From 49e286b04cf9065628fde38c80496211752f140e Mon Sep 17 00:00:00 2001
From: 23rd <23rd@vivaldi.net>
Date: Sat, 28 Mar 2020 03:27:30 +0300
Subject: [PATCH] Added scroll to active and not completely visible
 SideBarButtons.

---
 .../window/window_filters_menu.cpp            | 28 +++++++++++++++++++
 .../SourceFiles/window/window_filters_menu.h  |  4 +++
 2 files changed, 32 insertions(+)

diff --git a/Telegram/SourceFiles/window/window_filters_menu.cpp b/Telegram/SourceFiles/window/window_filters_menu.cpp
index 216583320..36f9ad979 100644
--- a/Telegram/SourceFiles/window/window_filters_menu.cpp
+++ b/Telegram/SourceFiles/window/window_filters_menu.cpp
@@ -122,8 +122,10 @@ void FiltersMenu::setup() {
 		const auto j = _filters.find(_activeFilterId);
 		if (j != end(_filters)) {
 			j->second->setActive(true);
+			scrollToButton(j->second);
 		} else if (!_activeFilterId) {
 			_all->setActive(true);
+			scrollToButton(_all);
 		}
 	}, _outer.lifetime());
 
@@ -132,6 +134,32 @@ void FiltersMenu::setup() {
 	});
 }
 
+void FiltersMenu::scrollToButton(not_null<Ui::RpWidget*> widget) {
+	const auto globalPosition = widget->mapToGlobal(QPoint(0, 0));
+	const auto localTop = _scroll.mapFromGlobal(globalPosition).y();
+	const auto localBottom = localTop + widget->height() - _scroll.height();
+	const auto isTopEdge = (localTop < 0);
+	const auto isBottomEdge = (localBottom > 0);
+	if (!isTopEdge && !isBottomEdge) {
+		return;
+	}
+
+	_scrollToAnimation.stop();
+	const auto scrollTop = _scroll.scrollTop();
+	const auto scrollTo = scrollTop + (isBottomEdge ? localBottom : localTop);
+
+	auto scroll = [=] {
+		_scroll.scrollToY(qRound(_scrollToAnimation.value(scrollTo)));
+	};
+
+	_scrollToAnimation.start(
+		std::move(scroll),
+		scrollTop,
+		scrollTo,
+		st::slideDuration,
+		anim::sineInOut);
+}
+
 void FiltersMenu::refresh() {
 	const auto filters = &_session->session().data().chatsFilters();
 	if (filters->list().empty() || _ignoreRefresh) {
diff --git a/Telegram/SourceFiles/window/window_filters_menu.h b/Telegram/SourceFiles/window/window_filters_menu.h
index 34aea5a6b..347aac0a9 100644
--- a/Telegram/SourceFiles/window/window_filters_menu.h
+++ b/Telegram/SourceFiles/window/window_filters_menu.h
@@ -7,6 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
+#include "ui/effects/animations.h"
 #include "ui/widgets/side_bar_button.h"
 #include "ui/widgets/scroll_area.h"
 #include "ui/wrap/vertical_layout.h"
@@ -49,6 +50,7 @@ private:
 	void showEditBox(FilterId id);
 	void showRemoveBox(FilterId id);
 	void remove(FilterId id);
+	void scrollToButton(not_null<Ui::RpWidget*> widget);
 
 	const not_null<SessionController*> _session;
 	const not_null<Ui::RpWidget*> _parent;
@@ -68,6 +70,8 @@ private:
 
 	base::unique_qptr<Ui::PopupMenu> _popupMenu;
 
+	Ui::Animations::Simple _scrollToAnimation;
+
 };
 
 } // namespace Window