[PyGame] image color

[Zman350x]

I have an image of a white robot. How can I change the color white of that image to another color, like red or blue or green or something?

Happy Valentine's

[nilamo]

Once you've loaded the image as a surface, then you can access that surface's pixels with a PixelArray.  The PixelArray class has a replace method, which replaces all instances of one color with another (so you don't need to check individual pixels yourself).  When you create a PixelArray, it locks the underlying surface until it's garbage collected, so you should delete it when you're done (or use a function and return from it).

http://www.pygame.org/docs/ref/pixelarra...ay.replace

So...

surface = load_image() # ...whatever you're already doing
pixels = PixelArray(surface)
pixels.replace(Color(255, 255, 255, 255), Color(0, 0, 255, 255))
del pixels

[Zman350x]

could I replace the color with an alpha value? I want to change white to clear.

[nilamo]

Absolutely :)

Color() takes for arguments, rgba. If you pass 0 as the final parameter, then it should be fully transparent (and the other three parameters wouldn't matter at that point).

[Zman350x]

I tried that. it ignored the final value

[nilamo]

What about Surface.set_colorkey()?

Set the transparent colorkey
set_colorkey(Color, flags=0) -> None
set_colorkey(None) -> None
Set the current color key for the Surface. When blitting this Surface onto a destination, any pixels that have the same color as the colorkey will be transparent. The color can be an RGB color or a mapped color integer. If None is passed, the colorkey will be unset.

The colorkey will be ignored if the Surface is formatted to use per pixel alpha values. The colorkey can be mixed with the full Surface alpha value.

The optional flags argument can be set to pygame.RLEACCEL to provide better performance on non accelerated displays. An RLEACCEL Surface will be slower to modify, but quicker to blit as a source.

So, if you set the colorkey to whatever color you want to be transparent, that... might... work?

[metulburr]

I made a script to show this example. Without the image you are using i can only use an example image
   

You can change which color is the transparent by change the from_ color. And it shows as white as the background is white before the image is drawn. 

import pygame as pg
   
pg.init()
  
COLORKEY = (0,0,0) #black

RED =    (221,0,0)
ORANGE = (254,98,98)
YELLOW = (254,246,0)
GREEN =  (0,187,0)
BLUE =   (0,155,254)
INDIGO = (0,0,131)
VIOLET = (48,0,155)
    
def swap_color(surf, from_, to_):
    arr = pg.PixelArray(surf)
    arr.replace(from_,to_)
    del arr
   
class Rainbow:
    def __init__(self, screen_rect):
        self.screen_rect = screen_rect
        self.image = pg.image.load('rainbow.png').convert()
        self.rect = self.image.get_rect(center=self.screen_rect.center)
        swap_color(self.image, (0,187,0), COLORKEY)
        self.image.set_colorkey(COLORKEY)
           
    def draw(self, surf):
        surf.blit(self.image, self.rect)
   
screen = pg.display.set_mode((1920,1080))
screen_rect = screen.get_rect()
player = Rainbow(screen_rect)
done = False
while not done:
    screen.fill((255,255,255))
    for event in pg.event.get(): 
        if event.type == pg.QUIT:
            done = True
    player.draw(screen)
    pg.display.update()