Merge pull request #69 from takluyver/simplify-slides-export

Rehash and simplify slide export

nbconvert/exporters/exporter.py

@@ -71,7 +71,6 @@ class Exporter(LoggingConfigurable):
                                   'nbconvert.preprocessors.coalesce_streams',
                                   'nbconvert.preprocessors.SVG2PDFPreprocessor',
                                   'nbconvert.preprocessors.CSSHTMLHeaderPreprocessor',
-                                  'nbconvert.preprocessors.RevealHelpPreprocessor',
                                   'nbconvert.preprocessors.LatexPreprocessor',
                                   'nbconvert.preprocessors.HighlightMagicsPreprocessor',
                                   'nbconvert.preprocessors.ExtractOutputPreprocessor',

nbconvert/exporters/slides.py

@@ -1,28 +1,97 @@
 """HTML slide show Exporter class"""
 
-#-----------------------------------------------------------------------------
-# Copyright (c) 2013, the IPython Development Team.
-#
+# Copyright (c) Jupyter Development Team.
 # Distributed under the terms of the Modified BSD License.
-#
-# The full license is in the file COPYING.txt, distributed with this software.
-#-----------------------------------------------------------------------------
 
-#-----------------------------------------------------------------------------
-# Imports
-#-----------------------------------------------------------------------------
+from copy import deepcopy
+from warnings import warn
 
-from nbconvert import preprocessors
 from traitlets.config import Config
+from traitlets import Unicode
 
 from .html import HTMLExporter
 
-#-----------------------------------------------------------------------------
-# Classes
-#-----------------------------------------------------------------------------
+def prepare(nb):
+    """Add some convenenience metadata on cells for the slide template.
+    """
+    nb = deepcopy(nb)
+
+    for cell in nb.cells:
+        # Make sure every cell has a slide_type
+        cell.metadata.slide_type = cell.metadata.get('slideshow', {}).get('slide_type', '-')
+
+    # Find the first visible cell
+    for index, cell in enumerate(nb.cells):
+        if cell.metadata.slide_type not in {'notes', 'skip'}:
+            cell.metadata.slide_type = 'slide'
+            cell.metadata.slide_start = True
+            cell.metadata.subslide_start = True
+            first_slide_ix = index
+            break
+    else:
+        raise ValueError("All cells are hidden, cannot create slideshow")
+
+    in_fragment = False
+
+    for index, cell in enumerate(nb.cells[first_slide_ix+1:],
+                                 start=(first_slide_ix+1)):
+
+        previous_cell = nb.cells[index - 1]
+
+        # Slides are <section> elements in the HTML, subslides (the vertically
+        # stacked slides) are also <section> elements inside the slides,
+        # and fragments are <div>s within subslides. Subslide and fragment
+        # elements can contain content:
+        # <section>
+        #   <section>
+        #     (content)
+        #     <div class="fragment">(content)</div>
+        #   </section>
+        # </section>
+
+        # Get the slide type. If type is subslide or slide,
+        # end the last slide/subslide/fragment as applicable.
+        if cell.metadata.slide_type == 'slide':
+            previous_cell.metadata.slide_end = True
+            cell.metadata.slide_start = True
+        if cell.metadata.slide_type in {'subslide', 'slide'}:
+            previous_cell.metadata.fragment_end = in_fragment
+            previous_cell.metadata.subslide_end = True
+            cell.metadata.subslide_start = True
+            in_fragment = False
+
+        elif cell.metadata.slide_type == 'fragment':
+            cell.metadata.fragment_start = True
+            if in_fragment:
+                previous_cell.metadata.fragment_end = True
+            else:
+                in_fragment  = True
+
+    # The last cell will always be the end of a slide
+    nb.cells[-1].metadata.fragment_end = in_fragment
+    nb.cells[-1].metadata.subslide_end = True
+    nb.cells[-1].metadata.slide_end = True
+
+    return nb
 
 class SlidesExporter(HTMLExporter):
     """Exports HTML slides with reveal.js"""
+
+    reveal_url_prefix = Unicode(config=True,
+        help="""The URL prefix for reveal.js.
+        This can be a a relative URL for a local copy of reveal.js,
+        or point to a CDN.
+
+        For speaker notes to work, a local reveal.js prefix must be used.
+        """
+    )
+
+    def _reveal_url_prefix_default(self):
+        if 'RevealHelpPreprocessor.url_prefix' in self.config:
+            warn("Please update RevealHelpPreprocessor.url_prefix to "
+                 "SlidesExporter.reveal_url_prefix in config files.")
+            return self.config.RevealHelpPreprocessor.url_prefix
+        return 'reveal.js'
 
     def _file_extension_default(self):
         return '.slides.html'
@@ -32,12 +101,12 @@ def _template_file_default(self):
 
     output_mimetype = 'text/html'
 
-    @property
-    def default_config(self):
-        c = Config({
-            'RevealHelpPreprocessor': {
-                'enabled': True,
-                },
-            })
-        c.merge(super(SlidesExporter,self).default_config)
-        return c
+    def from_notebook_node(self, nb, resources=None, **kw):
+        self._init_resources(resources)
+        if 'reveal' not in resources:
+            resources['reveal'] = {}
+        resources['reveal']['url_prefix'] = self.reveal_url_prefix
+
+        nb = prepare(nb)
+
+        return super(SlidesExporter, self).from_notebook_node(nb, resources=resources, **kw)

nbconvert/exporters/tests/test_slides.py

@@ -3,8 +3,9 @@
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
+from nbformat import v4 as nbformat
 from .base import ExportersTestsBase
-from ..slides import SlidesExporter
+from ..slides import SlidesExporter, prepare
 
 
 class TestSlidesExporter(ExportersTestsBase):
@@ -34,3 +35,46 @@ def test_export_reveal(self):
         """
         (output, resources) = SlidesExporter(template_file='slides_reveal').from_filename(self._get_notebook())
         assert len(output) > 0
+
+    def build_notebook(self):
+        """Build a reveal slides notebook in memory for use with tests."""
+        outputs = [nbformat.new_output(output_type="stream", name="stdout", text="a")]
+
+        slide_metadata = {'slideshow' : {'slide_type': 'slide'}}
+        subslide_metadata = {'slideshow' : {'slide_type': 'subslide'}}
+        fragment_metadata = {'slideshow' : {'slide_type': 'fragment'}}
+
+        cells=[nbformat.new_code_cell(source="", execution_count=1, outputs=outputs),
+               nbformat.new_markdown_cell(source="", metadata=slide_metadata),
+               nbformat.new_code_cell(source="", execution_count=2, outputs=outputs),
+               nbformat.new_markdown_cell(source="", metadata=slide_metadata),
+               nbformat.new_markdown_cell(source="", metadata=subslide_metadata),
+               nbformat.new_markdown_cell(source="", metadata=fragment_metadata),
+               nbformat.new_code_cell(source="", execution_count=1, outputs=outputs)]
+
+        return nbformat.new_notebook(cells=cells)
+
+    def test_prepare(self):
+        nb = self.build_notebook()
+        nb = prepare(nb)
+        cells = nb.cells
+
+        # Make sure correct metadata tags are available on every cell.
+        for cell in cells:
+            assert 'slide_type' in cell.metadata
+
+        # Make sure slide end is only applied to the cells preceeding slide
+        # cells.
+        assert not cells[1].metadata.get('slide_end', False)
+
+        # Verify 'slide-end'
+        assert cells[0].metadata['slide_end']
+        assert cells[2].metadata['slide_end']
+        assert cells[2].metadata['subslide_end']
+
+        assert not cells[3].metadata.get('slide_end', False)
+        assert cells[3].metadata['subslide_end']
+
+        assert cells[-1].metadata['fragment_end']
+        assert cells[-1].metadata['subslide_end']
+        assert cells[-1].metadata['slide_end']

nbconvert/nbconvertapp.py

@@ -51,7 +51,7 @@ def validate(self, obj, value):
     'writer' : 'NbConvertApp.writer_class',
     'post': 'NbConvertApp.postprocessor_class',
     'output': 'NbConvertApp.output_base',
-    'reveal-prefix': 'RevealHelpPreprocessor.url_prefix',
+    'reveal-prefix': 'SlidesExporter.reveal_url_prefix',
     'nbformat': 'NotebookExporter.nbformat_version',
 })
 

nbconvert/preprocessors/__init__.py

@@ -3,7 +3,6 @@
 from .convertfigures import ConvertFiguresPreprocessor
 from .svg2pdf import SVG2PDFPreprocessor
 from .extractoutput import ExtractOutputPreprocessor
-from .revealhelp import RevealHelpPreprocessor
 from .latex import LatexPreprocessor
 from .csshtmlheader import CSSHTMLHeaderPreprocessor
 from .highlightmagics import HighlightMagicsPreprocessor