Quit gracefully after closing the main window.

pixelocr/gui/ocrengine.py

@@ -23,6 +23,9 @@ from PyQt4.QtCore import (
     slot,
     QThread, 
 )
+from PyQt4.QtGui import (
+    qApp
+)
 
 from ..image import Image
 from ..page import Page, Glyph, Space
@@ -68,6 +71,7 @@ class OCREngine(QThread):
             yield self.recognize_glyph(glyph)
 
     def recognize_glyph(self, glyph):
+        qApp.processEvents()
         if isinstance(glyph, Space):
             return ' '
         try: