MRG: Add "highlight" parameter to Evoked.plot() to conveniently highlight time periods

doc/changes/latest.inc

@@ -59,6 +59,8 @@ Enhancements
 
 - :func:`mne.viz.plot_evoked_topomap` and :meth:`mne.Evoked.plot_topomap` can now average the topographic maps across different time periods for each time point. To do this, pass a list of periods via the ``average`` parameter (:gh:`10610` by `Richard Höchenberger`_)
 
+- :func:`mne.viz.plot_evoked` and :meth:`mne.Evoked.plot` gained a new parameter, ``highlight``, to visually highlight time periods of interest (:gh:`10614` by `Richard Höchenberger`_)
+
 Bugs
 ~~~~
 - Make ``color`` parameter check in in :func:`mne.viz.plot_evoked_topo` consistent (:gh:`10217` by :newcontrib:`T. Wang` and `Stefan Appelhoff`_)

mne/evoked.py

@@ -430,14 +430,16 @@ def plot(self, picks=None, exclude='bads', unit=True, show=True, ylim=None,
              xlim='tight', proj=False, hline=None, units=None, scalings=None,
              titles=None, axes=None, gfp=False, window_title=None,
              spatial_colors=False, zorder='unsorted', selectable=True,
-             noise_cov=None, time_unit='s', sphere=None, verbose=None):
+             noise_cov=None, time_unit='s', sphere=None, *, highlight=None,
+             verbose=None):
         return plot_evoked(
             self, picks=picks, exclude=exclude, unit=unit, show=show,
             ylim=ylim, proj=proj, xlim=xlim, hline=hline, units=units,
             scalings=scalings, titles=titles, axes=axes, gfp=gfp,
             window_title=window_title, spatial_colors=spatial_colors,
             zorder=zorder, selectable=selectable, noise_cov=noise_cov,
-            time_unit=time_unit, sphere=sphere, verbose=verbose)
+            time_unit=time_unit, sphere=sphere, highlight=highlight,
+            verbose=verbose)
 
     @copy_function_doc_to_method_doc(plot_evoked_image)
     def plot_image(self, picks=None, exclude='bads', unit=True, show=True,

mne/viz/evoked.py

@@ -199,7 +199,8 @@ def _plot_evoked(evoked, picks, exclude, unit, show, ylim, proj, xlim, hline,
                  selectable=True, zorder='unsorted',
                  noise_cov=None, colorbar=True, mask=None, mask_style=None,
                  mask_cmap=None, mask_alpha=.25, time_unit='s',
-                 show_names=False, group_by=None, sphere=None):
+                 show_names=False, group_by=None, sphere=None, *,
+                 highlight=None):
     """Aux function for plot_evoked and plot_evoked_image (cf. docstrings).
 
     Extra param is:
@@ -273,6 +274,15 @@ def _plot_evoked(evoked, picks, exclude, unit, show, ylim, proj, xlim, hline,
 
     _check_option('gfp', gfp, [True, False, 'only'])
 
+    if highlight is not None:
+        highlight = np.array(highlight, dtype=float)
+        highlight = np.atleast_2d(highlight)
+        if highlight.shape[1] != 2:
+            raise ValueError(
+                f'"highlight" must be reshapable into a 2D array with shape '
+                f'(n, 2). Got {highlight.shape}.'
+            )
+
     scalings = _handle_default('scalings', scalings)
     titles = _handle_default('titles', titles)
     units = _handle_default('units', units)
@@ -351,7 +361,7 @@ def _plot_evoked(evoked, picks, exclude, unit, show, ylim, proj, xlim, hline,
                     units, scalings, hline, gfp, types, zorder, xlim, ylim,
                     times, bad_ch_idx, titles, ch_types_used, selectable,
                     False, line_alpha=1., nave=evoked.nave,
-                    time_unit=time_unit, sphere=sphere)
+                    time_unit=time_unit, sphere=sphere, highlight=highlight)
         plt.setp(axes, xlabel='Time (%s)' % time_unit)
 
     elif plot_type == 'image':
@@ -382,7 +392,7 @@ def _plot_evoked(evoked, picks, exclude, unit, show, ylim, proj, xlim, hline,
 def _plot_lines(data, info, picks, fig, axes, spatial_colors, unit, units,
                 scalings, hline, gfp, types, zorder, xlim, ylim, times,
                 bad_ch_idx, titles, ch_types_used, selectable, psd,
-                line_alpha, nave, time_unit, sphere):
+                line_alpha, nave, time_unit, sphere, *, highlight):
     """Plot data as butterfly plot."""
     from matplotlib import patheffects, pyplot as plt
     from matplotlib.widgets import SpanSelector
@@ -478,6 +488,7 @@ def _plot_lines(data, info, picks, fig, axes, spatial_colors, unit, units,
                                 linewidth=0.5)[0])
                     line_list[-1].set_pickradius(3.)
 
+            # Plot GFP / RMS
             if gfp:
                 if gfp in [True, 'only']:
                     if this_type == 'eeg':
@@ -530,7 +541,21 @@ def _plot_lines(data, info, picks, fig, axes, spatial_colors, unit, units,
                 for h in hline:
                     c = ('grey' if spatial_colors is True else 'r')
                     ax.axhline(h, linestyle='--', linewidth=2, color=c)
+
+            # Plot highlights
+            if highlight is not None:
+                this_ylim = ax.get_ylim() if (ylim is None or this_type not in
+                                              ylim.keys()) else ylim[this_type]
+                for this_highlight in highlight:
+                    ax.fill_betweenx(
+                        this_ylim, this_highlight[0], this_highlight[1],
+                        facecolor='orange', alpha=0.15, zorder=99
+                    )
+                # Put back the y limits as fill_betweenx messes them up
+                ax.set_ylim(this_ylim)
+
         lines.append(line_list)
+
     if selectable:
         for ax in np.array(axes)[selectables]:
             if len(ax.lines) == 1:
@@ -643,7 +668,7 @@ def plot_evoked(evoked, picks=None, exclude='bads', unit=True, show=True,
                 scalings=None, titles=None, axes=None, gfp=False,
                 window_title=None, spatial_colors=False, zorder='unsorted',
                 selectable=True, noise_cov=None, time_unit='s', sphere=None,
-                verbose=None):
+                *, highlight=None, verbose=None):
     """Plot evoked data using butterfly plots.
 
     Left click to a line shows the channel name. Selecting an area by clicking
@@ -749,6 +774,18 @@ def plot_evoked(evoked, picks=None, exclude='bads', unit=True, show=True,
 
         .. versionadded:: 0.16
     %(sphere_topomap_auto)s
+    highlight : array-like of float, shape(2,) | array-like of float, shape (n, 2) | None
+        Segments of the data to highlight by means of a light-yellow
+        background color. Can be used to put visual emphasis on certain
+        time periods. The time periods must be specified as ``array-like``
+        objects in the form of ``(t_start, t_end)`` in the unit given by the
+        ``time_unit`` parameter.
+        Multiple time periods can be specified by passing an ``array-like``
+        object of individual time periods (e.g., for 3 time periods, the shape
+        of the passed object would be ``(3, 2)``. If ``None``, no highlighting
+        is applied.
+
+        .. versionadded:: 1.1
     %(verbose)s
 
     Returns
@@ -759,14 +796,14 @@ def plot_evoked(evoked, picks=None, exclude='bads', unit=True, show=True,
     See Also
     --------
     mne.viz.plot_evoked_white
-    """
+    """  # noqa: E501
     return _plot_evoked(
         evoked=evoked, picks=picks, exclude=exclude, unit=unit, show=show,
         ylim=ylim, proj=proj, xlim=xlim, hline=hline, units=units,
         scalings=scalings, titles=titles, axes=axes, plot_type="butterfly",
         gfp=gfp, window_title=window_title, spatial_colors=spatial_colors,
         selectable=selectable, zorder=zorder, noise_cov=noise_cov,
-        time_unit=time_unit, sphere=sphere)
+        time_unit=time_unit, sphere=sphere, highlight=highlight)
 
 
 def plot_evoked_topo(evoked, layout=None, layout_scale=0.945,

mne/viz/tests/test_evoked.py

@@ -169,6 +169,20 @@ def test_plot_evoked():
         evoked.plot(verbose=True, time_unit='s')
     assert 'Need more than one' in log_file.getvalue()
 
+    # Test highlight
+    for highlight in [
+        (0, 0.1),
+        [(0, 0.1), (0.1, 0.2)]
+    ]:
+        fig = evoked.plot(time_unit='s', highlight=highlight)
+        for ax in fig.get_axes():
+            highlighted_areas = [child for child in ax.get_children()
+                                 if isinstance(child, PolyCollection)]
+            assert len(highlighted_areas) == len(np.atleast_2d(highlight))
+
+    with pytest.raises(ValueError, match='must be reshapable into a 2D array'):
+        fig = evoked.plot(time_unit='s', highlight=0.1)
+
 
 def test_constrained_layout():
     """Test that we handle constrained layouts correctly."""

mne/viz/utils.py

@@ -2233,7 +2233,7 @@ def _plot_psd(inst, fig, freqs, psd_list, picks_list, titles_list,
                     ylim=None, times=freqs, bad_ch_idx=[], titles=titles,
                     ch_types_used=ch_types_used, selectable=True, psd=True,
                     line_alpha=line_alpha, nave=None, time_unit='ms',
-                    sphere=sphere)
+                    sphere=sphere, highlight=None)
 
     for ii, (ax, xlabel) in enumerate(zip(ax_list, xlabels_list)):
         ax.grid(True, linestyle=':')

tutorials/evoked/20_visualize_evoked.py

@@ -84,6 +84,18 @@
 
 evks['aud/left'].plot(picks='mag', spatial_colors=True, gfp=True)
 
+# %%
+# Interesting time periods can be highlighted via the ``highlight`` parameter.
+
+time_ranges_of_interest = [
+    (0.05, 0.14),
+    (0.22, 0.27)
+]
+evks['aud/left'].plot(
+    picks='mag', spatial_colors=True, gfp=True,
+    highlight=time_ranges_of_interest
+)
+
 # %%
 # Plotting scalp topographies
 # ^^^^^^^^^^^^^^^^^^^^^^^^^^^