Add auto-scroll behavior when selecting text outside the visible area in RichTextLabel

scene/gui/rich_text_label.cpp

@@ -2596,6 +2596,11 @@ void RichTextLabel::gui_input(const Ref<InputEvent> &p_event) {
 								deselect();
 							}
 						}
+
+						if (!selection.drag_attempt) {
+							is_selecting_text = true;
+							click_select_held->start();
+						}
 					}
 				}
 			} else if (b->is_pressed() && b->is_double_click() && selection.enabled) {
@@ -2677,6 +2682,9 @@ void RichTextLabel::gui_input(const Ref<InputEvent> &p_event) {
 						}
 					}
 				}
+
+				is_selecting_text = false;
+				click_select_held->stop();
 			}
 		}
 
@@ -2865,13 +2873,37 @@ void RichTextLabel::gui_input(const Ref<InputEvent> &p_event) {
 
 	Ref<InputEventMouseMotion> m = p_event;
 	if (m.is_valid()) {
+		local_mouse_pos = get_local_mouse_position();
+		last_clamped_mouse_pos = local_mouse_pos.clamp(Vector2(), get_size());
+	}
+}
+
+void RichTextLabel::_update_selection() {
 	ItemFrame *c_frame = nullptr;
 	int c_line = 0;
 	Item *c_item = nullptr;
 	int c_index = 0;
 	bool outside;
 
-		_find_click(main, m->get_position(), &c_frame, &c_line, &c_item, &c_index, &outside, false);
+	// Handle auto scrolling.
+	const Size2 size = get_size();
+	if (!(local_mouse_pos.x >= 0.0 && local_mouse_pos.y >= 0.0 &&
+				local_mouse_pos.x < size.x && local_mouse_pos.y < size.y)) {
+		real_t scroll_delta = 0.0;
+		if (local_mouse_pos.y < 0) {
+			scroll_delta = -auto_scroll_speed * (1 - (local_mouse_pos.y / 15.0));
+		} else if (local_mouse_pos.y > size.y) {
+			scroll_delta = auto_scroll_speed * (1 + (local_mouse_pos.y - size.y) / 15.0);
+		}
+
+		if (scroll_delta != 0.0) {
+			vscroll->scroll(scroll_delta);
+			queue_redraw();
+		}
+	}
+
+	// Update selection area.
+	_find_click(main, last_clamped_mouse_pos, &c_frame, &c_line, &c_item, &c_index, &outside, false);
 	if (selection.click_item && c_item) {
 		selection.from_frame = selection.click_frame;
 		selection.from_line = selection.click_line;
@@ -2930,7 +2962,8 @@ void RichTextLabel::gui_input(const Ref<InputEvent> &p_event) {
 		queue_redraw();
 	}
 
-		_find_click(main, m->get_position(), nullptr, nullptr, &c_item, nullptr, &outside, true);
+	// Update meta hovering.
+	_find_click(main, local_mouse_pos, nullptr, nullptr, &c_item, nullptr, &outside, true);
 	Variant meta;
 	ItemMeta *item_meta;
 	ItemMeta *prev_meta = meta_hovering;
@@ -2954,7 +2987,6 @@ void RichTextLabel::gui_input(const Ref<InputEvent> &p_event) {
 			queue_redraw();
 		}
 	}
-	}
 }
 
 String RichTextLabel::get_tooltip(const Point2 &p_pos) const {
@@ -7783,6 +7815,11 @@ RichTextLabel::RichTextLabel(const String &p_text) {
 	parsing_bbcode.store(false);
 
 	set_clip_contents(true);
+
+	click_select_held = memnew(Timer);
+	add_child(click_select_held, false, INTERNAL_MODE_FRONT);
+	click_select_held->set_wait_time(0.05);
+	click_select_held->connect("timeout", callable_mp(this, &RichTextLabel::_update_selection));
 }
 
 RichTextLabel::~RichTextLabel() {

scene/gui/rich_text_label.h

@@ -36,6 +36,10 @@
 #include "scene/gui/scroll_bar.h"
 #include "scene/resources/text_paragraph.h"
 
+#ifdef TOOLS_ENABLED
+#include "editor/themes/editor_scale.h"
+#endif
+
 class CharFXTransform;
 class RichTextEffect;
 
@@ -667,6 +671,17 @@ private:
 	void _scroll_changed(double);
 	int _find_first_line(int p_from, int p_to, int p_vofs) const;
 
+#ifdef TOOLS_ENABLED
+	const real_t auto_scroll_speed = EDSCALE * 2.0f;
+#else
+	const real_t auto_scroll_speed = 2.0f;
+#endif
+	Vector2 last_clamped_mouse_pos;
+	Timer *click_select_held = nullptr;
+	Vector2 local_mouse_pos;
+	bool is_selecting_text = false;
+	void _update_selection();
+
 	_FORCE_INLINE_ float _calculate_line_vertical_offset(const Line &line) const;
 
 	virtual void gui_input(const Ref<InputEvent> &p_event) override;