Add drag and drop to TextEdit, LineEdit, RichTextLabel

doc/classes/Control.xml

@@ -500,6 +500,12 @@
 				See [method add_stylebox_override].
 			</description>
 		</method>
+		<method name="is_drag_successful" qualifiers="const">
+			<return type="bool" />
+			<description>
+				Returns [code]true[/code] if drag operation is successful.
+			</description>
+		</method>
 		<method name="minimum_size_changed">
 			<return type="void" />
 			<description>

doc/classes/TextEdit.xml

@@ -313,6 +313,13 @@
 				Returns if the given line is wrapped.
 			</description>
 		</method>
+		<method name="is_mouse_over_selection" qualifiers="const">
+			<return type="bool" />
+			<argument index="0" name="edges" type="bool" />
+			<description>
+				Returns whether the mouse is over selection. If [code]edges[/code] is [code]true[/code], the edges are considered part of the selection.
+			</description>
+		</method>
 		<method name="is_selection_active" qualifiers="const">
 			<return type="bool" />
 			<description>

doc/classes/Viewport.xml

@@ -114,6 +114,12 @@
 				Returns [code]true[/code] if there are visible modals on-screen.
 			</description>
 		</method>
+		<method name="gui_is_drag_successful" qualifiers="const">
+			<return type="bool" />
+			<description>
+				Returns [code]true[/code] if the drag operation is successful.
+			</description>
+		</method>
 		<method name="gui_is_dragging" qualifiers="const">
 			<return type="bool" />
 			<description>

scene/gui/control.cpp

@@ -757,6 +757,10 @@ void Control::set_drag_preview(Control *p_control) {
 	get_viewport()->_gui_set_drag_preview(this, p_control);
 }
 
+bool Control::is_drag_successful() const {
+	return is_inside_tree() && get_viewport()->gui_is_drag_successful();
+}
+
 bool Control::is_window_modal_on_top() const {
 	if (!is_inside_tree()) {
 		return false;
@@ -2852,6 +2856,7 @@ void Control::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("set_drag_forwarding", "target"), &Control::set_drag_forwarding);
 	ClassDB::bind_method(D_METHOD("set_drag_preview", "control"), &Control::set_drag_preview);
+	ClassDB::bind_method(D_METHOD("is_drag_successful"), &Control::is_drag_successful);
 
 	ClassDB::bind_method(D_METHOD("warp_mouse", "to_position"), &Control::warp_mouse);
 

scene/gui/control.h

@@ -310,6 +310,7 @@ class Control : public CanvasItem {
 	virtual void drop_data(const Point2 &p_point, const Variant &p_data);
 	void set_drag_preview(Control *p_control);
 	void force_drag(const Variant &p_data, Control *p_control);
+	bool is_drag_successful() const;
 
 	void set_custom_minimum_size(const Size2 &p_custom);
 	Size2 get_custom_minimum_size() const;

scene/gui/line_edit.cpp

@@ -31,11 +31,13 @@
 #include "line_edit.h"
 
 #include "core/message_queue.h"
+#include "core/os/input.h"
 #include "core/os/keyboard.h"
 #include "core/os/os.h"
 #include "core/print_string.h"
 #include "core/translation.h"
 #include "label.h"
+#include "scene/main/viewport.h"
 
 #ifdef TOOLS_ENABLED
 #include "editor/editor_scale.h"
@@ -79,7 +81,9 @@ void LineEdit::_gui_input(Ref<InputEvent> p_event) {
 				return;
 			}
 
-			shift_selection_check_pre(b->get_shift());
+			if (b->get_shift()) {
+				shift_selection_check_pre(true);
+			}
 
 			set_cursor_at_pixel_pos(b->get_position().x);
 
@@ -124,7 +128,7 @@ void LineEdit::_gui_input(Ref<InputEvent> p_event) {
 					deselect();
 					selection.cursor_start = cursor_pos;
 					selection.creating = true;
-				} else if (selection.enabled) {
+				} else if (selection.enabled && !selection.doubleclick) {
 					selection.drag_attempt = true;
 				}
 			}
@@ -146,6 +150,9 @@ void LineEdit::_gui_input(Ref<InputEvent> p_event) {
 			}
 			selection.creating = false;
 			selection.doubleclick = false;
+			if (!drag_action) {
+				selection.drag_attempt = false;
+			}
 
 			show_virtual_keyboard();
 		}
@@ -170,6 +177,11 @@ void LineEdit::_gui_input(Ref<InputEvent> p_event) {
 				selection_fill_at_cursor();
 			}
 		}
+
+		if (drag_action && can_drop_data(m->get_position(), get_viewport()->gui_get_drag_data())) {
+			drag_caret_force_displayed = true;
+			set_cursor_at_pixel_pos(m->get_position().x);
+		}
 	}
 
 	Ref<InputEventKey> k = p_event;
@@ -641,28 +653,50 @@ bool LineEdit::can_drop_data(const Point2 &p_point, const Variant &p_data) const
 		return drop_override;
 	}
 
-	return p_data.get_type() == Variant::STRING;
+	return is_editable() && p_data.get_type() == Variant::STRING;
 }
 
 void LineEdit::drop_data(const Point2 &p_point, const Variant &p_data) {
 	Control::drop_data(p_point, p_data);
 
-	if (p_data.get_type() == Variant::STRING) {
+	if (p_data.get_type() == Variant::STRING && is_editable()) {
 		set_cursor_at_pixel_pos(p_point.x);
-		int selected = selection.end - selection.begin;
+		int caret_column_tmp = cursor_pos;
+		bool is_inside_sel = selection.enabled && cursor_pos >= selection.begin && cursor_pos <= selection.end;
+		if (Input::get_singleton()->is_key_pressed(KEY_CONTROL)) {
+			is_inside_sel = selection.enabled && cursor_pos > selection.begin && cursor_pos < selection.end;
+		}
+		if (selection.drag_attempt) {
+			selection.drag_attempt = false;
+			if (!is_inside_sel) {
+				if (!Input::get_singleton()->is_key_pressed(KEY_CONTROL)) {
+					if (caret_column_tmp > selection.end) {
+						caret_column_tmp = caret_column_tmp - (selection.end - selection.begin);
+					}
+					selection_delete();
+				}
 
-		Ref<Font> font = get_font("font");
-		if (font != nullptr) {
-			for (int i = selection.begin; i < selection.end; i++) {
-				cached_width -= font->get_char_size(pass ? secret_character[0] : text[i]).width;
+				set_cursor_position(caret_column_tmp);
+				append_at_cursor(p_data);
 			}
+		} else if (selection.enabled && cursor_pos >= selection.begin && cursor_pos <= selection.end) {
+			caret_column_tmp = selection.begin;
+			selection_delete();
+			set_cursor_position(caret_column_tmp);
+			append_at_cursor(p_data);
+			grab_focus();
+		} else {
+			append_at_cursor(p_data);
+			grab_focus();
 		}
-
-		text.erase(selection.begin, selected);
-
-		append_at_cursor(p_data);
-		selection.begin = cursor_pos - selected;
-		selection.end = cursor_pos;
+		select(caret_column_tmp, cursor_pos);
+		if (!text_changed_dirty) {
+			if (is_inside_tree()) {
+				MessageQueue::get_singleton()->push_call(this, "_text_changed");
+			}
+			text_changed_dirty = true;
+		}
+		update();
 	}
 }
 
@@ -910,7 +944,7 @@ void LineEdit::_notification(int p_what) {
 				}
 			}
 
-			if ((char_ofs == cursor_pos || using_placeholder) && draw_caret) { // May be at the end, or placeholder.
+			if ((char_ofs == cursor_pos || using_placeholder || drag_caret_force_displayed) && draw_caret) { // May be at the end, or placeholder.
 				if (ime_text.length() == 0) {
 					int caret_x_ofs = x_ofs;
 					if (using_placeholder) {
@@ -977,6 +1011,25 @@ void LineEdit::_notification(int p_what) {
 				update();
 			}
 		} break;
+		case Control::NOTIFICATION_DRAG_BEGIN: {
+			drag_action = true;
+		} break;
+		case Control::NOTIFICATION_DRAG_END: {
+			if (is_drag_successful()) {
+				if (selection.drag_attempt) {
+					selection.drag_attempt = false;
+					if (is_editable() && !Input::get_singleton()->is_key_pressed(KEY_CONTROL)) {
+						selection_delete();
+						// } else if (deselect_on_focus_loss_enabled) {
+						// 	deselect();
+					}
+				}
+			} else {
+				selection.drag_attempt = false;
+			}
+			drag_action = false;
+			drag_caret_force_displayed = false;
+		} break;
 	}
 }
 
@@ -1033,6 +1086,9 @@ void LineEdit::undo() {
 	} else if (undo_stack_pos == undo_stack.front()) {
 		return;
 	}
+
+	deselect();
+
 	undo_stack_pos = undo_stack_pos->prev();
 	TextOperation op = undo_stack_pos->get();
 	text = op.text;
@@ -1054,6 +1110,9 @@ void LineEdit::redo() {
 	if (undo_stack_pos == undo_stack.back()) {
 		return;
 	}
+
+	deselect();
+
 	undo_stack_pos = undo_stack_pos->next();
 	TextOperation op = undo_stack_pos->get();
 	text = op.text;

scene/gui/line_edit.h

@@ -92,6 +92,9 @@ class LineEdit : public Control {
 
 	bool virtual_keyboard_enabled = true;
 
+	bool drag_action = false;
+	bool drag_caret_force_displayed = false;
+
 	Ref<Texture> right_icon;
 
 	struct Selection {

scene/gui/rich_text_label.cpp

@@ -33,6 +33,7 @@
 #include "core/math/math_defs.h"
 #include "core/os/keyboard.h"
 #include "core/os/os.h"
+#include "label.h"
 #include "scene/scene_string_names.h"
 
 #ifdef TOOLS_ENABLED
@@ -1047,6 +1048,9 @@ void RichTextLabel::_notification(int p_what) {
 				update();
 			}
 		}
+		case Control::NOTIFICATION_DRAG_END: {
+			selection.drag_attempt = false;
+		} break;
 	}
 }
 
@@ -1129,6 +1133,9 @@ void RichTextLabel::_gui_input(Ref<InputEvent> p_event) {
 				Item *item = nullptr;
 
 				bool outside;
+
+				selection.drag_attempt = false;
+
 				_find_click(main, b->get_position(), &item, &line, &outside);
 
 				if (item) {
@@ -1138,13 +1145,18 @@ void RichTextLabel::_gui_input(Ref<InputEvent> p_event) {
 
 						// Erase previous selection.
 						if (selection.active) {
-							selection.from = nullptr;
-							selection.from_char = '\0';
-							selection.to = nullptr;
-							selection.to_char = '\0';
-							selection.active = false;
-
-							update();
+							if (_is_click_inside_selection()) {
+								selection.drag_attempt = true;
+								selection.click = nullptr;
+							} else {
+								selection.from = nullptr;
+								selection.from_char = '\0';
+								selection.to = nullptr;
+								selection.to_char = '\0';
+								selection.active = false;
+
+								update();
+							}
 						}
 					}
 				}
@@ -1154,6 +1166,8 @@ void RichTextLabel::_gui_input(Ref<InputEvent> p_event) {
 				Item *item = nullptr;
 				bool outside;
 
+				selection.drag_attempt = false;
+
 				_find_click(main, b->get_position(), &item, &line, &outside);
 
 				while (item && item->type != ITEM_TEXT) {
@@ -1174,6 +1188,25 @@ void RichTextLabel::_gui_input(Ref<InputEvent> p_event) {
 					}
 				}
 			} else if (!b->is_pressed()) {
+				if (selection.drag_attempt) {
+					selection.drag_attempt = false;
+					int line = 0;
+					Item *item = nullptr;
+					bool outside;
+					_find_click(main, b->get_position(), &item, &line, &outside);
+					selection.click = item;
+					selection.click_char = line;
+					if (_is_click_inside_selection()) {
+						selection.active = false;
+						selection.from = nullptr;
+						selection.from_char = '\0';
+						selection.to = nullptr;
+						selection.to_char = '\0';
+						selection.active = false;
+
+						update();
+					}
+				}
 				selection.click = nullptr;
 
 				if (!b->is_doubleclick() && !scroll_updated) {
@@ -2476,6 +2509,22 @@ void RichTextLabel::set_selection_enabled(bool p_enabled) {
 	}
 }
 
+Variant RichTextLabel::get_drag_data(const Point2 &p_point) {
+	if (selection.drag_attempt && selection.enabled) {
+		String t = get_selected_text();
+		Label *l = memnew(Label);
+		l->set_text(t);
+		set_drag_preview(l);
+		return t;
+	}
+
+	return Variant();
+}
+
+bool RichTextLabel::_is_click_inside_selection() const {
+	return (selection.click->index >= selection.from->index && selection.click->index <= selection.to->index && (selection.click->index > selection.from->index || selection.click_char >= selection.from_char) && (selection.click->index < selection.to->index || selection.click_char <= selection.to_char));
+}
+
 bool RichTextLabel::search(const String &p_string, bool p_from_selection, bool p_search_previous) {
 	ERR_FAIL_COND_V(!selection.enabled, false);
 	Item *it = main;
@@ -2985,6 +3034,7 @@ RichTextLabel::RichTextLabel() {
 	selection.click = nullptr;
 	selection.active = false;
 	selection.enabled = false;
+	selection.drag_attempt = false;
 
 	visible_characters = -1;
 	percent_visible = 1;

scene/gui/rich_text_label.h

@@ -358,13 +358,15 @@ class RichTextLabel : public Control {
 
 		bool active; // anything selected? i.e. from, to, etc. valid?
 		bool enabled; // allow selections?
+		bool drag_attempt;
 	};
 
 	Selection selection;
 
 	int visible_characters;
 	float percent_visible;
 
+	bool _is_click_inside_selection() const;
 	int _process_line(ItemFrame *p_frame, const Vector2 &p_ofs, int &y, int p_width, int p_line, ProcessMode p_mode, const Ref<Font> &p_base_font, const Color &p_base_color, const Color &p_font_color_shadow, bool p_shadow_as_outline, const Point2 &shadow_ofs, const Point2i &p_click_pos = Point2i(), Item **r_click_item = nullptr, int *r_click_char = nullptr, bool *r_outside = nullptr, int p_char_count = 0);
 	void _find_click(ItemFrame *p_frame, const Point2i &p_click, Item **r_click_item = nullptr, int *r_click_char = nullptr, bool *r_outside = nullptr);
 
@@ -465,6 +467,7 @@ class RichTextLabel : public Control {
 	VScrollBar *get_v_scroll() { return vscroll; }
 
 	virtual CursorShape get_cursor_shape(const Point2 &p_pos) const;
+	virtual Variant get_drag_data(const Point2 &p_point);
 
 	void set_selection_enabled(bool p_enabled);
 	bool is_selection_enabled() const;