Allow linux users manipulate wm_class and wm_instance of windows

crates/bevy_internal/Cargo.toml

@@ -48,8 +48,8 @@ filesystem_watcher = ["bevy_asset/filesystem_watcher"]
 serialize = ["bevy_input/serialize"]
 
 # Display server protocol support (X11 is enabled by default)
-wayland = ["bevy_winit/wayland"]
-x11 = ["bevy_winit/x11"]
+wayland = ["bevy_winit/wayland", "bevy_window/wayland"]
+x11 = ["bevy_winit/x11", "bevy_window/x11"]
 
 # enable rendering of font glyphs using subpixel accuracy
 subpixel_glyph_atlas = ["bevy_text/subpixel_glyph_atlas"]

crates/bevy_window/Cargo.toml

@@ -8,6 +8,10 @@ repository = "https://github.com/bevyengine/bevy"
 license = "MIT OR Apache-2.0"
 keywords = ["bevy"]
 
+[features]
+wayland = []
+x11 = []
+
 [dependencies]
 # bevy
 bevy_app = { path = "../bevy_app", version = "0.8.0-dev" }
@@ -22,3 +26,6 @@ raw-window-handle = "0.4.2"
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 web-sys = "0.3"
+
+[package.metadata.docs.rs]
+features = ["x11"]

crates/bevy_window/src/window.rs

@@ -610,6 +610,26 @@ pub struct WindowDescriptor {
     pub resize_constraints: WindowResizeConstraints,
     pub scale_factor_override: Option<f64>,
     pub title: String,
+    #[cfg(all(
+        any(
+            target_os = "linux",
+            target_os = "freebsd",
+            target_os = "netbsd",
+            target_os = "openbsd"
+        ),
+        any(feature = "x11", feature = "wayland")
+    ))]
+    pub desktop_id: String,
+    #[cfg(all(
+        any(
+            target_os = "linux",
+            target_os = "freebsd",
+            target_os = "netbsd",
+            target_os = "openbsd"
+        ),
+        feature = "x11"
+    ))]
+    pub desktop_instance: String,
     #[doc(alias = "vsync")]
     pub present_mode: PresentMode,
     pub resizable: bool,
@@ -633,6 +653,26 @@ impl Default for WindowDescriptor {
     fn default() -> Self {
         WindowDescriptor {
             title: "app".to_string(),
+            #[cfg(all(
+                any(
+                    target_os = "linux",
+                    target_os = "freebsd",
+                    target_os = "netbsd",
+                    target_os = "openbsd"
+                ),
+                any(feature = "x11", feature = "wayland")
+            ))]
+            desktop_id: "app".to_string(),
+            #[cfg(all(
+                any(
+                    target_os = "linux",
+                    target_os = "freebsd",
+                    target_os = "netbsd",
+                    target_os = "openbsd"
+                ),
+                feature = "x11"
+            ))]
+            desktop_instance: "Main".to_string(),
             width: 1280.,
             height: 720.,
             position: None,

crates/bevy_winit/src/winit_windows.rs

@@ -4,6 +4,17 @@ use bevy_window::{Window, WindowDescriptor, WindowId, WindowMode};
 use raw_window_handle::HasRawWindowHandle;
 use winit::dpi::LogicalSize;
 
+#[cfg(all(
+    any(
+        target_os = "linux",
+        target_os = "freebsd",
+        target_os = "netbsd",
+        target_os = "openbsd"
+    ),
+    any(feature = "x11", feature = "wayland")
+))]
+use winit::platform::unix::WindowBuilderExtUnix;
+
 #[derive(Debug, Default)]
 pub struct WinitWindows {
     pub windows: HashMap<winit::window::WindowId, winit::window::Window>,
@@ -102,6 +113,44 @@ impl WinitWindows {
         #[allow(unused_mut)]
         let mut winit_window_builder = winit_window_builder.with_title(&window_descriptor.title);
 
+        #[allow(unused_mut)]
+        #[cfg(all(
+            any(
+                target_os = "linux",
+                target_os = "freebsd",
+                target_os = "netbsd",
+                target_os = "openbsd"
+            ),
+            feature = "x11"
+        ))]
+        let mut winit_window_builder = winit_window_builder.with_class(
+            window_descriptor.desktop_instance.clone(), // That's actually WM_INSTANCE
+            window_descriptor.desktop_id.clone(),       // And that's WM_CLASS
+        );
+
+        // The right `with_class` function signature is:
+        //    fn with_class(mut self, instance: String, class: String) -> Self;
+
+        // When winit is upgraded to v0.27.0, change this to
+        // let mut winit_window_builder = winit_window_builder.with_name(
+        //     window_descriptor.desktop_id.clone(),
+        //     window_descriptor.desktop_instance.clone()
+        // )
+        // (Source) https://github.com/rust-windowing/winit/blob/ce890c34551d9fb542f10dcb644d22d382e0c921/src/platform/unix.rs#L288
+
+        #[allow(unused_mut)]
+        #[cfg(all(
+            any(
+                target_os = "linux",
+                target_os = "freebsd",
+                target_os = "netbsd",
+                target_os = "openbsd"
+            ),
+            feature = "wayland"
+        ))]
+        let mut winit_window_builder =
+            winit_window_builder.with_app_id(window_descriptor.desktop_id.clone());
+
         #[cfg(target_arch = "wasm32")]
         {
             use wasm_bindgen::JsCast;