ENH: coreg opacity slider

mne/gui/__init__.py

@@ -130,7 +130,6 @@ def coregistration(tabbed=False, split=True, width=None, inst=None,
         'scrollable': (scrollable, True),
         'head_inside': (head_inside, True),
         'guess_mri_subject': guess_mri_subject,
-        'head_opacity': head_opacity,
         'scale': scale,
         'advanced_rendering': advanced_rendering,
     }
@@ -152,7 +151,7 @@ def coregistration(tabbed=False, split=True, width=None, inst=None,
         advanced_rendering = \
             config.get('MNE_COREG_ADVANCED_RENDERING', 'true') == 'true'
     if head_opacity is None:
-        head_opacity = config.get('MNE_COREG_HEAD_OPACITY', 1.)
+        head_opacity = config.get('MNE_COREG_HEAD_OPACITY', 0.8)
     if head_inside is None:
         head_inside = \
             config.get('MNE_COREG_HEAD_INSIDE', 'true').lower() == 'true'
@@ -191,11 +190,11 @@ def coregistration(tabbed=False, split=True, width=None, inst=None,
     block = not MNE_3D_BACKEND_TESTING
     return CoregistrationUI(
         info_file=inst, subject=subject, subjects_dir=subjects_dir,
-        head_resolution=head_high_res, orient_glyphs=orient_to_surface,
-        scale_by_distance=scale_by_distance, project_eeg=project_eeg,
-        mark_inside=mark_inside, trans=trans, size=(width, height),
-        show=show, block=block, interaction=interaction,
-        verbose=verbose
+        head_resolution=head_high_res, head_opacity=head_opacity,
+        orient_glyphs=orient_to_surface, scale_by_distance=scale_by_distance,
+        project_eeg=project_eeg,mark_inside=mark_inside, trans=trans,
+        size=(width, height), show=show, block=block,
+        interaction=interaction, verbose=verbose
     )
 
 

mne/gui/_coreg.py

@@ -44,8 +44,8 @@ class CoregistrationUI(HasTraits):
     %(fiducials)s
     head_resolution : bool
         If True, use a high-resolution head surface. Defaults to False.
-    head_transparency : bool
-        If True, display the head surface with transparency. Defaults to False.
+    head_opacity : float
+        The opacity of the head surface. Defaults to 0.8.
     hpi_coils : bool
         If True, display the HPI coils. Defaults to True.
     head_shape_points : bool
@@ -99,7 +99,7 @@ class CoregistrationUI(HasTraits):
     _head_shape_points = Bool()
     _eeg_channels = Bool()
     _head_resolution = Bool()
-    _head_transparency = Bool()
+    _head_opacity = Float()
     _helmet = Bool()
     _grow_hair = Float()
     _subject_to = Unicode()
@@ -113,12 +113,12 @@ class CoregistrationUI(HasTraits):
     @verbose
     def __init__(self, info_file, subject=None, subjects_dir=None,
                  fiducials='auto', head_resolution=None,
-                 head_transparency=None, hpi_coils=None,
+                 head_opacity=None, hpi_coils=None,
                  head_shape_points=None, eeg_channels=None, orient_glyphs=None,
                  scale_by_distance=None, project_eeg=None, mark_inside=None,
                  sensor_opacity=None, trans=None, size=None, bgcolor=None,
                  show=True, block=False, interaction='terrain', *,
-                 standalone=None,
+                 head_transparency=None, standalone=None,
                  verbose=None):
         if standalone is not None:
             depr_message = ('standalone is deprecated and will be replaced by '
@@ -130,6 +130,17 @@ def __init__(self, info_file, subject=None, subjects_dir=None,
                 warn(depr_message + ' Since you passed values for both '
                      'standalone and block, standalone will be ignored.',
                      DeprecationWarning)
+        if head_transparency is not None:
+            depr_message = ('head_transparency is deprecated and will be'
+                            ' replaced by head_opacity in 1.1.')
+            if head_opacity is None:
+                head_opacity = 0.8 if head_transparency else 1.0
+                warn(depr_message, DeprecationWarning)
+            else:
+                warn(depr_message + ' Since you passed values for both '
+                     'head_transparency and head_opacity, '
+                     'head_transparency will be ignored.',
+                     DeprecationWarning)
         from ..viz.backends.renderer import _get_renderer
         from ..viz.backends._utils import _qt_app_exec
 
@@ -151,7 +162,6 @@ def _get_default(var, val):
         self._mouse_no_mvt = -1
         self._to_cf_t = None
         self._omit_hsp_distance = 0.0
-        self._head_opacity = 1.0
         self._fid_colors = tuple(
             DEFAULTS['coreg'][f'{key}_color'] for key in
             ('lpa', 'nasion', 'rpa'))
@@ -166,9 +176,8 @@ def _get_default(var, val):
             head_shape_points=_get_default(head_shape_points, True),
             eeg_channels=_get_default(eeg_channels, True),
             head_resolution=_get_default(head_resolution, True),
-            head_transparency=_get_default(head_transparency, False),
+            head_opacity=_get_default(head_opacity, 0.8),
             helmet=False,
-            head_opacity=0.5,
             sensor_opacity=_get_default(sensor_opacity, 1.0),
             fiducials=("LPA", "Nasion", "RPA"),
             fiducial="LPA",
@@ -205,6 +214,7 @@ def _get_default(var, val):
         # setup the window
         self._renderer = _get_renderer(
             size=self._defaults["size"], bgcolor=self._defaults["bgcolor"])
+        self._renderer.enable_depth_peeling()
         self._renderer._window_close_connect(self._clean)
         self._renderer.set_interaction(interaction)
         self._renderer._status_bar_initialize()
@@ -234,7 +244,8 @@ def _get_default(var, val):
         self._set_head_shape_points(self._defaults["head_shape_points"])
         self._set_eeg_channels(self._defaults["eeg_channels"])
         self._set_head_resolution(self._defaults["head_resolution"])
-        self._set_head_transparency(self._defaults["head_transparency"])
+        self._set_head_opacity(self._defaults["head_opacity"])
+        self._old_head_opacity = self._head_opacity
         self._set_helmet(self._defaults["helmet"])
         self._set_grow_hair(self._defaults["grow_hair"])
         self._set_skip_fiducials(self._defaults["skip_fiducials"])
@@ -352,8 +363,8 @@ def _set_eeg_channels(self, state):
     def _set_head_resolution(self, state):
         self._head_resolution = bool(state)
 
-    def _set_head_transparency(self, state):
-        self._head_transparency = bool(state)
+    def _set_head_opacity(self, value):
+        self._head_opacity = value
 
     def _set_helmet(self, state):
         self._helmet = bool(state)
@@ -458,13 +469,15 @@ def _lock_fids_changed(self, change=None):
                           "fit_fiducials", "fit_icp"]
         fits_widgets = ["fits_fiducials", "fits_icp"]
         fid_widgets = ["fid_X", "fid_Y", "fid_Z", "fids_file", "fids"]
-        self._set_head_transparency(self._lock_fids)
         if self._lock_fids:
+            self._head_opacity = self._old_head_opacity
             self._forward_widget_command(locked_widgets, "set_enabled", True)
             self._scale_mode_changed()
             self._display_message()
             self._update_distance_estimation()
         else:
+            self._old_head_opacity = self._head_opacity
+            self._head_opacity = 1.0
             self._forward_widget_command(locked_widgets, "set_enabled", False)
             self._forward_widget_command(fits_widgets, "set_enabled", False)
             self._display_message("Placing MRI fiducials - "
@@ -542,12 +555,11 @@ def _eeg_channels_changed(self, change=None):
     def _head_resolution_changed(self, change=None):
         self._update_plot(["head"])
 
-    @observe("_head_transparency")
-    def _head_transparency_changed(self, change=None):
-        self._head_opacity = self._defaults["head_opacity"] \
-            if self._head_transparency else 1.0
-        self._actors["head"].GetProperty().SetOpacity(self._head_opacity)
-        self._renderer._update()
+    @observe("_head_opacity")
+    def _head_opacity_changed(self, change=None):
+        if "head" in self._actors:
+            self._actors["head"].GetProperty().SetOpacity(self._head_opacity)
+            self._renderer._update()
 
     @observe("_helmet")
     def _helmet_changed(self, change=None):
@@ -1238,6 +1250,15 @@ def _configure_dock(self):
             tooltip="Enable/Disable helmet",
             layout=view_options_layout,
         )
+        self._widgets["head_opacity"] = self._renderer._dock_add_slider(
+            name="Head opacity",
+            value=self._head_opacity,
+            rng=[0.25, 1.0],
+            callback=self._set_head_opacity,
+            compact=True,
+            double=True,
+            layout=view_options_layout,
+        )
         self._renderer._dock_add_stretch()
 
         self._renderer._dock_initialize(

mne/gui/tests/test_coreg_gui.py

@@ -105,6 +105,10 @@ def test_coreg_gui_pyvista(tmp_path, renderer_interactive_pyvistaqt):
     with pytest.warns(DeprecationWarning, match='standalone is deprecated'):
         CoregistrationUI(info_file=None, subject='sample',
                          subjects_dir=subjects_dir, standalone=False)
+    with pytest.warns(DeprecationWarning, match='head_transparency '
+                                                'is deprecated'):
+        CoregistrationUI(info_file=None, subject='sample',
+                         subjects_dir=subjects_dir, head_transparency=False)
 
     config = get_config(home_dir=os.environ.get('_MNE_FAKE_HOME_DIR'))
     tmp_trans = tmp_path / 'tmp-trans.fif'
@@ -153,10 +157,8 @@ def test_coreg_gui_pyvista(tmp_path, renderer_interactive_pyvistaqt):
     coreg._on_pick(vtk_picker, None)  # also pick when locked
 
     # lock fiducials
-    assert not coreg._head_transparency
     coreg._set_lock_fids(True)
     assert coreg._lock_fids
-    assert coreg._head_transparency
 
     # fitting (no scaling)
     assert coreg._nasion_weight == 10.
@@ -181,6 +183,9 @@ def test_coreg_gui_pyvista(tmp_path, renderer_interactive_pyvistaqt):
     assert coreg._orient_glyphs
     assert coreg._scale_by_distance
     assert coreg._mark_inside
+    assert_allclose(
+        coreg._head_opacity,
+        float(config.get('MNE_COREG_HEAD_OPACITY', '0.8')))
     assert coreg._project_eeg == \
         (config.get('MNE_COREG_PROJECT_EEG', '') == 'true')
     assert coreg._hpi_coils