Create Iterable mouse click event in Python? - python-3.x

Question

I am trying to show image to user and asking to click on 4 points for a rectangle from user and once user is done he will press 'c' and exit and my script should return the touch points by user.
For this approach I have written below script using OpenCV,, but not sure how to make class for this purpose iterable, might be I am wrong with some OO technical part but requirement and logic is correct because when not created inside class both functions works fine.
Code:
class mouse_select_points:
''' Select 4 user points from user and crop to straighten'''
__depends__ = ['img_path']
__provides__ = ['ratio','image_resized','click_points']
def __init__(self, thickness=2,shape=(400,600),click_count=0,click_points=[],img_path=""):
self.thickness = thickness
self.shape = shape
self.lent = click_count
self.refPt = click_points
self.img = img_path
self.font = cv2.FONT_HERSHEY_SIMPLEX
def __call__(self):
image = cv2.imread(self.img)
print("first loaded image size:",image.shape)
orig_resized = image.copy() #create a copy of resized image
ratio = image.shape[1] / 600.0
self.shape = image.shape
cv2.namedWindow("image")
cv2.setMouseCallback("image", self._click_and_crop, param = [image] ) #setting param as image to be sent to mouse click function callback
# keep looping until the 'c' key is pressed
while True:
# display the image and wait for a keypress
cv2.imshow("image", image)
cv2.putText(image,"press 'c' to crop or 'r' to reset",(10,15), self.font, .5,(255,255,255),1,cv2.LINE_AA)
key = cv2.waitKey(1) & 0xFF
# if the 'c' key is pressed, break from the loop
elif key == ord("c") and self.lent == 4:
break
return ratio,orig_resized,self.refPt
def _click_and_crop(self,event, x, y, flags, param):
image = param[0]
# if the left mouse button was clicked, record the starting
# (x, y) coordinates and indicate that cropping is being performed
if event == cv2.EVENT_LBUTTONDOWN:
self.refPt.append([x, y])
cv2.circle(image,(int(x),int(y)),self.thickness,(255,1,255),-1)
self.lent += 1
print("inside if")
cv2.imshow("image", image)
##testing
ratio,orig_image = mouse_select_points(img_path=r"Image1.JPG")

Answer 1

I think you want to pick the points repeatly. Here is it.
#!/usr/bin/python3
# 2018.06.13 13:40:12 CST
# 2018.06.13 14:17:49 CST
import cv2
class PickPoints:
''' Select 4 user points from user and crop to straighten'''
__depends__ = ['img_path']
__provides__ = ['ratio','image_resized','click_points']
def __init__(self, thickness=2,shape=(400,600),click_count=0,click_points=[],img_path=""):
self.thickness = thickness
self.shape = shape
self.lent = click_count
self.refPt = click_points
self.img = img_path
self.font = cv2.FONT_HERSHEY_SIMPLEX
def __call__(self):
image = cv2.imread(self.img)
#print("first loaded image size:",image.shape)
print("="*60)
orig_resized = image.copy() #create a copy of resized image
self.shape = image.shape
self.lent = 0
self.refPt = []
self.to_exit = False
cv2.namedWindow("image")
cv2.setMouseCallback("image", self._click_and_crop, param = [image] ) #setting param as image to be sent to mouse click function callback
# keep looping until the 'c' key is pressed
while True:
# display the image and wait for a keypress
cv2.imshow("image", image)
cv2.putText(image,"press 'c' to crop or 'r' to reset",(10,15), self.font, .5,(255,255,255),1,cv2.LINE_AA)
key = cv2.waitKey(30) & 0xFF
# if the 'c' key is pressed, break from the loop
if key == ord("r"):
print("Reset")
self.lent = 0
self.refPt = []
image[:] = orig_resized
if key == ord("c"):
pass
if self.to_exit or key in (27, ord('q'), ord('Q')):
print("Exist")
cv2.destroyAllWindows()
self.to_exit = False
break
return self.refPt
def _click_and_crop(self,event, x, y, flags, param):
image = param[0]
# if the left mouse button was clicked, record the starting
# (x, y) coordinates and indicate that cropping is being performed
if event == cv2.EVENT_LBUTTONDOWN:
if len(self.refPt) <4:
self.refPt.append([x, y])
cv2.circle(image,(int(x),int(y)),self.thickness,(0,255,0),-1)
self.lent += 1
print("#{} {}".format(self.lent, self.refPt[-1]))
cv2.imshow("image", image)
if event == cv2.EVENT_RBUTTONDOWN:
self.to_exit = True
##testing
fname = "/home/auss/Pictures/test.png"
pk = PickPoints(img_path=fname)
print(pk())
print(pk())
print(pk())