.alpha_composite()
Published Mar 20, 2025
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In Pillow, the .alpha_composite()
method merges two images by overlaying the foreground onto the background using their alpha (transparency) channels. It returns a new image with the composite result.
Syntax
PIL.Image.alpha_composite(image1, image2)
Parameters:
image1
(Image): The background image, which must be inRGBA
mode.image2
(Image): The foreground image, which must also be inRGBA
mode.
Return value:
Returns a new RGBA image with the composite result.
Note: The
.alpha_composite()
method requires bothimage1
andimage2
parameters to have the same dimensions (width and height); otherwise, it won’t work as expected.
Example
The following example demonstrates the use of the .alpha_composite()
method:
from PIL import Image# Open background and foreground imagesbackground = Image.open("ocean.png").convert("RGBA")foreground = Image.open("ship.png").convert("RGBA")# Composite the imagesresult = Image.alpha_composite(background, foreground)# Display and save the resultresult.show()result.save('ship-on-ocean.png')
Original Background Image:
Original Foreground Image:
Result Composite Image:
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