tweak inkscape configurability

now you only specify the 'inkscape' path if it's non-default,
rather than re-specifying the whole command (whole command still configurable for non-Inkscape use case).

IPython/nbconvert/transformers/svg2pdf.py

@@ -1,94 +1,95 b''
 """Module containing a transformer that converts outputs in the notebook from 
 one format to another.
 """
 #-----------------------------------------------------------------------------
 # Copyright (c) 2013, the IPython 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
 #-----------------------------------------------------------------------------
 
 import base64
 import io
 import os
 import sys
 import subprocess
 
 from IPython.utils.tempdir import TemporaryDirectory
 from IPython.utils.traitlets import Unicode
 
 from .convertfigures import ConvertFiguresTransformer
 
 
 #-----------------------------------------------------------------------------
 # Constants
 #-----------------------------------------------------------------------------
 
-INKSCAPE_COMMAND = 'inkscape --without-gui --export-pdf="{to_filename}" "{from_filename}"'
-INKSCAPE_OSX_COMMAND = '/Applications/Inkscape.app/Contents/Resources/bin/inkscape --without-gui --export-pdf="{to_filename}" "{from_filename}"'
-
+INKSCAPE_APP = '/Applications/Inkscape.app/Contents/Resources/bin/inkscape'
 
 #-----------------------------------------------------------------------------
 # Classes
 #-----------------------------------------------------------------------------
 
 class SVG2PDFTransformer(ConvertFiguresTransformer):
     """
     Converts all of the outputs in a notebook from SVG to PDF.
     """
 
     from_format = Unicode('svg', config=True, help='Format the converter accepts')
     to_format = Unicode('pdf', config=False, help='Format the converter writes')
+    
     command = Unicode(config=True,
         help="""The command to use for converting SVG to PDF
         
         This string is a template, which will be formatted with the keys
         to_filename and from_filename.
         
         The conversion call must read the SVG from {from_flename},
         and write a PDF to {to_filename}.
         """)
     
     def _command_default(self):
+        return self.inkscape + \
+               ' --without-gui --export-pdf="{to_filename}" "{from_filename}"'
+    
+    inkscape = Unicode(config=True, help="The path to Inkscape, if necessary")
+    def _inkscape_default(self):
         if sys.platform == "darwin":
-            return INKSCAPE_OSX_COMMAND
-        elif sys.platform == "win32":
-            # windows not yet supported
-            return ""
-        else:
-            return INKSCAPE_COMMAND
+            if os.path.isfile(INKSCAPE_APP):
+                return INKSCAPE_APP
+        return "inkscape"
 
 
     def convert_figure(self, data_format, data):
         """
         Convert a single SVG figure to PDF.  Returns converted data.
         """
 
         #Work in a temporary directory
         with TemporaryDirectory() as tmpdir:
             
             #Write fig to temp file
             input_filename = os.path.join(tmpdir, 'figure.' + data_format)
             # SVG data is unicode text
             with io.open(input_filename, 'w', encoding='utf8') as f:
                 f.write(data)
 
             #Call conversion application
             output_filename = os.path.join(tmpdir, 'figure.pdf')
             shell = self.command.format(from_filename=input_filename, 
                                    to_filename=output_filename)
             subprocess.call(shell, shell=True) #Shell=True okay since input is trusted.
 
             #Read output from drive
             # return value expects a filename
             if os.path.isfile(output_filename):
                 with open(output_filename, 'rb') as f:
                     # PDF is a nb supported binary, data type, so base64 encode.
                     return base64.encodestring(f.read())
             else:
                 raise TypeError("Inkscape svg to png conversion failed")