Converting physical coordinates to id coordinates

Hello. I am a beginner VTK user and I need an immediate help. I am working on a extension on an old code. As I understand, I need to give Pick() function id coordinates( back then, code was working properly with id coordinates). But now, I have physical coordinates(as I understand, again) and Pick() do not work with these. So, I tried conversion with TransformPhysicalPointToContinuousIndex() but it did not work. It changed nothing. Returned the exact same physicalcoordinates. Thanks,

def leftButtonPressEvent(self, obj, event):

                global data, vec, i, noktagoster, goster, x, y, mousehareket, clickPosold, selet, pointposOld, arb, distp

               

                # print('right',event)

                clickPos = self.GetInteractor().GetEventPosition()

                picker = vtk.vtkPropPicker()

                self.NewPickedActor = picker.GetActor()

                picker.Pick(clickPos[0], clickPos[1], 0, self.GetDefaultRenderer())

                pointpos = picker.GetPickPosition()

                x, y, z = pointpos
                
                vtri = [x, y, z]
                print("VTRI first: "+str(pointpos))
                
                vec.append(vtri)
                print(i)
                i = i + 1
                
                f = open("hamsi.txt", "a")
                f.write(str(vec[i][2]) + "\n")
                f.close()

                if i == 0:

                    MouseInteractor.cagir(vec)

                else:
                    MouseInteractor.cagir(vec)
                    
                    diffx = (vec[1][0] - vec[0][0])/100#will be adjusted afterwards
                    diffy = (vec[1][1] - vec[0][1])/100
                    temp = [0, 0,0]  # holds only x and y
                    temp[0] = vec[0][0]
                    temp[1] = vec[0][1]
                    #while (
                    #   abs(temp[0] - vec[1][0]) > 0.18 or abs(temp[1] - vec[1][1]) > 0.18
                    #):
                    for q in range(100):



                        
                        temp[0] += diffx
                        
                        
                        temp[1] += diffy
                        
                        
                        '''print("temp[0]: "+str(temp[0]))
                        print("temp[1]: "+str(temp[1]))
                        print("vec[1][0]: "+str(vec[1][0]))
                        print("vec[1][1]: "+str(vec[1][1]))'''
                        #clickPos = self.GetInteractor().GetEventPosition()#need to be temp x y and world z
                        #print(type(clickPos))
                        picker = vtk.vtkPropPicker()
                        temp_id=[0,0,0]
                        convert=vtk.vtkImageData()
                        convert.TransformPhysicalPointToContinuousIndex(temp[0],temp[1],0,temp_id)
                        print(temp_id)
                                                
                        

                        #self.NewPickedActor = picker.GetActor()
                        #temp=tuple(temp)
                        print("temp[0]: "+str(temp[0]))
                        print("temp[1]: "+str(temp[1]))
                        picker.Pick(temp[0],temp[1],0,self.GetDefaultRenderer())
                        #temp=list(temp)
                        pointpos = picker.GetPickPosition()
                        
                        x, y, z = pointpos

                        vtri = [x, y, z]
                        print("VTRI: "+str(vtri))
                        vec.append(vtri)
                        print(i)
                        i = i + 1

                        f = open("hamsi.txt", "a")
                        f.write(str(vec[i][2]) + "\n")
                        f.close()
                        MouseInteractor.cagir(vec)