create configurable preprocessors

converters/template.py

@@ -16,17 +16,18 b' a conversion of IPython notebooks to some other format should inherit.'
 #-----------------------------------------------------------------------------
 
 from __future__ import print_function, absolute_import
-from .transformers import extract_figure_transformer
 import converters.transformers as trans
 from converters.jinja_filters import (python_comment, indent,
         rm_fake, remove_ansi, markdown, highlight,
         ansi2html, markdown2latex, escape_tex)
 
 
+
 # Stdlib imports
 import io
 import os
 from IPython.utils import path
+from IPython.utils.traitlets import MetaHasTraits
 
 from jinja2 import Environment, FileSystemLoader
 env = Environment(
@@ -118,8 +119,8 b' class ConverterTemplate(Configurable):'
                     the others.
                     """
             )
-    
-    pre_transformer_order = List(['haspyout_transformer'],
+
+    pre_transformer_order = List(['haspyout_transformer', 'Foobar'],
             config=True,
               help= """
                     An ordered list of pre transformer to apply to the ipynb
@@ -169,10 +170,14 b' class ConverterTemplate(Configurable):'
         self.ext = '.tplx' if self.tex_environement else '.tpl'
         self.nb = None
         self.preprocessors = preprocessors
+
         for name in self.pre_transformer_order:
-            self.preprocessors.append(getattr(trans, name))
+            tr = getattr(trans, name)
+            if isinstance(tr, MetaHasTraits):
+                tr = tr(config=config)
+            self.preprocessors.append(tr)
         if self.extract_figures:
-            self.preprocessors.append(extract_figure_transformer)
+            self.preprocessors.append(trans.ExtractFigureTransformer(config=config))
 
         self.env.filters['filter_data_type'] = self.filter_data_type
         self.env.filters['pycomment'] = python_comment
@@ -218,3 +223,5 b' class ConverterTemplate(Configurable):'
         with io.open(filename) as f:
             self.nb = nbformat.read(f, 'json')
 
+
+

converters/transformers.py

@@ -2,6 +2,41 b''
 
 """
 
+from __future__ import print_function
+
+from IPython.config.configurable import Configurable
+from IPython.utils.traitlets import Unicode, Bool, Dict
+
+class ConfigurableTransformers(Configurable):
+    """ A configurable transformer """
+
+    def __init__(self, config=None, **kw):
+        super(ConfigurableTransformers, self).__init__(config=config, **kw)
+
+    def __call__(self, nb, other):
+        try :
+            for worksheet in nb.worksheets :
+                for index, cell in enumerate(worksheet.cells):
+                    worksheet.cells[index], other = self.cell_transform(cell, other, index)
+            return nb, other
+        except NotImplementedError as error :
+            raise NotImplementedError('should be implemented by subclass')
+
+    def cell_transform(self, cell, other, index):
+        """
+        Overwrite if you want to apply a transformation on each cell
+        """
+        raise NotImplementedError('should be implemented by subclass')
+
+
+class Foobar(ConfigurableTransformers):
+    message = Unicode('-- nothing', config=True)
+
+
+    def cell_transform(self, cell, other, index):
+        return cell, other
+
+
 def cell_preprocessor(function):
     """ wrap a function to be executed on all cells of a notebook
 
@@ -22,7 +57,7 b' def cell_preprocessor(function):'
 def haspyout_transformer(cell, other, count):
     """
     Add a haspyout flag to cell that have it
-    
+
     Easier for templating, where you can't know in advance
     wether to write the out prompt
 
@@ -37,28 +72,54 b' def haspyout_transformer(cell, other, count):'
 
 
 # todo, make the key part configurable.
-def _new_figure(data, fmt, count):
-    """Create a new figure file in the given format.
 
-    Returns a path relative to the input file.
-    """
-    figname = '_fig_%02i.%s' % (count, fmt)
+class ExtractFigureTransformer(ConfigurableTransformers):
+    enabled = Bool(False,
+            config=True,
+            help=""" If set to false, this transformer will be no-op """
+            )
 
-    # Binary files are base64-encoded, SVG is already XML
-    if fmt in ('png', 'jpg', 'pdf'):
-        data = data.decode('base64')
+    extra_ext_map =  Dict({},
+            config=True,
+            help="""extra map to override extension based on type.
+            Usefull for latex where svg will be converted to pdf before inclusion
+            """
+            )
 
-    return figname, data
 
-@cell_preprocessor
-def extract_figure_transformer(cell, other, count):
-    for i, out in enumerate(cell.get('outputs', [])):
-        for type in ['html', 'pdf', 'svg', 'latex', 'png', 'jpg', 'jpeg']:
-            if out.hasattr(type):
-                figname, data = _new_figure(out[type], type, count)
-                cell.outputs[i][type] = figname
-                out['key_'+type] = figname
-                other[figname] = data
-                count = count+1
-    return cell, other
+    #to do change this to .format {} syntax
+    key_tpl = Unicode('_fig_%02i.%s', config=True)
+
+    def _get_ext(self, ext):
+        if ext in self.extra_ext_map :
+            return self.extra_ext_map[ext]
+        return ext
+
+    def _new_figure(self, data, fmt, count):
+        """Create a new figure file in the given format.
+
+        Returns a path relative to the input file.
+        """
+        figname = self.key_tpl % (count, self._get_ext(fmt))
+        key     = self.key_tpl % (count, fmt)
+
+        # Binary files are base64-encoded, SVG is already XML
+        if fmt in ('png', 'jpg', 'pdf'):
+            data = data.decode('base64')
+
+        return figname, key, data
+
+
+    def cell_transform(self, cell, other, count):
+        if not self.enabled:
+            return cell, other
+        for i, out in enumerate(cell.get('outputs', [])):
+            for type in ['html', 'pdf', 'svg', 'latex', 'png', 'jpg', 'jpeg']:
+                if out.hasattr(type):
+                    figname, key, data = self._new_figure(out[type], type, count)
+                    cell.outputs[i][type] = figname
+                    out['key_'+type] = figname
+                    other[key] = data
+                    count = count+1
+        return cell, other
 

profile/full_html.nbcv

@@ -1,5 +1,8 b''
 c = get_config()
 
+
 c.ConverterTemplate.extract_figures=False
 c.ConverterTemplate.template_file='fullhtml'
 c.ConverterTemplate.tex_environement=False
+
+c.ExtractFigureTransformer.enabled = False

profile/latex_base.nbcv

@@ -1,5 +1,7 b''
 c = get_config()
 
-c.ConverterTemplate.extract_figures=False
+c.ConverterTemplate.extract_figures=True
 c.ConverterTemplate.template_file='latex_base'
 c.ConverterTemplate.tex_environement=True
+
+c.ExtractFigureTransformer.extra_ext_map={'svg':'pdf'}

runme.py

@@ -17,6 +17,8 b' from IPython.config.application import Application'
 from IPython.config.loader import ConfigFileNotFound
 from IPython.utils.traitlets import List, Unicode, Type, Bool, Dict, CaselessStrEnum
 
+from converters.transformers import (ConfigurableTransformers,Foobar,ExtractFigureTransformer)
+
 
 class NbconvertApp(Application):
 
@@ -24,6 +26,9 b' class NbconvertApp(Application):'
     def __init__(self, **kwargs):
         super(NbconvertApp, self).__init__(**kwargs)
         self.classes.insert(0,ConverterTemplate)
+        # register class here to have help with help all
+        self.classes.insert(0,ExtractFigureTransformer)
+        self.classes.insert(0,Foobar)
         # ensure those are registerd
 
     def load_config_file(self, profile_name):
@@ -54,11 +59,6 b' class NbconvertApp(Application):'
 
         template_file = sys.argv[1]
 
-        if template_file.startswith('latex'):
-            tex_environement=True
-        else:
-            tex_environement=False
-
         C = ConverterTemplate(tplfile=sys.argv[1],
                 config=self.config)
         C.read(ipynb_file)

templates/tex/latex_base.tplx

@@ -37,7 +37,14 b' it introduces a new line'
 
 ((*- block data_png -*))
 \begin{center}
-\includegraphics[width=0.7\textwidth]{(((output.png)))}
+\includegraphics[width=0.7\textwidth]{(((output.key_png)))}
+\par
+\end{center}
+((*- endblock -*))
+
+((*- block data_svg -*))
+\begin{center}
+\includegraphics[width=0.7\textwidth]{(((output.key_svg)))}
 \par
 \end{center}
 ((*- endblock -*))