Add image resizing option

Author: juhasch

src/jupyter_contrib_nbextensions/nbconvert_support/pre_embedimages.py

@@ -1,7 +1,7 @@
 """Nbconvert preprocessor for the python-markdown nbextension."""
 
 from nbconvert.preprocessors import Preprocessor
-from traitlets import Bool, Float, Unicode
+from traitlets import Bool, Unicode
 import re
 import os
 import base64
@@ -15,7 +15,8 @@
 
 class EmbedImagesPreprocessor(Preprocessor):
     """
-    :mod:`nbconvert` Preprocessor to embed images in a markdown cell as attachment inside the notebook itself.
+    :mod:`nbconvert` Preprocessor to embed images in a markdown cell as
+        attachment inside the notebook itself.
 
     This :class:`~nbconvert.preprocessors.Preprocessor` replaces kernel code in
     markdown cells with the results stored in the cell metadata.
@@ -35,21 +36,26 @@ class EmbedImagesPreprocessor(Preprocessor):
 
         EmbedImagesPreprocessor.embed_remote_images=True
 
-    to additionally embeds all images referenced by an url (e.g. http://jupyter.org/assets/nav_logo.svg) instead
-    of a local file name. Also
+    to additionally embeds all images referenced by an url
+    (e.g. http://jupyter.org/assets/nav_logo.svg) instead of a local file name.
+    Also
 
         EmbedImagesPreprocessor.resize=small
 
-    Let's you scale-down the size of an image. This is useful if you want to save space by not embedding large
-    images and instead use a smaller (scaled) version. Works only for raster images (i.e. png, jpg).
-    Valid resize settings are: small = 500px, mid = 1000px, large = 2000px for maximum size in length or width
-    No upscaling of small images will be performed.
+    Let's you scale-down the size of an image. This is useful if you want to
+    save space by not embedding large images and instead use a smaller (scaled)
+    version. Works only for raster images (i.e. png, jpg).
+    Valid resize settings are: small = 500px, mid = 1000px, large = 2000px
+    for maximum size in length or width.  No upscaling of small images will
+    be performed.
 
     Example::
 
-            $ jupyter nbconvert --to html --EmbedImagesPreprocessor.embed_images=True --EmbedImagesPreprocessor.scale=large mynotebook.ipynb
+            $ jupyter nbconvert --to html --EmbedImagesPreprocessor.embed_images=True
+                --EmbedImagesPreprocessor.resize=large mynotebook.ipynb
 
-    *Note:* To embed images after conversion to HTML you can also use the `html_embed` exporter
+    *Note:* To embed images after conversion to HTML you can also use the
+           `html_embed` exporter
     """
 
     embed_images = Bool(False, help="Embed images as attachment").tag(config=True)
@@ -80,7 +86,7 @@ def replfunc_md(self, match):
 
         # resize settings: small -> 500px, mid -> 1000px, large -> 200px
         imgsizes = {'small': 500, 'mid': 1000, 'large': 2000}
-        if self.resize in imgsizes.keys()  and imgformat in ['png', 'jpg']:
+        if self.resize in imgsizes.keys() and imgformat in ['png', 'jpg']:
             from io import BytesIO
             try:
                 from PIL import Image
@@ -90,21 +96,21 @@ def replfunc_md(self, match):
             if Image:
                 # Only make images smaller when rescaling
                 im = Image.open(BytesIO(data))
-                size = im.size
-                factor = imgsizes[self.resize]/max(size)
+                factor = imgsizes[self.resize] / max(im.size)
                 if factor < 1.0:
-                    newsize = ( int(size[0]*factor), int(size[1]*factor))
+                    newsize = (int(im.size[0] * factor), int(im.size[1] * factor))
                     newim = im.resize(newsize)
                     fp = BytesIO()
-                    newim.save(fp, format=imgformat.replace('jpg', 'jpeg')) # PIL requires JPEG instead of JPG
+                    # PIL requires JPEG instead of JPG
+                    newim.save(fp, format=imgformat.replace('jpg', 'jpeg'))
                     data = fp.getvalue()
                     fp.close()
                     self.log.debug("Resized %d x %d image %s to size %d x %d pixels" %
-                                  (size[0], size[1], url, newsize[0], newsize[1]) )
+                                   (im.size[0], im.size[1], url, newsize[0], newsize[1]))
 
         self.log.debug("embedding url: %s, format: %s" % (url, imgformat))
         b64_data = base64.b64encode(data).decode("utf-8")
-        self.attachments[url] = { 'image/'+imgformat : b64_data }
+        self.attachments[url] = {'image/' + imgformat: b64_data}
 
         newimg = '![' + match.group(1) + '](attachment:' + match.group(2) + ')'
         return newimg

tox.ini

@@ -63,7 +63,7 @@ deps =
     flake8
     isort
 commands =
-    flake8 src tests setup.py
+    flake8 --max-line-length=120 src tests setup.py
     isort --verbose --check-only --diff --recursive src tests setup.py
 
 [testenv:docs]