How can I crop an image with Pygame?

问题:

I am learning pygame and want a graphic for a button with the three states: normal, hover, and pressed. I have an image like this one ...

... and I want to get a new Surface using a portion of it.

I'm loading the image with this code:

 buttonStates = pygame.image.load(os.path.join('image','button.png'))

How can I make a new surface using just a portion of that graphic?

回答1:

cropped = pygame.Surface((80, 80))
cropped.blit(buttonStates, (0, 0), (30, 30, 80, 80))

The blit method on a surface 'pastes' another surface on to it. The first argument to blit is the source surface. The second is the location to paste to (in this case, the top left corner). The third (optional) argument is the area of the source image to paste from -- in this case an 80x80 square 30px from the top and 30px from the left.

回答2:

You can also use the pygame.Surface.subsurface method to create subsurfaces that share their pixels with their parent surface. However, you have to make sure that the rect is inside of the image area or a ValueError: subsurface rectangle outside surface area will be raised.

subsurface = a_surface.subsurface((x, y, width, height))

回答3:

I think the best way to do it is crop the image of these 3 kind of buttons in a external program and load in different surface instead use pygame to crop it