Support by-emoji background resolve in preview.

Telegram/SourceFiles/history/view/media/history_view_theme_document.cpp

@@ -33,6 +33,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/cached_round_corners.h"
 #include "ui/painter.h"
 #include "ui/ui_utility.h"
+#include "window/section_widget.h"
 #include "window/window_session_controller.h"
 #include "window/themes/window_theme.h"
 #include "styles/style_chat.h"
@@ -471,13 +472,28 @@ ThemeDocumentBox::ThemeDocumentBox(
 	not_null<Element*> parent,
 	const Data::WallPaper &paper)
 : _parent(parent)
-, _preview(
-		parent,
+, _emojiId(paper.emojiId()) {
+	Window::WallPaperResolved(
+		&_parent->history()->owner(),
+		&paper
+	) | rpl::start_with_next([=](const Data::WallPaper *paper) {
+		_parent->repaint();
+		if (!paper) {
+			_preview.reset();
+		} else {
+			createPreview(*paper);
+		}
+	}, _lifetime);
+}
+
+void ThemeDocumentBox::createPreview(const Data::WallPaper &paper) {
+	_preview.emplace(
+		_parent,
 		paper.document(),
 		paper,
-		st::msgServicePhotoWidth) {
-	_preview.initDimensions();
-	_preview.resizeGetHeight(_preview.maxWidth());
+		st::msgServicePhotoWidth);
+	_preview->initDimensions();
+	_preview->resizeGetHeight(_preview->maxWidth());
 }
 
 ThemeDocumentBox::~ThemeDocumentBox() = default;
@@ -487,7 +503,9 @@ int ThemeDocumentBox::top() {
 }
 
 QSize ThemeDocumentBox::size() {
-	return { _preview.maxWidth(), _preview.minHeight() };
+	return _preview
+		? QSize(_preview->maxWidth(), _preview->minHeight())
+		: QSize(st::msgServicePhotoWidth, st::msgServicePhotoWidth);
 }
 
 QString ThemeDocumentBox::title() {
@@ -560,9 +578,11 @@ void ThemeDocumentBox::draw(
 		Painter &p,
 		const PaintContext &context,
 		const QRect &geometry) {
-	p.translate(geometry.topLeft());
-	_preview.draw(p, context);
-	p.translate(-geometry.topLeft());
+	if (_preview) {
+		p.translate(geometry.topLeft());
+		_preview->draw(p, context);
+		p.translate(-geometry.topLeft());
+	}
 }
 
 void ThemeDocumentBox::stickerClearLoopPlayed() {
@@ -575,11 +595,13 @@ std::unique_ptr<StickerPlayer> ThemeDocumentBox::stickerTakePlayer(
 }
 
 bool ThemeDocumentBox::hasHeavyPart() {
-	return _preview.hasHeavyPart();
+	return _preview && _preview->hasHeavyPart();
 }
 
 void ThemeDocumentBox::unloadHeavyPart() {
-	_preview.unloadHeavyPart();
+	if (_preview) {
+		_preview->unloadHeavyPart();
+	}
 }
 
 } // namespace HistoryView

Telegram/SourceFiles/history/view/media/history_view_theme_document.h

@@ -119,8 +119,12 @@ public:
 	void unloadHeavyPart() override;
 
 private:
+	void createPreview(const Data::WallPaper &paper);
+
 	const not_null<Element*> _parent;
-	ThemeDocument _preview;
+	QString _emojiId;
+	std::optional<ThemeDocument> _preview;
+	rpl::lifetime _lifetime;
 
 };
 

Telegram/SourceFiles/window/section_widget.cpp

@@ -56,43 +56,7 @@ struct ResolvedPaper {
 		peer,
 		Data::PeerUpdate::Flag::ChatWallPaper
 	) | rpl::map([=]() -> rpl::producer<const Data::WallPaper*> {
-		const auto paper = peer->wallPaper();
-		const auto id = paper ? paper->emojiId() : QString();
-		if (id.isEmpty()) {
-			return rpl::single(paper);
-		}
-		const auto themes = &peer->owner().cloudThemes();
-		auto fromThemes = [=](bool force)
-		-> rpl::producer<const Data::WallPaper*> {
-			if (themes->chatThemes().empty() && !force) {
-				return nullptr;
-			}
-			return Window::Theme::IsNightModeValue(
-			) | rpl::map([=](bool dark) -> const Data::WallPaper* {
-				const auto &list = themes->chatThemes();
-				const auto i = ranges::find(
-					list,
-					id,
-					&Data::CloudTheme::emoticon);
-				if (i != end(list)) {
-					using Type = Data::CloudThemeType;
-					const auto type = dark ? Type::Dark : Type::Light;
-					const auto j = i->settings.find(type);
-					if (j != end(i->settings) && j->second.paper) {
-						return &*j->second.paper;
-					}
-				}
-				return nullptr;
-			});
-		};
-		if (auto result = fromThemes(false)) {
-			return result;
-		}
-		themes->refreshChatThemes();
-		return themes->chatThemesUpdated(
-		) | rpl::take(1) | rpl::map([=] {
-			return fromThemes(true);
-		}) | rpl::flatten_latest();
+		return WallPaperResolved(&peer->owner(), peer->wallPaper());
 	}) | rpl::flatten_latest();
 }
 
@@ -202,6 +166,47 @@ struct ResolvedTheme {
 
 } // namespace
 
+rpl::producer<const Data::WallPaper*> WallPaperResolved(
+		not_null<Data::Session*> owner,
+		const Data::WallPaper *paper) {
+	const auto id = paper ? paper->emojiId() : QString();
+	if (id.isEmpty()) {
+		return rpl::single(paper);
+	}
+	const auto themes = &owner->cloudThemes();
+	auto fromThemes = [=](bool force)
+	-> rpl::producer<const Data::WallPaper*> {
+		if (themes->chatThemes().empty() && !force) {
+			return nullptr;
+		}
+		return Window::Theme::IsNightModeValue(
+		) | rpl::map([=](bool dark) -> const Data::WallPaper* {
+			const auto &list = themes->chatThemes();
+			const auto i = ranges::find(
+				list,
+				id,
+				&Data::CloudTheme::emoticon);
+			if (i != end(list)) {
+				using Type = Data::CloudThemeType;
+				const auto type = dark ? Type::Dark : Type::Light;
+				const auto j = i->settings.find(type);
+				if (j != end(i->settings) && j->second.paper) {
+					return &*j->second.paper;
+				}
+			}
+			return nullptr;
+		});
+	};
+	if (auto result = fromThemes(false)) {
+		return result;
+	}
+	themes->refreshChatThemes();
+	return themes->chatThemesUpdated(
+	) | rpl::take(1) | rpl::map([=] {
+		return fromThemes(true);
+	}) | rpl::flatten_latest();
+}
+
 AbstractSectionWidget::AbstractSectionWidget(
 	QWidget *parent,
 	not_null<SessionController*> controller,

Telegram/SourceFiles/window/section_widget.h

@@ -23,6 +23,8 @@ class Show;
 namespace Data {
 struct ReactionId;
 class ForumTopic;
+class WallPaper;
+class Session;
 } // namespace Data
 
 namespace Main {
@@ -251,4 +253,8 @@ private:
 	not_null<HistoryItem*> item,
 	const Data::ReactionId &id);
 
+[[nodiscard]] rpl::producer<const Data::WallPaper*> WallPaperResolved(
+	not_null<Data::Session*> owner,
+	const Data::WallPaper *paper);
+
 } // namespace Window