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Vacation notice: I’m away until 16th August 2026. I'm still working on Objo but replies may take longer than usual.

HTML viewer invert red & blue channels on linux (wayland)

Ormente

My very first bug for Garry ;-)

In my first test application, I'm using a color picker to paint the background of a canvas and define the background color of an HTMLviewer located above it. The chosen color is correctly applied to the canvas, but not to the HTML. Based on other tests, the red and blue channels are swapped, probably due to a difference in the graphics buffer format between X11 and Wayland.

A great opportunity to thank you for the fantastic work you're doing with Objo!

Garry

Hi, and welcome to Objo!

Thank you for taking the time to provide such a clear report and reproduction.

You’re not doing anything wrong. I’ve traced this to the Linux GTK rendering adapter used by Avalonia’s WebView component. It copies an RGBA image into a BGRA bitmap without converting the channel order, causing red and blue to be swapped. Objo’s Canvas uses a different rendering path, which explains why the same colour appears correctly there.

Although the defect is in an upstream dependency, Objo uses that adapter, so I’m treating this as an Objo-facing bug rather than closing it as unsupported or user error. I’ve logged it here:

https://feedback.objo.dev/bug/827

Unfortunately, Objo itself doesn’t receive or manipulate the WebView’s pixel buffer, so there isn’t a safe correction we can make inside HTMLViewer. The proper fix belongs in Avalonia’s GTK adapter. I've identified the precise change required and will propose it upstream: convert each row from RGBA to BGRA while copying the rendered image.

I’m sorry this was one of your first experiences with Objo. Your report was exactly what we needed to isolate the problem, and we’ll keep the Objo issue open while we pursue and track the upstream correction. If a test build becomes available, it would also be very helpful if you could confirm the result on your Wayland system.

Thanks again for reporting it.

Ormente

Garry

Thank you very much Garry.
In any case, the bug isn't a dealbreaker because the little utility I'm developing will be used on Windows.

I see that many bugs are surfacing, which is normal for such a young project with such an extensive scope! The speed at which you take these bugs into account, and resolve them most of the time, is simply impressive. And I'm not even talking about the addition of new features! It's clear that this is a work of passion.

So thanks again, and know that all this work is greatly appreciated.

Garry

Thank you so much for the encouragement and kind words. Objo is indeed my passion and I am working really hard to build it into a sustainable business. I appreciate your support 🙂