How to Preserve PNG Transparency When Blending in Pygame?

How to Preserve PNG Transparency When Blending with Pygame

When trying to overlay a PNG image with transparency onto a Pygame surface, users may encounter an issue where the transparent area becomes black after blitting. To resolve this, follow these steps:

1. Set Alpha Surface:
Ensure that the receiving surface (e.g., world) is created with the pygame.SRCALPHA flag to enable alpha transparency.

<code class="python">world = pygame.Surface((800, 600), pygame.SRCALPHA, 32)</code>

2. Convert Input Image:
To maintain transparency, convert the loaded PNG image using the convert_alpha() method, as recommended in the Pygame documentation:

<code class="python">treeImage = pygame.image.load("tree.png")
treeImage = treeImage.convert_alpha()</code>

3. Optimized Code:
With these modifications, the code will successfully blend the PNG image onto the world surface while preserving its transparency:

<code class="python">screen = pygame.display.set_mode((800, 600), pygame.DOUBLEBUF, 32)

world = pygame.Surface((800, 600), pygame.SRCALPHA, 32)
treeImage = pygame.image.load("tree.png").convert_alpha()

world.blit(treeImage, (0,0), (0,0,64,64))
screen.blit(world, pygame.rect.Rect(0,0, 800, 600))</code>

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