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

doc/py_tutorials/py_gui/py_drawing_functions/py_drawing_functions.markdown

@@ -5,8 +5,8 @@ Goal
 ----
 
 -   Learn to draw different geometric shapes with OpenCV
--   You will learn these functions : **cv2.line()**, **cv2.circle()** , **cv2.rectangle()**,
-    **cv2.ellipse()**, **cv2.putText()** etc.
+-   You will learn these functions : **cv.line()**, **cv.circle()** , **cv.rectangle()**,
+    **cv.ellipse()**, **cv.putText()** etc.
 
 Code
 ----
@@ -19,7 +19,7 @@ In all the above functions, you will see some common arguments as given below:
 -   thickness : Thickness of the line or circle etc. If **-1** is passed for closed figures like
     circles, it will fill the shape. *default thickness = 1*
 -   lineType : Type of line, whether 8-connected, anti-aliased line etc. *By default, it is
-    8-connected.* cv2.LINE_AA gives anti-aliased line which looks great for curves.
+    8-connected.* cv.LINE_AA gives anti-aliased line which looks great for curves.
 
 ### Drawing Line
 
@@ -27,27 +27,27 @@ To draw a line, you need to pass starting and ending coordinates of line. We wil
 image and draw a blue line on it from top-left to bottom-right corners.
 @code{.py}
 import numpy as np
-import cv2
+import cv2 as cv
 
 # Create a black image
 img = np.zeros((512,512,3), np.uint8)
 
 # Draw a diagonal blue line with thickness of 5 px
-cv2.line(img,(0,0),(511,511),(255,0,0),5)
+cv.line(img,(0,0),(511,511),(255,0,0),5)
 @endcode
 ### Drawing Rectangle
 
 To draw a rectangle, you need top-left corner and bottom-right corner of rectangle. This time we
 will draw a green rectangle at the top-right corner of image.
 @code{.py}
-cv2.rectangle(img,(384,0),(510,128),(0,255,0),3)
+cv.rectangle(img,(384,0),(510,128),(0,255,0),3)
 @endcode
 ### Drawing Circle
 
 To draw a circle, you need its center coordinates and radius. We will draw a circle inside the
 rectangle drawn above.
 @code{.py}
-cv2.circle(img,(447,63), 63, (0,0,255), -1)
+cv.circle(img,(447,63), 63, (0,0,255), -1)
 @endcode
 ### Drawing Ellipse
 
@@ -55,10 +55,10 @@ To draw the ellipse, we need to pass several arguments. One argument is the cent
 Next argument is axes lengths (major axis length, minor axis length). angle is the angle of rotation
 of ellipse in anti-clockwise direction. startAngle and endAngle denotes the starting and ending of
 ellipse arc measured in clockwise direction from major axis. i.e. giving values 0 and 360 gives the
-full ellipse. For more details, check the documentation of **cv2.ellipse()**. Below example draws a
+full ellipse. For more details, check the documentation of **cv.ellipse()**. Below example draws a
 half ellipse at the center of the image.
 @code{.py}
-cv2.ellipse(img,(256,256),(100,50),0,0,180,255,-1)
+cv.ellipse(img,(256,256),(100,50),0,0,180,255,-1)
 @endcode
 ### Drawing Polygon
 
@@ -68,30 +68,30 @@ polygon of with four vertices in yellow color.
 @code{.py}
 pts = np.array([[10,5],[20,30],[70,20],[50,10]], np.int32)
 pts = pts.reshape((-1,1,2))
-cv2.polylines(img,[pts],True,(0,255,255))
+cv.polylines(img,[pts],True,(0,255,255))
 @endcode
 
 @note If third argument is False, you will get a polylines joining all the points, not a closed
 shape.
 
-@note cv2.polylines() can be used to draw multiple lines. Just create a list of all the lines you
+@note cv.polylines() can be used to draw multiple lines. Just create a list of all the lines you
 want to draw and pass it to the function. All lines will be drawn individually. It is a much better
-and faster way to draw a group of lines than calling cv2.line() for each line.
+and faster way to draw a group of lines than calling cv.line() for each line.
 
 ### Adding Text to Images:
 
 To put texts in images, you need specify following things.
     -   Text data that you want to write
     -   Position coordinates of where you want put it (i.e. bottom-left corner where data starts).
-    -   Font type (Check **cv2.putText()** docs for supported fonts)
+    -   Font type (Check **cv.putText()** docs for supported fonts)
     -   Font Scale (specifies the size of font)
-    -   regular things like color, thickness, lineType etc. For better look, lineType = cv2.LINE_AA
+    -   regular things like color, thickness, lineType etc. For better look, lineType = cv.LINE_AA
         is recommended.
 
 We will write **OpenCV** on our image in white color.
 @code{.py}
-font = cv2.FONT_HERSHEY_SIMPLEX
-cv2.putText(img,'OpenCV',(10,500), font, 4,(255,255,255),2,cv2.LINE_AA)
+font = cv.FONT_HERSHEY_SIMPLEX
+cv.putText(img,'OpenCV',(10,500), font, 4,(255,255,255),2,cv.LINE_AA)
 @endcode
 
 ### Result