Dynamically draw circle using mouse in openCV

Question

I have been trying to make an OpenCV-Py program to draw rectangle, line, and circle on mouse click and drag. I could successfully do it for line and rectangle but the code for the circle is wrong and I need help with that.

import numpy as np
import cv2 as cv
import math
drawing = False # true if mouse is pressed
ix,iy = -1,-1
# mouse callback function
def draw_circle(event,x,y,flags,param):
    global ix,iy,drawing
    if event == cv.EVENT_LBUTTONDOWN:
        drawing = True
        ix,iy = x,y
    elif event == cv.EVENT_MOUSEMOVE:
        if drawing == True:
             k = cv.waitKey(33)

             if k == ord('r'):
                cv.rectangle(img,(ix,iy),(x,y),(0,255,0),-1)
             elif k==ord('c'):
                cv.circle(img,int(((ix+x)/2,(iy+y)/2)),int(math.sqrt( ((ix-x)**2)+((iy-y)**2) )),(0,0,255),-1)
             elif k== ord('l'):
                cv.line(img,(ix,iy),(x,y),(255,0,0),5)
    elif event == cv.EVENT_LBUTTONUP:
        drawing = False
img = np.zeros((512,512,3), np.uint8)
cv.namedWindow('image')
cv.setMouseCallback('image',draw_circle)
while(1):
    cv.imshow('image',img)
    k = cv.waitKey(1) & 0xFF
    if k == 27:
    break
cv.destroyAllWindows()

ERROR: Traceback (most recent call last): File "mouse.py", line 19, in draw_circle cv.circle(img,int(((ix+x)/2,(iy+y)/2)),int(math.sqrt( ((ix-x)**2)+((iy-y)**2) )),(0,0,255),-1) TypeError: int() argument must be a string, a bytes-like object or a number, not 'tuple'

try (int((ix+x)/2), int((iy+y)/2)) instead of int(((ix+x)/2,(iy+y)/2)) — Olivier Samson, Jun 02 '18 at 05:32

score -1 · Answer 1 · answered May 26 '21 at 15:26

To dynamically draw a circle with OpenCV,

import numpy as np
import cv2
import math
drawing = False # true if mouse is pressed
ix,iy = -1,-1

# Create a function based on a CV2 Event (Left button click)
def draw_circle(event,x,y,flags,param):
    global ix,iy,drawing
    
    if event == cv2.EVENT_LBUTTONDOWN:
        drawing = True
        # we take note of where that mouse was located
        ix,iy = x,y
        
    elif event == cv2.EVENT_MOUSEMOVE:
        drawing == True
        
    elif event == cv2.EVENT_LBUTTONUP:
        radius = int(math.sqrt( ((ix-x)**2)+((iy-y)**2)))
        cv2.circle(img,(ix,iy),radius,(0,0,255), thickness=1)
        drawing = False

# Create a black image
img = np.zeros((512,512,3), np.uint8)

# This names the window so we can reference it
cv2.namedWindow('image')

# Connects the mouse button to our callback function
cv2.setMouseCallback('image',draw_circle)

while(1):
    cv2.imshow('image',img)

    # EXPLANATION FOR THIS LINE OF CODE:
    # https://stackoverflow.com/questions/35372700/whats-0xff-for-in-cv2-waitkey1/39201163
    k = cv2.waitKey(1) & 0xFF
    if k == 27:
        break
# Once script is done, its usually good practice to call this line
# It closes all windows (just in case you have multiple windows called)
cv2.destroyAllWindows()

Dynamically draw circle using mouse in openCV

1 Answers1