Add illustrations of transforms with sphinx-gallery (#3652)

.gitignore

@@ -10,6 +10,8 @@ torchvision/version.py
 */**/*~
 *~
 docs/build
+docs/source/auto_examples/
+docs/source/gen_modules/
 .coverage
 htmlcov
 .*.swp

docs/Makefile

@@ -19,6 +19,15 @@ docset: html
 	cp $(SPHINXPROJ).docset/icon.png $(SPHINXPROJ).docset/icon@2x.png
 	convert $(SPHINXPROJ).docset/icon@2x.png -resize 16x16 $(SPHINXPROJ).docset/icon.png
 
+html-noplot:  # Avoids running the gallery examples, which may take time
+	$(SPHINXBUILD) -D plot_gallery=0 -b html $(ASPHINXOPTS)  "$(BUILDDIR)"/html
+	@echo
+	@echo "Build finished. The HTML pages are in $(BUILDDIR)/html."
+
+clean:
+	rm -rf $(BUILDDIR)/*
+	rm -rf auto_examples/
+
 .PHONY: help Makefile docset
 
 # Catch-all target: route all unknown targets to Sphinx using the new

docs/requirements.txt

-sphinx
+sphinx==2.4.4
+sphinx-gallery
+matplotlib
+numpy
 -e git+git://github.com/pytorch/pytorch_sphinx_theme.git#egg=pytorch_sphinx_theme

docs/source/conf.py

@@ -20,6 +20,10 @@
 # import os
 # import sys
 # sys.path.insert(0, os.path.abspath('.'))
+
+from pathlib import Path
+import os
+
 import torch
 import torchvision
 import pytorch_sphinx_theme
@@ -44,8 +48,16 @@ extensions = [
     'sphinx.ext.mathjax',
     'sphinx.ext.napoleon',
     'sphinx.ext.viewcode',
+    'sphinx_gallery.gen_gallery',
 ]
 
+sphinx_gallery_conf = {
+    'examples_dirs': '../../gallery/',   # path to your example scripts
+    'gallery_dirs': 'auto_examples',  # path to where to save gallery generated output
+    'backreferences_dir': 'gen_modules/backreferences',
+    'doc_module': ('torchvision',),
+}
+
 napoleon_use_ivar = True
 napoleon_numpy_docstring = False
 napoleon_google_docstring = True
@@ -248,3 +260,42 @@ def patched_make_field(self, types, domain, items, **kw):
 
 
 TypedField.make_field = patched_make_field
+
+
+def inject_minigalleries(app, what, name, obj, options, lines):
+    """Inject a minigallery into a docstring.
+
+    This avoids having to manually write the .. minigallery directive for every item we want a minigallery for,
+    as it would be easy to miss some.
+
+    This callback is called after the .. auto directives (like ..autoclass) have been processed,
+    and modifies the lines parameter inplace to add the .. minigallery that will show which examples
+    are using which object.
+
+    It's a bit hacky, but not *that* hacky when you consider that the recommended way is to do pretty much the same,
+    but instead with templates using autosummary (which we don't want to use):
+    (https://sphinx-gallery.github.io/stable/configuration.html#auto-documenting-your-api-with-links-to-examples)
+
+    For docs on autodoc-process-docstring, see the autodoc docs:
+    https://www.sphinx-doc.org/en/master/usage/extensions/autodoc.html
+    """
+
+    conf_file_path = Path(__file__).parent.absolute()
+    backrefs_path = conf_file_path / sphinx_gallery_conf['backreferences_dir'] / (name + '.examples')
+    if not (os.path.isfile(backrefs_path) and os.path.getsize(backrefs_path) > 0):
+        # We avoid showing the (empty) minigallery if there's nothing to show, i.e. if the object
+        # isn't used in any example.
+        # FIXME: this check can be removed once https://github.com/sphinx-gallery/sphinx-gallery/pull/813
+        # is merged and the new sphinx-gallery version (> 0.8.x) is released.
+        return
+
+    if what in ("class", "function"):
+        lines.append(f".. minigallery:: {name}")
+        lines.append(f"    :add-heading: Examples using ``{name.split('.')[-1]}``:")
+        # avoid heading entirely to avoid warning. As a bonud it actually renders better
+        lines.append("    :heading-level: 9")
+        lines.append("\n")
+
+
+def setup(app):
+    app.connect('autodoc-process-docstring', inject_minigalleries)

docs/source/index.rst

@@ -38,6 +38,12 @@ architectures, and common image transformations for computer vision.
    transforms
    utils
 
+.. toctree::
+   :maxdepth: 1
+   :caption: Examples
+
+   auto_examples/index
+
 .. automodule:: torchvision
    :members:
 

gallery/README.rst

+Example gallery
+===============
+
+Below is a gallery of examples
\ No newline at end of file

gallery/plot_transforms.py

+"""
+==========================
+Illustration of transforms
+==========================
+
+This example illustrates the various transforms available in :mod:`torchvision.transforms`.
+"""
+
+from PIL import Image
+from pathlib import Path
+import matplotlib.pyplot as plt
+import numpy as np
+
+import torchvision.transforms as T
+
+
+orig_img = Image.open(Path('assets') / 'astronaut.jpg')
+
+
+def plot(img, title="", with_orig=True, **kwargs):
+    def _plot(img, title, **kwargs):
+        plt.figure().suptitle(title, fontsize=25)
+        plt.imshow(np.asarray(img), **kwargs)
+        plt.axis('off')
+
+    if with_orig:
+        _plot(orig_img, "Original image")
+    _plot(img, title, **kwargs)
+
+
+####################################
+# Pad
+# ---
+# The :class:`~torchvision.transforms.Pad` transform
+# (see also :func:`~torchvision.transforms.functional.pad`)
+# fills image borders with some pixel values.
+padded_img = T.Pad(padding=30)(orig_img)
+plot(padded_img, "Padded image")
+
+####################################
+# Resize
+# ------
+# The :class:`~torchvision.transforms.Resize` transform
+# (see also :func:`~torchvision.transforms.functional.resize`)
+# resizes an image.
+resized_img = T.Resize(size=30)(orig_img)
+plot(resized_img, "Resized image")
+
+####################################
+# ColorJitter
+# -----------
+# The :class:`~torchvision.transforms.ColorJitter` transform
+# randomly changes the brightness, saturation, and other properties of an image.
+jitted_img = T.ColorJitter(brightness=.5, hue=.3)(orig_img)
+plot(jitted_img, "Jitted image")
+
+####################################
+# Grayscale
+# ---------
+# The :class:`~torchvision.transforms.Grayscale` transform
+# (see also :func:`~torchvision.transforms.functional.to_grayscale`)
+# converts an image to grayscale
+gray_img = T.Grayscale()(orig_img)
+plot(gray_img, "Grayscale image", cmap='gray')