Change layer widget height with animation.

Telegram/SourceFiles/info/info_layer_widget.cpp

@@ -86,15 +86,50 @@ void LayerWidget::setupHeightConsumers() {
 	}) | rpl::start_with_next([this] {
 		resizeToWidth(width());
 	}, lifetime());
+
+	_content->grabbingForExpanding(
+	) | rpl::start_with_next([=](bool grabbing) {
+		if (grabbing) {
+			_savedHeight = _contentHeight;
+			_savedHeightAnimation = base::take(_heightAnimation);
+			setContentHeight(_desiredHeight);
+		} else {
+			_heightAnimation = base::take(_savedHeightAnimation);
+			setContentHeight(_savedHeight);
+		}
+	}, lifetime());
+
 	_content->desiredHeightValue(
 	) | rpl::start_with_next([this](int height) {
-		accumulate_max(_desiredHeight, height);
+		if (!height) {
-		if (_content && !_inResize) {
+			// New content arrived.
+			_heightAnimated = _heightAnimation.animating();
+			return;
+		}
+		std::swap(_desiredHeight, height);
+		if (!height
+			|| (_heightAnimated && !_heightAnimation.animating())) {
+			setContentHeight(_desiredHeight);
+		} else {
+			_heightAnimated = true;
+			_heightAnimation.start([=] {
+				setContentHeight(_heightAnimation.value(_desiredHeight));
+			}, _contentHeight, _desiredHeight, st::slideDuration);
 			resizeToWidth(width());
 		}
 	}, lifetime());
 }
 
+void LayerWidget::setContentHeight(int height) {
+	if (_contentHeight == height) {
+		return;
+	}
+	_contentHeight = height;
+	if (_content && !_inResize) {
+		resizeToWidth(width());
+	}
+}
+
 void LayerWidget::showFinished() {
 	floatPlayerShowVisible();
 }
@@ -217,8 +252,8 @@ int LayerWidget::resizeGetHeight(int newWidth) {
 		st::infoLayerTopMaximal);
 	auto newBottom = newTop;
 
-	// Top rounding is included in _desiredHeight.
+	// Top rounding is included in _contentHeight.
-	auto desiredHeight = _desiredHeight + st::boxRadius;
+	auto desiredHeight = _contentHeight + st::boxRadius;
 	accumulate_min(desiredHeight, windowHeight - newTop - newBottom);
 
 	// First resize content to new width and get the new desired height.
@@ -230,6 +265,8 @@ int LayerWidget::resizeGetHeight(int newWidth) {
 	auto scrollTillBottom = _content->scrollTillBottom(contentHeight);
 	auto additionalScroll = std::min(scrollTillBottom, newBottom);
 
+	const auto expanding = (_desiredHeight > _contentHeight);
+
 	desiredHeight += additionalScroll;
 	contentHeight += additionalScroll;
 	_tillBottom = (newTop + desiredHeight >= windowHeight);
@@ -241,7 +278,8 @@ int LayerWidget::resizeGetHeight(int newWidth) {
 		contentLeft,
 		contentTop,
 		contentWidth,
-		contentHeight }, additionalScroll);
+		contentHeight,
+	}, expanding, additionalScroll);
 
 	auto newGeometry = QRect(newLeft, newTop, newWidth, desiredHeight);
 	if (newGeometry != geometry()) {

Telegram/SourceFiles/info/info_layer_widget.h

@@ -68,11 +68,17 @@ private:
 		not_null<const HistoryItem*> item) override;
 
 	void setupHeightConsumers();
+	void setContentHeight(int height);
 
 	not_null<Window::SessionController*> _controller;
 	object_ptr<WrapWidget> _content;
 
 	int _desiredHeight = 0;
+	int _contentHeight = 0;
+	int _savedHeight = 0;
+	Ui::Animations::Simple _heightAnimation;
+	Ui::Animations::Simple _savedHeightAnimation;
+	bool _heightAnimated = false;
 	bool _inResize = false;
 	bool _tillBottom = false;
 

Telegram/SourceFiles/info/info_section_widget.cpp

@@ -44,9 +44,10 @@ void SectionWidget::init() {
 
 	sizeValue(
 	) | rpl::start_with_next([wrap = _content.data()](QSize size) {
+		const auto expanding = false;
 		auto wrapGeometry = QRect{ { 0, 0 }, size };
 		auto additionalScroll = 0;
-		wrap->updateGeometry(wrapGeometry, additionalScroll);
+		wrap->updateGeometry(wrapGeometry, expanding, additionalScroll);
 	}, _content->lifetime());
 
 	_connecting = std::make_unique<Window::ConnectionState>(

Telegram/SourceFiles/info/info_wrap_widget.cpp

@@ -645,10 +645,10 @@ rpl::producer<bool> WrapWidget::topShadowToggledValue() const {
 
 rpl::producer<int> WrapWidget::desiredHeightForContent() const {
 	using namespace rpl::mappers;
-	return rpl::combine(
+	return rpl::single(0) | rpl::then(rpl::combine(
 		_content->desiredHeightValue(),
 		topWidget()->heightValue(),
-		_1 + _2);
+		_1 + _2));
 }
 
 rpl::producer<SelectedItems> WrapWidget::selectedListValue() const {
@@ -738,7 +738,14 @@ QPixmap WrapWidget::grabForShowAnimation(
 	//if (params.withTabs && _topTabs) {
 	//	_topTabs->hide();
 	//}
+	const auto expanding = _expanding;
+	if (expanding) {
+		_grabbingForExpanding = true;
+	}
 	auto result = Ui::GrabWidget(this);
+	if (expanding) {
+		_grabbingForExpanding = false;
+	}
 	if (params.withTopBarShadow) {
 		_topShadow->setVisible(true);
 	}
@@ -1007,11 +1014,15 @@ object_ptr<Ui::RpWidget> WrapWidget::createTopBarSurrogate(
 	return nullptr;
 }
 
-void WrapWidget::updateGeometry(QRect newGeometry, int additionalScroll) {
+void WrapWidget::updateGeometry(
+		QRect newGeometry,
+		bool expanding,
+		int additionalScroll) {
 	auto scrollChanged = (_additionalScroll != additionalScroll);
 	auto geometryChanged = (geometry() != newGeometry);
 	auto shrinkingContent = (additionalScroll < _additionalScroll);
 	_additionalScroll = additionalScroll;
+	_expanding = expanding;
 
 	if (geometryChanged) {
 		if (shrinkingContent) {
@@ -1038,6 +1049,10 @@ rpl::producer<int> WrapWidget::scrollTillBottomChanges() const {
 	) | rpl::flatten_latest();
 }
 
+rpl::producer<bool> WrapWidget::grabbingForExpanding() const {
+	return _grabbingForExpanding.value();
+}
+
 WrapWidget::~WrapWidget() = default;
 
 } // namespace Info

Telegram/SourceFiles/info/info_wrap_widget.h

@@ -118,11 +118,15 @@ public:
 
 	object_ptr<Ui::RpWidget> createTopBarSurrogate(QWidget *parent);
 
-	bool closeByOutsideClick() const;
+	[[nodiscard]] bool closeByOutsideClick() const;
 
-	void updateGeometry(QRect newGeometry, int additionalScroll);
+	void updateGeometry(
-	int scrollTillBottom(int forHeight) const;
+		QRect newGeometry,
-	rpl::producer<int>  scrollTillBottomChanges() const;
+		bool expanding,
+		int additionalScroll);
+	[[nodiscard]] int scrollTillBottom(int forHeight) const;
+	[[nodiscard]] rpl::producer<int> scrollTillBottomChanges() const;
+	[[nodiscard]] rpl::producer<bool> grabbingForExpanding() const;
 
 	~WrapWidget();
 
@@ -203,6 +207,8 @@ private:
 	std::unique_ptr<Controller> _controller;
 	object_ptr<ContentWidget> _content = { nullptr };
 	int _additionalScroll = 0;
+	bool _expanding = false;
+	rpl::variable<bool> _grabbingForExpanding = false;
 	//object_ptr<Ui::PlainShadow> _topTabsBackground = { nullptr };
 	//object_ptr<Ui::SettingsSlider> _topTabs = { nullptr };
 	object_ptr<TopBar> _topBar = { nullptr };