Merge pull request matplotlib#20140 from jklymak/doc-srcset-directive

DOC: make 2x versions of all gallery figures

Author: QuLogic

doc/conf.py

@@ -168,6 +168,8 @@ def _check_dependencies():
     'thumbnail_size': (320, 224),
     'compress_images': ('thumbnails', 'images'),
     'matplotlib_animations': True,
+    # 3.7 CI doc build should not use hidpi images during the testing phase
+    'image_srcset': [] if sys.version_info[:2] == (3, 7) else ["2x"],
 }
 
 plot_gallery = 'True'

requirements/doc/doc-requirements.txt

@@ -13,6 +13,10 @@ ipython
 ipywidgets
 numpydoc>=0.8
 sphinxcontrib-svg2pdfconverter>=1.1.0
-sphinx-gallery>=0.7
+# sphinx-gallery>=0.7   
+# b41e328 is PR 808 which adds the image_srcset directive.  When this is 
+# released with sphinx gallery, we can change to the last release w/o this feature:
+# sphinx-gallery>0.90
+git+git://github.com/sphinx-gallery/sphinx-gallery@b41e328#egg=sphinx-gallery
 sphinx-copybutton
 scipy