Линию не делает в пеинте, засранец:
import pyautogui
pyautogui.moveTo(500, 500)
pyautogui.mouseDown(button = 'right')
pyautogui.moveRel(100, 100, duration = 0.5)
pyautogui.moveRel(-100, 100, duration = 0.5)
pyautogui.moveRel(100, 100, duration = 0.5)
pyautogui.moveRel(-100, 100, duration = 0.5)
pyautogui.mouseUp(button = 'right')