mouse.py

import numpy as np
import cv2

# GOAL: use cv2.setMouseCallback()
events = [i for i in dir(cv2) if 'EVENT' in i]
print(events)

drawing = False # true if mouse is pressed
mode = True # if True, draw rectangle. Press 'm' to toggle to curve
ix,iy = -1,-1
# mouse callback function
def draw_circle(event,x,y,flags,param):
	global ix,iy,drawing,mode
	if event == cv2.EVENT_LBUTTONDOWN:
		drawing = True
		ix,iy = x,y
	elif event == cv2.EVENT_MOUSEMOVE: # for rectangles, will repeatedly draw rectangles => creates the "filled" appearance
		if drawing == True:
			if mode == True:
				pass
				#cv2.rectangle(img, (ix, iy), (x,y), (0,255,0), 5) removed to only draw rectangle outline
			else:
				cv2.circle(img, (x,y), 5, (0,0,255), -1)
	elif event == cv2.EVENT_LBUTTONUP:
		drawing = False
		if mode == True:
			cv2.rectangle(img,(ix,iy),(x,y),(0,255,0),5)
		else:
			cv2.circle(img,(x,y),5,(0,0,255),-1)

img = np.zeros((512,512,3), np.uint8)
cv2.namedWindow('image')
cv2.setMouseCallback('image', draw_circle)

while(1):
	cv2.imshow('image', img)
	k = cv2.waitKey(1) & 0xFF
	if k == ord('m'):
		mode = not mode
	elif k == 27:
		break
cv2.destroyAllWindows()