WIP: Add help window to the _TimeViewer

mne/viz/_brain/_timeviewer.py

@@ -6,6 +6,7 @@
 
 import time
 import numpy as np
+from ..utils import _show_help
 
 
 class IntSlider(object):
@@ -209,6 +210,8 @@ def __init__(self, brain):
         self.brain = brain
         self.brain.time_viewer = self
         self.plotter = brain._renderer.plotter
+        self.interactor = self.plotter.interactor
+        self.interactor.keyPressEvent = self.keyPressEvent
 
         # orientation slider
         orientation = [
@@ -397,17 +400,14 @@ def __init__(self, brain):
         self.playback_speed = default_playback_speed
         self.refresh_rate_ms = max(int(round(1000. / 60.)), 1)
         self.plotter.add_callback(self.play, self.refresh_rate_ms)
-        self.plotter.add_key_event('space', self.toggle_playback)
 
         # add toggle to show/hide interface
         self.visibility = True
-        self.plotter.add_key_event('y', self.toggle_interface)
 
-        # apply auto-scaling action
-        self.plotter.add_key_event('t', self.apply_auto_scaling)
-
-        # restore user scaling action
-        self.plotter.add_key_event('u', self.restore_user_scaling)
+        # display help
+        self.help_actor = self.plotter.add_text(
+            text="Press ? to show help window"
+        )
 
         # set the slider style
         self.set_slider_style(smoothing_slider)
@@ -418,8 +418,29 @@ def __init__(self, brain):
         self.set_slider_style(playback_speed_slider)
         self.set_slider_style(time_slider)
 
+        # setup key bindings
+        self.key_bindings = {
+            '?': self.help,
+            'y': self.toggle_interface,
+            't': self.apply_auto_scaling,
+            'u': self.restore_user_scaling,
+            ' ': self.toggle_playback,
+        }
+
+    def keyPressEvent(self, event):
+        callback = self.key_bindings.get(event.text())
+        if callback is not None:
+            callback()
+
     def toggle_interface(self):
         self.visibility = not self.visibility
+
+        # manage help text
+        if self.visibility:
+            self.help_actor.VisibilityOn()
+        else:
+            self.help_actor.VisibilityOff()
+
         # manage sliders
         for slider in self.plotter.slider_widgets:
             slider_rep = slider.GetRepresentation()
@@ -491,6 +512,24 @@ def set_slider_style(self, slider, show_label=True):
             if not show_label:
                 slider_rep.ShowSliderLabelOff()
 
+    def help(self):
+        pairs = [
+            ('?', 'Display help window'),
+            ('y', 'Toggle interface'),
+            ('t', 'Apply auto-scaling'),
+            ('u', 'Restore original clim'),
+            ('Space', 'Start/Pause playback'),
+        ]
+        text1, text2 = zip(*pairs)
+        text1 = '\n'.join(text1)
+        text2 = '\n'.join(text2)
+        _show_help(
+            col1=text1,
+            col2=text2,
+            width=5,
+            height=2,
+        )
+
 
 class _LinkViewer(object):
     """Class to link multiple _TimeViewer objects."""
@@ -515,9 +554,7 @@ def __init__(self, brains):
 
         # link toggle to start/pause playback
         for time_viewer in self.time_viewers:
-            plotter = time_viewer.plotter
-            plotter.clear_events_for_key('space')
-            plotter.add_key_event('space', self.toggle_playback)
+            time_viewer.key_bindings[' '] = self.toggle_playback
 
     def set_time_point(self, value):
         for time_viewer in self.time_viewers:

mne/viz/utils.py

@@ -1235,19 +1235,13 @@ def _select_bads(event, params, bads):
     return bads
 
 
-def _onclick_help(event, params):
-    """Draw help window."""
-    text, text2 = _get_help_text(params)
-
-    width, height = 9, 5
-
+def _show_help(col1, col2, width, height):
     fig_help = figure_nobar(figsize=(width, height), dpi=80)
     fig_help.canvas.set_window_title('Help')
-    params['fig_help'] = fig_help
 
     ax = fig_help.add_subplot(111)
-    celltext = [[c1, c2] for c1, c2 in zip(text.strip().split("\n"),
-                                           text2.strip().split("\n"))]
+    celltext = [[c1, c2] for c1, c2 in zip(col1.strip().split("\n"),
+                                           col2.strip().split("\n"))]
     table = ax.table(cellText=celltext, loc="center", cellLoc="left")
     table.auto_set_font_size(False)
     table.set_fontsize(12)
@@ -1269,6 +1263,17 @@ def _onclick_help(event, params):
         pass
 
 
+def _onclick_help(event, params):
+    """Draw help window."""
+    col1, col2 = _get_help_text(params)
+    params['fig_help'] = _show_help(
+        col1=col1,
+        col2=col2,
+        width=9,
+        height=5,
+    )
+
+
 def _key_press(event):
     """Handle key press in dialog."""
     import matplotlib.pyplot as plt