[feat] window opacity

[krymasa]

Describe the problem

I'm currently migrating from Electron to Tauri, but I've found that Tauri doesn't have a method like Electron's BrowserWindow.setOpacity to set the transparency of the entire window. It can only be achieved by setting the transparency of the web page through CSS. However, this doesn't meet my requirements because my application loads external web pages whose CSS I can't control. Therefore, I hope there could be a way similar to BrowserWindow.setOpacity to set the window's transparency.

Describe the solution you'd like

I hope there could be a way similar to BrowserWindow.setOpacity to set the window's transparency.

Alternatives considered

No response

Additional context

No response

[aoxiangtianyu-go]

This likely belongs at the tao level rather than in tauri, since window opacity is a platform-specific window behavior handled by tao’s Windows backend.

[FabianLars]

The background color settings have an alpha channel, does that work for you? Can't remember if it worked on all platforms already 🤔

Also, you probably still need to modify the website's css to make them transparent. There are no webview apis for us to overwrite that easily so it works by running js via https://docs.rs/tauri/latest/tauri/webview/struct.WebviewWindow.html#method.eval for example.

[krymasa]

The background color settings have an alpha channel, does that work for you? Can't remember if it worked on all platforms already 🤔背景颜色设置里有个透明度通道，你那边能用吗？我记不清是不是所有平台都支持了🤔

Also, you probably still need to modify the website's css to make them transparent. There are no webview apis for us to overwrite that easily so it works by running js via https://docs.rs/tauri/latest/tauri/webview/struct.WebviewWindow.html#method.eval for example.另外，您可能仍然需要修改网站的 CSS 才能使其透明。我们没有可以轻易覆盖的 WebView API，所以它可以通过例如 https://docs.rs/tauri/latest/tauri/webview/struct.WebviewWindow.html#method.eval 运行 JavaScript 来实现。

I roughly understand your meaning, but what I want to express is not the transparency at the webview level, but the transparency of the entire window. As far as I know, in the Win32 API, the transparency of a window can be changed by calling SetLayeredWindowAttributes. I have no idea whether a similar approach can be used in Tauri to achieve the functionality I described.

[FabianLars]

Yeah, that's the very first part of my message but i missed the "On Windows 8 and newer, if alpha channel is not 0, it will be ignored." part of our docs.