python – 如何在pygame中从一种颜色淡化到另一种颜色？

发布时间：2020-12-20 12:14:32 所属栏目：Python 来源：网络整理

导读：如何在pygame中从一种颜色淡入另一种颜色？我想慢慢地将圆圈的颜色从绿色变为蓝色,紫色变为粉红色,红色变为橙色,黄色变为绿色.我该怎么办？目前,我正在使用 def colour(): switcher = { 0: 0x2FD596,1: 0x2FC3D5,2: 0x2F6BD5,3: 0x432FD5,4: 0x702FD5,5: 0xB

如何在pygame中从一种颜色淡入另一种颜色？我想慢慢地将圆圈的颜色从绿色变为蓝色,紫色变为粉红色,红色变为橙色,黄色变为绿色.我该怎么办？目前,我正在使用

def colour():
    switcher = {
        0: 0x2FD596,1: 0x2FC3D5,2: 0x2F6BD5,3: 0x432FD5,4: 0x702FD5,5: 0xBC2FD5,6: 0xD52F91,7: 0xD52F43,8: 0xD57F2F,9: 0xD5D52F,10: 0x64D52F,11: 0x2FD557,}
    return switcher.get(round((datetime.datetime.now() - starting_time).total_seconds()%11))

但这在颜色和看起来笨重之间有很大的进步.

解决方法

关键是要简单计算每一步改变每个通道(a,r,g和b)的程度. Pygame的Color类非常方便,因为它允许在每个通道上进行迭代,并且它的输入很灵活,所以你可以改变它.在下面的例子中,’blue’到0x2FD596,它仍然会运行.

这是一个简单的运行示例：

import pygame
import itertools

pygame.init()

screen = pygame.display.set_mode((800,600))

colors = itertools.cycle(['green','blue','purple','pink','red','orange'])

clock = pygame.time.Clock()

base_color = next(colors)
next_color = next(colors)
current_color = base_color

FPS = 60
change_every_x_seconds = 3.
number_of_steps = change_every_x_seconds * FPS
step = 1

font = pygame.font.SysFont('Arial',50)

running = True
while running:

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

    text = font.render('fading {a} to {b}'.format(a=base_color,b=next_color),True,pygame.color.Color('black'))

    step += 1
    if step < number_of_steps:
        # (y-x)/number_of_steps calculates the amount of change per step required to 
        # fade one channel of the old color to the new color
        # We multiply it with the current step counter
        current_color = [x + (((y-x)/number_of_steps)*step) for x,y in zip(pygame.color.Color(base_color),pygame.color.Color(next_color))]
    else:
        step = 1
        base_color = next_color
        next_color = next(colors)

    screen.fill(pygame.color.Color('white'))
    pygame.draw.circle(screen,current_color,screen.get_rect().center,100)
    screen.blit(text,(230,100))
    pygame.display.update()
    clock.tick(FPS)

enter image description here

如果您不想依赖于帧速率而是使用基于时间的方法,则可以将代码更改为：

...
change_every_x_milliseconds = 3000.
step = 0

running = True
while running:

    ...

    if step < change_every_x_milliseconds:
        current_color = [x + (((y-x)/change_every_x_milliseconds)*step) for x,pygame.color.Color(next_color))]
    else:
        ...
    ...

    pygame.display.update()
    step += clock.tick(60)

（编辑：李大同）

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