gtk/wayland: support the ext-background-effect-v1 protocol

Fixes #10721

Author: pluiedev

build.zig.zon

@@ -91,8 +91,8 @@
             .lazy = true,
         },
         .wayland_protocols = .{
-            .url = "https://deps.files.ghostty.org/wayland-protocols-258d8f88f2c8c25a830c6316f87d23ce1a0f12d9.tar.gz",
-            .hash = "N-V-__8AAKw-DAAaV8bOAAGqA0-oD7o-HNIlPFYKRXSPT03S",
+            .url = "https://gitlab.freedesktop.org/wayland/wayland-protocols/-/archive/1.47/wayland-protocols-1.47.tar.gz",
+            .hash = "N-V-__8AAFdWDwA0ktbNUi9pFBHCRN4weXIgIfCrVjfGxqgA",
             .lazy = true,
         },
         .plasma_wayland_protocols = .{

build.zig.zon.json

@@ -167,6 +167,12 @@
     "dest": "vendor/p/N-V-__8AAKw-DAAaV8bOAAGqA0-oD7o-HNIlPFYKRXSPT03S",
     "sha256": "5cedcadde81b75e60f23e5e83b5dd2b8eb4efb9f8f79bd7a347d148aeb0530f8"
   },
+  {
+    "type": "archive",
+    "url": "https://gitlab.freedesktop.org/wayland/wayland-protocols/-/archive/1.47/wayland-protocols-1.47.tar.gz",
+    "dest": "vendor/p/N-V-__8AAFdWDwA0ktbNUi9pFBHCRN4weXIgIfCrVjfGxqgA",
+    "sha256": "dd2df14ab5f41038257aaedcc4b5fb9ac0ee018f3f0f94af9097028e60d33223"
+  },
   {
     "type": "archive",
     "url": "https://deps.files.ghostty.org/wuffs-122037b39d577ec2db3fd7b2130e7b69ef6cc1807d68607a7c232c958315d381b5cd.tar.gz",

build.zig.zon.nix

@@ -62,15 +62,12 @@ pub const Region = struct {
         width = @max(0, width - x * 2);
         height = @max(0, height - y * 2);
 
-        // Transform surface coordinates to device coordinates.
-        const scale: f64 = @floatFromInt(surface.getScaleFactor());
-
         // TODO: Add more regions to mitigate the "korners bug".
         try slices.append(alloc, .{
-            .x = @intFromFloat(x * scale),
-            .y = @intFromFloat(y * scale),
-            .width = @intFromFloat(width * scale),
-            .height = @intFromFloat(height * scale),
+            .x = @intFromFloat(x),
+            .y = @intFromFloat(y),
+            .width = @intFromFloat(width),
+            .height = @intFromFloat(height),
         });
 
         return .{

build.zig.zon.txt

@@ -17,6 +17,7 @@ const blur = @import("blur.zig");
 const wl = wayland.client.wl;
 const org = wayland.client.org;
 const xdg = wayland.client.xdg;
+const ext = wayland.client.ext;
 
 const log = std.log.scoped(.winproto_wayland);
 
@@ -30,6 +31,9 @@ pub const App = struct {
 
         kde_blur_manager: ?*org.KdeKwinBlurManager = null,
 
+        ext_bg_effect_manager: ?*ext.BackgroundEffectManagerV1 = null,
+        ext_bg_capabilities: ext.BackgroundEffectManagerV1.Capability = .{},
+
         // FIXME: replace with `zxdg_decoration_v1` once GTK merges
         // https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/6398
         kde_decoration_manager: ?*org.KdeKwinServerDecorationManager = null,
@@ -86,9 +90,19 @@ pub const App = struct {
         registry.setListener(*Context, registryListener, context);
         if (display.roundtrip() != .SUCCESS) return error.RoundtripFailed;
 
-        // Do another round-trip to get the default decoration mode
+        // Sometimes we need to do another roundtrip
+        // to get all information we need.
+        var needs_roundtrip = false;
         if (context.kde_decoration_manager) |deco_manager| {
             deco_manager.setListener(*Context, decoManagerListener, context);
+            needs_roundtrip = true;
+        }
+        if (context.ext_bg_effect_manager) |mgr| {
+            mgr.setListener(*Context, effectManagerListener, context);
+            needs_roundtrip = true;
+        }
+
+        if (needs_roundtrip) {
             if (display.roundtrip() != .SUCCESS) return error.RoundtripFailed;
         }
 
@@ -224,6 +238,18 @@ pub const App = struct {
             },
         }
     }
+
+    fn effectManagerListener(
+        _: *ext.BackgroundEffectManagerV1,
+        event: ext.BackgroundEffectManagerV1.Event,
+        context: *Context,
+    ) void {
+        switch (event) {
+            .capabilities => |cap| {
+                context.ext_bg_capabilities = cap.flags;
+            },
+        }
+    }
 };
 
 /// Per-window (wl_surface) state for the Wayland protocol.
@@ -239,6 +265,9 @@ pub const Window = struct {
     /// A token that, when present, indicates that the window is blurred.
     blur_token: ?*org.KdeKwinBlur = null,
 
+    /// Object that controls background effects like blur.
+    bg_effect: ?*ext.BackgroundEffectSurfaceV1 = null,
+
     /// Object that controls the decoration mode (client/server/auto)
     /// of the window.
     decoration: ?*org.KdeKwinServerDecoration = null,
@@ -362,38 +391,55 @@ pub const Window = struct {
     /// Update the blur state of the window.
     pub fn setBlur(self: *Window, region: blur.Region) !void {
         const compositor = self.app_context.compositor orelse return;
-        const manager = self.app_context.kde_blur_manager orelse return;
 
         const config = if (self.apprt_window.getConfig()) |v|
             v.get()
         else
             return;
         const blur_setting = config.@"background-blur";
 
-        if (blur_setting.enabled()) {
-            // Do we already have a blur token? If not, create one.
-            const token = self.blur_token orelse try manager.create(self.surface);
-            defer self.blur_token = token;
-
-            const wl_region = try compositor.createRegion();
-            errdefer wl_region.destroy();
-
-            for (region.slices.items) |slice| {
-                // X11 coming over to bite Wayland.
-                wl_region.add(
-                    @intCast(slice.x),
-                    @intCast(slice.y),
-                    @intCast(slice.width),
-                    @intCast(slice.height),
-                );
+        const wl_region = try compositor.createRegion();
+        errdefer wl_region.destroy();
+
+        for (region.slices.items) |slice| {
+            // X11 coming over to bite Wayland.
+            wl_region.add(
+                @intCast(slice.x),
+                @intCast(slice.y),
+                @intCast(slice.width),
+                @intCast(slice.height),
+            );
+        }
+
+        // Does the compositor support the `ext-background-effect-v1`
+        // protocol? If so, try that first, though it might not actually
+        // support the blur setting.
+        if (self.app_context.ext_bg_effect_manager) |mgr| fx: {
+            if (!self.app_context.ext_bg_capabilities.blur) break :fx;
+
+            if (blur_setting.enabled()) {
+                // Do we already have a blur token? If not, create one.
+                const effect = self.bg_effect orelse try mgr.getBackgroundEffect(self.surface);
+                defer self.bg_effect = effect;
+                effect.setBlurRegion(wl_region);
+            } else if (self.bg_effect) |effect| {
+                // Destroy the blur token if present.
+                effect.destroy();
+                self.bg_effect = null;
             }
+            return;
+        }
 
-            token.setRegion(wl_region);
-            token.commit();
-        } else {
-            // Destroy the blur token if present.
-            if (self.blur_token) |token| {
-                manager.unset(self.surface);
+        if (self.app_context.kde_blur_manager) |mgr| {
+            if (blur_setting.enabled()) {
+                // Do we already have a blur token? If not, create one.
+                const token = self.blur_token orelse try mgr.create(self.surface);
+                defer self.blur_token = token;
+                token.setRegion(wl_region);
+                token.commit();
+            } else if (self.blur_token) |token| {
+                // Destroy the blur token if present.
+                mgr.unset(self.surface);
                 token.release();
                 self.blur_token = null;
             }

flatpak/zig-packages.json

@@ -635,12 +635,14 @@ fn addGtkNg(
             plasma_wayland_protocols_dep.path("src/protocols/slide.xml"),
         );
         scanner.addSystemProtocol("staging/xdg-activation/xdg-activation-v1.xml");
+        scanner.addSystemProtocol("staging/ext-background-effect/ext-background-effect-v1.xml");
 
         scanner.generate("wl_compositor", 1);
         scanner.generate("org_kde_kwin_blur_manager", 1);
         scanner.generate("org_kde_kwin_server_decoration_manager", 1);
         scanner.generate("org_kde_kwin_slide_manager", 1);
         scanner.generate("xdg_activation_v1", 1);
+        scanner.generate("ext_background_effect_manager_v1", 1);
 
         step.root_module.addImport("wayland", b.createModule(.{
             .root_source_file = scanner.result,