Add switch on hover to TabBar

Author: KoBeWi

doc/classes/TabBar.xml

@@ -270,6 +270,9 @@
 		<member name="select_with_rmb" type="bool" setter="set_select_with_rmb" getter="get_select_with_rmb" default="false">
 			If [code]true[/code], enables selecting a tab with the right mouse button.
 		</member>
+		<member name="switch_on_drag_hover" type="bool" setter="set_switch_on_drag_hover" getter="get_switch_on_drag_hover" default="true">
+			If [code]true[/code], hovering over a tab while dragging something will switch to that tab. Does not have effect when hovering another tab to rearrange. The delay for when this happens is dictated by [theme_item hover_switch_wait_msec].
+		</member>
 		<member name="tab_alignment" type="int" setter="set_tab_alignment" getter="get_tab_alignment" enum="TabBar.AlignmentMode" default="0">
 			The position at which tabs will be placed.
 		</member>
@@ -403,6 +406,9 @@
 		<theme_item name="h_separation" data_type="constant" type="int" default="4">
 			The horizontal separation between the elements inside tabs.
 		</theme_item>
+		<theme_item name="hover_switch_wait_msec" data_type="constant" type="int" default="500">
+			During a drag-and-drop, this is how many milliseconds to wait before switching the tab.
+		</theme_item>
 		<theme_item name="icon_max_width" data_type="constant" type="int" default="0">
 			The maximum allowed width of the tab's icon. This limit is applied on top of the default size of the icon, but before the value set with [method set_tab_icon_max_width]. The height is adjusted according to the icon's ratio.
 		</theme_item>

doc/classes/TabContainer.xml

@@ -223,6 +223,9 @@
 		<member name="drag_to_rearrange_enabled" type="bool" setter="set_drag_to_rearrange_enabled" getter="get_drag_to_rearrange_enabled" default="false">
 			If [code]true[/code], tabs can be rearranged with mouse drag.
 		</member>
+		<member name="switch_on_drag_hover" type="bool" setter="set_switch_on_drag_hover" getter="get_switch_on_drag_hover" default="true">
+			If [code]true[/code], hovering over a tab while dragging something will switch to that tab. Does not have effect when hovering another tab to rearrange.
+		</member>
 		<member name="tab_alignment" type="int" setter="set_tab_alignment" getter="get_tab_alignment" enum="TabBar.AlignmentMode" default="0">
 			The position at which tabs will be placed.
 		</member>

editor/docks/editor_dock_manager.cpp

@@ -248,8 +248,12 @@ EditorDock *EditorDockManager::_get_dock_tab_dragged() {
 	Dictionary dock_drop_data = dock_slot[DOCK_SLOT_LEFT_BL]->get_viewport()->gui_get_drag_data();
 
 	// Check if we are dragging a dock.
-	const String type = dock_drop_data.get("type", "");
-	if (type == "tab_container_tab") {
+	if (dock_drop_data.get("type", "").operator String() != "tab") {
+		return nullptr;
+	}
+
+	const String tab_type = dock_drop_data.get("tab_type", "");
+	if (tab_type == "tab_container_tab") {
 		Node *source_tab_bar = EditorNode::get_singleton()->get_node(dock_drop_data["from_path"]);
 		if (!source_tab_bar) {
 			return nullptr;

editor/editor_node.cpp

@@ -1017,6 +1017,7 @@ void EditorNode::_notification(int p_what) {
 
 			if (EditorSettings::get_singleton()->check_changed_settings_in_group("interface/editor")) {
 				theme->set_constant("dragging_unfold_wait_msec", "Tree", (float)EDITOR_GET("interface/editor/dragging_hover_wait_seconds") * 1000);
+				theme->set_constant("hover_switch_wait_msec", "TabBar", (float)EDITOR_GET("interface/editor/dragging_hover_wait_seconds") * 1000);
 			}
 
 			if (EditorSettings::get_singleton()->check_changed_settings_in_group("interface/editor/dock_tab_style")) {

editor/inspector/editor_properties.cpp

@@ -3027,6 +3027,11 @@ bool EditorPropertyNodePath::is_drop_valid(const Dictionary &p_drag_data) const
 		return false;
 	}
 
+	Object *data_root = p_drag_data.get("scene_root", (Object *)nullptr);
+	if (data_root && get_tree()->get_edited_scene_root() != data_root) {
+		return false;
+	}
+
 	Node *dropped_node = get_tree()->get_edited_scene_root()->get_node(nodes[0]);
 	ERR_FAIL_NULL_V(dropped_node, false);
 

editor/scene/scene_tree_editor.cpp

@@ -1874,6 +1874,7 @@ Variant SceneTreeEditor::get_drag_data_fw(const Point2 &p_point, Control *p_from
 	Dictionary drag_data;
 	drag_data["type"] = "nodes";
 	drag_data["nodes"] = objs;
+	drag_data["scene_root"] = get_tree()->get_edited_scene_root();
 
 	tree->set_drop_mode_flags(Tree::DROP_MODE_INBETWEEN | Tree::DROP_MODE_ON_ITEM);
 	emit_signal(SNAME("nodes_dragged"));
@@ -1895,6 +1896,11 @@ bool SceneTreeEditor::can_drop_data_fw(const Point2 &p_point, const Variant &p_d
 		return false;
 	}
 
+	Object *data_root = d.get("scene_root", (Object *)nullptr);
+	if (data_root && get_tree()->get_edited_scene_root() != data_root) {
+		return false;
+	}
+
 	TreeItem *item = (p_point == Vector2(Math::INF, Math::INF)) ? tree->get_selected() : tree->get_item_at_position(p_point);
 	if (!item) {
 		return false;

editor/themes/editor_theme_manager.cpp

@@ -1204,6 +1204,7 @@ void EditorThemeManager::_populate_standard_styles(const Ref<EditorTheme> &p_the
 		p_theme->set_constant("outline_size", "TabContainer", 0);
 		p_theme->set_constant("h_separation", "TabBar", 4 * EDSCALE);
 		p_theme->set_constant("outline_size", "TabBar", 0);
+		p_theme->set_constant("hover_switch_wait_msec", "TabBar", (float)EDITOR_GET("interface/editor/dragging_hover_wait_seconds") * 1000);
 	}
 
 	// Separators.

scene/gui/tab_bar.cpp

@@ -33,6 +33,7 @@
 #include "scene/gui/box_container.h"
 #include "scene/gui/label.h"
 #include "scene/gui/texture_rect.h"
+#include "scene/main/timer.h"
 #include "scene/main/viewport.h"
 #include "scene/theme/theme_db.h"
 
@@ -501,6 +502,13 @@ void TabBar::_notification(int p_what) {
 				dragging_valid_tab = false;
 				queue_redraw();
 			}
+			[[fallthrough]];
+		}
+
+		case NOTIFICATION_MOUSE_EXIT: {
+			if (!hover_switch_delay->is_stopped()) {
+				hover_switch_delay->stop();
+			}
 		} break;
 
 		case NOTIFICATION_DRAW: {
@@ -1285,6 +1293,10 @@ void TabBar::_update_cache(bool p_update_hover) {
 	}
 }
 
+void TabBar::_hover_switch_timeout() {
+	set_current_tab(hover);
+}
+
 void TabBar::_on_mouse_exited() {
 	rb_hover = -1;
 	cb_hover = -1;
@@ -1424,6 +1436,10 @@ Variant TabBar::get_drag_data(const Point2 &p_point) {
 }
 
 bool TabBar::can_drop_data(const Point2 &p_point, const Variant &p_data) const {
+	if (switch_on_drag_hover) {
+		_handle_switch_on_hover(p_data);
+	}
+
 	bool drop_override = Control::can_drop_data(p_point, p_data);
 	if (drop_override) {
 		return drop_override;
@@ -1470,7 +1486,8 @@ Variant TabBar::_handle_get_drag_data(const String &p_type, const Point2 &p_poin
 	set_drag_preview(drag_preview);
 
 	Dictionary drag_data;
-	drag_data["type"] = p_type;
+	drag_data["type"] = "tab";
+	drag_data["tab_type"] = p_type;
 	drag_data["tab_index"] = tab_over;
 	drag_data["from_path"] = get_path();
 
@@ -1479,11 +1496,12 @@ Variant TabBar::_handle_get_drag_data(const String &p_type, const Point2 &p_poin
 
 bool TabBar::_handle_can_drop_data(const String &p_type, const Point2 &p_point, const Variant &p_data) const {
 	Dictionary d = p_data;
-	if (!d.has("type")) {
+	if (d.get("type", "").operator String() != "tab") {
 		return false;
 	}
 
-	if (String(d["type"]) == p_type) {
+	const String tab_type = d.get("tab_type", "");
+	if (tab_type == p_type) {
 		NodePath from_path = d["from_path"];
 		NodePath to_path = get_path();
 		if (from_path == to_path) {
@@ -1497,17 +1515,17 @@ bool TabBar::_handle_can_drop_data(const String &p_type, const Point2 &p_point,
 			}
 		}
 	}
-
 	return false;
 }
 
 void TabBar::_handle_drop_data(const String &p_type, const Point2 &p_point, const Variant &p_data, const Callable &p_move_tab_callback, const Callable &p_move_tab_from_other_callback) {
 	Dictionary d = p_data;
-	if (!d.has("type")) {
+	if (d.get("type", "").operator String() != "tab") {
 		return;
 	}
 
-	if (String(d["type"]) == p_type) {
+	const String tab_type = d.get("tab_type", "");
+	if (tab_type == p_type) {
 		int tab_from_id = d["tab_index"];
 		int hover_now = (p_point == Vector2(Math::INF, Math::INF)) ? current : get_closest_tab_idx_to_point(p_point);
 		NodePath from_path = d["from_path"];
@@ -1565,6 +1583,22 @@ void TabBar::_handle_drop_data(const String &p_type, const Point2 &p_point, cons
 	}
 }
 
+void TabBar::_handle_switch_on_hover(const Variant &p_data) const {
+	Dictionary d = p_data;
+	if (d.get("type", "").operator String() == "tab") {
+		// Dragging a tab shouldn't switch on hover.
+		return;
+	}
+
+	if (hover > -1 && hover != current) {
+		if (hover_switch_delay->is_stopped()) {
+			const_cast<TabBar *>(this)->hover_switch_delay->start(theme_cache.hover_switch_wait_msec * 0.001);
+		}
+	} else if (!hover_switch_delay->is_stopped()) {
+		hover_switch_delay->stop();
+	}
+}
+
 void TabBar::_move_tab_from(TabBar *p_from_tabbar, int p_from_index, int p_to_index) {
 	Tab moving_tab = p_from_tabbar->tabs[p_from_index];
 	moving_tab.accessibility_item_element = RID();
@@ -1983,6 +2017,14 @@ bool TabBar::get_scroll_to_selected() const {
 	return scroll_to_selected;
 }
 
+void TabBar::set_switch_on_drag_hover(bool p_enabled) {
+	switch_on_drag_hover = p_enabled;
+}
+
+bool TabBar::get_switch_on_drag_hover() const {
+	return switch_on_drag_hover;
+}
+
 void TabBar::set_select_with_rmb(bool p_enabled) {
 	select_with_rmb = p_enabled;
 }
@@ -2055,6 +2097,8 @@ void TabBar::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_scrolling_enabled"), &TabBar::get_scrolling_enabled);
 	ClassDB::bind_method(D_METHOD("set_drag_to_rearrange_enabled", "enabled"), &TabBar::set_drag_to_rearrange_enabled);
 	ClassDB::bind_method(D_METHOD("get_drag_to_rearrange_enabled"), &TabBar::get_drag_to_rearrange_enabled);
+	ClassDB::bind_method(D_METHOD("set_switch_on_drag_hover", "enabled"), &TabBar::set_switch_on_drag_hover);
+	ClassDB::bind_method(D_METHOD("get_switch_on_drag_hover"), &TabBar::get_switch_on_drag_hover);
 	ClassDB::bind_method(D_METHOD("set_tabs_rearrange_group", "group_id"), &TabBar::set_tabs_rearrange_group);
 	ClassDB::bind_method(D_METHOD("get_tabs_rearrange_group"), &TabBar::get_tabs_rearrange_group);
 	ClassDB::bind_method(D_METHOD("set_scroll_to_selected", "enabled"), &TabBar::set_scroll_to_selected);
@@ -2082,6 +2126,7 @@ void TabBar::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "max_tab_width", PROPERTY_HINT_RANGE, "0,99999,1,suffix:px"), "set_max_tab_width", "get_max_tab_width");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "scrolling_enabled"), "set_scrolling_enabled", "get_scrolling_enabled");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "drag_to_rearrange_enabled"), "set_drag_to_rearrange_enabled", "get_drag_to_rearrange_enabled");
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "switch_on_drag_hover"), "set_switch_on_drag_hover", "get_switch_on_drag_hover");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "tabs_rearrange_group"), "set_tabs_rearrange_group", "get_tabs_rearrange_group");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "scroll_to_selected"), "set_scroll_to_selected", "get_scroll_to_selected");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "select_with_rmb"), "set_select_with_rmb", "get_select_with_rmb");
@@ -2102,6 +2147,7 @@ void TabBar::_bind_methods() {
 	BIND_THEME_ITEM(Theme::DATA_TYPE_CONSTANT, TabBar, h_separation);
 	BIND_THEME_ITEM(Theme::DATA_TYPE_CONSTANT, TabBar, tab_separation);
 	BIND_THEME_ITEM(Theme::DATA_TYPE_CONSTANT, TabBar, icon_max_width);
+	BIND_THEME_ITEM(Theme::DATA_TYPE_CONSTANT, TabBar, hover_switch_wait_msec);
 
 	BIND_THEME_ITEM_CUSTOM(Theme::DATA_TYPE_STYLEBOX, TabBar, tab_unselected_style, "tab_unselected");
 	BIND_THEME_ITEM_CUSTOM(Theme::DATA_TYPE_STYLEBOX, TabBar, tab_hovered_style, "tab_hovered");
@@ -2152,5 +2198,10 @@ TabBar::TabBar() {
 	set_focus_mode(FOCUS_ALL);
 	connect(SceneStringName(mouse_exited), callable_mp(this, &TabBar::_on_mouse_exited));
 
+	hover_switch_delay = memnew(Timer);
+	hover_switch_delay->connect("timeout", callable_mp(this, &TabBar::_hover_switch_timeout));
+	hover_switch_delay->set_one_shot(true);
+	add_child(hover_switch_delay, false, INTERNAL_MODE_FRONT);
+
 	property_helper.setup_for_instance(base_property_helper, this);
 }

scene/gui/tab_bar.h

@@ -34,6 +34,8 @@
 #include "scene/property_list_helper.h"
 #include "scene/resources/text_line.h"
 
+class Timer;
+
 class TabBar : public Control {
 	GDCLASS(TabBar, Control);
 
@@ -130,6 +132,7 @@ class TabBar : public Control {
 	bool dragging_valid_tab = false;
 	bool scroll_to_selected = true;
 	int tabs_rearrange_group = -1;
+	bool switch_on_drag_hover = true;
 
 	static const int CURRENT_TAB_UNINITIALIZED = -2;
 	bool initialized = false;
@@ -143,6 +146,7 @@ class TabBar : public Control {
 		int h_separation = 0;
 		int tab_separation = 0;
 		int icon_max_width = 0;
+		int hover_switch_wait_msec = 500;
 
 		Ref<StyleBox> tab_unselected_style;
 		Ref<StyleBox> tab_hovered_style;
@@ -177,13 +181,16 @@ class TabBar : public Control {
 		Ref<StyleBox> button_hl_style;
 	} theme_cache;
 
+	Timer *hover_switch_delay = nullptr;
+
 	int get_tab_width(int p_idx) const;
 	Size2 _get_tab_icon_size(int p_idx) const;
 	void _ensure_no_over_offset();
 	bool _can_deselect() const;
 
 	void _update_hover();
 	void _update_cache(bool p_update_hover = true);
+	void _hover_switch_timeout();
 
 	void _on_mouse_exited();
 
@@ -218,6 +225,7 @@ class TabBar : public Control {
 	bool _handle_can_drop_data(const String &p_type, const Point2 &p_point, const Variant &p_data) const;
 	void _handle_drop_data(const String &p_type, const Point2 &p_point, const Variant &p_data, const Callable &p_move_tab_callback, const Callable &p_move_tab_from_other_callback);
 	void _draw_tab_drop(RID p_canvas_item);
+	void _handle_switch_on_hover(const Variant &p_data) const;
 
 	void add_tab(const String &p_str = "", const Ref<Texture2D> &p_icon = Ref<Texture2D>());
 
@@ -307,6 +315,9 @@ class TabBar : public Control {
 	void set_scroll_to_selected(bool p_enabled);
 	bool get_scroll_to_selected() const;
 
+	void set_switch_on_drag_hover(bool p_enabled);
+	bool get_switch_on_drag_hover() const;
+
 	void set_select_with_rmb(bool p_enabled);
 	bool get_select_with_rmb() const;
 

scene/gui/tab_container.cpp

@@ -1025,6 +1025,14 @@ Popup *TabContainer::get_popup() const {
 	return nullptr;
 }
 
+void TabContainer::set_switch_on_drag_hover(bool p_enabled) {
+	tab_bar->set_switch_on_drag_hover(p_enabled);
+}
+
+bool TabContainer::get_switch_on_drag_hover() const {
+	return tab_bar->get_switch_on_drag_hover();
+}
+
 void TabContainer::set_drag_to_rearrange_enabled(bool p_enabled) {
 	drag_to_rearrange_enabled = p_enabled;
 }
@@ -1102,6 +1110,8 @@ void TabContainer::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_tab_idx_from_control", "control"), &TabContainer::get_tab_idx_from_control);
 	ClassDB::bind_method(D_METHOD("set_popup", "popup"), &TabContainer::set_popup);
 	ClassDB::bind_method(D_METHOD("get_popup"), &TabContainer::get_popup);
+	ClassDB::bind_method(D_METHOD("set_switch_on_drag_hover", "enabled"), &TabContainer::set_switch_on_drag_hover);
+	ClassDB::bind_method(D_METHOD("get_switch_on_drag_hover"), &TabContainer::get_switch_on_drag_hover);
 	ClassDB::bind_method(D_METHOD("set_drag_to_rearrange_enabled", "enabled"), &TabContainer::set_drag_to_rearrange_enabled);
 	ClassDB::bind_method(D_METHOD("get_drag_to_rearrange_enabled"), &TabContainer::get_drag_to_rearrange_enabled);
 	ClassDB::bind_method(D_METHOD("set_tabs_rearrange_group", "group_id"), &TabContainer::set_tabs_rearrange_group);
@@ -1127,6 +1137,7 @@ void TabContainer::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "clip_tabs"), "set_clip_tabs", "get_clip_tabs");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "tabs_visible"), "set_tabs_visible", "are_tabs_visible");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "all_tabs_in_front"), "set_all_tabs_in_front", "is_all_tabs_in_front");
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "switch_on_drag_hover"), "set_switch_on_drag_hover", "get_switch_on_drag_hover");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "drag_to_rearrange_enabled"), "set_drag_to_rearrange_enabled", "get_drag_to_rearrange_enabled");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "tabs_rearrange_group"), "set_tabs_rearrange_group", "get_tabs_rearrange_group");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "use_hidden_tabs_for_min_size"), "set_use_hidden_tabs_for_min_size", "get_use_hidden_tabs_for_min_size");