wry on linux in the future

[nicopap]

The current version of wry, for linux support, depends on webkit2gtk, which depends on gtk, which is a whole windowing toolkit.

Contrast this to the wry platform-specific implementation for Windows and MacOS, which are little more than a thin layer on top of the existing provided system webviews.

While this setup may seem satisfactory right now, it has a major limitation. Namely raw-window-handle. The Windows and MacOS implementations are thin layers, this means it's actually trivial to modify them to accept/use a RawWindowHandle from the raw-window-handle crate, and enable interoperability with other projects such as wgpu.

I'm not sure there is a way to get a RawWindowHandle for a GTK window, or creating a GTK window from a RawWindowHandle. edit: I have been made aware of gdkx11

This means you can't use wry to embed the webview in other applications, which is the primary use case for webviews.

Enter WPE

So let's just drop linux support? (:smiling_face_with_tear: Linux user here)

Well, maybe we could find a different webview implementation for Linux. Why is it that we are limited to webkit2gtk? We aren't in fact! The developers of webkit2gtk also develop a version of webkit aimed at embedded systems, it is WPE Webkit. Now I hear you say "we target desktop, can't do with embedded solutions". But in actuality, WPE Webkit does itself only depend on standard linux desktop components.

Nothing easier than using WPE. In fact Igalia provides cog, a way to locally trial wpewebkit: https://github.com/Igalia/cog
I've managed to run WPE locally on my X11 machine fairly easily. And cog exposes (and accepts) the X11 window handles necessary to properly handle RawWindowHandle.

WPE is actually supposed to run on wayland compositors, so we also get wayland support for this.

Downsides:

• WPE requires either bundling the webview runtime or installing a very uncommon library.
• Require building a FFI crate to interact with cog.

I've had a very short glance at the cog source and it seems really nice.

[wusyong]

I want to add WPE port for a long time, but there are still a few blockers need to resolve.
They do have gir file, so it's possiblle we can generate the bindings.
But it will take quite some workload so I don't really have time to do it.

The problem first is we cannot really use cog. Last time, we tried to use existing GUI lib the webview library suggests (which is GTK), we have to write every single wrapper in tao.
Users always want as many feature as possible, such as multi-windows, menu, system tray, X-wing that can just shoot a a single missile to take down death star.
If we really have a binding crate for WPE, it must be able to support winit crate at least. There will still missing a few features. But it's a minimum subset everyone can use with.

So if anyone is interested in this port, these are two key steps need to be done imho:

• A binding crate generated by WPE
• It can be created from winit.

[nicopap]

I experimented on my side, and found someone who did experiment on their side as well. It's a lot harder than I expected. The gir generator requires setting up sys crate for all dependencies as well, otherwise it doesn't know what to do with types taken from dependencies. The generation of gir files is the easy part actually…

But I'm committed to at least get something on screen… I think a WPE-based webview could unlock currently impossible use cases (eg: embedding the webview in a cross-plateform way)

The end goal is to completely replace tao right? Since without GTK, tao is fully redundant with winit.

For the WPE crate, I think I'll only require a RawWindowHandle. My goal is to defer entirely the window handling to the app. Sounds also like a laudable goal for wry.

[wusyong]

Yes, one of my initial goal to use WPE is to get rid of GTK. In rust ecosystem, almost all frameworks use winit. If WPE can be created from winit, this means it can embedded into many rust GUI crates.

If you already have gir files, you can get started by reading gtk-rs's gir tutorial. This should help you create the sys crate. But I have not idea what's WPE's dependencies without libraries from GTK.