[Bug]: Inpainting Mask does not support alpha-white pixels (over API)

[peterpernhofer]

Checklist

• The issue exists after disabling all extensions
• The issue exists on a clean installation of webui
• The issue is caused by an extension, but I believe it is caused by a bug in the webui
• The issue exists in the current version of the webui
• The issue has not been reported before recently
• The issue has been reported before but has not been fixed yet

What happened?

Hi guys,
I'm using Inpainting over the API and want to ask if it's possible to transmit a mask with semi-transparent pixels (alpha channel). This would be very useful for my workflow, and maybe it's just a small bug in Auto1111 that could be fixed easily.

A similar request was already made by Physeo, but it was closed without a solution: #13089

Currently, if I pass a mask with a black background and pixels with an alpha value between 0 and 255, Automatic1111 does not process them correctly. Instead of interpreting semi-transparent areas as a soft mask, it seems to completely invert or overwrite the mask with solid white, affecting the entire image.

Thanks in advance for your answer! And of course, a huge thanks if this could be fixed :-)

Steps to reproduce the problem

1. Send an image to the Img2Img Inpainting API.
2. Provide a mask with an alpha channel, where some pixels are semi-transparent.
3. Observe that Automatic1111 incorrectly fills or inverts the mask instead of using the alpha values properly.

What should have happened?

If I pass a mask with a black background and semi-white pixels (Alpha > 0 && Alpha < 255), those pixels should influence the result less than fully opaque (Alpha = 255) areas. The inpainting process should respect the alpha transparency instead of converting the entire mask to solid white.

What browsers do you use to access the UI ?

No response

Sysinfo

sysinfo-2025-02-18-20-45.json

Console logs

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Additional information

No response