disable "export to pdf" if pdftex is not avaliable

uberwriter/UberwriterWindow.py

@@ -1022,6 +1022,12 @@ class UberwriterWindow(Window):
         self.focusmode_button.set_name('focus_toggle')
         self.preview_button.set_name('preview_toggle')
 
+        self.export_pdf_button = builder.get_object('mnu_export_pdf')
+
+        # Gray export to pdf if pdftex not avaliable
+        if not helpers.exist_executable('pdftex'):
+            self.export_pdf_button.set_sensitive(False)
+
         # Setup status bar hide after 3 seconds
 
         self.status_bar = builder.get_object('status_bar_box')

uberwriter_lib/helpers.py

@@ -20,6 +20,7 @@
 import logging
 import os
 import sys
+import shutil
 
 from . uberwriterconfig import get_data_file
 from . Builder import Builder
@@ -125,3 +126,6 @@ def alias(alternative_function_name):
         function.aliases.append(alternative_function_name)
         return function
     return decorator
+
+def exist_executable(command):
+    return shutil.which(command) is not None