带有 alpha 的 Pygame 表面不闪烁透明度 [英] Pygame surface with alpha not blitting transparency

问题描述

当鼠标没有悬停在我的游戏中时，我试图让用户界面变得透明.但是出于某种原因，当我将图像的 alpha 值设置为透明时，没有任何反应.这是一些可运行的代码，可以复制问题:

I'm trying to make a user interface thing transparent in my game when the mouse isn't hovering over it. But for some reason, when I set the alpha value of the image for it to become transparent, nothing happens. Here is some runnable code for it that replicates the problem:

import pygame
WHITE = (255, 255, 255)

class UI:
    def __init__(self):
        self.img = pygame.image.load("ink_bar_solid.png")
        self.img.set_alpha(0)
        self.ink_bar_rect = self.img.get_bounding_rect()
        self.x, self.y = 0, 10

resolution = (500, 500)
screen = pygame.display.set_mode(resolution)
mouse = pygame.mouse.get_pos
ink_bar = UI()
run = True

def mouse_over():
    if ink_bar.ink_bar_rect.collidepoint(mouse()):
        ink_bar.img.set_alpha(255)
    else:
        ink_bar.img.set_alpha(0)

while run:
    mouse_over()
    screen.fill(WHITE)
    screen.blit(ink_bar.img, (ink_bar.x, ink_bar.y))
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False
            break
    pygame.display.flip()
pygame.quit()

非常感谢任何帮助！我从某人那里得到了一条评论，他说他们使用了自己的图像并且效果很好......我在执行程序时收到了这个警告:

Any help is greatly appreciated! I got a comment from someone who said they used their own image and it worked fine... I'm getting this warning when I execute the program:

libpng warning: iCCP: known incorrect sRGB profile

是不是因为我的文件而无法正确 blit 的原因?

Is the reason why it doesn't blit properly because of my file?

推荐答案

set_alpha 方法似乎不适用于未转换的 png 文件.调用 convert方法还将显着提高 blit 性能:

The set_alpha method doesn't seem to work for unconverted png files. Calling the convert method will also improve the blit performance drastically:

self.img = pygame.image.load("ink_bar_solid.png").convert()

它也不适用于每像素 alpha 表面(使用 convert_alpha 转换的表面或使用 pygame.SRCALPHA 标志创建的表面).每像素表面的 alpha 可以通过用透明的白色填充它们并传递 pygame.BLEND_RGBA_MULT 特殊标志来改变，例如:

It also doesn't work for per-pixel alpha surfaces (surfaces converted with convert_alpha or created with the pygame.SRCALPHA flag). The alpha of per-pixel surfaces can be changed by filling them with a transparent white color and passing the pygame.BLEND_RGBA_MULT special flag, e.g.:

image = pygame.image.load('an_image.png').convert_alpha()
# Make a copy so that the original doesn't get modified.
transparent_image = image.copy()
transparent_image.fill((255, 255, 255, 100), special_flags=pygame.BLEND_RGBA_MULT)

这篇关于带有 alpha 的 Pygame 表面不闪烁透明度的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！