Improve main menu > settings transition animation.

Remove full window cache in case of settings shown as a section.

Telegram/SourceFiles/mainwidget.cpp

@@ -2399,6 +2399,9 @@ void MainWidget::showNewSection(
 		auto direction = (back || settingSection->forceAnimateBack())
 			? Window::SlideDirection::FromLeft
 			: Window::SlideDirection::FromRight;
+		if (Adaptive::OneColumn()) {
+			_controller->removeLayerBlackout();
+		}
 		settingSection->showAnimated(direction, animationParams);
 	} else {
 		settingSection->showFast();

Telegram/SourceFiles/mainwindow.cpp

@@ -372,6 +372,12 @@ void MainWindow::ui_hideSettingsAndLayer(anim::type animated) {
 	}
 }
 
+void MainWindow::ui_removeLayerBlackout() {
+	if (_layer) {
+		_layer->removeBodyCache();
+	}
+}
+
 MainWidget *MainWindow::mainWidget() {
 	return _main;
 }

Telegram/SourceFiles/mainwindow.h

@@ -111,6 +111,7 @@ public:
 		LayerOptions options,
 		anim::type animated);
 	void ui_hideSettingsAndLayer(anim::type animated);
+	void ui_removeLayerBlackout();
 	bool ui_isLayerShown();
 	void ui_showMediaPreview(
 		Data::FileOrigin origin,

Telegram/SourceFiles/window/layer_widget.cpp

@@ -43,7 +43,12 @@ public:
 	}
 
 	void setLayerBoxes(const QRect &specialLayerBox, const QRect &layerBox);
-	void setCacheImages(QPixmap &&bodyCache, QPixmap &&mainMenuCache, QPixmap &&specialLayerCache, QPixmap &&layerCache);
+	void setCacheImages(
+		QPixmap &&bodyCache,
+		QPixmap &&mainMenuCache,
+		QPixmap &&specialLayerCache,
+		QPixmap &&layerCache);
+	void removeBodyCache();
 	void startAnimation(Action action);
 	void skipAnimation(Action action);
 	void finishAnimating();
@@ -91,7 +96,11 @@ private:
 
 };
 
-void LayerStackWidget::BackgroundWidget::setCacheImages(QPixmap &&bodyCache, QPixmap &&mainMenuCache, QPixmap &&specialLayerCache, QPixmap &&layerCache) {
+void LayerStackWidget::BackgroundWidget::setCacheImages(
+		QPixmap &&bodyCache,
+		QPixmap &&mainMenuCache,
+		QPixmap &&specialLayerCache,
+		QPixmap &&layerCache) {
 	_bodyCache = std::move(bodyCache);
 	_mainMenuCache = std::move(mainMenuCache);
 	_specialLayerCache = std::move(specialLayerCache);
@@ -101,6 +110,13 @@ void LayerStackWidget::BackgroundWidget::setCacheImages(QPixmap &&bodyCache, QPi
 	setAttribute(Qt::WA_OpaquePaintEvent, !_bodyCache.isNull());
 }
 
+void LayerStackWidget::BackgroundWidget::removeBodyCache() {
+	if (!_bodyCache.isNull()) {
+		_bodyCache = {};
+		setAttribute(Qt::WA_OpaquePaintEvent, false);
+	}
+}
+
 void LayerStackWidget::BackgroundWidget::startAnimation(Action action) {
 	if (action == Action::ShowMainMenu) {
 		setMainMenuShown(true);
@@ -135,8 +151,8 @@ void LayerStackWidget::BackgroundWidget::checkIfDone() {
 		return;
 	}
 	_wasAnimating = false;
-	_bodyCache = _mainMenuCache = _specialLayerCache = _layerCache = QPixmap();
-	setAttribute(Qt::WA_OpaquePaintEvent, false);
+	_mainMenuCache = _specialLayerCache = _layerCache = QPixmap();
+	removeBodyCache();
 	if (_doneCallback) {
 		_doneCallback();
 	}
@@ -392,6 +408,11 @@ void LayerStackWidget::hideTopLayer(anim::type animated) {
 	}
 }
 
+void LayerStackWidget::removeBodyCache() {
+	_background->removeBodyCache();
+	setAttribute(Qt::WA_OpaquePaintEvent, false);
+}
+
 bool LayerStackWidget::layerShown() const {
 	return _specialLayer || currentLayer() || _mainMenu;
 }
@@ -418,7 +439,7 @@ void LayerStackWidget::setCacheImages() {
 		setFocus();
 	}
 	if (_mainMenu) {
-		setAttribute(Qt::WA_OpaquePaintEvent, false);
+		removeBodyCache();
 		hideChildren();
 		bodyCache = Ui::GrabWidget(parentWidget());
 		showChildren();

Telegram/SourceFiles/window/layer_widget.h

@@ -111,6 +111,7 @@ public:
 	void hideAll(anim::type animated);
 	void hideTopLayer(anim::type animated);
 	void setHideByBackgroundClick(bool hide);
+	void removeBodyCache();
 
 	bool showSectionInternal(
 		not_null<SectionMemento*> memento,

Telegram/SourceFiles/window/window_controller.cpp

@@ -516,6 +516,10 @@ void Controller::showSpecialLayer(
 	App::wnd()->showSpecialLayer(std::move(layer), animated);
 }
 
+void Controller::removeLayerBlackout() {
+	App::wnd()->ui_removeLayerBlackout();
+}
+
 not_null<MainWidget*> Controller::chats() const {
 	return App::wnd()->chatsWidget();
 }

Telegram/SourceFiles/window/window_controller.h

@@ -209,6 +209,7 @@ public:
 			anim::type animated = anim::type::normal) {
 		showSpecialLayer(nullptr, animated);
 	}
+	void removeLayerBlackout();
 
 	void showJumpToDate(
 		Dialogs::Key chat,