import cv2
import numpy as np


def nothing(x):
  pass

drawing = False # true if mouse is pressed
mode = True # if True, draw rectangle. Press 'm' to toggle to curve
ix,iy = -1,-1


switch = "Brush Size"
# Create a black image, a window
img = np.zeros((375,900,3), np.uint8)
cv2.namedWindow('image')

# create trackbars for color change
cv2.createTrackbar('R', 'image', 0, 255, nothing)
cv2.createTrackbar('G', 'image', 0, 255, nothing)
cv2.createTrackbar('B', 'image', 0, 255, nothing)

# create switch for ON/OFF functionality

cv2.createTrackbar(switch, 'image', 1, 10, nothing)



# mouse callback function
def draw_circle(event,x,y,flags,param):
    global ix,iy,drawing,mode
    # get current positions of four trackbars
    r = cv2.getTrackbarPos('R', 'image')
    g = cv2.getTrackbarPos('G', 'image')
    b = cv2.getTrackbarPos('B', 'image')
    s = cv2.getTrackbarPos(switch, 'image')
    if event == cv2.EVENT_LBUTTONDOWN:
        drawing = True
        ix,iy = x,y

    elif event == cv2.EVENT_MOUSEMOVE:
        if drawing == True:
            if mode != True:
               cv2.circle(img,(x,y),s,(r,g,b),-1)

    elif event == cv2.EVENT_LBUTTONUP:
        drawing = False
        if mode == True:
            cv2.rectangle(img,(ix,iy),(x,y),(r,g,b),19)
        else:
            cv2.circle(img,(x,y),s,(r,g,b),-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)

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