Python PIL：将透明图像混合到另一个上

Question

I need to blend an image over another image using Pythons PIL Library.

As you can see in the image below, my two source images are A and B. When I do:

imageA.paste(imageB, (0, 0), imageB)

I get C as a result, but the part at the top of the gray background is now transparent. Image D is what I get when I put B over A in Photoshop and is what I need to achieve with PIL.

What am I doing wrong? How can I compose B over A in PIL to get D instead of C?

Answer 1

I can't comment for now (rep constraint).

But I think what you really need, according to your need, is to do this instead:

imageB.paste(imageA, (0, 0), imageA)

Basically, that is, make B the background image to get the desired results, because that's what I see in D.

EDIT: Looking around more, I found this: https://stackoverflow.com/a/15919897/4029893

I think you should definitely use the alpha_composite method, since paste doesn't work as expected for background images with transparency.

Answer 2

使用RGBA作为透明蒙版

imageA.paste(imageB, (0, 0), imageB.convert('RGBA'))