Enable zooming graph_edit with scrollwheel

scene/gui/graph_edit.cpp

@@ -1312,25 +1312,17 @@ void GraphEdit::_gui_input(const Ref<InputEvent> &p_ev) {
 			minimap->update();
 		}
 
-		if (b->get_button_index() == BUTTON_WHEEL_UP && b->is_pressed()) {
-			//too difficult to get right
-			//set_zoom(zoom*ZOOM_SCALE);
-		}
-
-		if (b->get_button_index() == BUTTON_WHEEL_DOWN && b->is_pressed()) {
-			//too difficult to get right
-			//set_zoom(zoom/ZOOM_SCALE);
-		}
-		if (b->get_button_index() == BUTTON_WHEEL_UP && !Input::get_singleton()->is_key_pressed(KEY_SHIFT)) {
+		if (b->get_button_index() == BUTTON_WHEEL_UP && Input::get_singleton()->is_key_pressed(KEY_CONTROL)) {
+			set_zoom(zoom * ZOOM_SCALE);
+		} else if (b->get_button_index() == BUTTON_WHEEL_DOWN && Input::get_singleton()->is_key_pressed(KEY_CONTROL)) {
+			set_zoom(zoom / ZOOM_SCALE);
+		} else if (b->get_button_index() == BUTTON_WHEEL_UP && !Input::get_singleton()->is_key_pressed(KEY_SHIFT)) {
 			v_scroll->set_value(v_scroll->get_value() - v_scroll->get_page() * b->get_factor() / 8);
-		}
-		if (b->get_button_index() == BUTTON_WHEEL_DOWN && !Input::get_singleton()->is_key_pressed(KEY_SHIFT)) {
+		} else if (b->get_button_index() == BUTTON_WHEEL_DOWN && !Input::get_singleton()->is_key_pressed(KEY_SHIFT)) {
 			v_scroll->set_value(v_scroll->get_value() + v_scroll->get_page() * b->get_factor() / 8);
-		}
-		if (b->get_button_index() == BUTTON_WHEEL_RIGHT || (b->get_button_index() == BUTTON_WHEEL_DOWN && Input::get_singleton()->is_key_pressed(KEY_SHIFT))) {
+		} else if (b->get_button_index() == BUTTON_WHEEL_RIGHT || (b->get_button_index() == BUTTON_WHEEL_DOWN && Input::get_singleton()->is_key_pressed(KEY_SHIFT))) {
 			h_scroll->set_value(h_scroll->get_value() + h_scroll->get_page() * b->get_factor() / 8);
-		}
-		if (b->get_button_index() == BUTTON_WHEEL_LEFT || (b->get_button_index() == BUTTON_WHEEL_UP && Input::get_singleton()->is_key_pressed(KEY_SHIFT))) {
+		} else if (b->get_button_index() == BUTTON_WHEEL_LEFT || (b->get_button_index() == BUTTON_WHEEL_UP && Input::get_singleton()->is_key_pressed(KEY_SHIFT))) {
 			h_scroll->set_value(h_scroll->get_value() - h_scroll->get_page() * b->get_factor() / 8);
 		}
 	}