# is it possible to adjust convex hull to draw blue line instead of green line?

```i succeed to use code to draw green line, but green line not draw the
large area, expect second uploaded picture, the blue line connect
the bottom of red line graph```
```
im = img.copy()
cntcounter = 0
for cnt in contours:
#epsilon = 0.1*cv2.arcLength(cnt,True)
#approx = cv2.approxPolyDP(cnt,epsilon,True)
#peri = cv2.arcLength(cnt, True)
#approx = cv2.approxPolyDP(cnt, 0.15 * peri, True)
#print("len(approx)="+str(len(approx)))
#if len(approx) == 2:
print("approx=" + str(approx))
cntcounter = cntcounter + 1
print("here1")
#x,y,w,h = cv2.boundingRect(cnt)
hull = cv2.convexHull(cnt,returnPoints = True)
print("here2")
while im is None:
time.sleep(1)
if im is not None:
print("here3")
#cv2.rectangle(im, (x,y), (x+w, y+h), (0,255,0), 2)

#cv2.imwrite("C:\\Users\\tester\\Documents\\masda"+str(cntcounter)+".png",imi)

#im = cv2.line(im,(x,y),(x+w,y),(0,255,0),2)
#im = cv2.line(im,(x+w,y),(x+w,y+h),(0,255,0),2)
#im = cv2.line(im,(x,y+h),(x+w,y+h),(0,255,0),2)
#im = cv2.line(im,(x,y),(x,y+h),(0,255,0),2)
previousx = 0
previousy = 0
for c in hull:
if previousx != 0 and previousy != 0 and c[0][0] != 0 and
c[0][1] != 0 and abs(previousy - c[0][1]) > 10 and abs(c[0][0] - previousx) >
1:
while im is None:
time.sleep(1)

cv2.line(im,(previousx,previousy),(c[0][0],c[0][1]),(0,255,0),2)
print("")
#print("previousx=" + str(previousx))
#print("previousy=" + str(previousy))
#print("c[0][0]=" + str(c[0][0]))
#print("c[0][1]=" + str(c[0][1]))
previousx = c[0][0]
previousy = c[0][1]