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我昨天刚开始我的第一个 PyGame 项目，但我找不到如何正确使用 Mask 实体在移动的 Surface 上应用。

我为动画表面制作了一个特定的类

class LabelObject():
    def __init__(self, surface, x, y, endX, speed, idleTime):
        self.surface = surface
        self.x = x
        self.y = y
        self.endX = endX
        self.speed = speed
        self.idleTime = idleTime
        self.alpha = 255
        self.timer_start = 0
        self.timer_end = 0
        self.pos = self.surface.get_rect(x=self.x,y=self.y)

    def move(self):
        self.timer_start += 1
        if self.timer_start > self.idleTime:
            if self.pos.right > self.endX:
                self.pos.x += self.speed
            elif self.pos.x < self.x:
                self.timer_end += 1
                if self.timer_end > self.idleTime:
                    self.alpha -= 25
                if self.timer_end > self.idleTime + 11:
                    self.pos = self.surface.get_rect(x=self.x, y=self.y)
                    self.timer_start = 0
                    self.timer_end = 0
                    self.alpha = 255
        self.surface.set_alpha(self.alpha)

这个类的重点是检查表面是否超出给定区域，然后向左滑动以能够完全阅读其中呈现的文本。

在我的主循环中，我可以像这样将它粘贴到屏幕上

label = LabelObject(textSurface,20,10,100,-0.5,30)
while not over:
    for event in pygame.event.get():
         if event.type == pygame.QUIT
             over = True
    screen.fill((0,0,0))
    label.move()
    screen.blit(label.surface, label.pos)
    pygame.display.update()

这很好用，但我需要在它上面应用一个不必移动的面具。对于此示例，掩码的 Rect 将为(20, 10, 100-20, label.surface.get_height()). 我在网上看到了一些关于 Mask 的例子，但是当 mask 是静态的并且表面是移动的时，我没有找到使用它的方法。

编辑：我尝试在 blit 函数中使用 area 选项，但有些奇怪，区域和 Surface 移动不同步。

EDIT2：最后这里是带有区域选项的良好 blit 功能。只需要使用静态位置制作 blit，并使用动画位置制作区域：

self.screen.blit(label.surface, (label.x,label.y), area=pygame.Rect(label.x-label.pos.x, 0, label.endX-label.x, label.surface.get_height()))
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1 回答 1

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我尝试做完整的工作示例subsurface来切断完整图像的可见部分。Rect (sub_image_rect) 总是一样的——在同一个地方绘制。我只改变偏移量来切断图像的不同部分。

我使用文本和字体生成一些图像 - 每个人都可以在没有自己的图像的情况下运行它。

import pygame

# --- constants ---

BLACK = (  0,  0,  0)
RED   = (255,  0,  0)

# --- classes ---

class Label():

    def __init__(self, text, x, y, width):

        font = pygame.font.SysFont(None, 35)

        # generate full image
        self.image = font.render(text, True, RED)
        self.rect = self.image.get_rect(x=x, y=y)

        self.width = width
        self.speed = 1

        # offset of visible part
        self.offset_x = 0
        self.max_offset_x = self.rect.width - self.width

        # visible part of image
        self.sub_image = self.image.subsurface((self.offset_x,0), (self.width, self.rect.height))
        self.sub_image_rect = self.sub_image.get_rect(x=x, y=y)


    def move(self):

        # change offset
        self.offset_x += self.speed

        # change move direction
        if self.offset_x < 0:
            self.offset_x = 0
            self.speed = -self.speed
        elif self.offset_x > self.max_offset_x:
            self.offset_x = self.max_offset_x
            self.speed = -self.speed

        print self.offset_x, self.max_offset_x
        # visible part of image
        self.sub_image = self.image.subsurface((self.offset_x, 0),(self.width, self.rect.height))

    def draw(self, surface):
        surface.blit(self.sub_image, self.sub_image_rect)

# --- main ---

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

label = Label("Hello World of Python and Pygame!", 100, 100, 200)

# --- mainloop ---

fps = pygame.time.Clock()
running = True

while running:

    # --- events ---

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        elif event.type == pygame.KEYDOWN:
            if event.key ==  pygame.K_ESCAPE:
                running = False

    # --- updates ---

    label.move()

    # --- draws ---

    screen.fill(BLACK)

    label.draw(screen)

    fps.tick(25)
    pygame.display.flip()

# --- the end ---

pygame.quit()

编辑：我用areain做了例子blit。我只更改了 3 行 - 见# changed代码

import pygame

# --- constants ---

BLACK = (  0,  0,  0)
RED   = (255,  0,  0)

# --- classes ---

class Label():

    def __init__(self, text, x, y, width):

        font = pygame.font.SysFont(None, 35)

        # generate full image
        self.image = font.render(text, True, RED)
        self.rect = self.image.get_rect(x=x, y=y)

        self.width = width
        self.speed = 1

        # offset of visible part
        self.offset_x = 0
        self.max_offset_x = self.rect.width - self.width

        # visible part of image as 'rect' - 'width' is always the same
        self.sub_image_rect = self.image.get_rect(x=0, width=self.width) # changed

    def move(self):

        # change offset
        self.offset_x += self.speed

        # change move direction
        if self.offset_x < 0:
            self.offset_x = 0
            self.speed = -self.speed
        elif self.offset_x > self.max_offset_x:
            self.offset_x = self.max_offset_x
            self.speed = -self.speed

        # visible part of image - change only `x` 
        self.sub_image_rect.x = self.offset_x  # changed

    def draw(self, surface):
        surface.blit(self.image, self.rect, area=self.sub_image_rect)  # changed

# --- main ---

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

label = Label("Hello World of Python and Pygame!", 100, 100, 200)

# --- mainloop ---

fps = pygame.time.Clock()
running = True

while running:

    # --- events ---

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        elif event.type == pygame.KEYDOWN:
            if event.key ==  pygame.K_ESCAPE:
                running = False

    # --- updates ---

    label.move()

    # --- draws ---

    screen.fill(BLACK)

    label.draw(screen)

    fps.tick(25)
    pygame.display.flip()

# --- the end ---

pygame.quit()
于 2015-12-26T15:59:39.063 回答