How to make a “while mouse down” loop in pygame

Question

So I currently have this code for an airbrush in a drawing app. When the function is active, it should draw on a canvas, basically like an airbrush. But right now, I don't know how to make pygame detect a mouse down or mouse up and make a while loop out of it. Here is the code:

def airbrush():
    airbrush = True
    cur = pygame.mouse.get_pos()
    click = pygame.mouse.get_pressed()
    while click == True:
        pygame.draw.circle(gameDisplay, colorChosen, (cur[0] + random.randrange(brushSize), cur[1] + random.randrange(brushSize)), random.randrange(1, 5))
        pygame.display.update()
        clock.tick(60)

Right now, I have "while click" which doesn't work. What should I replace "click" with to make this work so that while the mouse is held down, it paints, but when the mouse is "up", it stops?

Answer 1

The state which is returned by pygame.mouse.get_pressed() is evaluated once when pygame.event.get() is called. The return value of pygame.mouse.get_pressed() is tuple with th states of the buttons.

Don't implement a separate event handling in a function. Do the event handling in the main loop:

done = False
while not done:
    clock.tick(60)
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            done = True

    airbrush()
    pygame.display.flip()

Evaluate the current state of a button (eg left button), of the current frame, in the function airbrush :

def airbrush():
    airbrush = True
    cur = pygame.mouse.get_pos()
    click = pygame.mouse.get_pressed()
    if click[0] == True: # evaluate left button
        pygame.draw.circle(gameDisplay, colorChosen, (cur[0] + random.randrange(brushSize), cur[1] + random.randrange(brushSize)), random.randrange(1, 5))