add option to combine pdfs with pdftk

multipage_export.inx

@@ -23,6 +23,7 @@
   <param name="options-title" type="description" appearance="header">Options</param>
   <param name="replace" type="boolean" gui-text="Replace existing files">false</param>
   <param name="autoname" type="boolean" gui-text="Name files from object IDs">false</param>
+  <param name="combine" type="boolean" gui-text="Combine into single PDF">false</param>
 
   <effect needs-live-preview="false">
     <object-type>all</object-type>

multipage_export.py

@@ -25,6 +25,7 @@ def __init__(self):
     self.OptionParser.add_option('-f', '--format',   action='store', type='string', dest='format',   help='File format')
     self.OptionParser.add_option('-a', '--autoname', action='store', type='string', dest='autoname', help='Use IDs for names')
     self.OptionParser.add_option('-r', '--replace',  action='store', type='string', dest='replace',  help='Replace existing files')
+    self.OptionParser.add_option('-c', '--combine',  action='store', type='string', dest='combine',  help='Combine into single PDF')
 
   def run_command(self, args):
     try:
@@ -123,11 +124,21 @@ def export(self, oid, fformat, output, tmpfile):
     else:
       self.rsvg_export(oid, fformat, output, tmpfile)
 
+  def pdftk_combine(self, output, file_paths):
+    output  = self.file_path("%s-%s" % (output, 'All'), 'pdf')
+    command = ['pdftk']
+
+    command.extend(file_paths)
+    command.extend(['cat', 'output', output])
+
+    self.run_command(command)
+
   def export_files(self):
     tmpfile = self.write_tempfile()
     fformat = self.options.format
     fname   = self.options.name
     findex  = 0
+    fpaths  = []
 
     for oid in self.options.ids:
       findex = findex + 1
@@ -137,12 +148,17 @@ def export_files(self):
       else:
         output = self.file_path("%s-%s" % (fname, findex), fformat)
 
+      fpaths.append(output)
+
       if self.options.replace == 'false' and os.path.exists(output):
         continue
 
       self.export(oid, fformat, output, tmpfile)
       self.remove_pt(output, fformat)
 
+    if self.options.combine == 'true' and fformat == 'pdf':
+      self.pdftk_combine(fname, fpaths)
+
   def effect(self):
     if self.options.name is None:
       inkex.errormsg('Please enter the folder name.')