Python Forum

I want to be able to draw lines between my mouse clicks, for example, click 1(put a dot, draws a line from 0,0 to point 1) click 2( puts dot, draws a line from point 1 to point 2) and so on,
look at DEF SCENE here's some of my code...

from pygame import *
init()
size = width, height = 800, 600
screen = display.set_mode(size)
button = 0
BLACK = (0, 0, 0)
RED = (255, 0, 0)
screen.fill(BLACK)
def getVal(tup):
    """ getVal returns the (position+1) of the first 1 within a tuple.
        This is used because MOUSEBUTTONDOWN and MOUSEMOTION deal with
        mouse events differently
    """
    for i in range(3):
        if tup[i]==1:
            return i+1
    return 0
    
def drawScene(screen, button):
    # Draw circle if the left mouse button is down.
    if button==1:
        draw.circle(screen,RED,(mx,my), 5)
        x,y = mouse.get_pos()
        draw.line(screen,RED,(0,0),(x,y),1) 
    display.flip()
    if button>1:  
        screen.fill(BLACK)
     
     
display.flip()
    
    
running = True
myClock = time.Clock()
 
while running:
    for e in event.get():
        keydown= pygame.Key.get_pressed()
        if KeyDown[pygame.K_ESCAPE]:
            quit()
        if e.type== QUIT:
            running=False
        if e.type== MOUSEBUTTONDOWN:
            mx,my = e.pos
            button= e.button
        if e.type== MOUSEMOTION:
            mx,my= e.pos
            button= getVal(e.buttons)
    drawScene(screen,button)
    myClock.tick(60)
quit()

Any help please?

The approach I would take is to save the location of each mouse click to a list, then loop over the list to draw lines from each point to the next.

points = []

if e.type== MOUSEBUTTONDOWN:
    points.append(mouse.get_pos())

if len(points) > 1:
    for i in range((len(points) - 1)):
        pg.draw.line(screen, (255, 255, 255), points[i], points[i +1], 2)

Should be pretty close.

Never get key pressed in event loop. When in event loop. Only use event items.
Example.

import pygame

def main():
    pygame.init()
    pygame.display.set_caption("Mouse Draw")
    surface = pygame.display.set_mode((800, 600))
    clock = pygame.time.Clock()
    rect = surface.get_rect()
    fps = 60

    line_surface = pygame.Surface(rect.size, pygame.SRCALPHA)
    line_surface.fill((0, 0, 0, 0))

    mouse_position = None
    display_line = None
    running = True
    while running:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                running = False
            elif event.type == pygame.MOUSEMOTION:
                if mouse_position:
                    display_line = mouse_position, event.pos
            elif event.type == pygame.MOUSEBUTTONDOWN:
                if event.button == 1:
                    if mouse_position:
                        pygame.draw.line(line_surface, pygame.Color("red"), mouse_position, event.pos)
                        mouse_position = None
                        display_line = None
                    else:
                        mouse_position = event.pos


        surface.fill(pygame.Color('black'))
        surface.blit(line_surface, (0, 0))

        if display_line:
            pygame.draw.line(surface, pygame.Color('lawngreen'), *display_line)

        pygame.display.update()
        clock.tick(fps)

main()

---

If you want it to be continues lines. Change line 28.

mouse_position = event.pos

Thanks so much, just had one more question... is there any way I can make the first line disappear when the second line gets drawn? (I'm making a game where it would be useful.) Thanks in advance!

This is programming. You can do what ever you put you mind too. So yes.

You need to put boolean variable around surface.blit(line_surface, (0, 0). Create show_lines = False before main loop. Then an if block around surface.blit(line_surface, (0, 0).
You need a new variable. draw_line = None under display_line before main loop.
Then in event mouse button down. draw_line = mouse_position, event.pos
Then you draw it like display_line.