added enums for corner and pixel indexes

enums.py

@@ -0,0 +1,20 @@
+from enum import Enum
+
+class corner(Enum):
+    cBottomLeft=0
+    cBottomRight=1
+    cTopLeft=2
+    cTopRight=3
+
+
+class pixel(Enum):
+    pBottomLeft=0
+    pBottom=1
+    pBottomRight=2
+    pLeft=3
+    pCenter=4
+    pRight=5
+    pTopLeft=6
+    pTop=7
+    pTopRight=8
+