Implemented scrolling factor for smooth trackpad scrolling

Working platforms platform: OSX, Windows.
Support for almost all ui elements, including project list.

8 files changed, 61 insertions, 23 deletions

diff --git a/scene/gui/graph_edit.cpp b/scene/gui/graph_edit.cpp
index 0bc48677dd..d5df3bac67 100644
--- a/scene/gui/graph_edit.cpp
+++ b/scene/gui/graph_edit.cpp
@@ -962,6 +962,18 @@ void GraphEdit::_gui_input(const InputEvent &p_ev) {
 			//too difficult to get right
 			//set_zoom(zoom/ZOOM_SCALE);
 		}
+		if (b.button_index == BUTTON_WHEEL_UP) {
+			h_scroll->set_value(h_scroll->get_value() - h_scroll->get_page() * b.factor / 8);
+		}
+		if (b.button_index == BUTTON_WHEEL_DOWN) {
+			h_scroll->set_value(h_scroll->get_value() + h_scroll->get_page() * b.factor / 8);
+		}
+		if (b.button_index == BUTTON_WHEEL_RIGHT) {
+			v_scroll->set_value(v_scroll->get_value() + v_scroll->get_page() * b.factor / 8);
+		}
+		if (b.button_index == BUTTON_WHEEL_LEFT) {
+			v_scroll->set_value(v_scroll->get_value() - v_scroll->get_page() * b.factor / 8);
+		}
 	}
 
 	if (p_ev.type == InputEvent::KEY && p_ev.key.scancode == KEY_D && p_ev.key.pressed && p_ev.key.mod.command) {
diff --git a/scene/gui/item_list.cpp b/scene/gui/item_list.cpp
index 1dc4230d2a..b79104ba39 100644
--- a/scene/gui/item_list.cpp
+++ b/scene/gui/item_list.cpp
@@ -533,10 +533,14 @@ void ItemList::_gui_input(const InputEvent &p_event) {
 	}
 	if (p_event.type == InputEvent::MOUSE_BUTTON && p_event.mouse_button.button_index == BUTTON_WHEEL_UP && p_event.mouse_button.pressed) {
 
+		scroll_bar->set_value(scroll_bar->get_value() - scroll_bar->get_page() * p_event.mouse_button.factor / 8);
+
 		scroll_bar->set_value(scroll_bar->get_value() - scroll_bar->get_page() / 8);
 	}
 	if (p_event.type == InputEvent::MOUSE_BUTTON && p_event.mouse_button.button_index == BUTTON_WHEEL_DOWN && p_event.mouse_button.pressed) {
 
+		scroll_bar->set_value(scroll_bar->get_value() + scroll_bar->get_page() * p_event.mouse_button.factor / 8);
+
 		scroll_bar->set_value(scroll_bar->get_value() + scroll_bar->get_page() / 8);
 	}
 
diff --git a/scene/gui/popup_menu.cpp b/scene/gui/popup_menu.cpp
index 6ac6eac655..9b9dd820b2 100644
--- a/scene/gui/popup_menu.cpp
+++ b/scene/gui/popup_menu.cpp
@@ -273,7 +273,7 @@ void PopupMenu::_gui_input(const InputEvent &p_event) {
 
 						Point2 pos = get_position();
 						int s = (vseparation + font->get_height()) * 3;
-						pos.y -= s;
+						pos.y -= (s * b.factor);
 						set_position(pos);
 
 						//update hover
@@ -293,7 +293,7 @@ void PopupMenu::_gui_input(const InputEvent &p_event) {
 
 						Point2 pos = get_position();
 						int s = (vseparation + font->get_height()) * 3;
-						pos.y += s;
+						pos.y += (s * b.factor);
 						set_position(pos);
 
 						//update hover
diff --git a/scene/gui/rich_text_label.cpp b/scene/gui/rich_text_label.cpp
index e5a17298e4..6e5f218a66 100644
--- a/scene/gui/rich_text_label.cpp
+++ b/scene/gui/rich_text_label.cpp
@@ -780,12 +780,14 @@ void RichTextLabel::_gui_input(InputEvent p_event) {
 			if (b.button_index == BUTTON_WHEEL_UP) {
 
 				if (scroll_active)
-					vscroll->set_value(vscroll->get_value() - vscroll->get_page() / 8);
+
+					vscroll->set_value(vscroll->get_value() - vscroll->get_page() * b.factor * 0.5 / 8);
 			}
 			if (b.button_index == BUTTON_WHEEL_DOWN) {
 
 				if (scroll_active)
-					vscroll->set_value(vscroll->get_value() + vscroll->get_page() / 8);
+
+					vscroll->set_value(vscroll->get_value() + vscroll->get_page() * b.factor * 0.5 / 8);
 			}
 		} break;
 		case InputEvent::KEY: {
diff --git a/scene/gui/scroll_container.cpp b/scene/gui/scroll_container.cpp
index 9146fa9393..a89c2b27c9 100644
--- a/scene/gui/scroll_container.cpp
+++ b/scene/gui/scroll_container.cpp
@@ -85,20 +85,32 @@ void ScrollContainer::_gui_input(const InputEvent &p_gui_input) {
 			const InputEventMouseButton &mb = p_gui_input.mouse_button;
 
 			if (mb.button_index == BUTTON_WHEEL_UP && mb.pressed) {
-				if (h_scroll->is_visible_in_tree() && !v_scroll->is_visible_in_tree()) {
-					// only horizontal is enabled, scroll horizontally
-					h_scroll->set_value(h_scroll->get_value() - h_scroll->get_page() / 8);
+				// only horizontal is enabled, scroll horizontally
+				if (h_scroll->is_visible() && !v_scroll->is_visible()) {
+					h_scroll->set_value(h_scroll->get_value() - h_scroll->get_page() / 8 * mb.factor);
 				} else if (v_scroll->is_visible_in_tree()) {
-					v_scroll->set_value(v_scroll->get_value() - v_scroll->get_page() / 8);
+					v_scroll->set_value(v_scroll->get_value() - v_scroll->get_page() / 8 * mb.factor);
 				}
 			}
 
 			if (mb.button_index == BUTTON_WHEEL_DOWN && mb.pressed) {
-				if (h_scroll->is_visible_in_tree() && !v_scroll->is_visible_in_tree()) {
-					// only horizontal is enabled, scroll horizontally
-					h_scroll->set_value(h_scroll->get_value() + h_scroll->get_page() / 8);
-				} else if (v_scroll->is_visible_in_tree()) {
-					v_scroll->set_value(v_scroll->get_value() + v_scroll->get_page() / 8);
+				// only horizontal is enabled, scroll horizontally
+				if (h_scroll->is_visible() && !v_scroll->is_visible()) {
+					h_scroll->set_value(h_scroll->get_value() + h_scroll->get_page() / 8 * mb.factor);
+				} else if (v_scroll->is_visible()) {
+					v_scroll->set_value(v_scroll->get_value() + v_scroll->get_page() / 8 * mb.factor);
+				}
+			}
+
+			if (mb.button_index == BUTTON_WHEEL_LEFT && mb.pressed) {
+				if (h_scroll->is_visible_in_tree()) {
+					h_scroll->set_value(h_scroll->get_value() - h_scroll->get_page() * mb.factor / 8);
+				}
+			}
+
+			if (mb.button_index == BUTTON_WHEEL_RIGHT && mb.pressed) {
+				if (h_scroll->is_visible_in_tree()) {
+					h_scroll->set_value(h_scroll->get_value() + h_scroll->get_page() * mb.factor / 8);
 				}
 			}
 
diff --git a/scene/gui/spin_box.cpp b/scene/gui/spin_box.cpp
index ba8ca63721..83d535a2e7 100644
--- a/scene/gui/spin_box.cpp
+++ b/scene/gui/spin_box.cpp
@@ -115,13 +115,15 @@ void SpinBox::_gui_input(const InputEvent &p_event) {
 			} break;
 			case BUTTON_WHEEL_UP: {
 				if (line_edit->has_focus()) {
-					set_value(get_value() + get_step());
+
+					set_value(get_value() + get_step() * mb.factor);
 					accept_event();
 				}
 			} break;
 			case BUTTON_WHEEL_DOWN: {
 				if (line_edit->has_focus()) {
-					set_value(get_value() - get_step());
+
+					set_value(get_value() - get_step() * mb.factor);
 					accept_event();
 				}
 			} break;
diff --git a/scene/gui/text_edit.cpp b/scene/gui/text_edit.cpp
index 3c8545bd75..fb986cfb97 100644
--- a/scene/gui/text_edit.cpp
+++ b/scene/gui/text_edit.cpp
@@ -334,7 +334,10 @@ void TextEdit::_update_scrollbars() {
 		v_scroll->show();
 		v_scroll->set_max(total_rows);
 		v_scroll->set_page(visible_rows);
-		v_scroll->set_value(cursor.line_ofs);
+
+		if (fabs(v_scroll->get_value() - (double)cursor.line_ofs) >= 1) {
+			v_scroll->set_value(cursor.line_ofs);
+		}
 
 	} else {
 		cursor.line_ofs = 0;
@@ -346,7 +349,9 @@ void TextEdit::_update_scrollbars() {
 		h_scroll->show();
 		h_scroll->set_max(total_width);
 		h_scroll->set_page(visible_width);
-		h_scroll->set_value(cursor.x_ofs);
+		if (fabs(h_scroll->get_value() - (double)cursor.x_ofs) >= 1) {
+			h_scroll->set_value(cursor.x_ofs);
+		}
 
 	} else {
 
@@ -1480,17 +1485,18 @@ void TextEdit::_gui_input(const InputEvent &p_gui_input) {
 			}
 
 			if (mb.pressed) {
+
 				if (mb.button_index == BUTTON_WHEEL_UP && !mb.mod.command) {
-					v_scroll->set_value(v_scroll->get_value() - 3);
+					v_scroll->set_value(v_scroll->get_value() - (3 * mb.factor));
 				}
 				if (mb.button_index == BUTTON_WHEEL_DOWN && !mb.mod.command) {
-					v_scroll->set_value(v_scroll->get_value() + 3);
+					v_scroll->set_value(v_scroll->get_value() + (3 * mb.factor));
 				}
 				if (mb.button_index == BUTTON_WHEEL_LEFT) {
-					h_scroll->set_value(h_scroll->get_value() - 3);
+					h_scroll->set_value(h_scroll->get_value() - (100 * mb.factor));
 				}
 				if (mb.button_index == BUTTON_WHEEL_RIGHT) {
-					h_scroll->set_value(h_scroll->get_value() + 3);
+					h_scroll->set_value(h_scroll->get_value() + (100 * mb.factor));
 				}
 				if (mb.button_index == BUTTON_LEFT) {
 
diff --git a/scene/gui/tree.cpp b/scene/gui/tree.cpp
index 258e6c9a9f..67c97c2e52 100644
--- a/scene/gui/tree.cpp
+++ b/scene/gui/tree.cpp
@@ -2341,11 +2341,11 @@ void Tree::_gui_input(InputEvent p_event) {
 				} break;
 				case BUTTON_WHEEL_UP: {
 
-					v_scroll->set_value(v_scroll->get_value() - v_scroll->get_page() / 8);
+					v_scroll->set_value(v_scroll->get_value() - v_scroll->get_page() * b.factor / 8);
 				} break;
 				case BUTTON_WHEEL_DOWN: {
 
-					v_scroll->set_value(v_scroll->get_value() + v_scroll->get_page() / 8);
+					v_scroll->set_value(v_scroll->get_value() + v_scroll->get_page() * b.factor / 8);
 				} break;
 			}