests/widgets/clip3d_test.py | 66 +++++++++++++++++++++++++++++++-----
 2 files changed, 61 insertions(+), 37 deletions(-)

diff --git a/src/plopp/widgets/clip3d.py b/src/plopp/widgets/clip3d.py
index 81630cf55..0a0201793 100644
--- a/src/plopp/widgets/clip3d.py
+++ b/src/plopp/widgets/clip3d.py
@@ -203,11 +203,7 @@ class ClipValueTool(ipw.HBox):
         A function to update the scene.
     """
 
-    def __init__(
-        self,
-        limits: sc.Variable,
-        update: Callable,
-    ):
+    def __init__(self, limits: sc.Variable, update: Callable):
         self._limits = limits
         self._unit = self._limits.unit
         self.visible = True
@@ -251,28 +247,9 @@ def toggle(self, owner: ipw.Button):
         owner.tooltip = 'Hide cut' if self.visible else 'Show cut'
         self._update()
 
-    def toggle_border(self, value: bool):
-        """ """
+    def toggle_border(self, _):
         return
 
-    # def move(self, value: dict[str, Any]):
-    #     """
-    #     """
-    #     return
-    #     # Early return if relative difference between new and old value is small.
-    #     # This also prevents flickering of an existing cut when a new cut is added.
-    #     if (
-    #         np.abs(np.array(value['new']) - np.array(value['old'])).max()
-    #         < 0.01 * self.slider.step
-    #     ):
-    #         return
-    #     for outline, val in zip(self.outlines, value['new'], strict=True):
-    #         pos = list(outline.position)
-    #         axis = 'xyz'.index(self._direction)
-    #         pos[axis] = val
-    #         outline.position = pos
-    #     self._throttled_update()
-
     @property
     def range(self):
         return sc.scalar(self.slider.value[0], unit=self._unit), sc.scalar(
@@ -329,14 +306,13 @@ def __init__(self, fig: BaseFig):
 
         self._value_limits = sc.concat(
             [
-                min(n().min() for n in self._original_nodes),
-                max(n().max() for n in self._original_nodes),
+                min(n().data.min() for n in self._original_nodes),
+                max(n().data.max() for n in self._original_nodes),
             ],
             dim="dummy",
         )
 
         self.add_cut_label = ipw.Label('Add cut:')
-        # layout = {'width': '40px', 'padding': '0px 0px 0px 0px'}
         self.add_x_cut = ipw.Button(
             description='X',
             icon='plus',
diff --git a/tests/widgets/clip3d_test.py b/tests/widgets/clip3d_test.py
index 02f588d45..73a2c6de7 100644
--- a/tests/widgets/clip3d_test.py
+++ b/tests/widgets/clip3d_test.py
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright (c) 2023 Scipp contributors (https://github.com/scipp)
-
+import pytest
 import scipp as sc
 
 from plopp import Node
@@ -9,20 +9,27 @@
 from plopp.widgets import ClippingPlanes
 
 
-def test_add_remove_cuts():
-    da = scatter()
-    fig = scatter3dfigure(Node(da), x='x', y='y', z='z', cbar=True)
+@pytest.mark.parametrize('multiple_nodes', [False, True])
+def test_add_remove_cuts(multiple_nodes):
+    a = scatter()
+    nodes = [Node(a)]
+    if multiple_nodes:
+        b = a.copy()
+        b.coords['x'] += sc.scalar(60, unit='m')
+        nodes.append(Node(b))
+
+    fig = scatter3dfigure(*nodes, x='x', y='y', z='z', cbar=True)
     clip = ClippingPlanes(fig)
-    assert len(fig.artists) == 1
+    assert len(fig.artists) == 1 * len(nodes)
     clip.add_x_cut.click()
-    assert len(fig.artists) == 2
+    assert len(fig.artists) == 2 * len(nodes)
     npoints_in_cutx = list(fig.artists.values())[-1]._data.shape[0]
     clip.add_y_cut.click()
-    assert len(fig.artists) == 2
+    assert len(fig.artists) == 2 * len(nodes)
     npoints_in_cutxy = list(fig.artists.values())[-1]._data.shape[0]
     assert npoints_in_cutxy > npoints_in_cutx
     clip.add_z_cut.click()
-    assert len(fig.artists) == 2
+    assert len(fig.artists) == 2 * len(nodes)
     npoints_in_cutxyz = list(fig.artists.values())[-1]._data.shape[0]
     assert npoints_in_cutxyz > npoints_in_cutxy
     clip.delete_cut.click()
@@ -36,7 +43,48 @@ def test_add_remove_cuts():
     clip.tabs.selected_index = 0
     assert list(fig.artists.values())[-1]._data.shape[0] == npoints_in_cutx
     clip.delete_cut.click()
-    assert len(fig.artists) == 1
+    assert len(fig.artists) == 1 * len(nodes)
+
+
+@pytest.mark.parametrize('multiple_nodes', [False, True])
+def test_value_cuts(multiple_nodes):
+    a = scatter()
+    nodes = [Node(a)]
+    if multiple_nodes:
+        b = a.copy()
+        b.coords['x'] += sc.scalar(60, unit='m')
+        nodes.append(Node(b))
+    fig = scatter3dfigure(*nodes, x='x', y='y', z='z', cbar=True)
+    clip = ClippingPlanes(fig)
+    clip.add_v_cut.click()
+    vcut = clip.cuts[-1]
+    npoints = list(fig.artists.values())[-1]._data.shape[0]
+    vcut.slider.value = [vcut.slider.min, vcut.slider.value[1]]
+    clip.update_state()  # Need to manually update state due to debounce mechanism
+    # We should now have more points in the cut than before because the range is wider
+    npoints2 = list(fig.artists.values())[-1]._data.shape[0]
+    assert npoints2 > npoints
+
+    clip.cut_operation.value = 'OR'
+    # Add a second value cut
+    clip.add_v_cut.click()
+    vcut2 = clip.cuts[-1]
+    vcut2.slider.value = [
+        0.5 * (vcut2.slider.value[1] + vcut2.slider.max),
+        vcut2.slider.max,
+    ]
+    clip.update_state()  # Need to manually update state due to debounce mechanism
+    # We should now have more points in the cut than before because the range is wider
+    npoints3 = list(fig.artists.values())[-1]._data.shape[0]
+    assert npoints3 > npoints2
+
+    clip.delete_cut.click()
+    assert list(fig.artists.values())[-1]._data.shape[0] == npoints2
+    # If the tool is not displayed, the tab selected index does not update when a cut
+    # is deleted, so we need to manually set it to the correct value
+    clip.tabs.selected_index = 0
+    clip.delete_cut.click()
+    assert len(fig.artists) == 1 * len(nodes)
 
 
 def test_move_cut():

From e322de88a9b4267964033cb613761dfaf89c2670 Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@ess.eu>
Date: Thu, 7 Aug 2025 22:55:24 +0200
Subject: [PATCH 04/10] add test with spatial and value cuts

---
 tests/widgets/clip3d_test.py | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/tests/widgets/clip3d_test.py b/tests/widgets/clip3d_test.py
index 73a2c6de7..5f48bac0b 100644
--- a/tests/widgets/clip3d_test.py
+++ b/tests/widgets/clip3d_test.py
@@ -87,6 +87,36 @@ def test_value_cuts(multiple_nodes):
     assert len(fig.artists) == 1 * len(nodes)
 
 
+@pytest.mark.parametrize('multiple_nodes', [False, True])
+def test_mixing_spatial_and_value_cuts(multiple_nodes):
+    a = scatter()
+    nodes = [Node(a)]
+    if multiple_nodes:
+        b = a.copy()
+        b.coords['x'] += sc.scalar(60, unit='m')
+        nodes.append(Node(b))
+    fig = scatter3dfigure(*nodes, x='x', y='y', z='z', cbar=True)
+    clip = ClippingPlanes(fig)
+
+    # Add a spatial cut
+    clip.add_y_cut.click()
+    npoints = list(fig.artists.values())[-1]._data.shape[0]
+    clip.cut_operation.value = 'AND'
+
+    # Add a value cut
+    clip.add_v_cut.click()
+    # Adding value selection should limit the number of points further
+    assert list(fig.artists.values())[-1]._data.shape[0] < npoints
+
+    clip.delete_cut.click()
+    assert list(fig.artists.values())[-1]._data.shape[0] == npoints
+    # If the tool is not displayed, the tab selected index does not update when a cut
+    # is deleted, so we need to manually set it to the correct value
+    clip.tabs.selected_index = 0
+    clip.delete_cut.click()
+    assert len(fig.artists) == 1 * len(nodes)
+
+
 def test_move_cut():
     da = scatter()
     fig = scatter3dfigure(Node(da), x='x', y='y', z='z', cbar=True)

From 0e365d46a472fa955b2eefe5666cca8f59eb6618 Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@ess.eu>
Date: Wed, 4 Feb 2026 13:26:45 +0100
Subject: [PATCH 05/10] fix docstrings and change name to ClippingManager

---
 src/plopp/plotting/scatter3d.py | 8 ++++----
 src/plopp/widgets/clip3d.py     | 7 ++++---
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/src/plopp/plotting/scatter3d.py b/src/plopp/plotting/scatter3d.py
index 207131a9a..e869b1058 100644
--- a/src/plopp/plotting/scatter3d.py
+++ b/src/plopp/plotting/scatter3d.py
@@ -126,7 +126,7 @@ def scatter3d(
         A three-dimensional interactive scatter plot.
     """
     from ..graphics import scatter3dfigure
-    from ..widgets import ClippingPlanes, ToggleTool
+    from ..widgets import ClippingManager, ToggleTool
 
     if 'ax' in kwargs:
         raise ValueError(
@@ -160,11 +160,11 @@ def scatter3d(
         vmin=vmin,
         **kwargs,
     )
-    clip_planes = ClippingPlanes(fig)
+    clip_manager = ClippingManager(fig)
     fig.toolbar['cut3d'] = ToggleTool(
-        callback=clip_planes.toggle_visibility,
+        callback=clip_manager.toggle_visibility,
         icon='layer-group',
         tooltip='Hide/show spatial cutting tool',
     )
-    fig.bottom_bar.add(clip_planes)
+    fig.bottom_bar.add(clip_manager)
     return fig
diff --git a/src/plopp/widgets/clip3d.py b/src/plopp/widgets/clip3d.py
index 0a0201793..fb258d6d0 100644
--- a/src/plopp/widgets/clip3d.py
+++ b/src/plopp/widgets/clip3d.py
@@ -190,10 +190,10 @@ def _throttled_update(self):
 class ClipValueTool(ipw.HBox):
     """
     A tool that provides a slider to extract a points in a three-dimensional
-    scatter plot based on a value selection criterion, and add it to the scene as an
+    scatter plot based on a value selection criterion, and adds it to the scene as an
     opaque cut. The slider controls the range of the selection.
 
-    .. versionadded:: 25.08.0
+    .. versionadded:: 26.2.0
 
     Parameters
     ----------
@@ -261,10 +261,11 @@ def _throttled_update(self, _):
         self._update()
 
 
-class ClippingPlanes(ipw.HBox):
+class ClippingManager(ipw.HBox):
     """
     A widget to make clipping planes for spatial cutting (see :class:`Clip3dTool`) to
     make spatial cuts in the X, Y, and Z directions on a three-dimensional scatter plot.
+    The widget also allows to make value-based cuts using :class:`ClipValueTool`.
 
     .. versionadded:: 24.04.0
 

From ba8ed03c63700d2fe9a3f3aa6cb7186161996f79 Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@ess.eu>
Date: Wed, 4 Feb 2026 13:56:27 +0100
Subject: [PATCH 06/10] change pixels to em sizes

---
 src/plopp/widgets/__init__.pyi |  4 ++--
 src/plopp/widgets/clip3d.py    | 14 +++++++-------
 src/plopp/widgets/linesave.py  |  2 +-
 src/plopp/widgets/slice.py     |  4 ++--
 src/plopp/widgets/style.py     |  2 +-
 src/plopp/widgets/tools.py     |  6 +++---
 6 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/src/plopp/widgets/__init__.pyi b/src/plopp/widgets/__init__.pyi
index 225f8a653..14a91f325 100644
--- a/src/plopp/widgets/__init__.pyi
+++ b/src/plopp/widgets/__init__.pyi
@@ -3,7 +3,7 @@
 
 from .box import Box, HBar, VBar
 from .checkboxes import Checkboxes
-from .clip3d import Clip3dTool, ClippingPlanes
+from .clip3d import Clip3dTool, ClippingManager
 from .drawing import DrawingTool, PointsTool
 from .linesave import LineSaveTool
 from .slice import RangeSliceWidget, SliceWidget, slice_dims
@@ -15,7 +15,7 @@ __all__ = [
     "ButtonTool",
     "Checkboxes",
     "Clip3dTool",
-    "ClippingPlanes",
+    "ClippingManager",
     "ColorTool",
     "DrawingTool",
     "HBar",
diff --git a/src/plopp/widgets/clip3d.py b/src/plopp/widgets/clip3d.py
index fb258d6d0..9ebb975a8 100644
--- a/src/plopp/widgets/clip3d.py
+++ b/src/plopp/widgets/clip3d.py
@@ -114,13 +114,13 @@ def __init__(
             step=dx * 0.01,
             description=direction.upper(),
             style={'description_width': 'initial'},
-            layout={'width': '470px', 'padding': '0px'},
+            layout={'width': '35.6em', 'padding': '0px'},
         )
 
         self.cut_visible = ipw.Button(
             icon='eye-slash',
             tooltip='Hide cut',
-            layout={'width': '16px', 'padding': '0px'},
+            layout={'width': '1.23em', 'padding': '0px'},
         )
 
         for outline, val in zip(self.outlines, self.slider.value, strict=True):
@@ -222,13 +222,13 @@ def __init__(self, limits: sc.Variable, update: Callable):
             step=dx * 0.01,
             description="Values",
             style={'description_width': 'initial'},
-            layout={'width': '470px', 'padding': '0px'},
+            layout={'width': '35.6em', 'padding': '0px'},
         )
 
         self.cut_visible = ipw.Button(
             icon='eye-slash',
             tooltip='Hide cut',
-            layout={'width': '16px', 'padding': '0px'},
+            layout={'width': '1.23em', 'padding': '0px'},
         )
 
         self.unit_label = ipw.Label(f'[{self._unit}]')
@@ -301,7 +301,7 @@ def __init__(self, fig: BaseFig):
         self.cuts = []
         self._operation = 'or'
 
-        self.tabs = ipw.Tab(layout={'width': '550px'})
+        self.tabs = ipw.Tab(layout={'width': '41.6em'})
         self._original_nodes = list(self._view.graph_nodes.values())
         self._nodes = {}
 
@@ -352,7 +352,7 @@ def __init__(self, fig: BaseFig):
             description='Opacity:',
             tooltip='Set the opacity of the background',
             style={'description_width': 'initial'},
-            layout={'width': '160px', 'padding': '0px 0px 0px 0px'},
+            layout={'width': '12.1em', 'padding': '0px 0px 0px 0px'},
         )
         self.opacity.observe(self._set_opacity, names='value')
 
@@ -372,7 +372,7 @@ def __init__(self, fig: BaseFig):
             value='OR',
             disabled=True,
             tooltip='Operation to combine multiple cuts',
-            layout={'width': '78px', 'padding': '0px 0px 0px 0px'},
+            layout={'width': '5.9em', 'padding': '0px 0px 0px 0px'},
         )
         self.cut_operation.observe(self.change_operation, names='value')
 
diff --git a/src/plopp/widgets/linesave.py b/src/plopp/widgets/linesave.py
index 1987c261b..87d76b233 100644
--- a/src/plopp/widgets/linesave.py
+++ b/src/plopp/widgets/linesave.py
@@ -35,7 +35,7 @@ def __init__(self, data_node: Node, slider_node: Node, fig: View):
         self.button = ipw.Button(description='Save line')
         self.button.on_click(self.save_line)
         self.container = VBar()
-        super().__init__([self.button, self.container], layout={'width': '350px'})
+        super().__init__([self.button, self.container], layout={'width': '26.5em'})
 
     def _update_container(self):
         self.container.children = [line['tool'] for line in self._lines.values()]
diff --git a/src/plopp/widgets/slice.py b/src/plopp/widgets/slice.py
index cbfac7ee4..6f85cd626 100644
--- a/src/plopp/widgets/slice.py
+++ b/src/plopp/widgets/slice.py
@@ -32,7 +32,7 @@ def __init__(
             'value': (size - 1) // 2 if slider_constr is ipw.IntSlider else None,
             'continuous_update': True,
             'readout': False,
-            'layout': {"width": "200px", "margin": "0px 0px 0px 10px"},
+            'layout': {"width": "15.2em", "margin": "0px 0px 0px 10px"},
         }
         self.dim_label = ipw.Label(value=dim)
         self.slider = slider_constr(**widget_args)
@@ -40,7 +40,7 @@ def __init__(
             value=True,
             tooltip="Continuous update",
             indent=False,
-            layout={"width": "20px"},
+            layout={"width": "1.52em"},
         )
         self.label = ipw.Label(
             value=coord_element_to_string(coord[dim, self.slider.value])
diff --git a/src/plopp/widgets/style.py b/src/plopp/widgets/style.py
index 3c1a5068d..4e9ab3389 100644
--- a/src/plopp/widgets/style.py
+++ b/src/plopp/widgets/style.py
@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright (c) 2023 Scipp contributors (https://github.com/scipp)
 
-BUTTON_LAYOUT = {"layout": {"width": "37px", "padding": "0px 0px 0px 0px"}}
+BUTTON_LAYOUT = {"layout": {"width": "2.8em", "padding": "0px 0px 0px 0px"}}
diff --git a/src/plopp/widgets/tools.py b/src/plopp/widgets/tools.py
index 0aec24f40..8c9a48eec 100644
--- a/src/plopp/widgets/tools.py
+++ b/src/plopp/widgets/tools.py
@@ -54,7 +54,7 @@ def __call__(self, *ignored):
 
 class PlusMinusTool(ipw.HBox):
     def __init__(self, plus, minus):
-        layout = {'width': '16px', 'padding': '0px'}
+        layout = {'width': '1.23em', 'padding': '0px'}
         self.callback = {'plus': plus.pop('callback'), 'minus': minus.pop('callback')}
         self._plus = ipw.Button(icon='plus', **{**{'layout': layout}, **plus})
         self._minus = ipw.Button(icon='minus', **{**{'layout': layout}, **minus})
@@ -230,10 +230,10 @@ class ColorTool(ipw.HBox):
     """
 
     def __init__(self, text: str, color: str):
-        layout = ipw.Layout(display="flex", justify_content="flex-end", width='150px')
+        layout = ipw.Layout(display="flex", justify_content="flex-end", width='11.4em')
         self.text = ipw.Label(value=text, layout=layout)
         self.color = ipw.ColorPicker(
-            concise=True, value=color, description='', layout={'width': "30px"}
+            concise=True, value=color, description='', layout={'width': "2.3em"}
         )
         self.button = ipw.Button(icon='times', **BUTTON_LAYOUT)
         super().__init__([self.text, self.color, self.button])

From e55d32e43d47a04e98978f3ab30f783cf7804dd0 Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@ess.eu>
Date: Wed, 4 Feb 2026 14:31:52 +0100
Subject: [PATCH 07/10] handle selection inside clip tool and make direction
 member public

---
 src/plopp/widgets/clip3d.py | 69 ++++++++++++++++++++++---------------
 1 file changed, 41 insertions(+), 28 deletions(-)

diff --git a/src/plopp/widgets/clip3d.py b/src/plopp/widgets/clip3d.py
index 9ebb975a8..844c51443 100644
--- a/src/plopp/widgets/clip3d.py
+++ b/src/plopp/widgets/clip3d.py
@@ -66,16 +66,16 @@ def __init__(
         border_visible: bool = True,
     ):
         self._limits = limits
-        self._direction = direction
-        axis = 'xyz'.index(self._direction)
+        self.direction = direction
+        axis = 'xyz'.index(self.direction)
         self.dim = self._limits[axis].dim
         self._unit = self._limits[axis].unit
         self.visible = True
         self._update = update
         self._border_visible = border_visible
 
-        w_axis = 2 if self._direction == 'x' else 0
-        h_axis = 2 if self._direction == 'y' else 1
+        w_axis = 2 if self.direction == 'x' else 0
+        h_axis = 2 if self.direction == 'y' else 1
         width = (self._limits[w_axis][1] - self._limits[w_axis][0]).value
         height = (self._limits[h_axis][1] - self._limits[h_axis][0]).value
 
@@ -95,10 +95,10 @@ def __init__(
                 material=p3.LineBasicMaterial(color=color, linewidth=linewidth),
             ),
         ]
-        if self._direction == 'x':
+        if self.direction == 'x':
             for outline in self.outlines:
                 outline.rotateY(0.5 * np.pi)
-        if self._direction == 'y':
+        if self.direction == 'y':
             for outline in self.outlines:
                 outline.rotateX(0.5 * np.pi)
 
@@ -158,20 +158,20 @@ def toggle_border(self, value: bool):
         # the cut, the border visibility is in sync with the parent button.
         self._border_visible = value
 
-    def move(self, value: dict[str, Any]):
+    def move(self, change: dict[str, Any]):
         """
         Move the outline of the cut according to new position given by the slider.
         """
         # Early return if relative difference between new and old value is small.
         # This also prevents flickering of an existing cut when a new cut is added.
         if (
-            np.abs(np.array(value['new']) - np.array(value['old'])).max()
+            np.abs(np.array(change['new']) - np.array(change['old'])).max()
             < 0.01 * self.slider.step
         ):
             return
-        for outline, val in zip(self.outlines, value['new'], strict=True):
+        for outline, val in zip(self.outlines, change['new'], strict=True):
             pos = list(outline.position)
-            axis = 'xyz'.index(self._direction)
+            axis = 'xyz'.index(self.direction)
             pos[axis] = val
             outline.position = pos
         self._throttled_update()
@@ -182,6 +182,13 @@ def range(self):
             self.slider.value[1], unit=self._unit
         )
 
+    def make_selection(self, da: sc.DataArray) -> sc.Variable:
+        """
+        Make a selection variable based on the current slider range.
+        """
+        xmin, xmax = self.range
+        return (da.coords[self.dim] >= xmin) & (da.coords[self.dim] < xmax)
+
     @debounce(0.3)
     def _throttled_update(self):
         self._update()
@@ -208,7 +215,7 @@ def __init__(self, limits: sc.Variable, update: Callable):
         self._unit = self._limits.unit
         self.visible = True
         self._update = update
-        self._direction = 'v'
+        self.direction = 'v'
 
         center = self._limits.mean().value
         vmin = self._limits[0].value
@@ -233,7 +240,7 @@ def __init__(self, limits: sc.Variable, update: Callable):
 
         self.unit_label = ipw.Label(f'[{self._unit}]')
         self.cut_visible.on_click(self.toggle)
-        self.slider.observe(self._throttled_update, names='value')
+        self.slider.observe(self.move, names='value')
 
         super().__init__([self.slider, ipw.Label(f'[{self._unit}]'), self.cut_visible])
 
@@ -256,8 +263,25 @@ def range(self):
             self.slider.value[1], unit=self._unit
         )
 
+    def make_selection(self, da: sc.DataArray) -> sc.Variable:
+        """
+        Make a selection variable based on the current slider range.
+        """
+        xmin, xmax = self.range
+        return (da.data >= xmin) & (da.data < xmax)
+
+    def move(self, change: dict[str, Any]):
+        # Early return if relative difference between new and old value is small.
+        # This also prevents flickering of an existing cut when a new cut is added.
+        if (
+            np.abs(np.array(change['new']) - np.array(change['old'])).max()
+            < 0.01 * self.slider.step
+        ):
+            return
+        self._throttled_update()
+
     @debounce(0.3)
-    def _throttled_update(self, _):
+    def _throttled_update(self):
         self._update()
 
 
@@ -417,10 +441,7 @@ def _add_cut(self, direction: Literal['x', 'y', 'z', 'v']):
         Add a cut in the specified direction.
         """
         if direction == 'v':
-            cut = ClipValueTool(
-                limits=self._value_limits,
-                update=self.update_state,
-            )
+            cut = ClipValueTool(limits=self._value_limits, update=self.update_state)
         else:
             cut = Clip3dTool(
                 direction=direction,
@@ -437,7 +458,7 @@ def _add_cut(self, direction: Literal['x', 'y', 'z', 'v']):
 
     def _remove_cut(self, _):
         cut = self.cuts.pop(self.tabs.selected_index)
-        if cut._direction != 'v':
+        if cut.direction != 'v':
             self._view.canvas.remove(cut.outlines)
         self.tabs.children = self.cuts
         self.update_state()
@@ -453,7 +474,7 @@ def update_controls(self):
         self.delete_cut.disabled = not at_least_one_cut
         self.cut_borders_visibility.disabled = not at_least_one_cut
         self.cut_operation.disabled = not at_least_one_cut
-        self.tabs.titles = [cut._direction.upper() for cut in self.cuts]
+        self.tabs.titles = [cut.direction.upper() for cut in self.cuts]
         self.opacity.disabled = not at_least_one_cut
         opacity = self.opacity.value if at_least_one_cut else 1.0
         self._set_opacity({'new': opacity})
@@ -506,15 +527,7 @@ def update_state(self):
 
         for n in self._original_nodes:
             da = n.request_data()
-            selections = []
-            for cut in visible_cuts:
-                xmin, xmax = cut.range
-                if cut._direction == 'v':
-                    selections.append((da.data >= xmin) & (da.data < xmax))
-                else:
-                    selections.append(
-                        (da.coords[cut.dim] >= xmin) & (da.coords[cut.dim] < xmax)
-                    )
+            selections = [cut.make_selection(da) for cut in visible_cuts]
             selection = OPERATIONS[self._operation](selections)
             if selection.sum().value > 0:
                 if n.id not in self._nodes:

From fc9ded448af9471953ff9b50d1e634850bda2e3b Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@ess.eu>
Date: Wed, 4 Feb 2026 14:45:06 +0100
Subject: [PATCH 08/10] direction -> kind

---
 src/plopp/widgets/clip3d.py | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/src/plopp/widgets/clip3d.py b/src/plopp/widgets/clip3d.py
index 844c51443..7ceb48185 100644
--- a/src/plopp/widgets/clip3d.py
+++ b/src/plopp/widgets/clip3d.py
@@ -46,7 +46,7 @@ class Clip3dTool(ipw.HBox):
     ----------
     limits:
         The spatial extent of the points in the 3d figure in the XYZ directions.
-    direction:
+    kind:
         The direction normal to the slice.
     update:
         A function to update the scene.
@@ -59,23 +59,23 @@ class Clip3dTool(ipw.HBox):
     def __init__(
         self,
         limits: tuple[sc.Variable, sc.Variable, sc.Variable],
-        direction: Literal['x', 'y', 'z'],
+        kind: Literal['x', 'y', 'z'],
         update: Callable,
         color: str = 'red',
         linewidth: float = 1.5,
         border_visible: bool = True,
     ):
         self._limits = limits
-        self.direction = direction
-        axis = 'xyz'.index(self.direction)
+        self.kind = kind
+        axis = 'xyz'.index(self.kind)
         self.dim = self._limits[axis].dim
         self._unit = self._limits[axis].unit
         self.visible = True
         self._update = update
         self._border_visible = border_visible
 
-        w_axis = 2 if self.direction == 'x' else 0
-        h_axis = 2 if self.direction == 'y' else 1
+        w_axis = 2 if self.kind == 'x' else 0
+        h_axis = 2 if self.kind == 'y' else 1
         width = (self._limits[w_axis][1] - self._limits[w_axis][0]).value
         height = (self._limits[h_axis][1] - self._limits[h_axis][0]).value
 
@@ -95,10 +95,10 @@ def __init__(
                 material=p3.LineBasicMaterial(color=color, linewidth=linewidth),
             ),
         ]
-        if self.direction == 'x':
+        if self.kind == 'x':
             for outline in self.outlines:
                 outline.rotateY(0.5 * np.pi)
-        if self.direction == 'y':
+        if self.kind == 'y':
             for outline in self.outlines:
                 outline.rotateX(0.5 * np.pi)
 
@@ -112,7 +112,7 @@ def __init__(
             max=vmax,
             value=[center[axis] - delta, center[axis] + delta],
             step=dx * 0.01,
-            description=direction.upper(),
+            description=self.kind.upper(),
             style={'description_width': 'initial'},
             layout={'width': '35.6em', 'padding': '0px'},
         )
@@ -171,7 +171,7 @@ def move(self, change: dict[str, Any]):
             return
         for outline, val in zip(self.outlines, change['new'], strict=True):
             pos = list(outline.position)
-            axis = 'xyz'.index(self.direction)
+            axis = 'xyz'.index(self.kind)
             pos[axis] = val
             outline.position = pos
         self._throttled_update()
@@ -205,7 +205,7 @@ class ClipValueTool(ipw.HBox):
     Parameters
     ----------
     limits:
-        The spatial extent of the points in the 3d figure in the XYZ directions.
+        The range of values in the original data.
     update:
         A function to update the scene.
     """
@@ -215,7 +215,7 @@ def __init__(self, limits: sc.Variable, update: Callable):
         self._unit = self._limits.unit
         self.visible = True
         self._update = update
-        self.direction = 'v'
+        self.kind = 'v'
 
         center = self._limits.mean().value
         vmin = self._limits[0].value
@@ -436,15 +436,15 @@ def __init__(self, fig: BaseFig):
 
         self.layout.display = 'none'
 
-    def _add_cut(self, direction: Literal['x', 'y', 'z', 'v']):
+    def _add_cut(self, kind: Literal['x', 'y', 'z', 'v']):
         """
-        Add a cut in the specified direction.
+        Add a cut of the specified kind.
         """
-        if direction == 'v':
+        if kind == 'v':
             cut = ClipValueTool(limits=self._value_limits, update=self.update_state)
         else:
             cut = Clip3dTool(
-                direction=direction,
+                kind=kind,
                 limits=self._limits,
                 update=self.update_state,
                 border_visible=self.cut_borders_visibility.value,
@@ -458,7 +458,7 @@ def _add_cut(self, direction: Literal['x', 'y', 'z', 'v']):
 
     def _remove_cut(self, _):
         cut = self.cuts.pop(self.tabs.selected_index)
-        if cut.direction != 'v':
+        if cut.kind != 'v':
             self._view.canvas.remove(cut.outlines)
         self.tabs.children = self.cuts
         self.update_state()
@@ -474,7 +474,7 @@ def update_controls(self):
         self.delete_cut.disabled = not at_least_one_cut
         self.cut_borders_visibility.disabled = not at_least_one_cut
         self.cut_operation.disabled = not at_least_one_cut
-        self.tabs.titles = [cut.direction.upper() for cut in self.cuts]
+        self.tabs.titles = [cut.kind.upper() for cut in self.cuts]
         self.opacity.disabled = not at_least_one_cut
         opacity = self.opacity.value if at_least_one_cut else 1.0
         self._set_opacity({'new': opacity})

From 3d85a438d06ec849e1f5b769a508b548440ba40d Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@ess.eu>
Date: Wed, 4 Feb 2026 14:54:19 +0100
Subject: [PATCH 09/10] fix class name in tests

---
 tests/widgets/clip3d_test.py | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/tests/widgets/clip3d_test.py b/tests/widgets/clip3d_test.py
index 5f48bac0b..1541dc181 100644
--- a/tests/widgets/clip3d_test.py
+++ b/tests/widgets/clip3d_test.py
@@ -6,7 +6,7 @@
 from plopp import Node
 from plopp.data.testing import data_array, scatter
 from plopp.graphics import scatter3dfigure
-from plopp.widgets import ClippingPlanes
+from plopp.widgets import ClippingManager
 
 
 @pytest.mark.parametrize('multiple_nodes', [False, True])
@@ -19,7 +19,7 @@ def test_add_remove_cuts(multiple_nodes):
         nodes.append(Node(b))
 
     fig = scatter3dfigure(*nodes, x='x', y='y', z='z', cbar=True)
-    clip = ClippingPlanes(fig)
+    clip = ClippingManager(fig)
     assert len(fig.artists) == 1 * len(nodes)
     clip.add_x_cut.click()
     assert len(fig.artists) == 2 * len(nodes)
@@ -55,7 +55,7 @@ def test_value_cuts(multiple_nodes):
         b.coords['x'] += sc.scalar(60, unit='m')
         nodes.append(Node(b))
     fig = scatter3dfigure(*nodes, x='x', y='y', z='z', cbar=True)
-    clip = ClippingPlanes(fig)
+    clip = ClippingManager(fig)
     clip.add_v_cut.click()
     vcut = clip.cuts[-1]
     npoints = list(fig.artists.values())[-1]._data.shape[0]
@@ -96,7 +96,7 @@ def test_mixing_spatial_and_value_cuts(multiple_nodes):
         b.coords['x'] += sc.scalar(60, unit='m')
         nodes.append(Node(b))
     fig = scatter3dfigure(*nodes, x='x', y='y', z='z', cbar=True)
-    clip = ClippingPlanes(fig)
+    clip = ClippingManager(fig)
 
     # Add a spatial cut
     clip.add_y_cut.click()
@@ -120,7 +120,7 @@ def test_mixing_spatial_and_value_cuts(multiple_nodes):
 def test_move_cut():
     da = scatter()
     fig = scatter3dfigure(Node(da), x='x', y='y', z='z', cbar=True)
-    clip = ClippingPlanes(fig)
+    clip = ClippingManager(fig)
     clip.add_x_cut.click()
     xcut = clip.cuts[-1]
     assert xcut.outlines[0].position[0] == xcut.slider.value[0]
@@ -139,7 +139,7 @@ def test_operation_or():
     dim = 'pix'
     da = data_array(ndim=3).flatten(to=dim)
     fig = scatter3dfigure(Node(da), x='xx', y='yy', z='zz', cbar=True)
-    clip = ClippingPlanes(fig)
+    clip = ClippingManager(fig)
     clip.cut_operation.value = 'OR'
 
     clip.add_x_cut.click()
@@ -177,7 +177,7 @@ def test_operation_and():
     dim = 'pix'
     da = data_array(ndim=3).flatten(to=dim)
     fig = scatter3dfigure(Node(da), x='xx', y='yy', z='zz', cbar=True)
-    clip = ClippingPlanes(fig)
+    clip = ClippingManager(fig)
     clip.cut_operation.value = 'AND'
 
     clip.add_x_cut.click()
@@ -212,7 +212,7 @@ def test_operation_xor():
     dim = 'pix'
     da = data_array(ndim=3).flatten(to=dim)
     fig = scatter3dfigure(Node(da), x='xx', y='yy', z='zz', cbar=True)
-    clip = ClippingPlanes(fig)
+    clip = ClippingManager(fig)
     clip.cut_operation.value = 'XOR'
 
     clip.add_x_cut.click()

From 5d29903c4e0473d1691e85ec3ab013c1a44634c5 Mon Sep 17 00:00:00 2001
From: Neil Vaytet <neil.vaytet@ess.eu>
Date: Wed, 4 Feb 2026 15:42:44 +0100
Subject: [PATCH 10/10] update api reference

---
 docs/api-reference/index.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/docs/api-reference/index.md b/docs/api-reference/index.md
index 7195de8a1..6d73f1c95 100644
--- a/docs/api-reference/index.md
+++ b/docs/api-reference/index.md
@@ -79,7 +79,8 @@
    widgets.drawing.PointsTool
 
    widgets.clip3d.Clip3dTool
-   widgets.clip3d.ClippingPlanes
+   widgets.clip3d.ClipValueTool
+   widgets.clip3d.ClippingManager
 ```
 
 ## Backends