Plot overlay images

doc/user_guide/visualisation.rst

@@ -736,6 +736,25 @@ __ plot.spectra_
     functionality is only enabled if a ``matplotlib`` backend that supports the
     ``button_press_event`` in the figure canvas is being used.
 
+It is also possible to plot multiple images overlayed on the same figure by 
+passing the argument `overlay=True` to the 
+:py:func:`~.drawing.utils.plot_images` function. This should only be done when
+images have the same scale (eg. for elemental maps from the same dataset).
+Using the same data as above, the Fe and Pt signals can be plotted using
+different colours. Any color can be input via matplotlib color characters or
+hex values.
+
+.. code-block:: python
+
+    >>> si_EDS = hs.load("core_shell.hdf5")
+    >>> im = si_EDS.get_lines_intensity()
+    >>> hs.plot.plot_images(im,scalebar='all', overlay=True, suptitle=False, 
+    >>>                     axes_decor='off')
+
+.. figure::  images/plot_images_overlay.png
+  :align:   center
+  :width:   500
+
 .. _plot.spectra:
 
 Plotting several spectra

hyperspy/tests/drawing/test_plot_signal2d.py

@@ -561,3 +561,19 @@ def test_plot_autoscale_data_changed(autoscale):
     else:
         np.testing.assert_allclose(imf._vmin, _vmin)
         np.testing.assert_allclose(imf._vmax, _vmax)
+
+@pytest.mark.parametrize("axes_decor", ['all', 'off'])
+@pytest.mark.parametrize("label", ['auto', ['b','g']])
+@pytest.mark.parametrize("colors", ['auto', ['b','g']])
+@pytest.mark.parametrize("alphas", [1.0, [0.9,0.9]])
+@pytest.mark.mpl_image_compare(baseline_dir=baseline_dir,
+                               tolerance=default_tol, style=style_pytest_mpl)
+def test_plot_overlay(axes_decor,label,colors,alphas):
+    s1 = hs.signals.Signal2D(np.arange(100).reshape(10, 10))
+    s2 = hs.signals.Signal2D(np.arange(99,-1,-1).reshape(10, 10))
+    ax = hs.plot.plot_images([s1,s2], overlay=True, scalebar='all',
+                             label=label, suptitle=False,
+                             axes_decor=axes_decor, colors=colors,
+                             alphas=alphas)
+
+    return ax[0].figure