Python Draw Arrow on Image

Draw different shapes on image using Python OpenCV

In this article, you will learn to draw different spaces on a image using Python OpenCV module.

OpenCV provides different functionality to draw different shapes, like circle, rectangle, triangle, ellipses, and so on. This is basically required in building a computer vision project, where we usually modify the image by drawing some shapes. For example, to draw a rectangle for highlighting the detected face in face recognition program.

Technical Requirements

The technical requirements for drawing different shapes are as follows -

• Python Package
• OpenCV Package

Draw Lines

Python OpenCV module provides line() method to draw line segments. The syntax of line() method -

                      cv2.line(image, start_point, end_point, color, thickness)                  

Here, the image is the image on which line to be drawn, start_point is the starting coordinates of line, end_point is the ending coordinates of line, color is the color of line segment and thickness is the thickness of line.

Example of Draw Lines

          import cv2     # image path  path = r'nature.jpg'  # using imread()   img = cv2.imread(path)   cv2.line(img, (0, 0), (400, 400), (255,0,0), 3) cv2.line(img, (0, 200), (200, 0), (198, 33, 6), 4) cv2.line(img, (200, 0), (200, 400), (7, 35, 122), 3) cv2.line(img, (200, 0), (400, 400), (243, 240, 35), 3)  cv2.imshow('image', img) cv2.waitKey(0); cv2.destroyAllWindows(); cv2.waitKey(1)        

Output

Draw Rectangle

The rectangle() method is used to draw a simple or filled rectangle on a given image. The syntax is -

                      cv2.rectangle(image, start_point, end_point, color, thickness)                  

Example

          import cv2     # image path  path = r'nature.jpg'  # using imread()   img = cv2.imread(path)  cv2.rectangle(img, (10, 10), (100, 100), (7, 35, 122), 3) cv2.rectangle(img, (150, 150), (300, 300), (129, 255, 43 ), -1)  cv2.imshow('image', img) cv2.waitKey(0); cv2.destroyAllWindows(); cv2.waitKey(1)                  

Output

Draw Circle

The OpenCV has circle() method to draw a simple or filled circle on a given image.

                      cv2.circle(image, center_coordinates, radius, color, thickness)                  

Example

          import cv2     # image path  path = r'nature.jpg'  # using imread()   img = cv2.imread(path)  cv2.circle(img, (50, 50), 50, (66, 9, 47), 3) cv2.circle(img, (250, 200), 60, (52, 229, 81), -1)  cv2.imshow('image', img) cv2.waitKey(0); cv2.destroyAllWindows(); cv2.waitKey(1)                  

Output

Drawing Arrows

The arrowedLine() method allows us to create an arrow on a specified image. The syntax is -

                      arrowedLine(img, start_point, end_point, color, thickness, line_type, shift, tip_length)                  

In the above syntax, the line_type specifies type of line for drawing, shift denotes number of fractional bits in the point coordinates and tip_length is the length of arrow tip in relation to the arrow length.

Example

          import cv2     # image path  path = r'nature.jpg'  # using imread()   img = cv2.imread(path)  cv2.arrowedLine(img, (100, 100), (200, 100), (63, 52, 155), 3, 8, 0, 0.1) cv2.arrowedLine(img, (170, 170), (220, 170), (220, 25, 6), 3, cv2.LINE_AA, 0, 0.3)  cv2.imshow('image', img) cv2.waitKey(0); cv2.destroyAllWindows(); cv2.waitKey(1)        

Output

Drawing Ellipses

The OpenCV has ellipse() method to draw a simple or filled ellipse on a given image.

                      ellipse(img, center, axes, angle, start_angle, end_angle, color, thickness)                  

Example

          import cv2     # image path  path = r'nature.jpg'  # using imread()   img = cv2.imread(path)  cv2.ellipse(img, (80, 80), (20, 50), 0, 0, 360, (16, 248, 220), 3) cv2.ellipse(img, (200, 200), (10, 50), 0, 0, 360, (219, 9, 222), 3)  cv2.imshow('image', img) cv2.waitKey(0); cv2.destroyAllWindows(); cv2.waitKey(1)                  

Output

Drawing Text

Python OpenCV has putText() method to draw a text string on a given image. The syntax of putText() is -

                      putText(image, text, org, font, fontScale, color, thickness)                  

Example

          import cv2     # image path  path = r'nature.jpg'  # using imread()   img = cv2.imread(path)  x1 = 'Our Beautiful Nature' x2 = 'etutorialspoint.com'  cv2.putText(img, x1, (10, 30), cv2.FONT_HERSHEY_SIMPLEX, 1,(0,0,255),2 ) cv2.putText(img, x2, (10, 70), cv2.FONT_HERSHEY_SIMPLEX, 1,(255,0,0),1 )  cv2.imshow('image', img) cv2.waitKey(0); cv2.destroyAllWindows(); cv2.waitKey(1)                  

Output

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Python Draw Arrow on Image

Source: https://www.etutorialspoint.com/index.php/305-python-draw-different-shapes-on-image

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