python - How do I make this pygame program to change from a drawing state to non drawing state when clicked and vice versa? -

i want simulation of paint work such if mouse button pressed, starts drawing ( button released instantly). again, when button pressed, should stop drawing.

there no error. in present case shared remains pen down (drawing) mode. have tried get_pressed function succeeded in drawing when key remains pressed. tried making equal (a,0,0) , vary a achieve goal unsuccessful.

after few attempts resulted in drawing mode turning on or off instantaneously instead of on click.

here's part controls action:

while keepgoing:     clock.tick(30)      event in pygame.event.get():         if event.type == pygame.quit:             keepgoing = false         elif event.type == pygame.mousemotion:             lineend = pygame.mouse.get_pos()             if pygame.mousebuttonup:                 pygame.draw.line(background, drawcolor, linestart, lineend, linewidth)             linestart = lineend         elif event.type == pygame.keydown:             mydata = (event, background, drawcolor, linewidth, keepgoing)             mydata = checkkeys(mydata)             (event, background, drawcolor, linewidth, keepgoing) = mydata     screen.blit(background, (0, 0))     mylabel = showstats(drawcolor, linewidth)     screen.blit(mylabel, (450, 450))     pygame.display.flip() 

complete code link: http://codeshare.io/gbpc0

here's minimal example of want do:

import pygame screen = pygame.display.set_mode((800, 600)) line_start = none  while true:   mouse_pos = pygame.mouse.get_pos()   e in pygame.event.get():     if e.type == pygame.quit:       break     if e.type == pygame.mousebuttonup:       line_start = none if line_start else mouse_pos   else:     if line_start:       pygame.draw.line(screen, pygame.color.color('white'), line_start, mouse_pos, 1)       line_start = mouse_pos     pygame.display.flip()     continue   break 

it keeps track of state (are in drawing or non-drawing mode?) storing none or last mouse position in line_start on mousebuttonup event.