ENH: eyetracking plot_heatmap function

doc/documentation/datasets.rst

@@ -481,17 +481,32 @@ EYELINK
 =======
 :func:`mne.datasets.eyelink.data_path`
 
-Two small example datasets of eye-tracking data from SR Research EyeLink. the "eeg-et"
-dataset contains both EEG (EGI) and eye-tracking (ASCII format) data recorded from a
+Two small example datasets of eye-tracking data from SR Research EyeLink.
+
+EEG-Eyetracking
+^^^^^^^^^^^^^^^
+:func:`mne.datasets.eyelink.data_path`. Data exists at ``/eeg-et/``.
+
+Contains both EEG (EGI) and eye-tracking (ASCII format) data recorded from a
 pupillary light reflex experiment, stored in separate files. 1 participant fixated
 on the screen while short light flashes appeared. Event onsets were recorded by a
 photodiode attached to the screen and were sent to both the EEG and eye-tracking
-systems. The second dataset, in the "freeviewing" directory, contains only eye-tracking
-data (ASCII format) from 1 participant who was free-viewing a natural scene.
+systems. 
 
 .. topic:: Examples
 
     * :ref:`tut-eyetrack`
+
+Freeviewing
+^^^^^^^^^^^
+:func:`mne.datasets.eyelink.data_path`. Data exists at ``/freeviewing/``.
+
+Contains eye-tracking data (ASCII format) from 1 participant who was free-viewing a
+video of a natural scene. In some videos, the natural scene was pixelated such that
+the people in the scene were unrecognizable.
+
+.. topic:: Examples
+
     * :ref:`tut-eyetrack-heatmap`
 
 References

examples/visualization/eyetracking_plot_heatmap.py

@@ -10,6 +10,8 @@
 
 .. seealso:: :ref:`tut-importing-eyetracking-data`
 
+.. seealso:: :ref:`tut-eyetrack`
+
 """
 
 # %%
@@ -26,11 +28,6 @@
 import mne
 from mne.viz.eyetracking import plot_gaze
 
-
-# define variables to pass to the plot_gaze function
-px_width, px_height = 1920, 1080
-cmap = plt.get_cmap("viridis")
-
 task_fpath = mne.datasets.eyelink.data_path() / "freeviewing"
 et_fpath = task_fpath / "sub-01_task-freeview_eyetrack.asc"
 stim_fpath = task_fpath / "stim" / "naturalistic.png"
@@ -52,9 +49,6 @@
     raw, events=events, event_id=event_dict, tmin=0, tmax=20, baseline=None
 )
 
-# %%
-# .. seealso:: :ref:`tut-eyetrack`
-#
 
 # %%
 # Plot a heatmap of the eye-tracking data
@@ -66,6 +60,8 @@
 # screen resolution of the participant screen (1920x1080) as the width and height. We
 # can also use the sigma parameter to smooth the plot.
 
+px_width, px_height = 1920, 1080
+cmap = plt.get_cmap("viridis")
 plot_gaze(epochs["natural"], width=px_width, height=px_height, cmap=cmap, sigma=50)
 
 # %%

mne/viz/eyetracking/tests/test_heatmap.py

@@ -31,7 +31,6 @@ def test_plot_heatmap(axes):
         epochs, width=width, height=height, axes=axes, cmap="Greys", sigma=None
     )
     img = fig.axes[0].images[0].get_array()
-    # We simulated a 2D histogram where only values of 960 and 540 are present
-    # Check that the heatmap data only contains these values
-    np.testing.assert_array_almost_equal(np.where(img.T)[0], data[0].mean())  # 960
-    np.testing.assert_array_almost_equal(np.where(img.T)[1], data[1].mean())  # 540
+    # We simulated a 2D histogram where only the central pixel (960, 540) was active
+    assert img.T[width // 2, height // 2] == 1  # central pixel is active
+    assert np.sum(img) == 1  # only the central pixel should be active