Add to Tab.init and fix compilation errors

src/apprt/gtk/Paned.zig

@@ -19,7 +19,7 @@ const Child = union(enum) {
 const Parent = union(enum) {
     tab: *Tab,
     paned: *Paned,
-}
+};
 
 // We'll need to keep a reference to the Window this belongs to for various reasons
 window: *c.GtkWindow,
@@ -91,7 +91,7 @@ pub fn newSurface(self: *Paned, parent_: ?*CoreSurface) !*Surface {
     try surface.init(self.window.app, .{
         .window = self,
         .gl_area = @ptrCast(gl_area),
-        .title_label = @ptrCast(label_text),
+        .title_label = @ptrCast(self.label_text),
         .font_size = font_size,
     });
     return surface;

src/apprt/gtk/Tab.zig

@@ -6,30 +6,56 @@ const Allocator = std.mem.Allocator;
 const Paned = @import("Paned.zig");
 const Surface = @import("Surface.zig");
 const Window = @import("Window.zig");
-const c = import("c.zig");
+const c = @import("c.zig");
 
 const Child = union(enum) {
     surface: *Surface,
     paned: *Paned,
-}
+};
 
 window: *Window,
 label_text: *c.GtkLabel,
 close_button: *c.GtkButton,
+// We'll put our children into this box instead of packing them directly, so
+// that we can send the box into `c.g_signal_connect_data` for the close button
+box: *c.GtkBox,
+// The child can be either a Surface if the tab is not split or a Paned
 child: Child,
+// We'll update this every time a Surface gains focus, so that we have it
+// when we switch to another Tab. Then when we switch back to this tab, we
+// can easily re-focus that terminal.
+focus_child: *Surface,
 
 pub fn create(alloc: Allocator, window: *Window) !*Tab {
     var tab = try alloc.create(Tab);
-    errdefer alloc.destroy(paned);
+    errdefer alloc.destroy(tab);
     try tab.init(window);
 }
 
-pub fn init(self: *Tab, window) !void {
+pub fn init(self: *Tab, window: *Window) !void {
     self.* = .{
-        window = Window,
-        label_text = undefined,
-        close_button = undefined,
-        child = undefined,
+        .window = window,
+        .label_text = undefined,
+        .close_button = undefined,
+        .box = undefined,
+        .child = undefined,
+        .focus_child = undefined,
     };
-    // todo - write the function and initialize everything
-}
+
+    // Build the tab label
+    const label_box_widget = c.gtk_box_new(c.GTK_ORIENTATION_HORIZONTAL, 0);
+    const label_box: *c.GtkBox = @ptrCast(label_box_widget);
+    const label_text_widget = c.gtk_label_new("Ghostty");
+    const label_text: *c.GtkLabel = @ptrCast(label_text_widget);
+    self.label_text = label_text;
+    c.gtk_box_append(label_box, label_text_widget);
+    const label_close_widget = c.gtk_button_new_from_icon_name("window-close");
+    const label_close: *c.GtkButton = @ptrCast(label_close_widget);
+    c.gtk_button_has_frame(label_close, 0);
+    c.gtk_box_append(label_box, label_close_widget);
+    self.close_button = label_close;
+    const box_widget = c.gtk_box_new(c.GTK_ORIENTATION_VERTICAL, 0);
+    const box: *c.GtkBox = @ptrCast(box_widget);
+    self.box = box;
+    // todo - write the rest of function and initialize a new Surface
+}