Merge pull request #3863 from damianavila/speaker_notes

Added working speaker notes for slides.

To resume, I fetch the cdn containing the files we need to make speaker notes works. Then I pass this info using the resources dict to the write which output the files in the correct path...
I make some other additions to make this feature an option from the command line, ie:

if you want a simple slideshow:
ipython nbconvert your_slides.ipynb --to slides

if you want a simple served slideshow:
ipython nbconvert your_slides.ipynb --to slides --post serve

if you want to use a local copy of the reveal.js library:
ipython nbconvert your_slides.ipynb --to slides --post serve --local reveal.js

and if you want to use speaker notes:
ipython nbconvert your_slides.ipynb --to slides --post serve --notes True
or
ipython nbconvert your_slides.ipynb --to slides --post serve --notes True --local reveal.js 
but this last one is redundant because if you are using a local reveal.js library the speaker notes are functional by default.

IPython/nbconvert/nbconvertapp.py

@@ -61,7 +61,9 b' nbconvert_aliases.update({'
     'template' : 'Exporter.template_file',
     'writer' : 'NbConvertApp.writer_class',
     'post': 'NbConvertApp.post_processor_class',
-    'output': 'NbConvertApp.output_base'
+    'output': 'NbConvertApp.output_base',
+    'offline-slides': 'RevealHelpTransformer.url_prefix',
+    'slide-notes': 'RevealHelpTransformer.speaker_notes'
 })
 
 nbconvert_flags = {}

IPython/nbconvert/templates/slides_reveal.tpl

@@ -135,7 +135,7 b" transition: Reveal.getQueryHash().transition || 'linear', // default/cube/page/c"
 dependencies: [
 { src: "{{resources.reveal.url_prefix}}/lib/js/classList.js", condition: function() { return !document.body.classList; } },
 { src: "{{resources.reveal.url_prefix}}/plugin/highlight/highlight.js", async: true, callback: function() { hljs.initHighlightingOnLoad(); } },
-{ src: "{{resources.reveal.url_prefix}}/plugin/notes/notes.js", async: true, condition: function() { return !!document.body.classList; } }
+{ src: "{{resources.reveal.notes_prefix}}/plugin/notes/notes.js", async: true, condition: function() { return !!document.body.classList; } }
 // { src: 'http://s7.addthis.com/js/300/addthis_widget.js', async: true},
 ]
 });

IPython/nbconvert/transformers/revealhelp.py

@@ -12,8 +12,11 b''
 # Imports
 #-----------------------------------------------------------------------------
 
+import os
+import urllib2
+
 from .base import Transformer
-from IPython.utils.traitlets import Unicode
+from IPython.utils.traitlets import Unicode, Bool
 
 #-----------------------------------------------------------------------------
 # Classes and functions
@@ -26,6 +29,11 b' class RevealHelpTransformer(Transformer):'
                          help="""If you want to use a local reveal.js library,
                          use 'url_prefix':'reveal.js' in your config object.""")
 
+    speaker_notes = Bool(False, 
+                         config=True, 
+                         help="""If you want to use the speaker notes 
+                         set this to True.""")
+
     def call(self, nb, resources):
         """
         Called once to 'transform' contents of the notebook.
@@ -57,5 +65,30 b' class RevealHelpTransformer(Transformer):'
         if not isinstance(resources['reveal'], dict):
             resources['reveal'] = {}
         resources['reveal']['url_prefix'] = self.url_prefix
+        resources['reveal']['notes_prefix'] = self.url_prefix
+
+        cdn = 'http://cdn.jsdelivr.net/reveal.js/2.4.0'
+        local = 'local'
+        html_path = 'plugin/notes/notes.html'
+        js_path = 'plugin/notes/notes.js'
+
+        html_infile = os.path.join(cdn, html_path)
+        js_infile = os.path.join(cdn, js_path)
+        html_outfile = os.path.join(local, html_path)
+        js_outfile = os.path.join(local, js_path)
+
+        if self.speaker_notes:
+            if 'outputs' not in resources:
+                resources['outputs'] = {}
+            resources['outputs'][html_outfile] = self.notes_helper(html_infile)
+            resources['outputs'][js_outfile] = self.notes_helper(js_infile)
+            resources['reveal']['notes_prefix'] = local
 
         return nb, resources
+
+    def notes_helper(self, infile):
+        """Helper function to get the content from an url."""
+
+        content = urllib2.urlopen(infile).read()
+
+        return content

docs/source/interactive/nbconvert.rst

@@ -63,7 +63,12 b' The currently supported export formats are:'
   This generates a Reveal.js HTML slideshow.
   It must be served by an HTTP server.  The easiest way to get this is to add
   ``--post serve`` on the command-line.
-
+  If you want to use the speaker notes plugin, just add
+  ``--slide-notes=True`` on the command-line.
+  For low connectivity environments, you can use a local copy of the reveal.js library, 
+  just add ``--offline-slides=reveal.js`` on the command-line, and do not forget to move
+  your downloaded ``reveal.js`` library to the same folder where your slides are located.
+  
 * ``--to markdown``
 
   Simple markdown output.  Markdown cells are unaffected,