apprt/gtk-ng: render a single artificial split

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

@@ -66,8 +66,28 @@ pub const SplitTree = extern struct {
                 .{
                     .nick = "Tree Model",
                     .blurb = "Underlying data model for the tree.",
-                    .accessor = C.privateBoxedFieldAccessor("tree"),
+                    .accessor = .{
+                        .getter = getTreeValue,
+                        .setter = setTreeValue,
                     },
+                },
+            );
+        };
+    };
+
+    pub const signals = struct {
+        /// Emitted whenever the tree property is about to change.
+        ///
+        /// The new value is given as the signal parameter. The old value
+        /// can still be retrieved from the tree property.
+        pub const @"tree-will-change" = struct {
+            pub const name = "tree-change";
+            pub const connect = impl.connect;
+            const impl = gobject.ext.defineSignal(
+                name,
+                Self,
+                &.{?*const Surface.Tree},
+                void,
             );
         };
     };
@@ -76,6 +96,9 @@ pub const SplitTree = extern struct {
         /// The tree datastructure containing all of our surface views.
         tree: ?*Surface.Tree,
 
+        // Template bindings
+        tree_bin: *adw.Bin,
+
         pub var offset: c_int = 0;
     };
 
@@ -91,6 +114,52 @@ pub const SplitTree = extern struct {
         return tree.isEmpty();
     }
 
+    /// Get the tree data model that we're showing in this widget. This
+    /// does not clone the tree.
+    pub fn getTree(self: *Self) ?*Surface.Tree {
+        return self.private().tree;
+    }
+
+    /// Set the tree data model that we're showing in this widget. This
+    /// will clone the given tree.
+    pub fn setTree(self: *Self, tree: ?*const Surface.Tree) void {
+        const priv = self.private();
+
+        // Emit the signal so that handlers can witness both the before and
+        // after values of the tree.
+        signals.@"tree-will-change".impl.emit(
+            self,
+            null,
+            .{tree},
+            null,
+        );
+
+        if (priv.tree) |old_tree| {
+            ext.boxedFree(Surface.Tree, old_tree);
+            priv.tree = null;
+        }
+
+        if (tree) |new_tree| {
+            priv.tree = ext.boxedCopy(Surface.Tree, new_tree);
+        }
+
+        self.as(gobject.Object).notifyByPspec(properties.tree.impl.param_spec);
+    }
+
+    fn getTreeValue(self: *Self, value: *gobject.Value) void {
+        gobject.ext.Value.set(
+            value,
+            self.private().tree,
+        );
+    }
+
+    fn setTreeValue(self: *Self, value: *const gobject.Value) void {
+        self.setTree(gobject.ext.Value.get(
+            value,
+            ?*Surface.Tree,
+        ));
+    }
+
     //---------------------------------------------------------------
     // Virtual methods
 
@@ -127,9 +196,48 @@ pub const SplitTree = extern struct {
         _: *gobject.ParamSpec,
         _: ?*anyopaque,
     ) callconv(.c) void {
+        const priv = self.private();
+        const tree: *const Surface.Tree = self.private().tree orelse &.empty;
+
+        // Reset our widget tree.
+        priv.tree_bin.setChild(null);
+        if (!tree.isEmpty()) {
+            priv.tree_bin.setChild(buildTree(tree, 0));
+        }
+
+        // Dependent properties
         self.as(gobject.Object).notifyByPspec(properties.@"is-empty".impl.param_spec);
     }
 
+    /// Builds the widget tree associated with a surface split tree.
+    ///
+    /// The final returned widget is expected to be a floating reference,
+    /// ready to be attached to a parent widget.
+    fn buildTree(
+        tree: *const Surface.Tree,
+        current: Surface.Tree.Node.Handle,
+    ) *gtk.Widget {
+        switch (tree.nodes[current]) {
+            .leaf => |v| {
+                // We have to setup our signal handlers.
+                return v.as(gtk.Widget);
+            },
+
+            .split => |s| return gobject.ext.newInstance(
+                gtk.Paned,
+                .{
+                    .orientation = @as(gtk.Orientation, switch (s.layout) {
+                        .horizontal => .horizontal,
+                        .vertical => .vertical,
+                    }),
+                    .@"start-child" = buildTree(tree, s.left),
+                    .@"end-child" = buildTree(tree, s.right),
+                    // TODO: position/ratio
+                },
+            ).as(gtk.Widget),
+        }
+    }
+
     //---------------------------------------------------------------
     // Class
 
@@ -162,11 +270,13 @@ pub const SplitTree = extern struct {
             });
 
             // Bindings
+            class.bindTemplateChildPrivate("tree_bin", .{});
 
             // Template Callbacks
             class.bindTemplateCallback("notify_tree", &propTree);
 
             // Signals
+            signals.@"tree-will-change".impl.register(.{});
 
             // Virtual methods
             gobject.Object.virtual_methods.dispose.implement(class, &dispose);

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

@@ -2302,6 +2302,7 @@ pub const Surface = extern struct {
     const C = Common(Self, Private);
     pub const as = C.as;
     pub const ref = C.ref;
+    pub const refSink = C.refSink;
     pub const unref = C.unref;
     const private = C.private;
 

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

@@ -118,6 +118,7 @@ pub const Tab = extern struct {
         surface_bindings: *gobject.BindingGroup,
 
         // Template bindings
+        split_tree: *SplitTree,
         surface: *Surface,
 
         pub var offset: c_int = 0;
@@ -161,6 +162,16 @@ pub const Tab = extern struct {
         // We need to do this so that the title initializes properly,
         // I think because its a dynamic getter.
         self.as(gobject.Object).notifyByPspec(properties.@"active-surface".impl.param_spec);
+
+        // Setup our initial split tree.
+        // TODO: Probably make this a property
+        const surface: *Surface = .new();
+        defer surface.unref();
+        _ = surface.refSink();
+        const alloc = Application.default().allocator();
+        var tree = Surface.Tree.init(alloc, surface) catch unreachable;
+        defer tree.deinit();
+        priv.split_tree.setTree(&tree);
     }
 
     //---------------------------------------------------------------
@@ -271,6 +282,7 @@ pub const Tab = extern struct {
             });
 
             // Bindings
+            class.bindTemplateChildPrivate("split_tree", .{});
             class.bindTemplateChildPrivate("surface", .{});
 
             // Template Callbacks

src/apprt/gtk-ng/ui/1.5/split-tree.blp

@@ -7,9 +7,8 @@ template $GhosttySplitTree: Adw.Bin {
   Box {
     orientation: vertical;
 
-    Box surface_box {
+    Adw.Bin tree_bin {
       visible: bind template.is-empty inverted;
-      orientation: vertical;
       hexpand: true;
       vexpand: true;
     }

src/apprt/gtk-ng/ui/1.5/tab.blp

@@ -14,5 +14,5 @@ template $GhosttyTab: Box {
     close-request => $surface_close_request();
   }
 
-  $GhosttySplitTree {}
+  $GhosttySplitTree split_tree {}
 }