1 files changed, 88 insertions, 0 deletions
diff --git a/vcl/unx/gtk4/notifyinglayout.cxx b/vcl/unx/gtk4/notifyinglayout.cxx
new file mode 100644
index 0000000000..46b9a2d95f
--- /dev/null
+++ b/vcl/unx/gtk4/notifyinglayout.cxx
@@ -0,0 +1,88 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include "notifyinglayout.hxx"
+
+struct _NotifyingLayout
+{
+    GtkLayoutManager parent_instance;
+
+    GtkWidget* m_pWidget;
+    GtkLayoutManager* m_pOrigManager;
+    Link<void*, void> m_aLink;
+};
+
+G_DEFINE_TYPE(NotifyingLayout, notifying_layout, GTK_TYPE_LAYOUT_MANAGER)
+
+static void notifying_layout_measure(GtkLayoutManager* pLayoutManager, GtkWidget* widget,
+                                     GtkOrientation orientation, int for_size, int* minimum,
+                                     int* natural, int* minimum_baseline, int* natural_baseline)
+{
+    NotifyingLayout* self = NOTIFYING_LAYOUT(pLayoutManager);
+    GtkLayoutManagerClass* pKlass
+        = GTK_LAYOUT_MANAGER_CLASS(G_OBJECT_GET_CLASS(self->m_pOrigManager));
+    pKlass->measure(self->m_pOrigManager, widget, orientation, for_size, minimum, natural,
+                    minimum_baseline, natural_baseline);
+}
+
+static void notifying_layout_allocate(GtkLayoutManager* pLayoutManager, GtkWidget* widget,
+                                      int width, int height, int baseline)
+{
+    NotifyingLayout* self = NOTIFYING_LAYOUT(pLayoutManager);
+    GtkLayoutManagerClass* pKlass
+        = GTK_LAYOUT_MANAGER_CLASS(G_OBJECT_GET_CLASS(self->m_pOrigManager));
+    pKlass->allocate(self->m_pOrigManager, widget, width, height, baseline);
+    self->m_aLink.Call(nullptr);
+}
+
+static GtkSizeRequestMode notifying_layout_get_request_mode(GtkLayoutManager* pLayoutManager,
+                                                            GtkWidget* widget)
+{
+    NotifyingLayout* self = NOTIFYING_LAYOUT(pLayoutManager);
+    GtkLayoutManagerClass* pKlass
+        = GTK_LAYOUT_MANAGER_CLASS(G_OBJECT_GET_CLASS(self->m_pOrigManager));
+    return pKlass->get_request_mode(self->m_pOrigManager, widget);
+}
+
+static void notifying_layout_class_init(NotifyingLayoutClass* klass)
+{
+    GtkLayoutManagerClass* layout_class = GTK_LAYOUT_MANAGER_CLASS(klass);
+
+    layout_class->get_request_mode = notifying_layout_get_request_mode;
+    layout_class->measure = notifying_layout_measure;
+    layout_class->allocate = notifying_layout_allocate;
+}
+
+static void notifying_layout_init(NotifyingLayout* self)
+{
+    self->m_pWidget = nullptr;
+    self->m_pOrigManager = nullptr;
+
+    // prevent loplugin:unreffun firing on macro generated function
+    (void)notifying_layout_get_instance_private(self);
+}
+
+void notifying_layout_start_watch(NotifyingLayout* self, GtkWidget* pWidget,
+                                  const Link<void*, void>& rLink)
+{
+    self->m_pWidget = pWidget;
+    self->m_aLink = rLink;
+
+    self->m_pOrigManager = gtk_widget_get_layout_manager(self->m_pWidget);
+    g_object_ref(self->m_pOrigManager);
+
+    gtk_widget_set_layout_manager(pWidget, GTK_LAYOUT_MANAGER(self));
+}
+
+void notifying_layout_stop_watch(NotifyingLayout* self)
+{
+    gtk_widget_set_layout_manager(self->m_pWidget, self->m_pOrigManager);
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */