英文:
Pass `special_flags` argument to group.draw in pygame
问题
有没有办法将 `special_flags` 参数传递给 `Group.draw`，以便它使用这些标志调用 `.blit` 方法？
我尝试过像这样将其作为关键字参数传递：
```python
group.draw(surface, special_flags=pygame.BLEND_SOURCE_ALPHA)
但是会出现以下错误：
Traceback (most recent call last):
File "C:\Users\MarciAdam\PycharmProjects\pygame_stuff_1\main.py", line 394, in <module>
group.draw(surface, special_flags=pygame.BLEND_RGBA_MAX)
TypeError: draw() got an unexpected keyword argument 'special_flags'
我知道我可以像这样做：
for sprite in group.sprites():
surface.blit(sprite.image, sprite.rect, special_flags=pygame.BLEND_SOURCE_ALPHA)
但是对于更复杂的组类型，例如 LayeredUpdates，我需要复制大量的pygame代码。
<details>
<summary>英文:</summary>
Is there a way to pass the `special_flags` argument to `Group.draw` so that it calls the `.blit` method with those flags?
I've tried just passing it as a keyword argument like this:
```python
group.draw(surface, special_flags=pygame.BLEND_SOURCE_ALPHA)
but it gives this error:
Traceback (most recent call last):
File "C:\Users\MarciAdam\PycharmProjects\pygame_stuff_1\main.py", line 394, in <module>
group.draw(surface, special_flags=pygame.BLEND_RGBA_MAX)
TypeError: draw() got an unexpected keyword argument 'special_flags'
I know I could do something like this:
for sprite in group.sprites():
surface.blit(sprite.image, sprite.rect, special_flags=pygame.BLEND_SOURCE_ALPHA)
but I would need to duplicate a lot of the pygame code for the more complicated group types eg. LayeredUpdates.
答案1
得分: 0
除非您自己实现，否则您无法将该标志传递给pygame.sprite.Group.draw，因为该函数只有一个参数（也可以参考pygame.sprite.Group()是什么）：
>draw(Surface) -> List[Rect]
建议：
唯一的方法是使用“for”循环绘制精灵。我建议编写一个函数来实现这一点，或者实现您自己的MyGroup类，继承自pygame.sprite.Group：
class MyGroup(pygame.sprite.Group):
def __init__(self, *args):
super().__init__(*args)
def draw(self, surface, special_flags=0):
for sprite in self:
surface.blit(sprite.image, sprite.rect, special_flags=special_flags)
group = MyGroup()
group.draw(surface, special_flags=pygame.BLEND_RGBA_MAX)
如果您想要对pygame.sprite.LayeredUpdates或pygame.sprite.RenderUpdates执行相同操作，您必须自己实现这些对象的所有绘图特性。
一个完全不同的解决方案是使用 pygame.sprite.DirtySprite。这个类继承自pygame.sprite.Sprite，并具有额外的blendmode属性，这是blit的special_flags参数。
class MySprite(pygame.sprite.DirtySprite):
def __init__(self):
super().__init__()
self.dirty = 2
self.blendmode = pygame.BLEND_RGBA_MIN
# [...]
请注意，DirtySprite 只适用于 pygame.sprite.LayeredDirty，并且组中的所有精灵必须是这种类型。
英文:
Short answer:
What you want to do is not possible unless you implement it yourself.
You cannot pass that flag to pygame.sprite.Group.draw, because that function has only 1 argument (Also see What does pygame.sprite.Group() do):
>draw(Surface) -> List[Rect]
Suggestions:
The only way is to draw the sprite with a "for" loop. I suggest to write a function for this or implement your own MyGroup class derived from pygame.sprite.Group:
class MyGroup(pygame.sprite.Group):
def __init__(self, *args):
super().__init__(*args)
def draw(self, surface, special_flags=0):
for sprite in self:
surface.blit(sprite.image, sprite.rect, special_flags = special_flags)
group = MyGroup()
group.draw(surface, special_flags=pygame.BLEND_RGBA_MAX)
If you want to do the same for pygame.sprite.LayeredUpdates or pygame.sprite.RenderUpdates, you have to implement all the drawing features of these objects yourself.
A completely different solution is to use pygame.sprite.DirtySprite. This class is derived from pygame.sprite.Sprite and has an additional blendmode attribute which is its the special_flags argument of blit.
class MySprite(pygame.sprite.DirtySprite):
def __init__(self):
super().__init__()
self.dirty = 2
self.blendmode = pygame.BLEND_RGBA_MIN
# [...]
Note, DirtySprite only works with pygame.sprite.LayeredDirty and all sprites in the group must be of this type.
答案2
得分: 0
更新
现在在 pygame 版本 2.3.0 中可以使用，详见文档。
对于旧版本的 pygame，请参考Rabbid76的回答。
英文:
Update
It works in pygame version 2.3.0 now, see the documentation.
For older pygame versions see Rabbid76's answer.
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