Moved out setup of top and bottom scroll shadows to separated file.

Telegram/SourceFiles/boxes/edit_caption_box.cpp

@@ -37,13 +37,13 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/chat/attach/attach_single_file_preview.h"
 #include "ui/chat/attach/attach_single_media_preview.h"
 #include "ui/controls/emoji_button.h"
+#include "ui/effects/scroll_content_shadow.h"
 #include "ui/image/image.h"
 #include "ui/toast/toast.h"
 #include "ui/ui_utility.h"
 #include "ui/widgets/checkbox.h"
 #include "ui/widgets/input_fields.h"
 #include "ui/widgets/scroll_area.h"
-#include "ui/wrap/fade_wrap.h"
 #include "ui/wrap/slide_wrap.h"
 #include "ui/wrap/vertical_layout.h"
 #include "window/window_session_controller.h"
@@ -125,9 +125,7 @@ EditCaptionBox::EditCaptionBox(
 	PrepareEditText(item)))
 , _emojiToggle(base::make_unique_q<Ui::EmojiButton>(
 	this,
-	st::boxAttachEmoji))
-, _topShadow(base::make_unique_q<Ui::FadeShadow>(this))
-, _bottomShadow(base::make_unique_q<Ui::FadeShadow>(this)) {
+	st::boxAttachEmoji)) {
 	Expects(item->media() != nullptr);
 	Expects(item->media()->allowsEditCaption());
 
@@ -151,7 +149,7 @@ void EditCaptionBox::prepare() {
 
 	rebuildPreview();
 	setupEditEventHandler();
-	setupShadows();
+	SetupShadowsToScrollContent(this, _scroll, _contentHeight.events());
 
 	setupControls();
 	setupPhotoEditorEventHandler();
@@ -282,31 +280,6 @@ void EditCaptionBox::setupField() {
 	_field->setTextCursor(cursor);
 }
 
-void EditCaptionBox::setupShadows() {
-	using namespace rpl::mappers;
-
-	const auto _topShadow = Ui::CreateChild<Ui::FadeShadow>(this);
-	const auto _bottomShadow = Ui::CreateChild<Ui::FadeShadow>(this);
-	_scroll->geometryValue(
-	) | rpl::start_with_next([=](const QRect &geometry) {
-		_topShadow->resizeToWidth(geometry.width());
-		_topShadow->move(
-			geometry.x(),
-			geometry.y());
-		_bottomShadow->resizeToWidth(geometry.width());
-		_bottomShadow->move(
-			geometry.x(),
-			geometry.y() + geometry.height() - st::lineWidth);
-	}, _topShadow->lifetime());
-
-	_topShadow->toggleOn(_scroll->scrollTopValue() | rpl::map(_1 > 0));
-	_bottomShadow->toggleOn(rpl::combine(
-		_scroll->scrollTopValue(),
-		_scroll->heightValue(),
-		_contentHeight.events(),
-		_1 + _2 < _3));
-}
-
 void EditCaptionBox::setupControls() {
 	auto hintLabelToggleOn = _previewRebuilds.events_starting_with(
 		{}

Telegram/SourceFiles/boxes/edit_caption_box.h

@@ -27,7 +27,6 @@ class AbstractSinglePreview;
 class InputField;
 class EmojiButton;
 class VerticalLayout;
-class FadeShadow;
 enum class AlbumType;
 } // namespace Ui
 
@@ -51,7 +50,6 @@ private:
 	void rebuildPreview();
 	void setupEditEventHandler();
 	void setupPhotoEditorEventHandler();
-	void setupShadows();
 	void setupField();
 	void setupControls();
 
@@ -81,7 +79,6 @@ private:
 	const base::unique_qptr<Ui::ScrollArea> _scroll;
 	const base::unique_qptr<Ui::InputField> _field;
 	const base::unique_qptr<Ui::EmojiButton> _emojiToggle;
-	const base::unique_qptr<Ui::FadeShadow> _topShadow, _bottomShadow;
 
 	base::unique_qptr<Ui::AbstractSinglePreview> _content;
 	base::unique_qptr<ChatHelpers::TabbedPanel> _emojiPanel;

Telegram/SourceFiles/boxes/reactions_settings_box.cpp

@@ -23,11 +23,11 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "settings/settings_common.h"
 #include "ui/chat/chat_style.h"
 #include "ui/chat/chat_theme.h"
+#include "ui/effects/scroll_content_shadow.h"
 #include "ui/layers/generic_box.h"
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/labels.h"
 #include "ui/widgets/scroll_area.h"
-#include "ui/wrap/fade_wrap.h"
 #include "ui/wrap/vertical_layout.h"
 #include "window/section_widget.h"
 #include "window/window_session_controller.h"
@@ -373,37 +373,6 @@ void AddMessage(
 	}, widget->lifetime());
 }
 
-void SetupShadows(
-		not_null<Ui::RpWidget*> parent,
-		not_null<Ui::ScrollArea*> scroll,
-		not_null<Ui::RpWidget*> inner) {
-	using namespace rpl::mappers;
-
-	const auto topShadow = Ui::CreateChild<Ui::FadeShadow>(parent.get());
-	const auto bottomShadow = Ui::CreateChild<Ui::FadeShadow>(parent.get());
-	scroll->geometryValue(
-	) | rpl::start_with_next_done([=](const QRect &geometry) {
-		topShadow->resizeToWidth(geometry.width());
-		topShadow->move(
-			geometry.x(),
-			geometry.y());
-		bottomShadow->resizeToWidth(geometry.width());
-		bottomShadow->move(
-			geometry.x(),
-			geometry.y() + geometry.height() - st::lineWidth);
-	}, [t = Ui::MakeWeak(topShadow), b = Ui::MakeWeak(bottomShadow)] {
-		Ui::DestroyChild(t.data());
-		Ui::DestroyChild(b.data());
-	}, topShadow->lifetime());
-
-	topShadow->toggleOn(scroll->scrollTopValue() | rpl::map(_1 > 0));
-	bottomShadow->toggleOn(rpl::combine(
-		scroll->scrollTopValue(),
-		scroll->heightValue(),
-		inner->heightValue(),
-		_1 + _2 < _3));
-}
-
 } // namespace
 
 void ReactionsSettingsBox(
@@ -503,7 +472,10 @@ void ReactionsSettingsBox(
 	}
 	check->raise();
 
-	SetupShadows(scrollContainer, scroll, buttonsContainer);
+	Ui::SetupShadowsToScrollContent(
+		scrollContainer,
+		scroll,
+		buttonsContainer->heightValue());
 
 	box->setTitle(tr::lng_settings_chat_reactions_title());
 	box->setWidth(st::boxWideWidth);

Telegram/SourceFiles/boxes/send_files_box.cpp

@@ -26,11 +26,11 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "core/mime_type.h"
 #include "base/event_filter.h"
 #include "ui/effects/animations.h"
+#include "ui/effects/scroll_content_shadow.h"
 #include "ui/widgets/checkbox.h"
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/input_fields.h"
 #include "ui/widgets/scroll_area.h"
-#include "ui/wrap/fade_wrap.h"
 #include "ui/wrap/vertical_layout.h"
 #include "ui/chat/attach/attach_prepare.h"
 #include "ui/chat/attach/attach_send_files_way.h"
@@ -312,34 +312,6 @@ void SendFilesBox::enqueueNextPrepare() {
 	});
 }
 
-void SendFilesBox::setupShadows() {
-	using namespace rpl::mappers;
-
-	const auto topShadow = Ui::CreateChild<Ui::FadeShadow>(this);
-	const auto bottomShadow = Ui::CreateChild<Ui::FadeShadow>(this);
-	_scroll->geometryValue(
-	) | rpl::start_with_next_done([=](const QRect &geometry) {
-		topShadow->resizeToWidth(geometry.width());
-		topShadow->move(
-			geometry.x(),
-			geometry.y());
-		bottomShadow->resizeToWidth(geometry.width());
-		bottomShadow->move(
-			geometry.x(),
-			geometry.y() + geometry.height() - st::lineWidth);
-	}, [t = Ui::MakeWeak(topShadow), b = Ui::MakeWeak(bottomShadow)] {
-		Ui::DestroyChild(t.data());
-		Ui::DestroyChild(b.data());
-	}, topShadow->lifetime());
-
-	topShadow->toggleOn(_scroll->scrollTopValue() | rpl::map(_1 > 0));
-	bottomShadow->toggleOn(rpl::combine(
-		_scroll->scrollTopValue(),
-		_scroll->heightValue(),
-		_inner->heightValue(),
-		_1 + _2 < _3));
-}
-
 void SendFilesBox::prepare() {
 	_send = addButton(
 		(_sendType == Api::SendType::Normal
@@ -359,7 +331,7 @@ void SendFilesBox::prepare() {
 	setupSendWayControls();
 	preparePreview();
 	initPreview();
-	setupShadows();
+	SetupShadowsToScrollContent(this, _scroll, _inner->heightValue());
 
 	boxClosing() | rpl::start_with_next([=] {
 		if (!_confirmed && _cancelledCallback) {

Telegram/SourceFiles/boxes/send_files_box.h

@@ -123,7 +123,6 @@ private:
 	void refreshControls();
 	void setupSendWayControls();
 	void setupCaption();
-	void setupShadows();
 
 	void setupEmojiPanel();
 	void updateSendWayControlsVisibility();