Add drag and drop to TextEdit

4 files changed, 158 insertions, 8 deletions

diff --git a/doc/classes/TextEdit.xml b/doc/classes/TextEdit.xml
index 16d8595b4e..d14f8a9b35 100644
--- a/doc/classes/TextEdit.xml
+++ b/doc/classes/TextEdit.xml
@@ -586,6 +586,13 @@
 				Returns whether the menu is visible. Use this instead of [code]get_menu().visible[/code] to improve performance (so the creation of the menu is avoided).
 			</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_overtype_mode_enabled" qualifiers="const">
 			<return type="bool" />
 			<description>
diff --git a/scene/gui/line_edit.cpp b/scene/gui/line_edit.cpp
index 69b08fda3c..30a6f0fc9a 100644
--- a/scene/gui/line_edit.cpp
+++ b/scene/gui/line_edit.cpp
@@ -322,7 +322,7 @@ void LineEdit::gui_input(const Ref<InputEvent> &p_event) {
 					deselect();
 					selection.start_column = caret_column;
 					selection.creating = true;
-				} else if (selection.enabled) {
+				} else if (selection.enabled && !selection.double_click) {
 					selection.drag_attempt = true;
 				}
 			}
@@ -588,13 +588,19 @@ void LineEdit::drop_data(const Point2 &p_point, const Variant &p_data) {
 	if (p_data.get_type() == Variant::STRING && is_editable()) {
 		set_caret_at_pixel_pos(p_point.x);
 		int caret_column_tmp = caret_column;
+		bool is_inside_sel = selection.enabled && caret_column >= selection.begin && caret_column <= selection.end;
+		if (Input::get_singleton()->is_key_pressed(Key::CTRL)) {
+			is_inside_sel = selection.enabled && caret_column > selection.begin && caret_column < selection.end;
+		}
 		if (selection.drag_attempt) {
 			selection.drag_attempt = false;
-			if (caret_column < selection.begin || caret_column > selection.end) {
-				if (caret_column_tmp > selection.end) {
-					caret_column_tmp = caret_column_tmp - (selection.end - selection.begin);
+			if (!is_inside_sel) {
+				if (!Input::get_singleton()->is_key_pressed(Key::CTRL)) {
+					if (caret_column_tmp > selection.end) {
+						caret_column_tmp = caret_column_tmp - (selection.end - selection.begin);
+					}
+					selection_delete();
 				}
-				selection_delete();
 
 				set_caret_column(caret_column_tmp);
 				insert_text_at_caret(p_data);
@@ -975,7 +981,7 @@ void LineEdit::_notification(int p_what) {
 			if (is_drag_successful()) {
 				if (selection.drag_attempt) {
 					selection.drag_attempt = false;
-					if (is_editable()) {
+					if (is_editable() && !Input::get_singleton()->is_key_pressed(Key::CTRL)) {
 						selection_delete();
 					} else if (deselect_on_focus_loss_enabled) {
 						deselect();
diff --git a/scene/gui/text_edit.cpp b/scene/gui/text_edit.cpp
index 2cb9d10fca..dedcc266e0 100644
--- a/scene/gui/text_edit.cpp
+++ b/scene/gui/text_edit.cpp
@@ -39,6 +39,7 @@
 #include "core/os/os.h"
 #include "core/string/string_builder.h"
 #include "core/string/translation.h"
+#include "label.h"
 
 #include "scene/main/window.h"
 
@@ -1224,7 +1225,7 @@ void TextEdit::_notification(int p_what) {
 
 							if (caret.draw_pos.x >= xmargin_beg && caret.draw_pos.x < xmargin_end) {
 								caret.visible = true;
-								if (draw_caret) {
+								if (draw_caret || drag_caret_force_displayed) {
 									if (caret_type == CaretType::CARET_TYPE_BLOCK || overtype_mode) {
 										//Block or underline caret, draw trailing carets at full height.
 										int h = font->get_height(font_size);
@@ -1391,7 +1392,7 @@ void TextEdit::_notification(int p_what) {
 				DisplayServer::get_singleton()->virtual_keyboard_hide();
 			}
 
-			if (deselect_on_focus_loss_enabled) {
+			if (deselect_on_focus_loss_enabled && !selection.drag_attempt) {
 				deselect();
 			}
 		} break;
@@ -1411,6 +1412,30 @@ void TextEdit::_notification(int p_what) {
 				update();
 			}
 		} break;
+		case Control::NOTIFICATION_DRAG_BEGIN: {
+			selection.selecting_mode = SelectionMode::SELECTION_MODE_NONE;
+			drag_action = true;
+			dragging_minimap = false;
+			dragging_selection = false;
+			can_drag_minimap = false;
+			click_select_held->stop();
+		} 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::CTRL)) {
+						delete_selection();
+					} else if (deselect_on_focus_loss_enabled) {
+						deselect();
+					}
+				}
+			} else {
+				selection.drag_attempt = false;
+			}
+			drag_action = false;
+			drag_caret_force_displayed = false;
+		} break;
 	}
 }
 
@@ -1495,6 +1520,7 @@ void TextEdit::gui_input(const Ref<InputEvent> &p_gui_input) {
 
 				set_caret_line(row, false, false);
 				set_caret_column(col);
+				selection.drag_attempt = false;
 
 				if (mb->is_shift_pressed() && (caret.column != prev_col || caret.line != prev_line)) {
 					if (!selection.active) {
@@ -1538,6 +1564,9 @@ void TextEdit::gui_input(const Ref<InputEvent> &p_gui_input) {
 
 						update();
 					}
+				} else if (is_mouse_over_selection()) {
+					selection.selecting_mode = SelectionMode::SELECTION_MODE_NONE;
+					selection.drag_attempt = true;
 				} else {
 					selection.active = false;
 					selection.selecting_mode = SelectionMode::SELECTION_MODE_POINTER;
@@ -1551,6 +1580,7 @@ void TextEdit::gui_input(const Ref<InputEvent> &p_gui_input) {
 				if (!mb->is_double_click() && (OS::get_singleton()->get_ticks_msec() - last_dblclk) < triple_click_timeout && mb->get_position().distance_to(last_dblclk_pos) < triple_click_tolerance) {
 					// Triple-click select line.
 					selection.selecting_mode = SelectionMode::SELECTION_MODE_LINE;
+					selection.drag_attempt = false;
 					_update_selection_mode_line();
 					last_dblclk = 0;
 				} else if (mb->is_double_click() && text[caret.line].length()) {
@@ -1601,10 +1631,16 @@ void TextEdit::gui_input(const Ref<InputEvent> &p_gui_input) {
 			}
 		} else {
 			if (mb->get_button_index() == MouseButton::LEFT) {
+				if (selection.drag_attempt && is_mouse_over_selection()) {
+					selection.active = false;
+				}
 				dragging_minimap = false;
 				dragging_selection = false;
 				can_drag_minimap = false;
 				click_select_held->stop();
+				if (!drag_action) {
+					selection.drag_attempt = false;
+				}
 				if (DisplayServer::get_singleton()->has_feature(DisplayServer::FEATURE_CLIPBOARD_PRIMARY)) {
 					DisplayServer::get_singleton()->clipboard_set_primary(get_selected_text());
 				}
@@ -1689,6 +1725,14 @@ void TextEdit::gui_input(const Ref<InputEvent> &p_gui_input) {
 			hovered_gutter = current_hovered_gutter;
 			update();
 		}
+
+		if (drag_action && can_drop_data(mpos, get_viewport()->gui_get_drag_data())) {
+			drag_caret_force_displayed = true;
+			Point2i pos = get_line_column_at_pos(get_local_mouse_pos());
+			set_caret_line(pos.y, false);
+			set_caret_column(pos.x);
+			dragging_selection = true;
+		}
 	}
 
 	if (draw_minimap && !dragging_selection) {
@@ -2406,6 +2450,75 @@ bool TextEdit::is_text_field() const {
 	return true;
 }
 
+Variant TextEdit::get_drag_data(const Point2 &p_point) {
+	if (selection.active && selection.drag_attempt) {
+		String t = get_selected_text();
+		Label *l = memnew(Label);
+		l->set_text(t);
+		set_drag_preview(l);
+		return t;
+	}
+
+	return Variant();
+}
+
+bool TextEdit::can_drop_data(const Point2 &p_point, const Variant &p_data) const {
+	bool drop_override = Control::can_drop_data(p_point, p_data); // In case user wants to drop custom data.
+	if (drop_override) {
+		return drop_override;
+	}
+
+	return is_editable() && p_data.get_type() == Variant::STRING;
+}
+
+void TextEdit::drop_data(const Point2 &p_point, const Variant &p_data) {
+	Control::drop_data(p_point, p_data);
+
+	if (p_data.get_type() == Variant::STRING && is_editable()) {
+		Point2i pos = get_line_column_at_pos(get_local_mouse_pos());
+		int caret_row_tmp = pos.y;
+		int caret_column_tmp = pos.x;
+		if (selection.drag_attempt) {
+			selection.drag_attempt = false;
+			if (!is_mouse_over_selection(!Input::get_singleton()->is_key_pressed(Key::CTRL))) {
+				begin_complex_operation();
+				if (!Input::get_singleton()->is_key_pressed(Key::CTRL)) {
+					if (caret_row_tmp > selection.to_line) {
+						caret_row_tmp = caret_row_tmp - (selection.to_line - selection.from_line);
+					} else if (caret_row_tmp == selection.to_line && caret_column_tmp >= selection.to_column) {
+						caret_column_tmp = caret_column_tmp - (selection.to_column - selection.from_column);
+					}
+					delete_selection();
+				} else {
+					deselect();
+				}
+
+				set_caret_line(caret_row_tmp, true, false);
+				set_caret_column(caret_column_tmp);
+				insert_text_at_caret(p_data);
+				end_complex_operation();
+			}
+		} else if (is_mouse_over_selection()) {
+			caret_row_tmp = selection.from_line;
+			caret_column_tmp = selection.from_column;
+			set_caret_line(caret_row_tmp, true, false);
+			set_caret_column(caret_column_tmp);
+			insert_text_at_caret(p_data);
+			grab_focus();
+		} else {
+			deselect();
+			set_caret_line(caret_row_tmp, true, false);
+			set_caret_column(caret_column_tmp);
+			insert_text_at_caret(p_data);
+			grab_focus();
+		}
+
+		if (caret_row_tmp != caret.line || caret_column_tmp != caret.column) {
+			select(caret_row_tmp, caret_column_tmp, caret.line, caret.column);
+		}
+	}
+}
+
 Control::CursorShape TextEdit::get_cursor_shape(const Point2 &p_pos) const {
 	Point2i pos = get_line_column_at_pos(p_pos);
 	int row = pos.y;
@@ -3580,6 +3693,21 @@ bool TextEdit::is_dragging_cursor() const {
 	return dragging_selection || dragging_minimap;
 }
 
+bool TextEdit::is_mouse_over_selection(bool p_edges) const {
+	if (!has_selection()) {
+		return false;
+	}
+	Point2i pos = get_line_column_at_pos(get_local_mouse_pos());
+	int row = pos.y;
+	int col = pos.x;
+	if (p_edges) {
+		if ((row == selection.from_line && col == selection.from_column) || (row == selection.to_line && col == selection.to_column)) {
+			return true;
+		}
+	}
+	return (row >= selection.from_line && row <= selection.to_line && (row > selection.from_line || col > selection.from_column) && (row < selection.to_line || col < selection.to_column));
+}
+
 /* Caret */
 void TextEdit::set_caret_type(CaretType p_type) {
 	caret_type = p_type;
@@ -4776,6 +4904,7 @@ void TextEdit::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_minimap_line_at_pos", "position"), &TextEdit::get_minimap_line_at_pos);
 
 	ClassDB::bind_method(D_METHOD("is_dragging_cursor"), &TextEdit::is_dragging_cursor);
+	ClassDB::bind_method(D_METHOD("is_mouse_over_selection", "edges"), &TextEdit::is_mouse_over_selection);
 
 	/* Caret. */
 	BIND_ENUM_CONSTANT(CARET_TYPE_LINE);
diff --git a/scene/gui/text_edit.h b/scene/gui/text_edit.h
index 42b21cbe9c..a1b2ed59f5 100644
--- a/scene/gui/text_edit.h
+++ b/scene/gui/text_edit.h
@@ -375,6 +375,9 @@ private:
 
 	bool caret_mid_grapheme_enabled = false;
 
+	bool drag_action = false;
+	bool drag_caret_force_displayed = false;
+
 	void _emit_caret_changed();
 
 	void _reset_caret_blink_timer();
@@ -400,6 +403,7 @@ private:
 		int to_column = 0;
 
 		bool shiftclick_left = false;
+		bool drag_attempt = false;
 	} selection;
 
 	bool selecting_enabled = true;
@@ -611,6 +615,9 @@ public:
 	virtual Size2 get_minimum_size() const override;
 	virtual bool is_text_field() const override;
 	virtual CursorShape get_cursor_shape(const Point2 &p_pos = Point2i()) const override;
+	virtual Variant get_drag_data(const Point2 &p_point) override;
+	virtual bool can_drop_data(const Point2 &p_point, const Variant &p_data) const override;
+	virtual void drop_data(const Point2 &p_point, const Variant &p_data) override;
 	virtual String get_tooltip(const Point2 &p_pos) const override;
 	void set_tooltip_request_func(Object *p_obj, const StringName &p_function, const Variant &p_udata);
 
@@ -731,6 +738,7 @@ public:
 	int get_minimap_line_at_pos(const Point2i &p_pos) const;
 
 	bool is_dragging_cursor() const;
+	bool is_mouse_over_selection(bool p_edges = true) const;
 
 	/* Caret */
 	void set_caret_type(CaretType p_type);