对于 pygame.Surface 元素，有没有办法使用.fill() 来更改特定颜色？

Question

I'm making a game and have a fish sprite with alpha colour pink, I want to change the colour pink on to something else, so fo instance here I tried to change it to orange but instead it made it red because I think it's blending somehow? Is there a way I can fill in just the alpha pixels or specify a colour to change?

Thanks, all the best

self.image = pygame.image.load(os.path.join(game_folder,"boxfish.png")).convert()
self.image.set_colorkey(Colour.pink)
self.rect = self.image.get_rect()
self.image.fill(Colour.orange,special_flags = 3)

Answer 1

A very quick way of doing it is just to use transform.threshold .

Or you can use this function

def change_color(img, oldcolor, newcolor):
    for x in range(img.get_width()):
        for y in range(img.get_height()):
            pixel_color = img.get_at((x, y))  # Preserve the alpha value.
            if oldcolor == pixel_color:
                img.set_at((x, y), newcolor)  # Set the color of the pixel.

Answer 2

Since the entire sprite "colour" is filled with pink, a neat way to solve this issue is to make the sprites main colour transparent, and then overlay it onto a same-sized rectangle of the desired hue.

First make a fish with a transparent background (I used TheGIMP to edit it).

clear_fish.png

Then in your sprite class (or however you want to implement it), create a pygame.Surface the same size, filling it with the desired colour. Then blit() the clear-fish image on top of the coloured surface.

fish_image = pygame.image.load( 'clear_fish.png' )  # un-coloured fish
fish_rect  = fish_image.get_rect()

# Apply some coloured scales to the fish
fish_scales= pygame.Surface( ( fish_rect.width, fish_rect.height ) )
fish_scales.fill( colour )
fish_scales.blit( fish_image, (0,0) )
fish_image = fish_scales               # use the coloured fish

Ref: Full Example Code ~

import pygame
import random

# Window size
WINDOW_WIDTH    = 600
WINDOW_HEIGHT   = 600
WINDOW_SURFACE  = pygame.HWSURFACE|pygame.DOUBLEBUF|pygame.RESIZABLE

DARK_BLUE = (   3,   5,  54)


### initialisation
pygame.init()
pygame.mixer.init()
window = pygame.display.set_mode( ( WINDOW_WIDTH, WINDOW_HEIGHT ), WINDOW_SURFACE )
pygame.display.set_caption("1-Fish, 2-Fish, Pink Fish, Clear Fish")

class FishSprite( pygame.sprite.Sprite ):
    def __init__( self, colour ):
        pygame.sprite.Sprite.__init__( self )
        self.image = pygame.image.load( 'clear_fish.png' )
        self.rect  = self.image.get_rect()

        # Apply some coloured scales to the fish
        fish_scales= pygame.Surface( ( self.rect.width, self.rect.height ) )
        fish_scales.fill( colour )
        fish_scales.blit( self.image, (0,0) )
        self.image = fish_scales                # use the coloured fish

        # Start position is randomly across the screen
        self.rect.center = ( random.randint(0, WINDOW_WIDTH), random.randint(0,WINDOW_HEIGHT) )

    def update(self):
        # Just move a bit
        self.rect.x += random.randrange( -1, 2 )
        self.rect.y += random.randrange( -1, 2 )


### Sprites
fish_sprites = pygame.sprite.Group()
fish_sprites.add( FishSprite( ( 255, 200,  20 ) ) )  # add some fish
fish_sprites.add( FishSprite( ( 255,  20, 200 ) ) )
fish_sprites.add( FishSprite( (  55,  00, 200 ) ) )
fish_sprites.add( FishSprite( (  20, 200,  20 ) ) )

### Main Loop
clock = pygame.time.Clock()
done = False
while not done:

    # Handle user-input
    for event in pygame.event.get():
        if ( event.type == pygame.QUIT ):
            done = True
        elif ( event.type == pygame.MOUSEBUTTONUP ):
            # On mouse-click add a fish
            mouse_pos     = pygame.mouse.get_pos()
            random_red    = random.randint( 50, 250 )
            random_green  = random.randint( 50, 250 )
            random_blue   = random.randint( 50, 250 )
            random_colour = ( random_red, random_green, random_blue )
            fish_sprites.add( FishSprite( random_colour ) ) 

    # Update the window, but not more than 60fps
    fish_sprites.update()
    window.fill( DARK_BLUE )
    fish_sprites.draw( window )
    pygame.display.flip()

    # Clamp FPS
    clock.tick_busy_loop(60)


pygame.quit()