Add option for a touch-friendly drag handle in SplitContainer

doc/classes/SplitContainer.xml

@@ -53,6 +53,9 @@
 		<member name="split_offset" type="int" setter="set_split_offset" getter="get_split_offset" default="0">
 			The initial offset of the splitting between the two [Control]s, with [code]0[/code] being at the end of the first [Control].
 		</member>
+		<member name="touch_dragger_enabled" type="bool" setter="set_touch_dragger_enabled" getter="is_touch_dragger_enabled" default="false">
+			If [code]true[/code], a touch-friendly drag handle will be enabled for better usability on smaller screens. Unlike the standard grabber, this drag handle overlaps the [SplitContainer]'s children and does not affect their minimum separation. The standard grabber will no longer be drawn when this option is enabled.
+		</member>
 		<member name="vertical" type="bool" setter="set_vertical" getter="is_vertical" default="false">
 			If [code]true[/code], the [SplitContainer] will arrange its children vertically, rather than horizontally.
 			Can't be changed when using [HSplitContainer] and [VSplitContainer].
@@ -102,14 +105,23 @@
 			[b]Note:[/b] To obtain [theme_item separation] values less than the size of the grabber icon, for example a [code]1 px[/code] hairline, set [theme_item h_grabber] or [theme_item v_grabber] to a new [ImageTexture], which effectively sets the grabber icon size to [code]0 px[/code].
 		</theme_item>
 		<theme_item name="grabber" data_type="icon" type="Texture2D">
-			The icon used for the grabber drawn in the middle area.
+			The icon used for the grabber drawn in the middle area. This is only used in [HSplitContainer] and [VSplitContainer]. For [SplitContainer], see [theme_item h_grabber] and [theme_item v_grabber] instead.
 		</theme_item>
 		<theme_item name="h_grabber" data_type="icon" type="Texture2D">
 			The icon used for the grabber drawn in the middle area when [member vertical] is [code]false[/code].
 		</theme_item>
+		<theme_item name="h_touch_dragger" data_type="icon" type="Texture2D">
+			The icon used for the drag handle when [member touch_dragger_enabled] is [code]true[/code] and [member vertical] is [code]false[/code].
+		</theme_item>
+		<theme_item name="touch_dragger" data_type="icon" type="Texture2D">
+			The icon used for the drag handle when [member touch_dragger_enabled] is [code]true[/code]. This is only used in [HSplitContainer] and [VSplitContainer]. For [SplitContainer], see [theme_item h_touch_dragger] and [theme_item v_touch_dragger] instead.
+		</theme_item>
 		<theme_item name="v_grabber" data_type="icon" type="Texture2D">
 			The icon used for the grabber drawn in the middle area when [member vertical] is [code]true[/code].
 		</theme_item>
+		<theme_item name="v_touch_dragger" data_type="icon" type="Texture2D">
+			The icon used for the drag handle when [member touch_dragger_enabled] is [code]true[/code] and [member vertical] is [code]true[/code].
+		</theme_item>
 		<theme_item name="split_bar_background" data_type="style" type="StyleBox">
 			Determines the background of the split bar if its thickness is greater than zero.
 		</theme_item>

scene/gui/split_container.cpp

@@ -30,6 +30,7 @@
 
 #include "split_container.h"
 
+#include "scene/gui/texture_rect.h"
 #include "scene/main/viewport.h"
 #include "scene/theme/theme_db.h"
 
@@ -161,7 +162,7 @@ void SplitContainerDragger::_notification(int p_what) {
 		case NOTIFICATION_DRAW: {
 			SplitContainer *sc = Object::cast_to<SplitContainer>(get_parent());
 			draw_style_box(sc->theme_cache.split_bar_background, split_bar_rect);
-			if (sc->dragger_visibility == sc->DRAGGER_VISIBLE && (dragging || mouse_inside || !sc->theme_cache.autohide)) {
+			if (sc->dragger_visibility == sc->DRAGGER_VISIBLE && (dragging || mouse_inside || !sc->theme_cache.autohide) && !sc->touch_dragger_enabled) {
 				Ref<Texture2D> tex = sc->_get_grabber_icon();
 				float available_size = sc->vertical ? (sc->get_size().x - tex->get_size().x) : (sc->get_size().y - tex->get_size().y);
 				if (available_size - sc->drag_area_margin_begin - sc->drag_area_margin_end > 0) { // Draw the grabber only if it fits.
@@ -208,10 +209,26 @@ Ref<Texture2D> SplitContainer::_get_grabber_icon() const {
 	}
 }
 
+Ref<Texture2D> SplitContainer::_get_touch_dragger_icon() const {
+	if (is_fixed) {
+		return theme_cache.touch_dragger_icon;
+	} else {
+		if (vertical) {
+			return theme_cache.touch_dragger_icon_v;
+		} else {
+			return theme_cache.touch_dragger_icon_h;
+		}
+	}
+}
+
 int SplitContainer::_get_separation() const {
 	if (dragger_visibility == DRAGGER_HIDDEN_COLLAPSED) {
 		return 0;
 	}
+
+	if (touch_dragger_enabled) {
+		return theme_cache.separation;
+	}
 	// DRAGGER_VISIBLE or DRAGGER_HIDDEN.
 	Ref<Texture2D> g = _get_grabber_icon();
 	return MAX(theme_cache.separation, vertical ? g->get_height() : g->get_width());
@@ -267,6 +284,9 @@ void SplitContainer::_resort() {
 		return;
 	}
 	dragging_area_control->set_visible(!collapsed);
+	if (touch_dragger_enabled) {
+		touch_dragger->set_visible(dragging_enabled);
+	}
 
 	_compute_split_offset(false); // This recalculates and sets computed_split_offset.
 
@@ -406,7 +426,15 @@ bool SplitContainer::is_collapsed() const {
 
 void SplitContainer::set_vertical(bool p_vertical) {
 	ERR_FAIL_COND_MSG(is_fixed, "Can't change orientation of " + get_class() + ".");
+	if (vertical == p_vertical) {
+		return;
+	}
 	vertical = p_vertical;
+	if (touch_dragger) {
+		touch_dragger->set_texture(_get_touch_dragger_icon());
+		touch_dragger->set_anchors_and_offsets_preset(Control::PRESET_CENTER);
+		touch_dragger->set_default_cursor_shape(vertical ? CURSOR_VSPLIT : CURSOR_HSPLIT);
+	}
 	update_minimum_size();
 	_resort();
 }
@@ -504,6 +532,59 @@ bool SplitContainer::is_show_drag_area_enabled() const {
 	return show_drag_area;
 }
 
+void SplitContainer::set_touch_dragger_enabled(bool p_enabled) {
+	if (touch_dragger_enabled == p_enabled) {
+		return;
+	}
+	touch_dragger_enabled = p_enabled;
+	if (p_enabled) {
+		touch_dragger = memnew(TextureRect);
+		touch_dragger->set_texture(_get_touch_dragger_icon());
+		touch_dragger->set_anchors_and_offsets_preset(Control::PRESET_CENTER);
+		touch_dragger->set_default_cursor_shape(vertical ? CURSOR_VSPLIT : CURSOR_HSPLIT);
+		touch_dragger->set_modulate(Color(1, 1, 1, 0.3));
+		touch_dragger->connect(SceneStringName(gui_input), callable_mp(this, &SplitContainer::_touch_dragger_gui_input));
+		touch_dragger->connect(SceneStringName(mouse_exited), callable_mp(this, &SplitContainer::_touch_dragger_mouse_exited));
+		dragging_area_control->add_child(touch_dragger, false, Node::INTERNAL_MODE_FRONT);
+	} else {
+		if (touch_dragger) {
+			touch_dragger->queue_free();
+			touch_dragger = nullptr;
+		}
+	}
+	dragging_area_control->queue_redraw();
+}
+
+bool SplitContainer::is_touch_dragger_enabled() const {
+	return touch_dragger_enabled;
+}
+
+void SplitContainer::_touch_dragger_mouse_exited() {
+	if (!dragging_area_control->dragging) {
+		touch_dragger->set_modulate(Color(1, 1, 1, 0.3));
+	}
+}
+
+void SplitContainer::_touch_dragger_gui_input(const Ref<InputEvent> &p_event) {
+	if (!touch_dragger_enabled) {
+		return;
+	}
+	Ref<InputEventMouseMotion> mm = p_event;
+	Ref<InputEventMouseButton> mb = p_event;
+
+	if (mb.is_valid() && mb->get_button_index() == MouseButton::LEFT) {
+		if (mb->is_pressed()) {
+			touch_dragger->set_modulate(Color(1, 1, 1, 1));
+		} else {
+			touch_dragger->set_modulate(Color(1, 1, 1, 0.3));
+		}
+	}
+
+	if (mm.is_valid() && !dragging_area_control->dragging) {
+		touch_dragger->set_modulate(Color(1, 1, 1, 0.6));
+	}
+}
+
 void SplitContainer::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_split_offset", "offset"), &SplitContainer::set_split_offset);
 	ClassDB::bind_method(D_METHOD("get_split_offset"), &SplitContainer::get_split_offset);
@@ -535,6 +616,9 @@ void SplitContainer::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("get_drag_area_control"), &SplitContainer::get_drag_area_control);
 
+	ClassDB::bind_method(D_METHOD("set_touch_dragger_enabled", "enabled"), &SplitContainer::set_touch_dragger_enabled);
+	ClassDB::bind_method(D_METHOD("is_touch_dragger_enabled"), &SplitContainer::is_touch_dragger_enabled);
+
 	ADD_SIGNAL(MethodInfo("dragged", PropertyInfo(Variant::INT, "offset")));
 	ADD_SIGNAL(MethodInfo("drag_started"));
 	ADD_SIGNAL(MethodInfo("drag_ended"));
@@ -544,6 +628,7 @@ void SplitContainer::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "dragging_enabled"), "set_dragging_enabled", "is_dragging_enabled");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "dragger_visibility", PROPERTY_HINT_ENUM, "Visible,Hidden,Hidden and Collapsed"), "set_dragger_visibility", "get_dragger_visibility");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "vertical"), "set_vertical", "is_vertical");
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "touch_dragger_enabled"), "set_touch_dragger_enabled", "is_touch_dragger_enabled");
 
 	ADD_GROUP("Drag Area", "drag_area_");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "drag_area_margin_begin", PROPERTY_HINT_NONE, "suffix:px"), "set_drag_area_margin_begin", "get_drag_area_margin_begin");
@@ -558,6 +643,9 @@ void SplitContainer::_bind_methods() {
 	BIND_THEME_ITEM(Theme::DATA_TYPE_CONSTANT, SplitContainer, separation);
 	BIND_THEME_ITEM(Theme::DATA_TYPE_CONSTANT, SplitContainer, minimum_grab_thickness);
 	BIND_THEME_ITEM(Theme::DATA_TYPE_CONSTANT, SplitContainer, autohide);
+	BIND_THEME_ITEM_CUSTOM(Theme::DATA_TYPE_ICON, SplitContainer, touch_dragger_icon, "touch_dragger");
+	BIND_THEME_ITEM_CUSTOM(Theme::DATA_TYPE_ICON, SplitContainer, touch_dragger_icon_h, "h_touch_dragger");
+	BIND_THEME_ITEM_CUSTOM(Theme::DATA_TYPE_ICON, SplitContainer, touch_dragger_icon_v, "v_touch_dragger");
 	BIND_THEME_ITEM_CUSTOM(Theme::DATA_TYPE_ICON, SplitContainer, grabber_icon, "grabber");
 	BIND_THEME_ITEM_CUSTOM(Theme::DATA_TYPE_ICON, SplitContainer, grabber_icon_h, "h_grabber");
 	BIND_THEME_ITEM_CUSTOM(Theme::DATA_TYPE_ICON, SplitContainer, grabber_icon_v, "v_grabber");

scene/gui/split_container.h

@@ -32,6 +32,8 @@
 
 #include "scene/gui/container.h"
 
+class TextureRect;
+
 class SplitContainerDragger : public Control {
 	GDCLASS(SplitContainerDragger, Control);
 	friend class SplitContainer;
@@ -82,10 +84,16 @@ private:
 
 	SplitContainerDragger *dragging_area_control = nullptr;
 
+	bool touch_dragger_enabled = false;
+	TextureRect *touch_dragger = nullptr;
+
 	struct ThemeCache {
 		int separation = 0;
 		int minimum_grab_thickness = 0;
 		bool autohide = false;
+		Ref<Texture2D> touch_dragger_icon;
+		Ref<Texture2D> touch_dragger_icon_h;
+		Ref<Texture2D> touch_dragger_icon_v;
 		Ref<Texture2D> grabber_icon;
 		Ref<Texture2D> grabber_icon_h;
 		Ref<Texture2D> grabber_icon_v;
@@ -94,6 +102,9 @@ private:
 	} theme_cache;
 
 	Ref<Texture2D> _get_grabber_icon() const;
+	Ref<Texture2D> _get_touch_dragger_icon() const;
+	void _touch_dragger_mouse_exited();
+	void _touch_dragger_gui_input(const Ref<InputEvent> &p_event);
 	void _compute_split_offset(bool p_clamp);
 	int _get_separation() const;
 	void _resort();
@@ -142,6 +153,9 @@ public:
 
 	Control *get_drag_area_control() { return dragging_area_control; }
 
+	void set_touch_dragger_enabled(bool p_enabled);
+	bool is_touch_dragger_enabled() const;
+
 	SplitContainer(bool p_vertical = false);
 };
 

scene/theme/default_theme.cpp

@@ -1184,6 +1184,10 @@ void fill_default_theme(Ref<Theme> &theme, const Ref<Font> &default_font, const
 
 	// Containers
 
+	theme->set_icon("h_touch_dragger", "SplitContainer", icons["h_dragger"]);
+	theme->set_icon("v_touch_dragger", "SplitContainer", icons["v_dragger"]);
+	theme->set_icon("touch_dragger", "VSplitContainer", icons["v_dragger"]);
+	theme->set_icon("touch_dragger", "HSplitContainer", icons["h_dragger"]);
 	theme->set_icon("h_grabber", "SplitContainer", icons["hsplitter"]);
 	theme->set_icon("v_grabber", "SplitContainer", icons["vsplitter"]);
 	theme->set_icon("grabber", "VSplitContainer", icons["vsplitter"]);

scene/theme/icons/h_dragger.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="30" height="60"><rect width="28" height="58" x="1" y="1" fill="#e0e0e0" fill-opacity=".6" stroke="#000" stroke-width=".8" rx="7"/></svg>

scene/theme/icons/v_dragger.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="60" height="30"><rect width="58" height="28" x="1" y="1" fill="#e0e0e0" fill-opacity=".6" stroke="#000" stroke-width=".8" rx="7"/></svg>