Various Python samples updated for Python 2/3 compatibility.

samples/python2/morphology.py

@@ -12,12 +12,17 @@ Keys:
   ESC - exit
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+import sys
+PY3 = sys.version_info[0] == 3
+
 import numpy as np
 import cv2
 
 
 if __name__ == '__main__':
-    print __doc__
+    print(__doc__)
 
     import sys
     from itertools import cycle
@@ -31,15 +36,20 @@ if __name__ == '__main__':
     img = cv2.imread(fn)
 
     if img is None:
-        print 'Failed to load image file:', fn
+        print('Failed to load image file:', fn)
         sys.exit(1)
 
     cv2.imshow('original', img)
 
     modes = cycle(['erode/dilate', 'open/close', 'blackhat/tophat', 'gradient'])
     str_modes = cycle(['ellipse', 'rect', 'cross'])
-    cur_mode = modes.next()
-    cur_str_mode = str_modes.next()
+
+    if PY3:
+        cur_mode = next(modes)
+        cur_str_mode = next(str_modes)
+    else:
+        cur_mode = modes.next()
+        cur_str_mode = str_modes.next()
 
     def update(dummy=None):
         sz = cv2.getTrackbarPos('op/size', 'morphology')
@@ -73,8 +83,14 @@ if __name__ == '__main__':
         if ch == 27:
             break
         if ch == ord('1'):
-            cur_mode = modes.next()
+            if PY3:
+                cur_mode = next(modes)
+            else:
+                cur_mode = modes.next()
         if ch == ord('2'):
-            cur_str_mode = str_modes.next()
+            if PY3:
+                cur_str_mode = next(str_modes)
+            else:
+                cur_str_mode = str_modes.next()
         update()
     cv2.destroyAllWindows()