Feature/svg2pdf

extensions/pre_svg2pdf.py

@@ -0,0 +1,153 @@
+# -*- coding: utf-8 -*-
+"""
+This preprocessor converts svg graphics embedded in markdown as '![My graphic](graphics.svg)'
+to PDF using Inkscape
+
+"""
+import base64
+import io
+import os
+import sys
+import subprocess
+
+from nbconvert.preprocessors import Preprocessor
+from six import StringIO, unichr
+import re
+import sys
+import subprocess
+from ipython_genutils.py3compat import cast_unicode_py2
+from ipython_genutils.tempdir import TemporaryDirectory
+from traitlets import Unicode
+
+
+INKSCAPE_APP = '/Applications/Inkscape.app/Contents/Resources/bin/inkscape'
+
+if sys.platform == "win32":
+    try:
+        import winreg
+    except ImportError:
+        import _winreg as winreg
+
+
+class SVG2PDFPreprocessor(Preprocessor):
+    def _from_format_default(self):
+        return 'image/svg+xml'
+    def _to_format_default(self):
+        return 'application/pdf'
+
+    output_filename_template = Unicode(
+        "{unique_key}_{cell_index}_{index}{extension}", config=True)
+
+    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":
+            if os.path.isfile(INKSCAPE_APP):
+                return INKSCAPE_APP
+        if sys.platform == "win32":
+            wr_handle = winreg.ConnectRegistry(None, winreg.HKEY_LOCAL_MACHINE)
+            try:
+                rkey = winreg.OpenKey(wr_handle, "SOFTWARE\\Classes\\inkscape.svg\\DefaultIcon")
+                inkscape = winreg.QueryValueEx(rkey, "")[0]
+            except FileNotFoundError:
+                raise FileNotFoundError("Inkscape executable not found")
+            return inkscape
+        return "inkscape"
+
+    def convert_figure(self, name, data):
+        """
+        Convert a single SVG figure to PDF.  Returns converted data.
+        """
+        #self.log.info(name, data)
+        #Work in a temporary directory
+        #self.log.info('Inkscape:', self.inkscape)
+        with TemporaryDirectory() as tmpdir:
+
+            #Write fig to temp file
+            input_filename = os.path.join(tmpdir, 'figure' + '.svg')
+            # SVG data is unicode text
+            with io.open(input_filename, 'w', encoding='utf8') as f:
+                f.write(data.decode('utf-8'))
+                #f.write(cast_unicode_py2(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 f.read()
+                    #return base64.encodestring(f.read())
+            else:
+                raise TypeError("Inkscape svg to pdf conversion failed")
+
+
+    def replfunc(self, match):
+        """
+        Replace svg image with pdf
+
+        Parameters
+        ----------
+        match: Regex match object
+            Markdown image tags with svg images
+
+        Returns
+        -------
+        img: string
+            New markdown image tag with pdf image
+        """
+        url = match.group(2) + '.svg'
+        if url.startswith('http'):
+            data = request.get(url)
+        else:
+            with open(url, 'rb') as f:
+                data = f.read()
+        if self.output_files_dir is not None and os.path.exists(self.output_files_dir) is False:
+            os.makedirs(self.output_files_dir)
+        else:
+            self.output_files_dir = ''
+        output_filename = os.path.join(self.output_files_dir, match.group(2) + '.pdf')
+        pdf_data = self.convert_figure(match.group(2), data)
+        self.log.info('Writing PDF image %s' % output_filename) 
+        with open(output_filename, 'wb') as f:
+            f.write(pdf_data)
+        new_img = "["+match.group(1)+"]("+output_filename+")"
+        return new_img
+
+    def preprocess_cell(self, cell, resources, index):
+        """
+        Find SVG links and convert to PDF
+
+        Parameters
+        ----------
+        cell : NotebookNode cell
+            Notebook cell being processed
+        resources : dictionary
+            Additional resources used in the conversion process.  Allows
+            preprocessors to pass variables into the Jinja engine.
+        index : int
+            Index of the cell being processed (see base.py)
+        """
+        self.output_files_dir = resources.get('output_files_dir', None)
+        if cell.cell_type == "markdown" and self.config.NbConvertApp.export_format in ("latex", "pdf"):
+            cell.source = re.sub('\[(.*)\]\((.+).svg\)',self.replfunc, cell.source, flags=re.IGNORECASE)           
+        return cell, resources