[Skia.GTK] Controls are not rendered correctly if hardware acceleration is enabled

[manfromarce]

Current behavior

Some controls are not rendered properly on GTK when hardware accelaration is enabled. In particular it seems that background and other visual properties are not applied in the correct region. You can see in the GIF below that for example menus and flyouts have a transparent area and the highlight color on mouse hover starts at the very bottom of each MenuItem, while a button with AccentButtonStyle has white foreground color (which is correct) but the background is not applied.

Expected behavior

How to reproduce it (as minimally and precisely as possible)

MyApp.zip

Workaround

It looks as expected when disabling hardware acceleration in the Gtk project:
host.RenderSurfaceType = RenderSurfaceType.Software;

Works on UWP/WinUI

Yes

Environment

Uno.WinUI / Uno.WinUI.WebAssembly / Uno.WinUI.Skia

NuGet package version(s)

4.6.19

Affected platforms

Skia (GTK on Linux/macOS/Windows)

IDE

No response

IDE version

No response

Relevant plugins

No response

Anything else we need to know?

No response

[jeromelaban]

Thanks for the report. We've made some recent changes for this that may help. Try updating to uno to the latest 4.7-dev prerelease bits.

[manfromarce]

I've updated to 4.7.0-dev.266 and it's interesting that flyouts look fine the first time they are displayed, but the second time they are transparent again. The other issues seem to be still there, the only difference is that controls derived from button have a new thin bottom border.

[jeromelaban]

Thanks for the update.

[jeromelaban]

@MartinZikmund does this look related to the clipping work you were looking at ? (fyi, it's not fixed in latest 4.7-dev)

[MartinZikmund]

Definitely odd, will look into it

[MartinZikmund]

@manfromarce Can you please verify whether the latest changes have resolved the issue by trying with the most recent -dev prerelease packages?

[manfromarce]

It doesn't seem to be fixed, sorry. I have tried 4.7.0-dev.584 on Windows only at the moment, but I can test it on Linux with a different hardware to see if anything changes.

[MartinZikmund]

@jeromelaban Are you able to repro the issues with 4.7.0-dev.584? On my side it looks right 🤔 . I took the zip above, updated all packages to 4.7.0-dev.584 and ran GTK with HW

Update: Tested with 150% and 200% scaling, but still no repro 🤔

[jeromelaban]

I'll test on my side. @manfromarce sometimes updating nuget packages does not pickup the latest version, can you try deleting the bin/obj folders and try again?

[manfromarce]

I've tried deleting the bin and obj folder but it didn't change

[MartinZikmund]

As seen in #14402, in some cases the 1 pixel guard band can cause quite disastrous issues when fractional scaling was enabled on GTK (see SimpleCalc screenshot of 150 scaling below, working ok in 100 and 200 scaling) - disabled in #14403