Is there any way to “clear” a surface?

问题:

Is there any way to clear a surface from anything that has been blitted to it?

回答1:

I don't know what API you're using, so here's a vague answer:

In virtually all cases "clearing" a surface simply blits a coloured quad of the same size as the surface onto it. The colour used is whatever you want your clear colour to be.

If you know how do blit, just blit a white quad of the same size onto the surface.

回答2:

You can't undo one graphic written over the top of another graphic any more than you can undo one chalk illustration drawn over the top of another chalk illustration on the same board.

What is typically done in graphics is what you'd do with the chalkboard - clear the whole lot, and next time only redraw what you want to keep.

回答3:

When I dont care about performance, I use:

mysurface.fill((0,0,0)) 

Which will draw the specified color (black in this case) across the entire surface. Is that what you meant by "clear"?

Oh, and you need, of course, to "flip" the surface after doing this for it to be visible on the screen.

回答4:

I had this problem too

To create the surface:

mask=pygame.Surface((180,100),pygame.SRCALPHA) 

To clear the surface:

mask.fill mask.set_alpha(255) 

Draw your lines/images etc

Then blit this surface onto your main surface using the Alpha Blend flag

screen.blit(mask,(0,0),special_flags=(pygame.BLEND_RGBA_ADD)) 

回答5:

If what you want is to make a pygame Surface object "clean", that is erase all images blited to it, to blit new images to it every game loop and keep the peer pixel alpha without creating a new surface, you can fill it, but instead of a solid color, use a transparent color

from pygame import Color, Surface empty = Color(0,0,0,0) #The last 0 indicates 0 alpha, a transparent color field = Surface((width, height), flags=SRCALPHA)  #Inside the game loop field.fill(empty) 

*Sorry is my english is bad, still learning

回答6:

.fill((255,255,255,0)) appears to work for me anyway.

回答7:

For pygame you can use Surface.fill

回答8:

Fill the surface with fill, then make it transparent with set_alpha

surface.fill surface.set_alpha(255) 

回答9:

I used the following in a game I made:

self.image = 0 #to empty it self.image = pygame.image.load("image") 

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