python: 'cv2.' -> 'cv.' via 'import cv2 as cv'

doc/py_tutorials/py_gui/py_mouse_handling/py_mouse_handling.markdown

@@ -5,7 +5,7 @@ Goal
 ----
 
 -   Learn to handle mouse events in OpenCV
--   You will learn these functions : **cv2.setMouseCallback()**
+-   You will learn these functions : **cv.setMouseCallback()**
 
 Simple Demo
 -----------
@@ -19,32 +19,32 @@ double-click etc. It gives us the coordinates (x,y) for every mouse event. With
 location, we can do whatever we like. To list all available events available, run the following code
 in Python terminal:
 @code{.py}
-import cv2
-events = [i for i in dir(cv2) if 'EVENT' in i]
+import cv2 as cv
+events = [i for i in dir(cv) if 'EVENT' in i]
 print( events )
 @endcode
 Creating mouse callback function has a specific format which is same everywhere. It differs only in
 what the function does. So our mouse callback function does one thing, it draws a circle where we
 double-click. So see the code below. Code is self-explanatory from comments :
 @code{.py}
-import cv2
 import numpy as np
+import cv2 as cv
 
 # mouse callback function
 def draw_circle(event,x,y,flags,param):
-    if event == cv2.EVENT_LBUTTONDBLCLK:
-        cv2.circle(img,(x,y),100,(255,0,0),-1)
+    if event == cv.EVENT_LBUTTONDBLCLK:
+        cv.circle(img,(x,y),100,(255,0,0),-1)
 
 # Create a black image, a window and bind the function to window
 img = np.zeros((512,512,3), np.uint8)
-cv2.namedWindow('image')
-cv2.setMouseCallback('image',draw_circle)
+cv.namedWindow('image')
+cv.setMouseCallback('image',draw_circle)
 
 while(1):
-    cv2.imshow('image',img)
-    if cv2.waitKey(20) & 0xFF == 27:
+    cv.imshow('image',img)
+    if cv.waitKey(20) & 0xFF == 27:
         break
-cv2.destroyAllWindows()
+cv.destroyAllWindows()
 @endcode
 More Advanced Demo
 ------------------
@@ -55,8 +55,8 @@ function has two parts, one to draw rectangle and other to draw the circles. Thi
 will be really helpful in creating and understanding some interactive applications like object
 tracking, image segmentation etc.
 @code{.py}
-import cv2
 import numpy as np
+import cv2 as cv
 
 drawing = False # true if mouse is pressed
 mode = True # if True, draw rectangle. Press 'm' to toggle to curve
@@ -66,40 +66,40 @@ ix,iy = -1,-1
 def draw_circle(event,x,y,flags,param):
     global ix,iy,drawing,mode
 
-    if event == cv2.EVENT_LBUTTONDOWN:
+    if event == cv.EVENT_LBUTTONDOWN:
         drawing = True
         ix,iy = x,y
 
-    elif event == cv2.EVENT_MOUSEMOVE:
+    elif event == cv.EVENT_MOUSEMOVE:
         if drawing == True:
             if mode == True:
-                cv2.rectangle(img,(ix,iy),(x,y),(0,255,0),-1)
+                cv.rectangle(img,(ix,iy),(x,y),(0,255,0),-1)
             else:
-                cv2.circle(img,(x,y),5,(0,0,255),-1)
+                cv.circle(img,(x,y),5,(0,0,255),-1)
 
-    elif event == cv2.EVENT_LBUTTONUP:
+    elif event == cv.EVENT_LBUTTONUP:
         drawing = False
         if mode == True:
-            cv2.rectangle(img,(ix,iy),(x,y),(0,255,0),-1)
+            cv.rectangle(img,(ix,iy),(x,y),(0,255,0),-1)
         else:
-            cv2.circle(img,(x,y),5,(0,0,255),-1)
+            cv.circle(img,(x,y),5,(0,0,255),-1)
 @endcode
 Next we have to bind this mouse callback function to OpenCV window. In the main loop, we should set
 a keyboard binding for key 'm' to toggle between rectangle and circle.
 @code{.py}
 img = np.zeros((512,512,3), np.uint8)
-cv2.namedWindow('image')
-cv2.setMouseCallback('image',draw_circle)
+cv.namedWindow('image')
+cv.setMouseCallback('image',draw_circle)
 
 while(1):
-    cv2.imshow('image',img)
-    k = cv2.waitKey(1) & 0xFF
+    cv.imshow('image',img)
+    k = cv.waitKey(1) & 0xFF
     if k == ord('m'):
         mode = not mode
     elif k == 27:
         break
 
-cv2.destroyAllWindows()
+cv.destroyAllWindows()
 @endcode
 Additional Resources
 --------------------