Support for Transparent Windows

[GPeaky]

Hello, i am making a desktop app that need some windows in transparent mode because they are builded above of a game. Making like an external overlay and i don´t actually know if floem have support for it

[GPeaky]

In windows

[panekj]

All windows in floem are transparent by default

[GPeaky]

Okay!, thanks i will try it. Floem have better performance than other options like tauri?

[dominikwilkowski]

Can you share what you end up with here once you got something transparent working. I'd love to use it too and maybe add it to the examples too

[GPeaky]

All the leaderboards, etc. are external to the game, and are fully transparent (The game in running in a windowed Fullscreen)

[dominikwilkowski]

Can you share the code for the transparent window?

[GPeaky]

This is what an example doit in tauri, i am trying to make it work with floem, but at the moment i could not doit

[jrmoulton]

@GPeaky the issue is here https://github.com/lapce/floem/blob/7e78abb06eac12609d661728ce2fbb0064d5451d/vger/src/lib.rs#L99

The issue is that vger auto selects the blend mode for the alpha channel and by default sets it to opaque and makes it so that windows aren't transparent. On macOS i need to change this to PostMultiplied in order to get it to work.

This should be fixable in a configurable way but I'm not sure how

[jrmoulton]

After changing to PostMultiplied and setting my backround color to have a 70% alpha.

I think this setting is platform dependent. @dzhou121 might know more