HackStudio: Reflect widget selections in the form widget tree view

You can now manipulate the widget selection either by clicking and
dragging the widgets using the cursor tool, or by interacting with
the form widget tree view. :^)

DevTools/HackStudio/FormEditorWidget.h

@@ -23,6 +23,13 @@ public:
 
     class WidgetSelection {
     public:
+        Function<void(GWidget&)> on_remove;
+        Function<void(GWidget&)> on_add;
+        Function<void()> on_clear;
+
+        void enable_hooks() { m_hooks_enabled = true; }
+        void disable_hooks() { m_hooks_enabled = false; }
+
         bool is_empty() const
         {
             return m_widgets.is_empty();
@@ -51,16 +58,22 @@ public:
         {
             ASSERT(m_widgets.contains(&widget));
             m_widgets.remove(&widget);
+            if (m_hooks_enabled && on_remove)
+                on_remove(widget);
         }
 
         void add(GWidget& widget)
         {
             m_widgets.set(&widget);
+            if (m_hooks_enabled && on_add)
+                on_add(widget);
         }
 
         void clear()
         {
             m_widgets.clear();
+            if (m_hooks_enabled && on_clear)
+                on_clear();
         }
 
         template<typename Callback>
@@ -76,6 +89,7 @@ public:
 
     private:
         HashTable<GWidget*> m_widgets;
+        bool m_hooks_enabled { true };
     };
 
     WidgetSelection& selection() { return m_selection; }

DevTools/HackStudio/WidgetTreeModel.cpp

@@ -75,3 +75,14 @@ void WidgetTreeModel::update()
 {
     did_update();
 }
+
+GModelIndex WidgetTreeModel::index_for_widget(GWidget& widget) const
+{
+    int parent_child_index = 0;
+    for (auto& parent_child : widget.parent_widget()->child_widgets()) {
+        if (parent_child == &widget)
+            return create_index(parent_child_index, 0, &widget);
+        ++parent_child_index;
+    }
+    return {};
+}

DevTools/HackStudio/WidgetTreeModel.h

@@ -15,6 +15,8 @@ public:
     virtual GModelIndex parent_index(const GModelIndex&) const override;
     virtual void update() override;
 
+    GModelIndex index_for_widget(GWidget&) const;
+
 private:
     explicit WidgetTreeModel(GWidget&);
 

DevTools/HackStudio/main.cpp

@@ -100,7 +100,7 @@ int main(int argc, char** argv)
     Function<void()> update_actions;
 
     g_window = GWindow::construct();
-    g_window->set_rect(100, 100, 800, 600);
+    g_window->set_rect(90, 90, 840, 600);
     g_window->set_title("HackStudio");
 
     auto widget = GWidget::construct();
@@ -164,7 +164,7 @@ int main(int argc, char** argv)
 
     auto form_editing_pane_container = GSplitter::construct(Orientation::Vertical, form_editor_inner_splitter);
     form_editing_pane_container->set_size_policy(SizePolicy::Fixed, SizePolicy::Fill);
-    form_editing_pane_container->set_preferred_size(170, 0);
+    form_editing_pane_container->set_preferred_size(190, 0);
     form_editing_pane_container->set_layout(make<GBoxLayout>(Orientation::Vertical));
 
     auto add_properties_pane = [&](auto& text, auto pane_widget) {
@@ -181,6 +181,28 @@ int main(int argc, char** argv)
 
     auto form_widget_tree_view = GTreeView::construct(nullptr);
     form_widget_tree_view->set_model(g_form_editor_widget->model());
+    form_widget_tree_view->on_selection_change = [&] {
+        g_form_editor_widget->selection().disable_hooks();
+        g_form_editor_widget->selection().clear();
+        form_widget_tree_view->selection().for_each_index([&](auto& index) {
+            // NOTE: Make sure we don't add the FormWidget itself to the selection,
+            //       since that would allow you to drag-move the FormWidget.
+            if (index.internal_data() != &g_form_editor_widget->form_widget())
+                g_form_editor_widget->selection().add(*(GWidget*)index.internal_data());
+        });
+        g_form_editor_widget->update();
+        g_form_editor_widget->selection().enable_hooks();
+    };
+
+    g_form_editor_widget->selection().on_add = [&](auto& widget) {
+        form_widget_tree_view->selection().add(g_form_editor_widget->model().index_for_widget(widget));
+    };
+    g_form_editor_widget->selection().on_remove = [&](auto& widget) {
+        form_widget_tree_view->selection().remove(g_form_editor_widget->model().index_for_widget(widget));
+    };
+    g_form_editor_widget->selection().on_clear = [&] {
+        form_widget_tree_view->selection().clear();
+    };
 
     add_properties_pane("Form widget tree:", form_widget_tree_view);
     add_properties_pane("Widget properties:", GTableView::construct(nullptr));