问题描述
我想在运行时动态更改rect的颜色。当前set_colour
用单一颜色值填充表面的所有像素。这行得通,但是在调用set_outline
之类的方法时会出现问题,该方法会修改表面的透明度。
class Rectangle(pg.sprite.Sprite):
def __init__(self):
pg.sprite.Sprite.__init__(self)
self.original_image = pg.Surface((10,10))
self.image = self.original_image
self.rect = self.image.get_rect()
def set_colour(self,colour_value):
self.colour = colour_value
self.image.fill(self.colour)
self.original_image.fill(self.colour)
def set_outline(self,thickness):
self.thickness = thickness
size = self.image.get_size()
calc = thickness/100
p_width,p_height = size[0],size[1]
width,height = size[0]*calc,size[1]*calc
self.image = self.image.convert_alpha()
center_x,center_y = (p_width//2)-(width//2),(p_height//2)-(height//2)
pg.draw.rect(self.image,(0,0),(center_x,center_y,width,height))
现在,如果我尝试在运行时更改该矩形的颜色,它将覆盖在set_outline
中创建的所有透明像素。
有没有一种方法可以将颜色遮罩或混合到矩形上,从而不会替换任何透明性?
解决方法
您可以通过2个步骤来实现。 self.original_image
包含具有所需颜色的填充矩形:
self.original_image.fill(self.colour)
生成一个完全白色的矩形和透明区域。将矩形与(self.image
)和混合模式BLEND_MAX
(请参见 pygame.Surface.blit
)混合:
whiteTransparent = pg.Surface(self.image.get_size(),pg.SRCALPHA)
whiteTransparent.fill((255,255,0))
self.image.blit(whiteTransparent,(0,0),special_flags=pg.BLEND_MAX)
现在,矩形是完全白色的,但是透明区域得以保留。使用混合模式BLEND_MULT
并将self.original_image
与self.image
混合以获得所需的结果:
self.image.blit(self.original_image,special_flags=pg.BLEND_MULT)
最小示例: repl.it/@Rabbid76/PyGame-ChangeColorOfSpriteArea
import pygame as pg
class Rectangle(pg.sprite.Sprite):
def __init__(self):
pg.sprite.Sprite.__init__(self)
self.original_image = pg.Surface((150,150))
self.image = self.original_image
self.rect = self.image.get_rect(center = (150,150))
def set_colour(self,colour_value):
self.colour = colour_value
self.original_image.fill(self.colour)
whiteTransparent = pg.Surface(self.image.get_size(),pg.SRCALPHA)
whiteTransparent.fill((255,0))
self.image.blit(whiteTransparent,special_flags=pg.BLEND_MAX)
self.image.blit(self.original_image,special_flags=pg.BLEND_MULT)
def set_outline(self,thickness):
self.thickness = thickness
size = self.image.get_size()
calc = thickness/100
p_width,p_height = size[0],size[1]
width,height = size[0]*calc,size[1]*calc
self.image = self.image.convert_alpha()
center_x,center_y = (p_width//2)-(width//2),(p_height//2)-(height//2)
pg.draw.rect(self.image,(center_x,center_y,width,height))
pg.init()
window = pg.display.set_mode((300,300))
clock = pg.time.Clock()
sprite = Rectangle()
sprite.set_colour((255,255))
sprite.set_outline(50)
group = pg.sprite.Group(sprite)
colorVal = 0
colorAdd = 5
run = True
while run:
clock.tick(60)
for event in pg.event.get():
if event.type == pg.QUIT:
run = False
sprite.set_colour((min(colorVal,255),max(0,min(511-colorVal,255)),255))
colorVal += colorAdd
if colorVal <= 0 or colorVal >= 511:
colorAdd *= -1
window.fill(0)
group.draw(window)
pg.display.flip()