从Pygame曲面删除像素

Question

我正在尝试使用pygame创建一个像素艺术制作程序(是的，我知道有更好的包可以使用(。我画像素的方法是通过surface.set_at((。我需要知道如何从pygame表面完全删除像素，这样我就可以有一个橡皮擦工具了。我不想用窗口的背景色填充像素，因为当使用pygame.image.save((从绘图中获取图像文件时，这仍然会渲染。有人能帮忙吗？这是我的代码：

import pygame
import sys
import math
pygame.init()
clock = pygame.time.Clock()
pygame.display.set_caption("Pixel Studio v1.1")
screen = pygame.display.set_mode((960, 720), pygame.RESIZABLE)
scroll_speed = 5
canvas_size = (32, 16)
color = (255, 255, 255)
canvas_surf = pygame.Surface(canvas_size, pygame.SRCALPHA)
zoom = 12
mouse_down = False
while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.image.save(canvas_surf, "canvas.png")
            pygame.quit()
            sys.exit()
        if event.type == pygame.MOUSEBUTTONDOWN:
            if event.button == pygame.BUTTON_LEFT:
                mouse_down = True
            if event.button == pygame.BUTTON_WHEELUP:
                if zoom > 2:
                    zoom -= scroll_speed
            if event.button == pygame.BUTTON_WHEELDOWN:
                    zoom += scroll_speed
        if event.type == pygame.MOUSEBUTTONUP:
            if event.button == pygame.BUTTON_LEFT:
                mouse_down = False
    if zoom < 2:
        zoom = 2
    screen.fill((50, 50, 50))
    #canvas_surf.fill((200, 200, 200))
    canvas_surf_scaled = pygame.transform.scale(canvas_surf,(canvas_surf.get_width() * zoom, canvas_surf.get_height() * zoom))
    canvas_rect = canvas_surf_scaled.get_rect(center=(screen.get_width()/2, screen.get_height()/2))
    mouse_pos = pygame.mouse.get_pos()
    if mouse_down:
        canvas_surf.set_at((math.floor((mouse_pos[0] - canvas_rect.x) / zoom), math.floor((mouse_pos[1] - canvas_rect.y) / zoom)), color)
    pygame.draw.rect(screen, ( 75, 75, 75), canvas_rect, 1,)
    screen.blit(canvas_surf_scaled, canvas_rect)
    pygame.display.flip()
    clock.tick(60)

Answer 1

如注释中所述，您可以通过将像素设置为alpha值为零的值来使其透明。

                            #r #g #b #a
canvas_surf.set_at((x, y), (0, 0, 0, 0))