transparent rectangle in pygame

Question

I am trying to draw simple semi-transparent rectangle in pygame. I have tried this code:

import pygame, sys,pygame.mixer

pygame.init()
size = (width, height) = (400, 400)
screen = pygame.display.set_mode(size)
screen.fill((255,255,255))
pygame.draw.rect(screen, (23, 100, 255, 50), (100,100,100,100),0)

running = True
while running:
    for event in pygame.event.get():
       if event.type == pygame.QUIT:
            pygame.quit()
            running = False

But as you can see, the rectangle is not semi-transparent. It's like I inserted the color 23, 100, 255, 255) rather than (23, 100, 255, 50).

Can you post a complete example? The above doesn't draw anything for me. — hexist, Oct 23 '12 at 09:14

score 6 · Answer 1 · answered Mar 16 '14 at 00:47

6

You can also use gfxdraw which has several options and accepts alpha in color.

You'll need to import:

import pygame.gfxdraw

And use with:

pygame.gfxdraw.box(screen, pygame.Rect(0,0,200,200), (100,0,0,127))

answered Mar 16 '14 at 00:47

Gustavo J.C.

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4
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score 5 · Answer 2 · answered Oct 23 '12 at 11:52

pygame.draw.rect documentation doesn't state support for alpha channel.

You should create a RGBA surface and fill it with the semi transparent color:

rect = pygame.Surface((100,100), pygame.SRCALPHA, 32)
rect.fill((23, 100, 255, 50))
screen.blit(rect, (100,100))

score 0 · Answer 3 · edited May 23 '17 at 12:32

0

I asked a question similar to this here. What I ended up doing was using the set_alpha() function after converting it to an alpha image. You may find something helpful in my question. Also, make sure you're not showing an older version of the rectangle that has 100% opacity behind the one that is semi-transparent.

edited May 23 '17 at 12:32

Community

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answered Oct 24 '12 at 12:36

Ben Schwabe

1,283
1
21
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transparent rectangle in pygame

3 Answers3