gtk-ng add border to bell features

src/apprt/gtk-ng/class/surface.zig

@@ -523,6 +523,22 @@ pub const Surface = extern struct {
         priv.gl_area.queueRender();
     }
 
+    /// Callback used to determine whether border should be shown around the
+    /// surface.
+    fn closureShouldBorderBeShown(
+        _: *Self,
+        config_: ?*Config,
+        bell_ringing_: c_int,
+    ) callconv(.c) c_int {
+        const config = if (config_) |v| v.get() else {
+            log.warn("config unavailable for computing whether border should be shown , likely bug", .{});
+            return @intFromBool(false);
+        };
+
+        const bell_ringing = bell_ringing_ != 0;
+        return @intFromBool(config.@"bell-features".border and bell_ringing);
+    }
+
     pub fn toggleFullscreen(self: *Self) void {
         signals.@"toggle-fullscreen".impl.emit(
             self,
@@ -2478,6 +2494,7 @@ pub const Surface = extern struct {
             class.bindTemplateCallback("notify_mouse_hidden", &propMouseHidden);
             class.bindTemplateCallback("notify_mouse_shape", &propMouseShape);
             class.bindTemplateCallback("notify_bell_ringing", &propBellRinging);
+            class.bindTemplateCallback("should_border_be_shown", &closureShouldBorderBeShown);
 
             // Properties
             gobject.ext.registerProperties(class, &.{

src/apprt/gtk-ng/css/style.css

@@ -102,6 +102,12 @@ label.resize-overlay {
   /* background-color: color-mix(in srgb, var(--error-bg-color), transparent); */
 }
 
+.surface .bell-overlay {
+  border-color: color-mix(in srgb, var(--accent-color), transparent 50%);
+  border-width: 3px;
+  border-style: solid;
+}
+
 /*
  * Command Palette
  */

src/apprt/gtk-ng/ui/1.2/surface.blp

@@ -54,6 +54,27 @@ template $GhosttySurface: Adw.Bin {
       valign: start;
     }
 
+    [overlay]
+    // The "border" bell feature is implemented here as an overlay rather than
+    // just adding a border to the GLArea or other widget for two reasons.
+    // First, adding a border to an existing widget causes a resize of the
+    // widget which undesirable side effects. Second, we can make it reactive
+    // here in the blueprint with relatively little code.
+    Revealer {
+      reveal-child: bind $should_border_be_shown(template.config, template.bell-ringing) as <bool>;
+      transition-type: crossfade;
+      transition-duration: 500;
+
+      Box bell_overlay {
+        styles [
+          "bell-overlay",
+        ]
+
+        halign: fill;
+        valign: fill;
+      }
+    }
+
     [overlay]
     $GhosttySurfaceChildExited child_exited_overlay {
       visible: bind template.child-exited;