I used the following sample image and coloured it using the following script. The script outputs a GUI containing trackbars to choose the RGB value and also to set the resolution. You have to click on a portion in the image to 'floodfill' it with a colour corresponding to the chosen RGB value.
#!/usr/bin/env python
# Python 2/3 compatibility
from __future__ import print_function
import numpy as np
import cv2
if __name__ == '__main__':
import sys
fn = 'floodfillshapes.png'
img = cv2.imread(fn, True)
if img is None:
print('Failed to load image file:', fn)
sys.exit(1)
h, w = img.shape[:2]
mask = np.zeros((h+2, w+2), np.uint8)
seed_pt = None
fixed_range = True
connectivity = 4
def update(dummy=None):
if seed_pt is None:
cv2.imshow('floodfill', img)
return
flooded = img.copy()
mask[:] = 0
# get current positions of trackbars
r = cv2.getTrackbarPos('R','floodfill')
g = cv2.getTrackbarPos('G','floodfill')
b = cv2.getTrackbarPos('B','floodfill')
lo = cv2.getTrackbarPos('lo', 'floodfill')
hi = cv2.getTrackbarPos('hi', 'floodfill')
flags = connectivity
if fixed_range:
flags |= cv2.FLOODFILL_FIXED_RANGE
cv2.floodFill(flooded, mask, seed_pt, (b, g, r), (lo,)*3, (hi,)*3, flags)
cv2.circle(flooded, seed_pt, 2, (0, 0, 255), -1)
cv2.imshow('floodfill', flooded)
def onmouse(event, x, y, flags, param):
global seed_pt
if flags & cv2.EVENT_FLAG_LBUTTON:
seed_pt = x, y
update()
update()
cv2.setMouseCallback('floodfill', onmouse)
cv2.createTrackbar('R','floodfill',0,255,update)
cv2.createTrackbar('G','floodfill',0,255,update)
cv2.createTrackbar('B','floodfill',0,255,update)
cv2.createTrackbar('lo', 'floodfill', 20, 255, update)
cv2.createTrackbar('hi', 'floodfill', 20, 255, update)
while True:
ch = 0xFF & cv2.waitKey()
if ch == 27:
break
if ch == ord('f'):
fixed_range = not fixed_range
print('using %s range' % ('floating', 'fixed')[fixed_range])
update()
if ch == ord('c'):
connectivity = 12-connectivity
print('connectivity =', connectivity)
update()
cv2.destroyAllWindows()
The output looks like this :