Add tutorial for 3D Slicer module

docs/source/slicer.rst

@@ -2,12 +2,17 @@
 3D Slicer GUI
 #############
 
-`3D Slicer <https://www.slicer.org/>`_ is an open source software platform for
+`3D Slicer <https://www.slicer.org/>`_ is an open-source software platform for
 medical image informatics, image processing,
 and three-dimensional visualization.
 
+You can download and install Slicer 4.11 from
+`their download website <https://www.download.slicer.org/>`_ or, if you are on
+macOS, using `Homebrew <https://docs.brew.sh/>`_:
+``brew cask install slicer-nightly``.
+
 TorchIO provides a 3D Slicer extension for quick experimentation and
-visualization of the package features.
+visualization of the package features without any coding.
 
 .. The TorchIO extension can be installed using the
 .. `Extensions Manager <https://www.slicer.org/wiki/Documentation/4.10/SlicerApplication/ExtensionsManager>`_.
@@ -28,3 +33,40 @@ of a transform looks like without any coding at all.
 
 .. image:: https://raw.githubusercontent.com/fepegar/SlicerTorchIO/master/Screenshots/TorchIO.png
     :alt: TorchIO Transforms module for 3D Slicer
+
+
+Usage example
+^^^^^^^^^^^^^
+
+Go to the `Sample Data` module to get an image we can use:
+
+.. image:: https://raw.githubusercontent.com/fepegar/SlicerTorchIO/master/Screenshots/usage_1.png
+    :alt: Go to Sample Data module
+
+
+Click on an image to download, for example MRHead [#]_,
+and go to the `TorchIO Transforms` module:
+
+.. [#] All the data in `Sample Data` can be downloaded and used in the TorchIO
+    Python library using the :py:class:`torchio.datasets.slicer.Slicer` class.
+
+.. image:: https://raw.githubusercontent.com/fepegar/SlicerTorchIO/master/Screenshots/usage_2.png
+    :alt: Download MRHead and go to TorchIO Transforms module
+
+
+Select the input and output volume nodes:
+
+.. image:: https://raw.githubusercontent.com/fepegar/SlicerTorchIO/master/Screenshots/usage_3.png
+    :alt: Select volume nodes
+
+
+Modify the transform parameters and click on `Apply transform`.
+Hovering the mouse over the transforms will show tooltips extracted from the
+TorchIO documentation.
+
+.. image:: https://raw.githubusercontent.com/fepegar/SlicerTorchIO/master/Screenshots/usage_4.png
+    :alt: Select volume nodes
+
+
+You can click on the `Toggle volumes` button to switch between input and output
+volumes.

torchio/datasets/slicer.py

@@ -11,7 +11,7 @@
 
 
 class Slicer(Subject):
-    """Sample data provided by 3D Slicer.
+    """Sample data provided by `3D Slicer <https://www.slicer.org/>`_.
 
     See `the website <https://www.slicer.org/wiki/SampleData>`_
     for more information.